Browse Topic: Chassis stiffness

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Prediction of Trimmed BIW Noise transfer function based on BIW response using Machine Learning2026-26-0640To be published on 01/16/2026
This research focuses on the prediction of the Noise Transfer Function (NTF) in a trimmed Body-in-White (BIW) structure by leveraging machine learning technique considering BIW-level NTF, dynamic stiffness at engine mount attachment points, and Vibration Transfer Function (VTF). The study employs an iterative methodology, adjusting the thickness of various BIW panels to analyse their impact on noise transfer characteristics. Frequency response functions are generated at the BIW attachment points to assess the effectiveness of these modifications. By systematically increasing and decreasing panel thicknesses, and stiffness at the attachment point and trimmed BIW level responses the study aims to optimize the acoustic performance of the BIW structure. The findings provide critical insights into the relationship between structural modifications and noise transfer, offering valuable guidance for automotive design and engineering during early design stage to reduce the development time.
Kulkarni, Prasad Ramesh, Bijwe, Vilas, Kulkarni, Shirish, Sahu, Dilip, Inamdar, Pushpak
Sound quality refinement and vibration reduction during Horn Application in Electric Vehicles2026-26-0338To be published on 01/16/2026
This paper focuses on the cabin sound quality refinement and the tactile vibration reduction during horn application in the electric vehicle. Horn cracking sound is perceived in the cabin while pressing the horn. Higher vibrations are also perceived in accelerator pedal during the particular event. Sound diagnosis is carried out to identify the frequencies contributing to cracking noise. Transfer path analysis is conducted to identify the nature of noise and the predominant path through which forces transfer. Based on finding from TPA, various recommendations are evaluated which reduced the noise to a certain extent. Operational Deflection Shape(ODS) is conducted on the horn, horn mounting bracket and on the body to identify the component having higher deflection at the problematic frequencies . Based on the outcome of ODS, recommendations like dynamic stiffness improvement on the horn bracket and the body is assessed and the effect of each outcome is discussed. With all the
S, Nataraja Moorthy
Investigation and Reduction of Road Noise due to transient road inputs in Electric Vehicle2026-26-0358To be published on 01/16/2026
Higher road noise is perceived in the cabin when the test vehicle encounters road irregularities like bump or pothole in the public roads. The sudden transfer of transient road inputs inside the body caused objectionable cabin noise. Measurements are conducted on the test track at different road surfaces to identify the patch where the objective data well correlated with the noise measured at the public road. Wavelet analysis is carried out to identify the frequency zones since the events are transient in nature. Transfer Path Analysis (TPA) is conducted in both time domain and frequency domain to identify the nature of the noise and the limitation in each of the methodologies are explained. The dominant path through which the transient road forces are transferring inside the body are also identified. Based on the outcome of TPA, various countermeasures like reduction of dynamic stiffness of suspension and cradle bushes , structural modifications on the path are proposed to reduce the
S, Nataraja Moorthy
Analysis of door seal compression and its influence on NVH performance in heavy-duty vehicle2026-26-0339To be published on 01/16/2026
Seals in a truck cabin is one of the major contributors for cabin noise in terms of structure borne as well as air borne noise transfer path. This study emphasizes on the effect of door seal compression prediction and its impact on structure borne NVH in trucks. Vibrations are regarded as quality criteria in the perception of customers. It is necessary to ascertain the contribution of seal stiffness on compression of the seal under closed condition of the door rather than uncompressed conditions. The dynamic stiffness of door seal is calculated by non-linear analysis. The simulations models are constructed using the Mooney - Rivlin theory for both 2D and 3D seals. This encompasses contemplating the relevant seal mounted boundary condition on the body and the door of the vehicle. The stiffness after compression of seal is extracted from this non-linear analysis which is further used to obtain the vibration modes for the doors in the truck cabin. Subsequently, the compressed seal
L, Kavya, Ramanathan, Vijay
Design & Optimization of CV shaft system to address powertrain induced NVH issues2026-26-0336To be published on 01/16/2026
The automotive industry is a crucial sector that plays a significant role globally. Government policies have a profound impact on this automotive industry in defining the regulatory standards and emission controls. Such regulations incentivized automakers to invest in research and development complying those standards towards reduction of vehicle emission which intern result in higher torsional vibrations and excitations amplitudes. To address the rising NVH related concerns in driveline system. Drive shafts (CV shafts) is an important component in power-train system in vehicle. Drive shaft’s main purpose to transfer torque from engines to wheels at multiple speeds with different articulation angles. The roughness generated by the engine follows a transfer path from engine to transaxle and transaxle to half shafts in monocoque vehicles which generates discomfort to the drivers whenever the vehicle is driven. The roughness can also be addressed by proper design of driveshaft stiffness
M A, Abdul Azarrudin, Jayachandran, Suresh kumar, KUMAR, SHIVANI, Bhardwaj, Kinshuk, M, DEVAMANALAN, Kanagaraj, Pothiraj
High-Frequency Dynamic Stiffness Measurements of Automotive Elastomers for Electric Vehicles2026-26-0312To be published on 01/16/2026
The increasing adoption of electric vehicles (EVs) has intensified the demand for advanced elastomeric materials capable of meeting stringent noise, vibration and harshness (NVH) requirements. Unlike internal combustion engine (ICE) vehicles, EVs lack traditional powertrain-induced masking noise. In the automotive industry the dynamic stiffness of elastomers for internal combustion engines are determined traditionally using hydraulic test rigs up to test frequencies of max. 1000 Hz. Measurements in excess of these frequencies were not possible and are only carried out using computerized FE or CAE calculation models. Electric drive systems generate distinct tonal noise components in the high-frequency range up to 10 kHz , which are well perceptible even at low sound pressure levels. Consequently, the dynamic stiffness characteristics of elastomers up to 3000 Hz are critical for optimizing NVH performance. This study focuses on the high-frequency dynamic stiffness testing of automotive
Bohne, Christian, Gröne, Michael
Assessing Millable Polyurethane in Powertrain Mounting Applications: A Comparative Study with Natural Rubber2026-26-0289To be published on 01/16/2026
In the automotive industry, the performance and longevity of elastomer components are critical to both vehicle durability and driver comfort. Powertrain mountings, play a crucial role in isolating vibrations and reducing noise. Traditionally, natural rubber (NR) has been the material of choice for these applications due to its excellent vibration isolation properties, flexibility, and cost-effectiveness. However, with evolving performance demands, there is growing interest in enhancing the durability and noise, vibration, and harshness (NVH) characteristics of powertrain mountings, along with improving their resistance to environmental stressors such as heat, oil, and wear. Unlike NR, which tends to degrade more quickly under such conditions, millable polyurethane (MPU) offers superior resistance, making it a promising candidate for extending the service life of these critical components. The objective of this study is to determine whether millable polyurethane (MPU) can serve as a
Murugesan, Annarajan, Pawar, Rohit
Refinement of Road Induced Steering Wheel Vibration in Electric Vehicle2026-26-0337To be published on 01/16/2026
Nowadays, customers expect excellent cabin insulation and superior ride comfort in electric vehicle. OEMs focuses on fine tuning the suspension system in electric vehicle to isolate the road shocks which finally offers superior ride quality. This paper focuses on the enhancing the ride comfort by reducing the steering wheel vibration which mainly originates due to road inputs. Higher steering wheel vibrations are perceived on the test vehicle when driven on rough road at the speed of 50 kmph. To determine the predominant force transfer path, Multi reference Transfer Path Analysis (MTPA) is performed on the front and rear suspension. Based on the finding from MTPA, various recommendations are explored and the effect of each modification is discussed. Apart from this, Operational Deflection Shape (ODS) analysis is carried out on the entire steering system to identify the deflection shape at the operating condition. Based on ODS findings, recommendations like dynamic stiffness
S, Nataraja Moorthy
Development of a Lightweight Front-End Structure Using Injection Molding Technology2026-26-0304To be published on 01/16/2026
This paper presents the development of a lightweight, functionally integrated Front-End Module (FEM) utilizing plastic-metal hybrid injection molding technology. The objective is to achieve modularization, part consolidation, weight reduction, and cost efficiency. The proposed design integrates multiple components into a single module which makes assembly faster and easier. A mounting strategy with fixation features was integrated into the structure to effectively support various components.To ensure structural performance, component-level Finite Element Analysis (FEA) was performed, including static strength, bending and torsional stiffness, hood retention tests, and modal analysis. Ribbing patterns were optimized to meet design stiffness targets while minimizing weight. Moldflow analysis was carried out to evaluate manufacturability, focusing on gate design, weld lines , warpage, and flow balance. Necessary design corrections were implemented prior to tool development to ensure
Srivastava, Sanjay, Thakoor, Shruti Ghanashyam, Sonkusare, Shailesh
Experimental Evaluation of Tyre Vertical Dynamic Stiffness and Damping for Ride Model Applications Using Flat Trac2026-26-0607To be published on 01/16/2026
The damping and vertical dynamic stiffness of a tyre are critical to ride comfort and overall dynamics, particularly for low-frequency excitations in urban and highway driving. Accurate ride models depend on precise tyre parameterization, as tyres are the primary interface between the vehicle and the road, absorbing surface irregularities before the suspension engages. This study investigates an experimental methodology characterizing the vertical dynamic behaviour of pneumatic tyres using a Flat Trac test machine. Contrary to the conventional approaches that depend on intricate shaker rigs or frequency dependence function models, the proposed technique uses a realistic force displacement loop-based technology which is appropriate for ride model applications. Dynamic stiffness is calculated as the peak force divided by peak displacement during vertical sinusoidal excitation. Damping is derived from hysteresis energy loss per cycle. The tests were conducted under various conditions by
Duryodhana, Dasari, Sethumadhavan, Arjun, Tomer, Avinash, Ghosh, Prasenjit, Mukhopadhyay, Rabindra
Methodology for optimizing the bench testing of Steering I shaft using vehicle level data to reduce overall product development time and cost.2026-26-0560To be published on 01/16/2026
Steering I-shaft with rubber coupling (or hardy disc) is an important part of complete steering system mainly in body on frame vehicles. Hardy discs are used to dampen the vibrations that transmit to steering wheel through frame, steering gear and I-shaft. They also support to accommodate the variation between frame and BIW of body on frame vehicles. They are made up of rubber or other polymer composites, which have less torsional stiffness as compared to metals. The overall torsional stiffness of steering system reduces since the hardy disc is used in series in steering system, that impacts on the overall performance of steering system. So, during development I shafts with different design, stiffness of hardy discs are used to optimize the steering and NVH performance of vehicle. Considering the development time and cost, each design of I-shaft cannot be validated at vehicle level. The torsional and axial force or displacement of hardy disc is measured at vehicle level on different
Kabdal, Amit
Achieving ride comfort in bus suspension by varying air spring performance2026-26-0081To be published on 01/16/2026
Air springs are widely used in commercial buses to obtain better quality of ride and comfort. Selecting the right air spring is a critical aspect of suspension design. However, this selection process is often constrained by the limited availability of off-the-shelf components as the development of a custom air spring involves long lead time and high tooling cost. This can be justifiable only at high production volumes. Air springs are tunable as compared to conventional mechanical metal springs. Their performance can be adjusted by varying the internal air pressure and volume, enabling them to accommodate a wide range of vehicle load conditions. In actual design practice, component packaging constraints and fixed mounting dimensions often restrict the choice of air spring. Additionally, Front and rear suspension requires air springs with different characteristics. To overcome these limitations, an auxiliary air tank is also called a ping tank that can be used along with an existing
Patre, Kamlesh, Salunkhe, Swapnil, Paranjape, Shekhar
Novel Approach on Material characterization Testing of various Wiring Harness2026-26-0548To be published on 01/16/2026
The automotive wiring harness (length of 4-5 km) is a very important and complex system in the development of a modern car due to a lot of new electric & electronic components and sensors. It is a very sensitive material unlike metals and is considered as a composite which is highly anisotropic in nature, as it consists of several different layers of copper/aluminum strands and insulation. Because of insulation, wiring harness exhibits viscous plastic behavior which is crucial in determining the durability and long-term performance of the cables. Material properties play an important role in determining the behavior of wiring harness after assembly into the car. Wiring harness may undergo Bending, Torsion and Tension loads, causing the stress and strain in the individual electrical wires. The lack of CAE validation of the wiring harness routing may lead to extra costs for the automotive OEMs over a period. This paper describes the novel method of Testing the Cables and Bundles used in
Beesetti, Siva, Kalkala Balakrishna, Prasad, James Aricatt, John, SHAH, Dipam, Tas, Onur, Krogmann, Stephan
Necessity of Body Torsional Rigidity of Personal Mobility Vehicles (PMVs) with an Inward Tilting Mechanism2024-32-001304/18/2025
In traditional four-wheeled automobiles, the imbalance between the roll moment, which is the product of the centrifugal force during a turn acting on the center of gravity and the height of the center of gravity, and roll stiffness, which is the product of the left-right difference in tire vertical load and the tread width and commonly used among automotive suspension engineers, of the front and rear sections necessitates body torsional rigidity. However, there is a lack of specific cases and guidelines for constructing the body structure of three-wheeled PMVs (Personal Mobility Vehicles) with a tilting mechanism from the perspective of vehicle dynamics characteristics. In this paper, the basic considerations related to the dynamics of such three-wheeled PMVs are investigated. We use the term “torsional rigidity” to refer to the stiffness as the torsional deformation of the body itself, and the term “roll stiffness” to refer to the moment that counteracts the roll moment during a turn
Haraguchi, Tetsunori, Kaneko, Tetsuya
HVAC NVH Refinement in Electric Vehicle2024-26-020601/16/2024
Customers expect much more advanced features and comfort in electric vehicles. It is challenging for NVH engineers to reduce the vibration levels to a great extent in the vehicle without adding cost and mass. This paper focuses on reducing the tactile vibration in electric vehicle when AC is switched on. Vibration levels were high and modulating in nature in test vehicle. Electric compressor is used for cabin cooling and battery cooling in the vehicle. Compressor is connected to body with the help of isolators. Depending upon cooling load, the compressor operates between 1000 rpm and 8000 rpm. The 1st order vibration of compressor was dominant on tactile locations at all the compressor speeds. Vibration levels were improved by reducing the dynamic stiffness of isolators . To reduce the transfer of compressor vibration further, isolators are provided on HVAC line connection on body and mufflers are provided in suction and discharge line to reduce the effect of pulsation. With the above
S, Nataraja moorthy, Rao, Manchi, Raghavendran, Prasath, Manivannan, Giridharan
Investigating The Factors Affecting Cabin Comfort for Agricultural Machinery2024-26-006701/16/2024
Customer expectations for cabin tractors from comfort perspective has grown multifold in the recent years. Cabin noise and vibration is one of the crucial parameter which drives comfort feel for the customer. This would enable customer to remain comfortable during long working hours. Moreover, Cabin Tractors with lesser noise levels found to have better acceptance by Customers all over the world. The Nebraska reports studied for US based tractor shows evolution of trend of cabin noise in 100-150hp tractors in last couple of decades. Undoubtedly, tractor manufacturers have put lot of efforts towards meeting legislation demand & stringent customer requirements for European and US market. This paper presents the work carried out for investigating major contributing factors affecting tractor cabin Noise & Vibration for an existing 75HP tractor. Virtual and experimental studies have been carried out to identify the principal source of noise and the transfer paths for cabin noise
Chavan, Amit, K, Somasundaram, gunasekaran, Pandiyanayagam, Chaudhari, Vishal V, Sati, Navin
Countermeasures for Low Frequency Boom noise Reduction in Electric Vehicle2024-26-021401/16/2024
Electric vehicles are much quieter than IC engine powered vehicles due to less mechanical components and absence of combustion. The lower cabin noise in electric vehicles make customers sensitive to even small disturbance in vehicle. Road boom noise is one of the major concerns to which the customers are sensitive in electric vehicles. The test vehicle is a front wheel driven compact SUV powered by electric motor. In normal plain road, noise levels are acceptable but when the vehicle has been driven on coarse road, the boom noise is perceived, and the levels are objectionable. Multi reference Transfer path Analysis (MTPA) is conducted to identify the path through which maximum forces are entering the body. Based on MTPA, modifications are proposed on the suspension bushes and the noise levels were assessed. Operational deflection shape (ODS) analysis is conducted on entire vehicle components like suspension links, sub frame, floor, roof, and doors to identify the deflection pattern of
S, Nataraja moorthy, Rao, Manchi, Raghavendran, Prasath, Selvam, Ebinezer
The science of Engine Mounts and its multidimensional impact on Noise and Vibrations in passenger car2024-26-020301/16/2024
A robust process of specifying engine mounting systems for internal combustion engine (ICE) powertrains have been established through decades of work and countless applications. Vehicle vibration is a critical consideration in the early stage of vehicle development. Apart from comfort, it also affects the overall vehicle's performance, reliability, Buzz-squeak & rattle (BSR), parts durability and robustness. The most dynamic system in a vehicle is the powertrain, a source of vibration inputs to the vehicle over the frequency range. The mounting system supports a powertrain in a vehicle and isolates the vibration generated from the powertrain to the vehicle. In addition, it also controls the overall dynamic movement of the powertrain system when the vehicle is subjected to road load excitations and avoids contact between the powertrain and other adjacent components of the vehicle. This paper investigates the effect of the mounting position, stiffness, and progressivity on overall
Hazra, Sandip, Mohare, Gourishkumar
Driveline Vibration Reduction in Light Weight All Wheel Drive Vehicle2024-26-022901/16/2024
The test vehicle is All Wheel Drive (AWD) vehicle which is powered by four-cylinder engine. The power is transferred from the powertrain to the wheel through power transfer unit (PTU), propeller shaft, flexible rubber coupling and Integrated Rear Differential Assembly (IRDA) . Higher Boom noise and vibration levels are observed when driving the vehicle at 5th gear WOT conditions. 2nd order NVH levels are dominant from 1200 rpm to 2000 rpm and 4th order NVH levels are dominant at 2300 rpm. Operational deflection shape (ODS) analysis is carried out on entire vehicle to identify the location where maximum deflection is observed at the problematic frequency. It is identified that higher torsional excitation from the powertrain is exciting the IRDA pitching mode and the propeller shaft bending mode which is the reason for higher 2nd order and 4th order NVH levels. The driveline forces are entering the body through the IRDA and rear cradle bushes. The dynamic stiffness of IRDA bushes is
S, Nataraja moorthy, Rao, Manchi, Raghavendran, Prasath
NVH Refinement of Structure borne tonal noise in electric vehicle2024-26-019801/16/2024
Globally all OEMs are moving towards electric vehicle to reduce emission and manage fuel cost. Customers expect highest level of refinement and sophistication in electric vehicle. At present, the customers are sensitive to high pitched tonal noise produced by electric powertrain which gives a lot of challenges to NVH engineers to arrive at a cost-effective solution in less span of time Higher structure borne tonal noise is perceived in electric vehicle at the vehicle speeds of 15 kmph and 60 kmph. The test vehicle is front wheel drive compact SUV powered by motor in the front. The electric powertrain is connected to subframe with help of three mounts. Transfer path analysis (TPA) using blocked forces method is carried out to identify the exact forces of the powertrain. Powertrain mount is characterized by applying the predicted forces and dynamic stiffness at problematic frequency is measured. By reducing the dynamic stiffness of powertrain mounts, the noise levels are reduced by ~ 5
S, Nataraja moorthy, Rao, Manchi, Raghavendran, Prasath, Selvam, Ebinezer
Analysis and Annihilation of Grunt Noise in Hydraulic Power Assisted Steering Systems2024-26-021801/16/2024
Hydraulic steering systems employ pressurized fluid to alleviate the effort needed to steer the wheels of an automobile. Hydraulic Power Assisted Systems (HPAS) are cost-efficient, yet intricate. As customer trends lean towards reduced effort and improved handling, HPAS must intervene more in steering, leading to increased pressure requirements from the HPAS pump. Consequently, HPAS components must withstand higher pressure liquid and operate with closer tolerances, occasionally resulting in anomalous functioning. This paper delves into one anomaly with HPAS systems "Grunt Noise", a phenomenon caused by the resonance of the Torsion bar (T-bar) with fluid pressure pulsations. An extensive study was conducted to identify load conditions for grunt noise generation, examine transfer paths and analyze its frequency band. The study also explored the cascading process, reproducing the vehicle-level phenomenon at the rig-level for the Rack and Pinion and later at Pinion Valve assembly level
SETHI, AJITESH, Titave, Uttam, Vardhanan K, Aravindha Vishnu, Zalaki, Nitin, Naidu, Sudhakara
Analysis and Reduction of Abnormal Suspension Noise in Sports Utility Vehicle2024-26-021701/16/2024
This paper focuses on reducing abnormal noise originating from suspension when driving on rough road at the speed of 20 kmph. The test vehicle is a front wheel driven monocoque SUV powered by four cylinder engine. Cabin noise levels are higher between 100 to 800 Hz. Vibration levels are measured on front and rear suspension components, front and rear subframe, subframe connections on body to identify the noise source locations. Since the noise levels are dominant only in certain rough patches at very narrow band of time, wavelet analysis is used for problematic frequency identification. Based on wavelet analysis, it is identified that the vibration levels are dominant on front lower control arm (LCA) due to inferior isolation performance. The dynamic stiffness of LCA bushes is reduced by ~ 30% to improve the isolator performance which reduced the noise levels by ~ 2 dB (A). Modal analysis is conducted on suspension components like LCA, stabiliser bar, shock absorber, tires and front
S, Nataraja Moorthy, Rao, Manchi Venkateswara, Raghavendran, Prasath, Manivannan, Giridharan
Influence of Rear Suspension Local Stiffness on Full vehicle Ride & handling Performance2024-26-006101/16/2024
One of the biggest challenges for automotive industry is with respect to material saving and to have control on cost of development and still meeting performance in each aspect. Stringent weight targets help industries to have good margin on component costs. In recent times we have seen vehicle underbody contribution to total vehicle is significant in range of 12% to 18%. Total weight directly impacts the range of electric vehicle which is a key metric for success from real-world usage point of view and customer appeal. Hence control on suspension and frame design for light weighting is prominent trend in industry, this leads to deterioration of suspension compliance as well as vehicle ride and handling performance. Sub-frame and knuckle play crucial role in definition of overall suspension stiffness. Present Study focusses on electric vehicle rear cradle design for weight saving with minimum reduction of stiffness. Understanding compliance which obtained from frame\cradle in vehicle
Asthana, Shivam, Rasal, Shraddhesh, Ganesh, Lingadalu, V, Jesse Daniel, Nidasosi, Basavraj, Ramkumar, J, NAYAK, Bhargav, M, Sudhan, Vellandi, Vikraman
Vehicle Dynamics Simulation Correlation : Impact of Flexible Tyre and Flexible Frame in Comfort Prediction of Two Wheelers Motorcycles and Scooters2024-26-005301/16/2024
For any two wheeler vehicle development, rider and pillion comfort while driving the vehicles over different kinds of road perturbations holds high importance. Designing a vehicle for comfort starts at the very beginning of its layout definition through vehicle geometric parameters, key hardpoints, mass-inertia distribution of subsystems and suspension characteristics. There is a need for highly reliable simulation models for comfort predictions as any change in layout during subsequent design stages is a very costly affair. Accurately predicting comfort using a full vehicle model is a challenging task though as it depends on how realistic the Simulation Model is to that of actual vehicle. While suspension stiffness and damping characteristics remain critical parameters for the comfort, selection of tyres are known to hold equal importance in vehicle comfort. The details to which the tyres are captured in the simulation model and the formulation of tyre interaction with roads in a
Govindula, Srikanth, Pandey, Pradyumn, Saraswat, Udit, Mishra, Ashish
Experimental Characterization of a Steel Spring Mount using Virtual Point Transformation2025-01-004605/05/2023
The application of virtual point transformation for determining the transfer dynamic stiffness of a steel spring mount is demonstrated in this experimental study. Rigid fixtures are attached to both ends of the spring, and frequency response functions are measured using impact hammer excitation. These measured frequency response functions are transformed to the virtual points, analogous to nodes in finite element analysis, with six degrees of freedom. This allows for high-quality frequency response functions to be obtained through specialized post-processing techniques. The six degrees of freedom transfer dynamic stiffness is then extracted using the inverse sub-structuring method, which eliminates the influence of the fixture dynamics. The results are validated by a direct measurement approach. Additionally, the study investigates the effects of liquid sprayed damping material coatings on the spring's transfer dynamic stiffness, revealing that certain damping materials significantly
Neihguk, David, Herrin, David, de Klerk PhD, Dennis
The accelerated roughness noise optimization of one PHEV vehicle2025-01-008705/05/2023
To optimize the ’kalakala’ noise that produced by the plug hybrid electric vehicle when accelerating with a small throttle while in the charging state. A LMS device was used to acquire the noise of the driver's outer ear . Through filtering and playback analysis, it was confirmed that the noise is mainly contains the frequency bands of 250-350Hz, 350-500Hz, and 500-700Hz. The three frequency bands of the noise were used as carriers for Hilbert transform, and their envelopes were obtained for Fourier transform analysis. It was found that the modulation order of the noise is 0.5 times that of the engine ignition order, and the modulation frequency is 20-30Hz, which let the customer hears like roughness. Regarding the spectral characteristics of this noise, firstly, at the excitation source, the impact of reducing engine combustion excitation on this noise is explored. At the same time, selected a reasonable moment of inertia and frequency of the pulley torsional damper, to decrease the
Shouhui, Huang, YUN, ZHAO, zhou, changshui
Studies on the dynamic characteristics of vibration energy recovery system 2022-01-033703/29/2022
The vehicle suspension plays a significant role in alleviating the vibrations translated from the rough road and most of the vibrations are dissipated by the hydraulic shock absorber. Vibration energy harvesting technology is widely concerned for the self-powered wireless sensor system in intelligent vehicle. However, the system dynamic characteristics changes due to the coupling between the vibration and electro-magnetic induction. Mechanical electromagnetic coupling is investigated in this paper, a quarter vehicle vibration energy recovery model including electromagnetic system is established. And this paper focuses on the dynamic stiffness and normalized damping, which are often ignored by researchers. A harmonic excitation is applied to the vehicle suspension, and the dynamic stiffness and damping in time domain is studied by changing the frequency of harmonic excitation. And the time-domain response function of vehicle vibration acceleration under harmonic excitation and square
Zhu, Hengjia, Liu, Yunhao, Tian, Siyuan, Yun, Shen, Zhang, Wei
Modeling and analysis of hydraulic bushings/mounts considering frequency and amplitude dependence 2022-01-032703/29/2022
The dynamic characteristics of hydraulic bushings/hydraulic mounts are related to their excitation amplitude and frequency, which are often not reflected in existing models. Based on the lumped parameter model of hydraulic bushings/mounts, this paper compares and analyzes the similarity of the working mechanism of hydraulic bushings and hydraulic mounts, and deduces the unified mechanical analog model. Based on the derived unified mechanical analog model, a nonlinear damping element is introduced at the concentrated mass of the liquid in the pipe to reflect the amplitude dependence of the resonance of the hydraulic bushings/mounts dynamic stiffness curve.At the same time, Maxwell element and Berg friction damping element are introduced at the equivalent spring element representing the upper chamber stiffness, so as to reflect the amplitude dependence of the dynamic stiffness curve of the hydraulic bushings/mounts in high frequency band caused by the nonlinear stiffness of the upper
jiang, jian, Yin, Zhihong, Shangguan, Wenbin
Research on high-frequency dynamic models of rubber mounts with second-stage isolation 2022-01-074003/29/2022
Rubber mount is a key component of the electric vehicle powertrain mount system, which can reduce the vibration transmitted from the powertrain to the body. The rubber mount with second-stage isolation means that a rubber vibration isolator is added to the metal bracket of the original rubber mount. Compared with the original rubber mount, the rubber mount with second-stage isolation has smaller dynamic stiffness and better vibration isolation performance in the high-frequency range. In this paper, the quasi-static characteristics of a rubber mount with second-stage isolation are tested, and the high-frequency dynamic characteristics of the rubber mount with second-stage isolation are calculated by the method of finite element simulation. According to its characteristics, an equivalent mechanical model including equivalent mass is established. The equivalent mechanical model is superimposed with the fractional derivative model and the Maxwell model to obtain two high-frequency dynamic
Zhang, Jiaqi, Liu PhD, Xiaoang
Neural-Network-Based Suspension Kinematics and Compliance Characteristics and Its Implementation in Full Vehicle Dynamics Model2022-01-033503/29/2022
Suspension kinematics and compliance strongly influence the handling performance of the vehicle. The kinematics and compliance characteristics are determined by the suspension geometry and stiffness of suspension linkage and elastic components. However, it is usually inefficient to model all the joints, bushings, and linkage deformation in a full vehicle model. By transforming the complex modeling problem into a data-driven problem tends to be a good solution. In this research, the neural-network-based suspension kinematics and compliance model is built and implemented into a 17 DOF full vehicle model, which is a hybrid model with state variables expressed in the global coordinate system and vehicle coordinate system. The original kinematics and compliance characteristics are derived from multibody dynamics simulation of the suspension system level. The comparison of the neural network model and traditional interpolation methods is also given out to illustrate the advantages and
Duan, Yupeng, Zhang, Yunqing, Wu, Jinglai
Structural design of a full-body composite monocoque chassis based on the type of carbon fiber fabrics2022-01-044403/29/2022
The number of stacked layup and orientation of carbon fiber/epoxy in a sandwich panel with the aluminum honeycomb core was optimized using finite element method (FEM) to improve the structural performance of the monocoque chassis for the electric Formula SAE (FSAE) racecar. To establish the selection criteria for fabrics and orientations, the single unidirectional (UD) and woven plies (W) were simulated under tensile and simple shear tests to determine their off and on-axis properties. Simulation results revealed that the unidirectional ply enhances the overall strength of laminate while woven ply is responsible for shear strength. Thus, the combination of unidirectional and woven plies was proposed. The four anisotropic laminates consisting of four plies with different orientations were simulated under three-point bending and plate twist tests to determine the flexural rigidity and twist stiffness (D66), respectively, and their mechanical properties were compared to the quasi
Sratong-on, Pimpet
SCV Chassis Performance Optimization through Parametric Beam Modelling & Simulation2021-28-018310/01/2021
In automotive product development, design and development of the chassis plays an important role since all the internal and external loads pass through the vehicle chassis. Durability, NVH, Dynamics as well as overall vehicle performance is dependent on the chassis structure. Even though passenger vehicle chassis has a ladder frame or a monocoque construction, small commercial vehicle chassis is a hybrid chassis with the cabin welded to the ladder frame. As mileage is critical for sale of SCVs, making a light-weight chassis is also important. This creates a trade-off between the performance and weight which needs to be optimized. In this study, a parametric beam model of the ladder frame & the cabin of the vehicle is created in COMSOL Multiphysics. The structure has been parameterized into the long member & crossmember geometry and sections. The model calculates the first 12 natural frequencies, global stiffness, and weight. It has been validated and further used for optimization study
THANAPATI, ALOK Ranjan, Bhalerao, Mihir, Deshmukh, Chandrakant, Krishnan, Hareesh
Bump steer and Brake steer optimization in steering linkages through TAGUCHI method DOE analysis2021-26-007909/22/2021
Due to recent infrastructural development and emerging competitive automotive markets in India, there is seen a huge shift in customer’s demand and vehicle drivability pattern in commercial vehicle industry. Now apart from ensuring better vehicle durability and best in class tyre life and fuel mileage, a vehicle manufacturer also has to focus on other key attributes like driver’s safety and ride comfort. Thus, for ensuring enhanced drivability, key parameters for ensuring better vehicle handling includes optimization of bump steer and brake steer. Both bump steer and brake steer are vehicle’s undesirable phenomenon where a driver is forced to constantly make steering wheel correction in order to safely maneuver the vehicle in the desired path. Since both bump steer and brake steer are caused due to the interactions of several vehicle parameters such as – drop arm and steering arm hard point, suspension stiffness, suspension eye and shackle position, caster angle, draglink length etc
Chopra, Nitin, P, Mahadevan
Test-driven full vehicle modelling for ADAS algorithm development2021-26-003309/22/2021
ADAS system development for safety as well as comfort is a major activity for all AOEMs and dedicated system suppliers. The development of these systems relies heavily on the availability of accurate driving dynamics models to validate the control algorithms and verify vehicle performance in realistic driving scenarios. AOEMs usually have access to high-fidelity full vehicle models but the availability of such models poses a significant challenge to software and sub-system suppliers. In order for them to develop their ADAS solutions, an accurate test-based model identification process using prototype or benchmark vehicles would be highly desirable. In this paper, a step-wise approach for the identification of the vehicle parameters in order to create an accurate 15-DOF (degree of freedom) vehicle dynamics model is proposed. The approach relies on an optimized use of vehicle driving test data to minimize test bench or laboratory testing. The test data is used to identify the various
Lugo, Lorenzo, Bartolozzi, Mirco, Vandermeulen, Wouter, Geluk, Theo, Dom, Steven
Virtual tuning and optimization of two wheeler suspension through MBD simulations2021-26-034809/22/2021
The design and tuning of stiffness and damping parameters of the suspension system is an essential step in arriving at the optimal riding comfort for a two wheeler. The conventional method of suspension design involves selecting baseline values of suspension parameters through bench-marking of similar vehicles, followed by extensive real life tests to tune these parameters over different load, speed and track conditions. This conventional approach is often time consuming and heavily dependent on physical prototypes of suspension. With the advent of tools to run optimization on Multi-Body Dynamic (MBD) simulations, a near complete tuning of suspension parameters can be performed entirely in the simulation domain. This paper presents an integrated approach towards the design and tuning of suspension stiffness and damping parameters using MBD simulations, by employing fully parameterized suspension stiffness and damping curves in the optimization process. The optimization is performed on
PK, Ram Kumar, Mishra, Ashish
Second-Order Sliding Mode Controller for Performance Analysis of Quarter Car Magnetorheological Suspension System2020-01-100504/14/2020
To achieve the simultaneous improvement in ride comfort of the passenger as well as the stability of the vehicle, a second-order sliding mode controller is proposed in this study. Super twisting algorithm attenuates the chattering effect present in the conventional sliding mode controller without affecting the stability of the system. The Lyapunov stability analysis is carried out to verify the stability of the controller. The effectiveness of the designed super twisting algorithm used second-order sliding mode controller is validated in a semiactive quarter car suspension with seat model. Modified Bouc-wen magnetorheological (MR) damper model is used as a semiactive damper and the voltage that has to be supplied to the magnetorheological damper is controlled by a super twisting algorithm and sliding mode controller. Continuous modulation filtering algorithm is adopted to convert the force signal of a controller into the equivalent voltage input to the MR damper. The entire system is
Soosairaj, Arockia Suthan, K, Arunachalam
Multi-Mode Controller Design for Active Seat Suspension with Energy-Harvesting2020-01-108304/14/2020
In this paper, a multi-mode active seat suspension with a single actuator is proposed and built. A one-DOF seat suspension system is modelled based on a quarter car model of commercial vehicle with an actuator which is comprised of a DC motor and a gear reducer. Aiming at improving ride comfort and reducing energy consumption, a multi-mode controller is established. According to the seat vertical acceleration and suspension dynamic travel signals, control strategies switch between three modes: active drive mode, energy harvesting mode and plug breaking mode. In active drive mode, the DC motor works in driving state and its output torque which calculated by LQR algorithm is controlled by a current-loop controller; In energy harvesting mode, the DC motor works in generator state by which induced current can charge the power source, in this mode, the DC motor is considered as a damper which damping coefficient is decided by the charging current and controlled by Skyhook algorithm; In plug
Zhang, Zhenrui, Zhang, Yunqing, Xu, Peijun
The Effect of Friction on Ride Comfort Simulation and Suspension Optimization2020-01-076504/14/2020
The design of suspension affects the vehicle dynamics such as ride comfort and handling stability. Nonlinear characteristics and friction are important characteristics of suspension system, and the influence on vehicle dynamic performance cannot be ignored. Based on the seven-degree-of-freedom vehicle vibration nonlinear model with friction, the vibration response process of the vehicle and the influence of suspension friction on vehicle ride comfort and suspension action process were studied. The results show that friction will significantly affects the simulation of ride comfort and coincide with the function of the shock absorber. The suspension shock absorbers of vehicles were optimized with and without suspension friction. The results showed that the suspension tended to choose softer shock absorbers when there was friction. However, both of the two optimizations are able to improve the ride comfort of vehicles, and the simulation results were similar. At the same time, it was
Xuwang, Wang, Chen, Xiaoyu, Xu, Peijun, Zhang, Yunqing
Study on Impact of SUV chassis stiffness on vehicle dynamics through CAE2020-01-100404/14/2020
Now a day’s automotive industry is a highly competitive market where continuous innovation in design and production of vehicles is required to gain market share and survive in the market. This resulted in the reduction of the life cycle of the design process and design tools. Identifying, understanding and refining these details is significant to develop sustainable cars. Body and Chassis stiffness are important specifications of a passenger car which affects handling, steering and ride characteristics of the vehicle. It has been proved that torsional, lateral and local chassis stiffness can play a role in giving the customer a premium feeling by affecting key metrics in the vehicle dynamics behaviour of a passenger car. In this paper, the effect of chassis stiffness on vehicle dynamics performance is studied using CAE. Different attributes of vehicle dynamics like vehicle handling, On-Center feel and vehicle ride are considered as performance characteristics. The chassis stiffness is
Lenka, Visweswara, Anthonysamy, Baskar, N, BALARAMAKRISHNA, Londhe, Abhijit
Sweating the details OF C8 DEVELOPMENT20AUTP04_0304/01/2020
How GM's Corvette engineers tackled challenges in the move to a mid-engine architecture. Shifting 500 lb (227 kg) of engine mass rearward by 7.5 feet (2.3 m) and moving 300 lb (136 kg) of transmission components aft by almost three feet transformed the 2020 Chevrolet Corvette Stingray into a budding supercar. General Motors' motive behind adopting a mid-engine layout for the eighth-generation (C8) Corvette was to improve acceleration, braking and handling via substantially increased rear-tire loading. While numerous test-drive reviews and ‘Of the Year’ trophies mark that mission accomplished, there are lessons behind the hoopla: how GM engineers solved problems they encountered reinventing America's sports car. “Porsche was our primary benchmark, especially in reference to their PDK dual-clutch automatic transmission's overall dynamics,” revealed executive chief engineer Tadge Juechter, in an interview with SAE's Automotive Engineering. He said GM also purchased a Ferrari 458 for
Sherman, Don
Crank-Lever Electromagnetic Damper (CLEMD) Design for Automobile Suspension System06-13-01-000202/04/2020
An effective damper is among the most important components of the suspension system. It ensures the right amount of damping force is acting on the suspension system to provide comfort to the passengers and proper road holding to tires. Unfortunately, the energy absorbed by the dampers from the suspension system gets wasted in the form of heat. In this article, it is proposed to use innovative electromagnetic damper (EMD) with a crank-lever mechanism to recover energy from the suspension system. The goal is to develop a lightweight design of EMD that can recover a high amount of power. For the design, an off-road vehicle is used since in off-road vehicles the amount of power wasted in the suspension system is high. Three different design approaches are used, which include single-stage gearbox type, two-stage gearbox type, and three-stage gearbox type of CLEMD. Out of them, the best design, i.e. three-stage gearbox type of CLEMD is selected because of minimum weight and inertia of the
Todmal, Prashant Eknath, Melzi, Stefano
Study on the Quantitative Relationship between Static Stiffness and Modal Parameters of an Aluminum Space Frame10-04-02-000701/27/2020
In this article, the quantitative relationship between the static stiffness, lightweight factor, and modal parameters of an aluminum space frame was investigated. Modal theory calculation and finite element method were employed in the analysis. Fifty modal parameters were extracted from the finite element model of the frame to calculate the bending stiffness, torsional stiffness, and lightweight factor of the frame. The deviations of the bending stiffness, torsional stiffness, and lightweight factor obtained from the modal theory and the finite element theory were found to be 0.91%, 1.72%, and 1.71%, respectively. It indicates that these two methods have similar accuracy. It was confirmed that the sum of each order modal compliance could be used to calculate the static compliance of the aluminum space frame. The first-order bending mode was found to be the corresponding mode order, which made the largest contribution to the bending stiffness. This method is also applicable for
Wang, Zhenhu, Xia, Erli, Chen, Ziming, Xue, Zhigang, Li, Luoxing
Modelling and Simulation of Vehicle Suspension System with Variable Stiffness Using Quasi-Zero Stiffness Mechanism10-04-01-000312/02/2019
The dynamics and comfort of a vehicle closely depends on the stiffness of its suspension system. The suspension system of a vehicle always had to trade-off between comfort and performance of a vehicle; since for comfort a softer suspension is preferred which in turn decreases the aerodynamics and cornering performance and increases the ride height of the vehicle; whereas in stiffer suspension the ride height can be lowered, but forces due to bumps are transferred all the way up to the drivers cabin. This article aims to design a vehicle suspension model with variable stiffness using quasi-zero stiffness (QZS) mechanism and study its force-displacement characteristics and minimize the fundamental stiffness of the suspension system. The model developed uses the principle of negative stiffness to achieve low stiffness for the softer suspension system. The mechanism designed comprises of a pushrod suspension system with three parallel springs attached to one end of the rocker arm, one
Saini, Mohit
Ride-Comfort Analysis for Commercial Truck Using MATLAB Simulink2019-28-242811/21/2019
Ride Comfort forms a core design aspect for suspension and is to be considered as primary requirement for vehicle performance in terms of drivability and uptime of passenger. Maintaining a balance between ride comfort and handling poses a major challenge to finalize the suspension specifications. The objective of this project it to perform ride- comfort analysis for a commercial truck using MATLAB Simulink. First, benchmarking was carried out on a 4x2 commercial truck and the physical parameters were obtained. Further, a mathematical model is developed using MATLAB Simulink R2015a and acceleration- time data is collected. An experimentation was carried out on the truck at speeds of 20 kmph, 30 kmph, 40 kmph and 50 kmph over a single hump to obtain actual acceleration time domain data. The model is then correlated with actual test over a single hump. This is followed by running the vehicle on Class A, B & C road profiles to account for random vibrations. Similarly, a simulation is done
Debnath, Sarnab, Bhanja, Subrat, Achanta, Krishna, Jain, Pranay, Bharti, Sumit, Agrewale, Mohammad Rafiq
System Level Design of a Self-Stabilizing Two-Wheeler Suspension Concept2019-28-012710/11/2019
Two-wheeler represent one of the most used mode of transport in countries like India. The data from NCRB shows that most injuries to two-wheeler motorists are after being thrown off the vehicle. A self-stabilized combined with enclosure prevents serious injury in case of a skidding of the two-wheeler. The primary objective of the work is to create a suspension system for the enclosed self-balancing two-wheeler such that it can withstand the load of the vehicle itself and the extra payload. Ride comfort was primary objective of the work. The suspension system was modeled from the first principles, solved using MATLABTM SIMULINKTM and kinematics simulation was performed to learn the behavior of the system in MSC ADAMSTM. Dynamic simulations were also carried out to check if the forces were under permissible levels for overall design. The parameters considered for the work were hard-points, suspension stiffness and damping. With manual parameter iterations, suspension parameters were
Sankarasubramanian, Hariharan, Prabhahar, Dhurai
Role of Dynamic Stiffness in Effective Isolation2019-01-149506/05/2019
In any machinery, avoiding noise and vibration completely is a difficult task due to the structural dynamic behaviors of components. To safeguard the operator, it is important to best isolate the operator station from NVH environment. Cabin isolation is an important aspect to minimize structure borne noise and tactile vibrations to be transferred into the cabin. Isolators are selected based on the isolation system inertial properties at mounting locations in the operating frequency range interested. The most important assumption to select isolators are that the active side and passive side of the isolators are nearly rigid so impedance mismatch is created for effective isolation. This paper describes the importance of dynamic stiffness of the structures on both the active and passive side for better NVH performance. NVH performance of passive side is evaluated analytically and computationally in terms of tactile vibrations and structure borne noise for various ratios of the dynamic
Dasabai, Balavardhan Reddy, Yang, Yuzhen
Simulation Analysis of a Dual-Purpose Intelligent Mobile Platform for Highway and Railway2019-01-149906/05/2019
Railways play a huge role in China's transportation industry. In order to ensure intelligence, advanced technology and high efficiency in functions such as railway inspection, rescue and transportation, a dual-purpose intelligent mobile platform for both roads and railways was developed. Due to the height limitation of this platform, resilient wheels and rubber dampers with short stroke are used as the suspension system for the rail chassis. Based on this special suspension form, the dynamic model of the whole platform is derived, and the simulation model of the whole platform is established in the simulation software. The effects of resilient wheels’ axial stiffness, radial stiffness and vertical stiffness, lateral stiffness of rubber dampers on the vertical and lateral stability of the platform were studied. It is found that the increase of the radial stiffness of the resilient wheels will deteriorate the vertical stability and lateral stability of the platform. The increase in the
Sun, Nan, Zhang, Wenming, Yang, Jue
A Non-Contact Overload Identification Method Based on Vehicle Dynamics2019-01-049004/02/2019
The vehicle overload seriously jeopardizes traffic safety and affects traffic efficiency. At present, the static weighing station and weigh-in-motion station are both relatively fixed, so the detection efficiency is not high and the traffic efficiency is affected; the on-board dynamic weighing equipment is difficult to be popularized because of the problem of being deliberately damaged or not accepted by the purchaser. This paper proposes an efficient, accurate, non-contact vehicle overload identification method which can keep the road unimpeded. The method can detect the vehicle overload by the relative distance (as the characteristic distance) between the dynamic vehicle's marking line and the road surface. First, the dynamics model of the vehicle suspension is set up. Then, the dynamic characteristic distance of the traffic vehicle is detected from the image acquired by the calibrated camera based on computer vision and image recognition technology. The data error caused by the
Zhou, Daolin, Tan, Gangfeng, Ding, Yiran, Yu, Shimin, Ma, Xiaofei, Wang, Shuai, Wang, Zhenyu
A Novel Three Steps Composited Parameter Matching Method of an Electromagnetic Regenerative Suspension System2019-01-017304/02/2019
The electromagnetic regenerative suspension has attracted much attention recently due to its potential to improve ride comfort and handling stability, at the same time recover kinetic energy which is typically dissipated in traditional shock absorbers. The key components of a ball-screw regenerative suspension system are a motor, a ball screw and a nut. For this kind of regenerative suspension, its damping character is determined by the motor's torque-speed capacity, which is different from the damping character of the traditional shock absorber. Therefore, it is necessary to establish a systematic approach for the parameter matching of ball-screw regenerative suspension, so that the damping character provided by it can ensure ride comfort and handling stability. In this paper, a 2-DOF quarter vehicle simulation model with regenerative suspension is constructed. The effects of the inertia force on ride comfort and handling stability are analyzed. A novel three steps composited matching
Cui, Dandan, Yongchang, Du
Research and Development of an Electromagnetic Actuated Active Suspension2019-01-085804/02/2019
Active suspension could achieve good ride comfort and road holding performance. Traditional active suspension which utilizes air actuator or hydraulic actuator features relatively slow response or high energy consumption. Utilizing Permanent Magnet Synchronous Motor (PMSM) as actuator, the Electromagnetic Actuated Active Suspension (EAAS) benefits quick response and energy harvesting from vibration at the same time. Benchmarked with luxury cars available on the market, design parameters and design boundary are determined. A mechanism includes push bar and bell crank is designed to transfer the rotary motion of PMSM into linear motion of suspension, or verse vice. A prototype of EAAS is built in compromise of limited budget and a test bench is designed and set up. Different from conventional quarter car model, the model of EAAS in this paper is investigated and the total inertial of PMSM, gearbox and suspension control arms are calculated and simplified as an equivalent mass. Also
Yin, Jun, He, Jiaxing, Luo, Jie, Chen, Xinbo, Wu, Lixin
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