Browse Topic: Pitch

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Development of a GUI-Based Pitch Sequence Optimization Tool for Tyre Noise Reduction2026-26-0330To be published on 01/16/2026
Minimizing tyre noise is essential for enhancing ride comfort, especially in electric vehicles where the absence of engine noise makes tyre-generated sound more prominent. This work presents the development of a GUI-based pitch sequence optimization tool to support tyre design engineers in generating acoustically optimized tread sequences. The tool operates in two modes: without constraints, where the pitch sequence is optimized freely to reduce tonal noise levels; and with constraints, where specific design rules are applied to preserve pattern consistency and manufacturability. This tool plays a pivotal role in the tire development process, serving as one of the key evaluation criteria for tread pattern approval before mould fabrication. By enabling engineers to generate balanced, low-noise pitch sequences that align with both acoustic targets and engineering constraints, the tool facilitates faster design iterations and smooth integration with downstream processes. Its successful
Sampathraghavan, Lakshmi, Ramarathnam, Krishna Kumar, Mantripragada PhD, Krishna Teja, Ramachandran, Neeraj
Reliability of Rubber Grommets by Stochastic Analysis of Geometric Tolerances2026-26-0501To be published on 01/16/2026
Manufacturing tolerances pose considerable challenges in the production of rubber-based components, often leading to dimensional variations that can compromise overall product reliability. These inconsistencies may result in a range of functional issues, including poor sealing, excessive wear, misfit during assembly, and premature failure. Among these components, grommets are especially sensitive due to the complex, non-linear behavior of rubber materials, making precise dimensional control critical to ensure consistent and dependable performance. Even minor deviations in grommet geometry can trigger substantial assembly difficulties. Issues such as misalignment, buckling, insertion challenges, and potential damage to neighboring parts are commonly encountered. These complications typically require multiple rounds of design revisions and physical testing, which extend development timelines and significantly increase production costs. Real-world observations from various automotive
Beesetti, Siva, Hattarke, Mallikarjun, James Aricatt, John, PATHAN, ERAM
Adopting Pothole mitigation system for improved ride, handling and enhanced component life2024-26-005901/16/2024
Potholes are a major cause of discomfort for riders and vehicle damage. The passive suspension systems which are used in the passenger vehicles are primarily reaction based. These can’t adapt to the changing road conditions which means the best ride quality and handling characteristics cannot be ensured for different driving situations. Passive suspension system also needs more maintenance due to its inability to reduce the impact of the road irregularities. In recent years, semi-active suspension systems have been developed to improve ride comfort and vehicle safety. Here, a semi-active suspension system with a road preview mechanism has been integrated with a TATA car model to investigate its impact on ride comfort, handling characteristics and component loads in digital domain. A quarter car vehicle model is used to compare different active damping control strategies. The best strategy is selected and integrated with a full vehicle model developed in a MBS tool to gain deeper
Mishra, Satyakam, PRASAD, TEJ, Maruenda Sanz, Javier
Effect of Varying Diffuser vane height on CC3 NASA 4:1 Centrifugal Stage Performance2022-26-121005/26/2022
This work is aimed at conducting a computational study to find out the effect of vane less space downstream of the Diffuser vane trailing edge, by varying the height of diffuser vane viz. 50%, 75% and 100% diffuser height, on centrifugal stage performance. The considered centrifugal compressor stage in this study is CC3 NASA 4:1 centrifugal stage. In all the cases diffuser leading edge radius is same. The compressor performance with full diffuser vane configuration (100% diffuser height) is computed and initially compared with test data. The diffuser vane height is then reduced to 50% and 75% of the original length from diffuser leading edge. Hence, the diffuser leading edge location remains same as original 100% diffuser vane height geometry whereas location of trailing edge changes according to vane height. Another part of study is to model 100% diffuser vane height with hub and shroud gaps respectively. The computational study is carried out using CFX v19.1. The paper presents
Kumar, Shailesh, Chougule, Hasham, Abdullah, Qizar, Goswami, Shraman
Research on Brake Comfort Based on Brake-by-Wire system Control2022-01-111303/29/2022
The vehicle will produce certain shock and vibration during the braking process, which will affect the driving experience of the driver. Aiming at the problems of pitch vibration, longitudinal vibration and shock during the braking process, this paper proposes a planning and following control method for target longitudinal acceleration in post-braking phase, and designs control trigger and termination strategies. Target longitudinal acceleration planning takes minimizing longitudinal shock as the design goal. The following control takes the brake pressure as the control object, and adopts the "feedforward +PID feedback" method to follow the target longitudinal acceleration. Based on Carsim and Simulink software, the simulation model of straight-line braking is established. In this model, the control target is longitudinal acceleration and the control object is four-wheel braking pressure. The results of straight-line braking simulation show that the proposed longitudinal acceleration
Xiong, Wei, Wang, Weiwei, Jiang, Kaihong, Hou, Liming, Shangguan, Wen-Bin
Multiphysics Simulation of Electric Motor NVH Performance with Eccentricity2021-01-107708/31/2021
With the emphasis of electrification in automotive industry, tremendous efforts are made to develop electric motors with high efficiency and power density, and reduce noise, vibration and harshness (NVH). A multiphysics simulation workflow is used to predict the eccentricity-induced noise for GM’s Bolt EV motor. Both static and dynamic eccentricities are investigated along with axial tilt. Analysis results show that these eccentricities play a critical role in the NVH behavior of the motor assembly. Transient electromagnetic (EM) analysis is performed first by extruding 2D stator and rotor sections to form 3D EM models. Sector model is duplicated to form full 360-degree model. Stator is split into three rotated sections to characterize stator skew, and the skew between two sections of rotor and magnets are also modelled. Sinusoidal current is applied and lumped-sum forces on each stator tooth are computed. Next, full 3D structural model is constructed, and EM forces are applied as
Zhang, Henry, Jaura, Ankur, Kumar, Dinesh, Sambharam, Tushar, Zhang, Zheming, He, Song, Zhang, Peng, GSJ, Gautam
On the Road Profile Estimation from Vehicle Dynamics Measurements2021-01-111508/31/2021
Ride comfort assessment is undoubtedly related to the interaction between the vehicle tires and the road surface. Indeed, the road profile represents the typical input for tire vertical load estimation in durability analysis and for active/semi-active suspension controller design. However, the road profile evaluation through direct experimental measurements involves long test time and excessive cost required by professional instrumentations to detect the road irregularities with sufficient accuracy. An alternative is shifting attention towards efficient and robust algorithms for indirect road profile evaluation. The object of this work aims at providing road profile estimation starting from vehicle dynamics measurements, through accessible and traditional sensors, with the application of a linear Kalman filter algorithm. The filter is designed and tuned by considering the pitch/bounce half-car models for the prediction phase and by measuring vertical accelerations and angular speeds
Vella, Angelo Domenico, Tota, Antonio, Vigliani, Alessandro
Novel Methodology to Compute Halfshaft Joint Forces and Virtually Simulate Powertrain Wiggle2021-01-066504/06/2021
Vibrations affect vehicle occupants and should be prevented early in design process. Powertrain (PT) wiggle is one of the well-known issues. It is the 3rd order lateral vibration, forced by half shaft inner LH/RH plunging tripod joints [1,2]. Lateral PT resonance (7-15Hz) occurs at certain vehicle speed during acceleration and may excite lateral, pitch and roll PT modes. Typically, PT wiggle occurs in speed range of 5-25kph. Vibration is noticeable on driver and passenger seats mostly in lateral direction. The inner half shaft joints are the major source of vibration. Unfortunately, existing MBD tools like Adams [3] are missing detailed tripod joint representation because of complex mechanical interactions inside the joint. At least three sliding contacts between tripod rollers and joint housing, lubricant inside the can and combination of rotation and plunging make the modeling too complicated. This paper is dedicated to provide a novel methodology in tripod joint modeling which
Opeiko, Alexandre, Paul, Abhishek, Vipradas, Aditya
Alleviating the Magnetic Effects on Magnetometers Using Vehicle Kinematics for Yaw Estimation for Autonomous Ground Vehicles2020-01-102504/14/2020
Autonomous vehicle operation is dependent upon accurate position estimation and thus a major concern of implementing the autonomous navigation is obtaining robust and accurate data from sensors. This is especially true, in case of Inertial Measurement Unit (IMU) sensor data. The IMU consists of a 3-axis gyro, 3-axis accelerometer, and 3-axis magnetometer. The IMU provides vehicle orientation in 3D space in terms of yaw, roll and pitch. Out of which, yaw is a major parameter to control the ground vehicle’s lateral position during navigation. The accelerometer is responsible for attitude (roll-pitch) estimates and magnetometer is responsible for yaw estimates. However, the magnetometer is prone to environmental magnetic disturbances which induce errors in the measurement. The present work focuses on alleviating magnetic disturbances for ground vehicles by fusing the vehicle kinematics information with IMU senor in an Extended Kalman filter (EKF) with the vehicle orientation represented
Dudekula, Ahammad Basha, Naber, Jeffrey D.
Numerical Simulation of Aircraft and Variable-Pitch Propeller Icing with Explicit Coupling2019-01-195406/10/2019
A 3D CFD methodology is presented to simulate ice build-up on propeller blades exposed to known icing conditions in flight, with automatic blade pitch variation at constant RPM to maintain the desired thrust. One blade of a six-blade propeller and a 70-passenger twin-engine turboprop are analyzed as stand-alone components in a multi-shot quasi-steady icing simulation. The thrust that must be generated by the propellers is obtained from the drag computed on the aircraft. The flight conditions are typical for a 70-passenger twin-engine turboprop in a holding pattern in Appendix C icing conditions: 190 kts at an altitude of 6,000 ft. The rotation rate remains constant at 850 rpm, a typical operating condition for this flight envelope. Two icing conditions are simulated: air static temperature -23 °C, LWC 0.2 g/m3 and MVD 20 microns resulting in rime ice, and air static temperature -16 °C, LWC 0.3 g/m3 and MVD 20 microns resulting in mixed ice with rime to glaze transition in the radial
Ozcer, Isik, Baruzzi, Guido S., Desai, Miraj, Yassin, Maged
Experimental Aerodynamic Simulation of Glaze Ice Accretion on a Swept Wing2019-01-198706/10/2019
Aerodynamic assessment of icing effects on swept wings is an important component of a larger effort to improve three-dimensional icing simulation capabilities. An understanding of ice-shape geometric fidelity and Reynolds and Mach number effects on iced-wing aerodynamics is needed to guide the development and validation of ice-accretion simulation tools. To this end, wind-tunnel testing was carried out for 8.9% and 13.3% scale semispan wing models based upon the Common Research Model airplane configuration. Various levels of geometric fidelity of an artificial ice shape representing a realistic glaze-ice accretion on a swept wing were investigated. The highest fidelity artificial ice shape reproduced all of the three-dimensional features associated with the glaze ice accretion. The lowest fidelity artificial ice shapes were simple, spanwise-varying horn ice geometries intended to represent the maximum ice thickness on the wing upper surface. The results presented in this paper show
Broeren, Andy P., Potapczuk, Mark G., Lee, Sam, Woodard, Brian S., Bragg, Michael B., Smith, Timothy G.
Sound Analysis Method for Warble Noise in Electric Actuators2019-01-152106/05/2019
Multiple automotive applications exist for small electric motors that are activated by vehicle occupants for various functions such as window lifts and seat adjusters. For such a motor to be described as high quality, not only should the sound it produces be low in amplitude, but it also needs to be free from pulsations and variations that might occur during its (otherwise) steady-state operation. If a motor’s sound contains pulsations or variations between 2 and 8 cycles per second, the variation is described as warble. To establish performance targets for warble noise at both the vehicle and component level a way to measure and quantify the warble noise must be established. Building on existing sound quality metrics such as loudness and pitch variation, a method is established by which processed sound data is put through a secondary operation of Fourier analysis. Thus warble can be reduced to a single value, and in this way, noise engineers have a basis to measure and report warble
Parker, Nathan T.
An Analysis of Sport Bike Motorcycle Dynamics during Front Wheel Over-Braking2019-01-042604/02/2019
There is extensive literature on motorcycle skid/brake to stop testing on a host of motorcycle types, rider experience, brake system configurations and the associated deceleration rates. Very little information exists on deceleration rates involved with over-braking the front wheel. The subject of this paper addresses the deceleration rates of sport bike type motorcycles during over-braking of the front wheel. Based on the physics of a two-wheeled vehicle like the motorcycle, once the front wheel is over-braked and becomes locked, the rider has very little time to recover from the skid and often times falls. Another over-braking scenario, especially on sport bike type motorcycles, is the possibility of the rear wheel lifting and pitching over the front wheel. During the initial phase of braking, weight transfer to the front wheel occurs creating a greater level of traction. As the motorcycle begins to fall or pitch over, the weight on the front wheel decreases significantly and
Fatzinger, Edward, Landerville, Jon, Bonsall, Jeffrey, Simacek, Daniel
Bolts, Screws, and Studs, Geometric Control RequirementsAS3063C (Current)02/26/2019
This SAE Aerospace Standard (AS) establishes the geometric control requirements for bolts, screws, and studs where worded notes and symbolized notes are used for straightness, concentricity, squareness, and runout.
E-25 General Standards for Aerospace and Propulsion Systems
Bolts, Screws, and Studs, Screw Thread RequirementsAS3062D (Current)02/13/2019
E-25 General Standards for Aerospace and Propulsion Systems
Development of the Anti-Lift-Control for Motorcycle2018-32-007610/30/2018
In motorcycle market, there is demand for technology that makes it possible to drive fast safely. One such technology has already been commercialized; control that prevents front lift while enabling maximum acceleration performance. We have developed a more accurate version of this control. In order to maximize acceleration performance, it is necessary to keep front lift angle as close to zero as possible. Reducing output driving force helps to keep the front lift angle low, but if output driving force is reduced too much, it will degrade acceleration performance. Feedback control that reduces output driving force when front lift is detected is effective for optimizing this trade off, but increasing feedback gain too much to reduce front lift angle will cause output driving force to change suddenly, making for a less comfortable ride. In order to solve this problem, we introduced feedforward control that estimates the equilibrium between power and front lift and restricts output
Mase, Taiki, Suzuki, Takashi
Angular Velocity Perception Threshold and Sense of Presence for a Three Degrees of Freedom (DOF) Driving Simulator in Virtual Environment2018-01-504310/22/2018
Angular velocity perception plays an important role for a better sense of presence in driving simulators. This paper deals with the angular velocity perception threshold and sense of presence. A three degrees of freedom (DOF: roll, pitch, and heave) driving simulator, a motion tracking sensor, a driving simulation software, and self-prepared questionnaires were used. Due to the subjective assessments, there were no significant differences between static and dynamic platform types. Eight different cases were investigated with respect to visual and inertial factors (field of view (FOV) and motion platform). Subjective evaluations showed that there were no significant differences between static and dynamic conditions. Lower FOV, static platform, stereo vision condition has provided the best condition (best realism depending on objective-subjective measure relationship).
Aykent, Baris, Chardonnet, Jean-Remy, Merienne, Frederic, Kemeny, Andras
Aerospace - Passive Side Stick Unit General Requirements for Fly by Wire Transport and BusinessARP6001A (Historical)10/04/2018
This SAE Aerospace Recommended Practice (ARP) provides general requirements for a generic “passive” side stick that could be used for fly by wire transport and business aircraft. It addresses the following: The functions to be implemented The geometric and mechanical characteristics The mechanical and electrical interfaces The safety and certification requirements
A-6A3 Flight Control and Vehicle Management Systems Cmt
Undercuts for Straight Screw Threads - MetricMA1508 (Current)08/23/2018
This SAE Aerospace Standard (MA) provides recommended dimensional data for screw thread undercuts for straight “MJ” metric screw threads in accordance with MA1370.
E-25 General Standards for Aerospace and Propulsion Systems
Bolts, Screws and Studs, Screw Thread RequirementsAS3062C (Historical)08/23/2018
E-25 General Standards for Aerospace and Propulsion Systems
DRIVE – TYPE XX ENGINE ACCESSORY - DESIGN STANDARD FORAS20010A (Current)07/16/2018
E-25 General Standards for Aerospace and Propulsion Systems
Aerodynamics of Open Wheel Racing Car in Pitching Position2018-01-072904/03/2018
Formula One (F1) racing cars are often running at high-speed with the pitching angle changing frequently due to road conditions. These pitching angle changes result in changes to the car’s aerodynamic characteristics that will directly affect handling stability and other performance factors including safety. This paper takes a F1 racing car as the model; the influence of the change of pitching angle on aerodynamic drag force and lift force are investigated. CFD code-PowerFLOW based LBM is used to simulate the aerodynamic characteristics with different pitching angles. The distribution of aerodynamic coefficients, velocity and pressure in the flow field are obtained; and the differences between different pitching angles were analyzed. The results show that as the pitching angle increases, the drag force increases and the lift force decreases. The down-force of the car is mainly supplied by the front wing and the rear wing. As the pitching angle increases, the lift force provided by the
Zhang, Yingchao, Yang, Chao, Wang, Qiliang, Zhan, Dapeng, Zhang, Zhe
Multi-Objective Optimization to Improve SUV Ride Performances Using MSC.ADAMS and Mode Frontier2018-01-057504/03/2018
Ride is an important attribute which must be accounted in the passenger segment vehicles. Excessive H point acceleration, Steering wheel acceleration, Pitch acceleration can reduce the comfort of the driver and the passengers during high frequency and low frequency rough road events. Excessive Understeer gradient, roll gradient, roll acceleration and Sprung mass lift could affect the Vehicle driver interaction during Steady state cornering, Braking and Step steer events. The concept architecture of the vehicle plays an important role in how comfort the vehicle will be. This paper discusses how to improve SUV ride performances by keeping handling performance attributes same or better than base vehicle. Multi Objective Optimization was carried out by keeping spring, bushing and damper characteristic as the design variables to avoid new system or component development time and cost. The first step in this process is DOE (Design of Experiments method) which allows to select critical or
Lenka, Visweswara Rao, Anthonysamy, Baskar, Londhe, Abhijit, Hatekar, Harshad
Simulation Research of a Hydraulic Interconnected Suspension Based on a Hydraulic Energy Regenerative Shock Absorber2018-01-058204/03/2018
The current paper proposes a hydraulic interconnected suspension system (HIS) based on a hydraulic energy-regenerative shock absorber (HESA) comparatively with the passive suspensions. The structure and working principles of the HIS system are introduced in order to investigate the damping performance and energy regeneration characteristics of the proposed system. Then, the dynamic characteristics of the HIS-HESA system have been investigated based on a 4-DOF longitudinal half vehicle model. In the simulation, two different road inputs were used in the dynamic characterization of the HIS-HESA; the warp sinusoidal excitation, and the random road signal. In addition, a comparative analysis was provided for the dynamic responses of the half vehicle model for both the HIS-HESA and the conventional suspension. Furthermore, a parametric analysis of the HIS-HESA has been carried out highlining the key parameters that have a remarkable effect on the HIS-HESA performance. The dynamic
Zou, Junyi, Guo, Xuexun, Xu, Lin, Abdelkareem, Mohamed A. A., Gong, Bian, Zhang, Jie, Tan, Gangfeng
Screw Thread Form, American National, Modified (National Round - NR)AS82C (Current)01/29/2018
This SAE Aerospace Standard (AS) defines an external thread with a rounded root radius based on a minimum root radius of .108 × Pitch.
E-25 General Standards for Aerospace and Propulsion Systems
New Quantum Computing Design Based on “Flip-Flop” QubitsTBMG-2815401/01/2018
Engineers have invented a new architecture for quantum computing based on novel “flip-flop” qubits. The new chip design allows for a silicon quantum processor that can be scaled up without the precise placement of atoms required in other approaches. It allows quantum bits (qubits) — the basic unit of information in a quantum computer — to be placed hundreds of nanometers apart and still remain coupled.
Nano-Motion Stages Rely on High-Precision Encoders for Accuracy and RepeatabilityTBMG-2773710/01/2017
ALIO Industries designs and builds very high precision automation stages for nano-level manufacturing and research applications, including microlithography, medical devices, and micro-machine tools. In this world where a misalignment of one micron might as well be one meter, Renishaw encoders have played a vital role in the performance of ALIO's True Nano™ and 6-D Nano Precision™ motion systems (Figure 1).
Calibration and Synchronization of Micro-Air-Vehicle AutopilotsTBMG-2718607/01/2017
Conventional calibration of an inertial measurement unit (IMU) through open-loop data collection includes typical flight simulator systems that provide processed stimuli to emulate real-life flight conditions. Other solutions involve testing inertial measurement devices on a multi-axis rate table using a processor internal to the inertial measurement devices, and transferring the signals directly to the processors for determining and storing the calibration coefficients of the inertial measurement devices internally so that they are self-calibrating. Unfortunately, conventional solutions typically involve evaluating control algorithms in a computer simulation before experimentation in the aircraft occurs. This can result in unstable flight during the first few cycles that could lead to failure of the aircraft.
Torsional Vibration Analysis of Six Speed MT Transmission and Driveline from Road to Lab2017-01-184506/05/2017
When a manual transmission (MT) powertrain is subjected to high speeds and high torques, the vehicle driveshaft, and other components experience an increase in stored potential energy. When the engine and driveshaft are decoupled during an up or down shift, the potential energy is released causing clunk during the shift event. The customer desires a smooth shift thus reduction of clunk will improve experience and satisfaction. In this study, a six-speed MT, rear-wheel-drive (RWD) passenger vehicle was used to experimentally capture acoustic and vibration data during the clunk event. To replicate the in-situ results, additional data was collected and analyzed for powertrain component roll and pitch. A lumped parameter model of key powertrain components was created to replicate the clunk event and correlate with test data. The lumped parameter model was used to modify clutch tip-out parameters, which resulted in reduced prop shaft oscillations. By reducing the prop shaft oscillations the
Furlich, Jon, Blough, Jason, Robinette, Darrell
Experimental and Numerical Investigations on Control Methods of Cavity Tone by Blowing Jet in an Upstream Boundary Layer2017-01-178606/05/2017
The objective of this paper is to clarify the mechanism for the reduction of cavity tone with blowing jets aligned in the spanwise direction in the upstream boundary layer. Also, the effects of spacing of the jets on the reduction are focused. To achieve these objectives, direct aeroacoustic simulations were conducted along with wind tunnel experiments. The depth-to-length ratio of cavity was D/L = 0.5. The incoming boundary layer was laminar, where the boundary layer thickness was δ/L = 0.055. The predicted flow fields without control show that two-dimensional large-scale vortices are shed and become acoustic sources in the cavity. The effects of spanwise spacing of spanwise-aligned jets on the cavity flow and tone were clarified with computations and experiments with the different pitches of s/L = 0.1 - 1.0 (s/δ = 1.8-18.2). As a result, the largest reduction level was obtained for s/L = 0.5. For this control condition, the predicted results show that longitudinal vortices are
Yokoyama, Hiroshi, Adachi, Ryo, Minato, Taiki, Iida, Akiyoshi
New Hybrid Genetic Algorithm for Pitch Sequence Optimization of CVT Variator Chain2017-01-112003/28/2017
A CVT variator chain system is superior in transmission efficiency to a belt system because of its lower internal friction. However, a chain produces more noise than a belt due to the long pitch length of contact between the pulleys and rocker pins. This study focuses on optimization of the pitch sequence for reducing chain noise. The previous pitch sequence was suitably combined of links of different lengths to improve noise dispersibility for reducing chain noise. First, the object function was defined as the reduction of the peak level of 1st-order chain noise combined with a well-balanced the levels on the low and high frequency sides. Interior background noise consisting of road noise and wind noise have the characteristic that they increase as the frequency decreases. Therefore, the object function was aimed at reducing the peak level of 1st-order chain noise by shifting the chain noise energy from the vicinity of the 1st-order band to the low frequency side in consideration of
Miyauchi, Arata, Tsutsumi, Kenji, Miura, Yoshitaka, Kageyama, Yusuke
Effect of Force Vectoring Spring implementation into a Twistbeam Rear Suspension2017-01-157303/28/2017
A twistbeam is a very cost effective rear suspension architecture which has drawbacks compared to an independent rear suspension. One drawback is the lateral compliance during cornering compromising the handling of the vehicle. Common solutions to correct this issue are complex reinforcements or an additional Watts linkage. However, these solutions drive high cost and additional weight. The challenge was to find a solution which reduces the gap to the functional performance of a multilink rear suspension. Due to the bush attachment, the set-up of a twistbeam is always a compromise between ride comfort and vehicle dynamics. The more comfort is desired the softer the bushings will be, resulting in less agility and slower vehicle response. The target was to determine a way to separate ride comfort and dynamic agility. A solution was found using a special set of springs working as a dynamic anti-compliance mechanism. The so-called force vectoring springs are designed in a way, that they
Carlitz, Andreas, Allibert, Sebastien, Schmitz, Thomas, Engels, Axel
Steady State Handling Performance Study & Optimization of Tractor-Semitrailers2017-26-033801/10/2017
Tractor-semitrailers make up large proportion of heavy commercial vehicles, handling stability of tractor-semitrailers is critical to driving safety. Handling behavior of Tractor-semitrailers is complex and depends on various parameters. This paper presents a mathematical approach & multi body dynamics (MBD) simulation based study to gain an insight as to, how changes to different parameters of the articulated vehicle affect it’s handling behavior and thus to obtain an optimized design in terms of vehicle handling. A Full vehicle multi body dynamic model is created and steady state cornering maneuvers are performed on simulation tool MSC ADAMS/View for calculating understeer gradient using constant radius test method. Various parameters affecting understeer gradient are identified, studied and their relative effect on understeer gradient is measured. These critical parameters were then optimized using MSC ADAMS/View tool to achieve the desired handling targets. This process, thus
Sonawane, Harish, Paliwal, Gaurav, Jain, Swejal, Gupta, Umashanker
Hover Testing of a Large Multi-Element Arc Wing VTOL Research Model2016-01-197909/20/2016
Technology to create a VTOL for general aviation that is fast, efficient, easy to fly, and affordable, has proven elusive. Bertelsen Design LLC has built a large research model to investigate the potential of the arc wing VTOL to fulfill these attributes. The aircraft that is the subject of this paper weighs approximately 145 kg (320 lbs) and features coaxial, dual-rotating propellers, diameter 1.91 m (75 inches). Power is from an MZ 202 two-cycle, two-cylinder engine. Wingspan is 1.82 m (72 inches). The arc wing differentiates this aircraft from previous deflected-slipstream prototypes, which suffered from pitch-trim issues during transition. This paper will present configuration details of the Bertelsen model, showing how it is possible to generate high lift from a short-span wing system. The Bertelsen model can hover out of ground effect using just two arc-wing elements: a main wing and a “slat”. More importantly, the paper will show that the mechanics are in place to accomplish
Bertelsen, William D.
Elimination of Yaw Component of Gyroscope Propagation Error During Arm Activity in MSLTBMG-2532409/01/2016
When updating attitude during arm motion, gyroscope propagation error soon becomes greater than the tilt being monitored. The solution is to add an accelerometer-only mode that can update attitude without using gyroscopes, and to add the ability to monitor pitch and roll separately. Accelerometer-only mode is used only when it is safe to assume that any vehicle shifting in yaw would also be accompanied by shifting in pitch and/or roll. For surface contact operations, it is important to monitor change in tilt of the vehicle resulting from arm motion.
Behavior of Adhesively Bonded Steel Double Hat-Section Components under Axial Quasi-Static and Impact Loading2016-01-039504/05/2016
An attractive strategy for joining metallic as well as non-metallic substrates through adhesive bonding. This technique of joining also offers the functionality for joining dissimilar materials. However, doubts are often expressed on the ability of such joints to perform on par with other mechanical fastening methodologies such as welding, riveting, etc. In the current study, adhesively-bonded single lap shear (SLS), double lap shear (DLS) and T-peel joints are studied initially under quasi-static loading using substrates made of a grade of mild steel and an epoxy-based adhesive of a renowned make (Huntsman). Additionally, single lap shear joints comprised of a single spot weld are tested under quasi-static loading. The shear strengths of adhesively-bonded SLS joints and spot-welded SLS joints are found to be similar. An important consideration in the deployment of adhesively bonded joints in automotive body structures would be the performance of such joints under impact loading. Due
Deb, Anindya, Chou, Clifford C., Srinivas, Gunti R., Gowda, Sanketh, Kurnool, Goutham
Development of Fracture Model for Laser Screw Welding2016-01-134404/05/2016
This paper describes the development of a fracture finite element (FE) model for laser screw welding (LSW) and validation of the model with experimental results. LSW was developed and introduced to production vehicles by Toyota Motor Corporation in 2013. LSW offers superb advantages such as increased productivity and short pitch welding. Although the authors had previously developed fracture FE models for conventional resistance spot welding (RSW), a fracture model for LSW has not been developed. To develop this fracture model, many comprehensive experiments were conducted. The results revealed that LSW had twice as many variations in fracture modes compared to RSW. Moreover, fracture mode bifurcations were also found to result from differences in clearance between welded plates. In order to analyze LSW fracture phenomena, detailed FE models using fine hexahedral elements were developed. The analytical results revealed that the fracture modes were determined not only by equivalent
Kumagai, Koushi, Kuwahara, Masaaki, Yasuki, Tsuyoshi, Koreishi, Norimasa
Study of Unsteady Aerodynamics of a Car Model in Dynamic Pitching Motion2016-01-160904/05/2016
The unsteady aerodynamic loads produced due to vehicle dynamic motions affect vehicle dynamic performance attributes such as straight-line stability or handling characteristics. To improve these dynamic performances, understanding the detailed mechanisms by which unsteady aerodynamic loads are caused during dynamic motions and the effects of unsteady aerodynamic loads on vehicle dynamic performance are needed. This paper describes the numerical study of unsteady aerodynamics of a 1/4 scale car model in dynamic pitching motion to clarify the detailed mechanisms by which unsteady aerodynamic loads are caused during the motion. Vortical structures around front wheelhouse and front under side of the body are analyzed by introducing schematic views to understand the mechanisms of unsteady flow fields. Furthermore, effects of aerodynamic devices devised based on the analyses on unsteady aerodynamics are discussed. Large-Eddy simulation with ALE method was conducted to analyze the transient
Nakae, Yusuke, Yamamura, Jun, Tanaka, Hiroshi, Yasuki, Tsuyoshi
Deployable Perimeter Truss with Blade Reel Deployment MechanismTBMG-2409803/01/2016
Solar sail technology depends heavily on the total surface area of the sail. In other words, minimizing mass and volume of its support structure is the main objective, particularly when it comes to launch configuration, i.e. mass, volume constraints, etc. There is a need to develop a low-cost concept of a deployable support structure that can stow in the EELV Secondary Payload Adapter (ESPA) volume, and carries as much sail material as possible. This structure must then be able to deploy the sail material out, and provide the surface area needed.
AS231-245 B.S.4 Chain (1/2" Pitch) and Fittings Assembly CodeAS231-7 (Current)12/04/2015
No scope available.
Engine and Airframe Technical Standards Committee (TSC)
AS200-209 B.SI. Chain (8mm Pitch) and Fittings Assembly CodeAS200-9 (Current)12/04/2015
No scope available.
Engine and Airframe Technical Standards Committee (TSC)
Algorithm for Determining Solar Aspect from Images Generated by the HEROES MissionTBMG-2327311/01/2015
The goal of the High Energy Replicated Optics to Explore the Sun (HEROES) mission was to adapt an existing balloon payload, known as High Energy Replicated Optics (HERO), for solar observation. HERO used an on-axis star camera for fine aspect sensing, but this camera was too sensitive to be used when pointed near or toward the Sun. The pitch and yaw aspect system (PYAS) replaced the star camera during solar pointing. The PYAS used a computer vision algorithm to generate aspect solutions based on observations of a carefully constructed scene.
Suspension and Mass Parameter Measurements of Wheeled Vehicles2015-01-275109/29/2015
The United States Army Tank Automotive Research, Development and Engineering Center (TARDEC) built systems to measure the suspension parameters, center of gravity, and moments of inertia of wheeled vehicles. This is part of an ongoing effort to model and predict vehicle dynamic behavior. The new machines, the Suspension Parameter Identification and Evaluation Rig (SPIdER) and the Vehicle Inertia Parameter Evaluation Rig (VIPER), have sufficient capacity to cover most heavy, wheeled vehicles. The SPIdER operates by holding the vehicle sprung mass nominally fixed while hydraulic cylinders move an “axle frame” in bounce or roll under each axle being tested. Up to two axles may be tested at once. Vertical forces at the tires, displacements of the wheel centers in three dimensions, and steer and camber angles are measured. Contact patch can move in lateral, longitudinal and steer motions of the suspension and the small deflections of the vehicle sprung mass resulting from the contact patch
Baseski, Igor, Norman, Kenneth, Ryan, David, Stahara, Stefanie
New Unconventional Airship Concept by Morphing the Lenticular Shape2015-01-257709/15/2015
The aim of this paper is to develop a new concept of unconventional airship based on morphing a lenticular shape while preserving the volumetric dimension. Lenticular shape is known to have relatively poor aerodynamic characteristics. It is also well known to have poor static and dynamic stability after the certain critical speed. The new shape presented in this paper is obtained by extending one and reducing the other direction of the original lenticular shape. The volume is kept constant through the morphing process. To improve the airship performance, four steps of morphing, starting from the lenticular shape, were obtained and compared in terms of aerodynamic characteristics, including drag, lift and pitching moment, and stability characteristics for two different operational scenarios. The comparison of the stability was carried out based on necessary deflection angle of the part of tail surface. The comparison results indicated that new shape concept possesses much better
Ceruti, Alessandro, Marzocca, Piergiovanni, Voloshin, Vitaly
Study on Fluidic Thrust Vectoring Techniques for Application in V/STOL Aircrafts2015-01-242309/15/2015
The art and science of thrust vectoring technology has seen a gradual shift towards fluidic thrust vectoring techniques owing to the potential they have to greatly influence the aircraft propulsion systems. The prime motive of developing a fluidic thrust vectoring system has been to reduce the weight of the mechanical thrust vectoring system and to further simplify the configuration. Aircrafts using vectored thrust rely to a lesser extent on aerodynamic control surfaces such as ailerons or elevator to perform various maneuvers and turns than conventional-engine aircrafts and thus have a greater advantage in combat situations. Fluidic thrust vectoring systems manipulate the primary exhaust flow with a secondary air stream which is typically bled from the engine compressor or fan. This causes the compressor operating curve to shift from the optimum condition, allowing the optimization of engine performance. These systems make both pitch and yaw vectoring possible. This paper elucidates
Jain, Samarth, Roy, Soumya, Gupta, Dhruv, Kumar, Vasu, Kumar, Naveen
Pipe Threads, Taper, Aeronautical National Form, Symbol ANPT - Design and Inspection StandardAS71051B (Current)07/27/2015
This document establishes the requirements for Aeronautical National Form (ANPT) pipe threads, gages, and gaging methods for determining conformity of aeronautical taper pipe threads to this standard.
G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies
Pipe Threads, Taper, Aeronautical National Form, Symbol ANPT - Design and Inspection StandardAS71051B-TEST-REC (Historical)07/27/2015
This document establishes the requirements for Aeronautical National Form (ANPT) pipe threads, gages, and gaging methods for determining conformity of aeronautical taper pipe threads to this standard.
G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies
Lattice-Boltzmann Analysis of Three-Dimensional Ice Shapes on a NACA 23012 Airfoil2015-01-208406/15/2015
A Lattice-Boltzmann approach is used to simulate the aerodynamics of complex three-dimensional ice shapes on a NACA 23012 airfoil. The digitally produced high fidelity geometrical ice shapes were created using a novel laser scanning technique in the NASA Icing Research Tunnel. The geometrically fully resolved unsteady simulations are conducted on two ice shapes representing a roughness type and a horn type icing on the leading edge of the airfoil. Comparisons between simulation and experiment of lift, drag, and pitching moment as well as pressure distributions indicate overall a good qualitative agreement in capturing the aerodynamic degradation. Especially for the horn-type ice shape, the quantitative agreement is also mostly very good. Analysis of the flow structures indicates furthermore a good capturing of the three-dimensional separation behavior of the flow.
König, Benedikt, Fares, Ehab, Broeren, Andy P.
Objective Evaluation of Hold Feeling for Passenger Car Seats2015-01-227106/15/2015
Modern automotive seats require improvements in their design, safety, comfort including sitting and riding comfort. Among those, seat comfort is known to be difficult to evaluate because the comfort is a human feeling. As an approach to evaluate the human comfort in an objective manner, an objective measure is proposed for seat riding comfort evaluation under low frequency vibratory conditions which represents typical roll and pitch motions of driving motor vehicles. The related feeling due to this low frequency vehicle motion is termed ‘hold feeling’ because the seated body may tend to deviate from the defined seating position under such vehicle motion input. Dynamic pressure measurements have been conducted in the frequency range up to 1.0 Hz to monitor the interface pressure change behavior of the seat-subject body. Temporal changes in body pressure in terms of the magnitude and the representative locations, and the time delay in pressure change at different segments of the seat are
Jun, Yong Du, Park, Bong Hyun, Seo, Kang Seok, Kim, Tae Hyun, Chae, Myoung Jae
Study of Stick-Slip Friction between Plunging Driveline2015-01-217106/15/2015
Driveline plunge mechanism dynamics has a significant contribution to the driver's perceivable transient NVH error states and to the transmission shift quality. As it accounts for the pitch or roll movements of the front powerplant and rear drive unit, the plunging joints exhibit resisting force in the fore-aft direction under various driveline torque levels. This paper tackles the difficult task of quantifying the coefficient of static friction and the coefficient of dynamic friction in a simple to use metric as it performs in the vehicle. The comparison of the dynamic friction to the static friction allows for the detection of the occurrence of stick-slip in the slip mechanism; which enables for immediate determination of the performance of the design parameters such as spline geometry, mating parts fit and finish, and lubrication. It also provides a simple format to compare a variety of designs available to the automotive design engineer.
Spencer, Winston, Bouzit, Djamel, Pace, Joseph, Dhillon, Sudeep
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