Browse Topic: Body-on-frame

Items (29)

Simplified Approach for Optimizing Lightening Holes in Truck Frames for Durability Performance

2017-01-13453/28/2017

During development of new vehicles, CAE driven optimizations are helpful in achieving the optimal designs. In the early phase of vehicle development there is an opportunity to explore shape changes, gage reduction or alternative materials as enablers to reduce weight. However, in later phases of vehicle development the window of opportunity closes on most of the enablers discussed above. The paper discusses a simplified methodology for reducing the weight in design cycle for truck frames using parametric Design of Experiments (DOE). In body-on-frame vehicles, reducing the weight of the frame in the design cycle without down gaging involves introducing lightening holes or cutouts while still maintaining the fatigue life. It is also known that the lightening holes might cause stress risers and be detrimental to the fatigue life of the component. Thus the ability to identify cutout locations while maintaining the durability performance becomes very critical. This paper describes a method of effectively locating these lightening holes on the truck frame, thereby reducing the weight of the vehicle while preserving the durability performance. The process to incorporate these lightening holes is a multi-step approach beginning with a stress envelope creation. The load paths for each component are identified based on the stress envelops generated in the fatigue code using a complete set of proving ground loading events. A subsequent step includes tuning those lightening holes to meet the durability, strength and stiffness requirements via the automated process of resizing the lightening holes to their optimal sizes. The final verification is carried out with the regular analysis procedure to verify the lightening holes effect on the durability performance of the structure.

bhat, Ramachandra, Sharma, Nitin, Rivard, Clifford, Thomson, Kevin

Medium Duty North American Delivery Van Frontal Barrier Crash Test Data for Crash Reconstruction

2015-01-14204/14/2015

Traditional accident reconstruction analysis methodologies include the study of the crush-energy relationship of vehicles. By analyzing the measured crush from a vehicle involved in a real world accident and comparing it to a test vehicle with a known energy, from a crash test, the real world vehicle's damage energy can be evaluated. In addition, the change-in-velocity (Delta-V) can be calculated. The largest source of publicly available crash tests is from the National Highway Traffic Safety Administration (NHTSA). NHTSA conducts numerous Federal Motor Vehicle Safety Standard (FMVSS) compliance and New Car Assessment Program (NCAP) testing for many passenger vehicles for sale in the United States. The NHTSA crash test data is available for analysis, but the data set is limited to production vehicles that are manufactured in significant quantities and it contains virtually no data relating to medium-to-heavy duty vehicles To date, there are no publically available controlled, full-scale, instrumented crash tests of any medium-duty, body-on-frame, delivery vans currently operating on North American roads. Accordingly, this series of full-scale crash tests of two medium-duty, body-on-frame, local vans will provide a basis for the analysis of the crush-energy relationship of these vehicles. This testing will also provide a basis for the study of the occupant kinematics experienced during these tests.

Steiner, John C., Olsen, John, Walli, Tom, Kress, Tyler, Armstrong, Christopher, Gallagher, Ralph, Husher, Stein, Kyes, John

Road Noise Identification and Reduction Measures

2013-01-19175/13/2013

In a scenario where cost and weight targets are becoming critical, we tend to produce lighter and more powerful vehicles. In this context, NVH becomes one of crucial parameters in overall performance delivery. Other than power train, road induced noise also becomes an important parameter within vehicle development. Predecessor vehicle is body over frame structure and here a monocoque vehicle is considered for study. Different techniques like transfer path analysis, vibro-acoustic modal analysis, operational deflection shapes are used to identify the major force paths, radiating panels and their sensitivity to noise at operator ear location. Simulation model of body is built with good correlation and input forces are given at different attachment points to predict the noise levels. This combined approach helped us in reducing the overall noise level at certain constant speed by 4 dB(A) and also with great ease. All recommendations from this exercise are implemented

Rao, Manchi Venkateswara, R., Prasath, Patil, Sanjeev, Mansinh, Kumbhar S.

Test Set-Up of BIW (Body in White) Stiffness Measurements

2013-01-14394/8/2013

It is repeatedly proved that any minor change in the parameters involved in the test set up of BIW Bending and Torsion Stiffness evaluation changes the final test results significantly. The primary aim of the Physical Stiffness Tests, in the development stage of an Automotive Body is to ensure CAE co-relation. The setup for the physical test must therefore be designed such that the constraints match exactly with the ones in CAE. This will avoid any issues of correlating the test conditions. Any deviations in the test results between the two can then be studied separately. At first, this paper analytically deals with the mounting points that should be used on the various vehicle body types based on the different types of suspensions they employ. Based on the theoretical conditions, a practical test set-up has been derived for testing the Bending Stiffness and the Torsion Stiffness separately. The paper mainly deals with the various degrees of freedom that either need to be constrained or kept free to maintain appropriate load paths during the test. Guidelines to ensure correct fixture designs for the front as well as the rear mounting points are also included.

Khanse, Karan R., Pathak, Shekhar P

Modeling Costs and Fuel Economy Benefits of Lightweighting Vehicle Closure Panels

2008-01-03704/14/2008

This paper illustrates a methodology in which complete material-manufacturing process cases for closure panels, reinforcements, and assembly are modeled and compared in order to identify the preferred option for a lightweight closure design. First, process-based cost models are used to predict the cost of lightweighting the closure set of a sample midsized sports utility vehicle (SUV) via material and process substitution. Weight savings are then analyzed using a powertrain simulation to understand the impact of lightweighting on fuel economy. The results are evaluated in the context of production volume and total mass change.

Montalbo, Trisha, Roth, Richard, Kirchain, Randolph, Lee, Theresa M.

Beamforming System Eases Crowded Wireless Spectrum

TBMG-59623/1/2007

Beamforming is critical to enable initiatives by the U.S. Federal Communications Commission (FCC) to increase spectrum capacity and provide additional cellular service and coverage through satellite and terrestrial systems. The key technology for this application is beamforming, which electronically steers data streams to and from a satellite via a combination of an array of antennas on the satellite and very sophisticated, ground-based computational engines.

Material Modeling and Finite Element Analysis of Hydroform - Short Glass Fiber Filled Thermoplastic Front-End Structures

2006-01-08244/3/2006

Increasing use of engineering thermoplastics in the applications such as load bearing automotive components necessitates accurate characterization and material modeling for predicting part performance using finite-element simulations. Uniaxial tensile test data on glass filled thermoplastic resins exhibit highly nonlinear deformation with no clear demarcation between elastic and plastic regions. Hence, the estimation of modulus and yield stress values, required for the finite element analysis, is invariably through the subjective interpretation of the CAE analyst, which may not be consistent and unique. Use of parameters such as tangent modulus, yield stress and the post yield data calculated at 0.2% strain for finite element computations does not yield good correlations with experimental values. This paper outlines an alternate approach for evaluating material parameters for short glass filled engineering thermoplastics. The proposed approach had been applied to automotive hybrid front-end structures. This hybrid Hydroform - Plastic Structure (HPS) is a Pressure Sequenced Hydroform (PSH) tube over-molded to an injection molded engineering thermoplastic (ETP) panel. The plastic material used here is a Polyphenylene Ether / Polyamide alloy with 30 % short glass (PPO / PA / 30 % GF) reinforcement. The finite-element formulation took the plastic-steel interactions of hybrid structures into account. Results of the proposed approach validated through the experimental tests on the front-end structure are presented and discussed.

Maity, Rajkumar, Prasad, PS, Goral, Thomas

Effect of Trigger Variation on Frontal Rail Crash Performance

2005-01-03584/11/2005

The frontal rail is one of the most important components of a vehicle in determining crash performance, especially for a body on frame vehicle. Prior research [1] has shown that the frontal rail absorbs a significant amount of impact energy in a crash condition. In order to optimize crash performance, a component level sensitivity study was conducted to determine the effect different types of triggers would have on the performance of the frontal rail. The objective of this study is to determine the sensitivity of trigger size, trigger shape, and trigger orientation as well as to improve corresponding trigger modeling methodology by comparing crushed components to crushed CAE models. In this sensitivity study, the location of the triggers was held fixed, while the size, shape, and orientation were varied. The metric that will be used to compare the performance of these different trigger shapes is the overall stiffness of the frontal rail. This sensitivity study indicates that the trigger size has a more significant effect on the crush performance of a frontal rail than those of the trigger shape and trigger orientation. Of the trigger shapes studied, further analysis of Square #1 is recommended. A comparison of CAE simulations to component level tests show that by following a step-by-step process, one can achieve a good correlation.

Casselle, Omowale, Tyan, Tau

Automotive Front End Structures Constructed by Over Molding Hydroform Metal Tubes to Engineering Thermoplastic Structures

2005-01-16804/11/2005

This paper presents a new type of engineered structure that combines a pressure sequenced hydroform (PSH) tube over molded to an injection molded engineering thermoplastic (ETP) panel. A unique attachment feature is formed during the molding process. This eliminates separate mechanical fasteners that would otherwise be necessary to connect the tube to the plastic panel. This paper takes the reader through the process that was used to bring about a Hydroform – Plastic Structure (HPS). From the initial brainstorming approaches through the validation testing, each step will show how this technology was developed. Details accompany each step to illustrate the finer points of the application development with this structure. The application under investigation is an automotive front-end module. The front-end module serves as a structural member and vehicle hardware integrator at the front of the engine compartment.

Goral, Thomas, Prasad, P. S., Brown, Mitch, Panter, Keith, Klages, Jerry, Longhouse, Blair

Automotive Engineering International 2004-11-01

AUTONOV0411/1/2004

2004 Paris Motor Show Highlights Though themes were distinctly elusive, there was a broad spectrum of technology, design, and styling on display from Europe-based manufacturers. Production-based cars race ahead The SCCA's Speed World Challenge has delivered automakers a U.S. platform for racecars that are closely related to the vehicles they sell. Let's come together Supplier parks are beginning to take hold in North America as automakers and their suppliers look to improve supply-chain efficiency and reduce costs. Grand ride for Grand Cherokee Jeep engineers give the 2005 model more on-road comfort, with all the off-road capability. Land Rovers makes a Discovery The new SUV, to be called LR3 in the United States, is the first all-new vehicle developed under Ford's leadership and is described as the most technologically advanced Land Rover so far. Nissan finds a new path The new 2005 Pathfinder is built on a more rugged body-on-frame platform and features a more powerful V6 and three-row seating. Supply-side interior design Staying on top of trends is important for companies who hope to secure contracts for larger portions of automotive interiors. Rising again? Japan may at last be seeing glimpses of a rising sun after an enormously long night and an ensuing slow and gloomy dawn. From Mocos to Majestas The Japanese OEMs do more (vehicles) with less (platforms). Tradition, transition, and transformation SAE 100 Future look: As the sun sets on the first 100 years of SAE, we reflect on a proud and rich tradition of contribution to the transportation industry. The diesel solution SAE 100 Future look: The future of commercial vehicles is a subject that we at Navistar International focus on every day. Providing commercial transportation solutions SAE 100 Future look: More than 100 years ago, two sons of German immigrants running a wagon-making operation in Brooklyn, NY, were approached by a customer with a problem. The future of trucking and technology As technology integration becomes ingrained in all facets of the commercial vehicle industry, the trucks of the future will be smarter, more adaptable, and more reliable.

Stochastic Analysis of a Body-on-Frame Vehicle to Achieve Reliable and Robust Shake Performance

2003-01-08733/3/2003

This paper addresses the influence of variability resulting from mount / bushing rates and gages of major structural members to the vehicle shake response. Comparisons of two vehicles to study the concepts of reliability and robustness from vehicle shake perspective are presented. The relationship between vehicle tunability and robustness has been addressed. The First Order Second Moment (FOSM) method is used to provide an initial estimate of the variability or robustness of the design. The influence of body gages, body mount rates and suspension bushings, for two different modal management strategies, has been included. These studies have been compared with Monte Carlo Simulation using a dynamically condensed model. The influence of modal management as a key enabler to achieve a reliable NVH performance has been presented. Various factors influencing robustness in modal management and vehicle shake performance have been discussed. Critical vehicle design parameters which, need to be controlled with tight tolerances to achieve a very robust and reliable system from shake perspective have been identified.

Avutapalli, Bhaskar, Avutapalli, Satya, Keshtkar, Hamid

Development of a Nonlinear Shock Absorber Model for Low-Frequency NVH Applications

2003-01-08603/3/2003

This paper dis cusses the development of a nonlinear shock absorber model for low-frequency CAE-NVH applications of body-on-frame vehicles. In CAE simulations, the shock absorber is represented by a linear damper model and is found to be inadequate in capturing the dynamics of shock absorbers. In particular, this model neither captures nonlinear behavior of shock absorbers nor distinguishes between compression and rebound motions of the suspension. Such an inadequacy limits the utility of CAE simulations in understanding the influence of shock absorbers on shake performance of body-on-frame vehicles in the low frequency range where shock absorbers play a significant role. Given this background, it becomes imperative to develop a shock absorber model that is not only sophisticated to describe shock absorber dynamics adequately but also simple enough to implement in full-vehicle simulations. This investigation addresses just that. The developed model is nonlinear and is constructed using control-force data of shock absorbers. While the model maintains simplicity without increasing vehicle model size, it describes shock absorber behavior both in compression and rebound. The shock absorber model is implemented in full-vehicle simulation of a full-size pickup truck, and the vehicle shake and impact harshness performances are evaluated. Numerical results show the influence of using a nonlinear model in lieu of a linear model. Moreover, a parametric study with respect to input excitation level shows that for large displacements of suspension, nonlinear damping plays a significant role in controlling the response. The nonlinear model also captures the frequency dependency of shock absorber characteristics; this offers considerable promise in analytically tuning shock absorber characteristics for different frequencies of operation.

Subramanian, S., Surampudi, R., Thomson, K. R.

Light Truck Frame Joint Stiffness Study

2003-01-02413/3/2003

Truck frame structural performance of body on frame vehicles is greatly affected by crossmember and joint design. While the structural characteristics of these joints vary widely, there is no known tool currently in use that quickly predicts joint stiffness early in the design cycle. This paper will describe a process used to evaluate the structural stiffness of frame joints based on research of existing procedures and implementation of newly developed methods. Results of five different joint tests selected from current production body-on-frame vehicles will be reported. Correlation between finite element analysis and test results will be shown. Three samples of each joint were tested and the sample variation will be shown. After physical and analytical testing was completed, a Design of Experiments approach was implemented to evaluate the sensitivity of joints with respect to gauge and shape modification. The results of the DOE were fitted to a response surface and brought into an Excel spreadsheet. The result is an easy-to-use Excel spreadsheet based Toolkit for evaluating joint stiffness.

Spencer, Christian, Vartanian, Katy, White, Michael, Law, S. Edward

Finite element simulation of drive shaft in truck/SUV frontal crash

2001-06-01066/4/2001

Drive shaft modelling effects frontal crash finite element simulation. A 35 mph rigid barrier impact of a body on frame SUV with an one piece drive shaft and a unibody SUV with a two piece drive shaft have been studied and simulated using finite element analyses. In the model, the drive shaft can take significant load in frontal impact crash. Assumptions regarding the drive shaft model can change the predicted engine motion in the simulation. This change influences the rocker @ B-pillar deceleration. Two modelling methods have been investigated in this study considering both joint mechanisms and material failure in dynamic impact. Model parameters for joint behavior and failure should be determined from vehicle design information and component testing. A body on frame SUV FEA model has been used to validate the drive shaft modeling technique by comparing the simulation results with crash test data. These drive shaft models have also been applied to a unibody SUV model to demonstrate the contribution of drive shaft for simulated frontal impact performance.

Chen, Xiaoming, Wagner, David A., Poisac, Jerome

Test Based Methods for High Frequency Structureborne Noise

2001-01-15234/30/2001

NVH engineers typically are dealing with issues that relate to shake, harshness and low frequency noise and vibration concerns. However there is a greater importance being placed on dealing with high frequency structureborne noise problems which are related to gear meshing forces and drivetrain dynamics. This paper presents a case study of a high frequency structureborne noise problem. The objective of the paper is to show the application and effectiveness of using various testing based techniques such as Transfer Path, Running modes, and Mobility analysis along with acoustic excited operating deflection shapes for solving these problems in a timely and effective manner.

Mir, Hamid

Integration of Chassis Frame Forming Analysis into Performance Models to More Accurately Evaluate Crashworthiness

9805512/23/1998

For Body on Frame vehicles, the chassis truck frame absorbs approximately 70% of the kinetic energy created from a frontal impact. Traditional performance analysis of the chassis utilizes standardized material properties for the Finite Element (FE) Model. These steel properties do not reflect any strain hardening effects that occur during the forming process. This paper proposes a process that integrates the frame side rail forming analysis results into the FE crash model. The process was implemented on one platform at Ford Motor Company to quantify the effects. The forming analysis provided material thinout, yield strength, and tensile strength which were input into the performance model. With the modified properties, the frame deceleration pulse and buckling mode exhibited different characteristics. The integration of CAE disciplines is the next step in increasing the predictability of analytical tools.

Kundrick, Ken, Kaufman, Mark, Gaines, David, Liu, Sheng-Dong

Design Consideration for Mounting a School Bus Body on a Truck Chassis

7202972/1/1972

This paper outlines the chassis requirements which enable the school bus body manufacturer to attach his own body successfully to the chassis with a minimum of interference. It describes the cooperative effort made by the major truck chassis and body manufacturers in recognizing problems and formulating objectives for their solution. The areas included in their discussions and formalized in design objectives were: dimensional references, changes made by the body manufacturer, and responsibilities of the chassis manufacturer. Detailed design illustrations are also presented. Finally, the paper describes body attachment, and then discusses problem areas that remain to be solved.

Hartman, G. L.

New Test Equipment for Transponder and VOR/ILS

7104892/1/1971

New equipment to be described includes a cockpit-operated transponder checker with frequency measuring capability and direct-reading binary and octal display, a digitally-controlled VOR/ILS audio signal generator with resolution of 0.01 deg and 0.001 ddm, and an updating program for HP211A/SG-1A RF signal generators providing zero phase shift, high-precision modulation measurements, leveled RF outputs, and single-chassis construction.

Schacher, Daniel

THE SEPARATE CHASSIS FRAME

6105301/1/1961

PIERCE, W. G.

CORVAIR'S CHALLENGE TO THE BODY BUILDER

6001261/1/1960

COTTER, BART

THE UNITIZED APPROACH TO LOW CARS

5803591/1/1958

JOHNSON, H. W.

BODIES, FRAMES, AND LOW PROFILES

5803631/1/1958

JOHNSON, PHILIP O.

Size, Structure, and Shape Of European Automobiles

5502421/1/1955

ECONOMIC conditions in postwar Western Europe are, according to Mr. Pomeroy, responsible for 90% of European cars being smaller, noisier, slightly lighter, but very similar to American cars, and somewhat faster than might be expected. How the designer ingeniously fits the passenger into the seemingly small space afforded by the European car is described in this paper. Other features of European automobiles discussed are their structure and styling.

Pomeroy, Laurence

UNITIZED BODY DESIGN - Bodies - With or Without Chassis Frames

UNIT FRAME AND BODY …

4001551/1/1940

THE eventual solution to the question: “Shall it be of unit design or shall it have a separate frame?” will be known only when a complete understanding is reached of the ride problem, including car feel and quietness, and a better understanding is obtained of the structure's influence on these performance phases, Mr. Sherman believes. Such knowledge, he predicts, will result eventually in the lightest, least-expensive and best performing automobile, be it unitary in structure, conventional, or something as yet unconsidered. His paper brings out some of these considerations which have proved to be of paramount importance in research work conducted by his company. Pointing out that it is impossible to predict ahead of time just how a new car design will perform, he contends that it will be much easier to adjust the job to the best rigidity range with the separate-frame construction than with the unitary construction. He shows that the stiffest all-steel body tested is only 1.8% as stiff as a true box having the average dimensions of a car body and having the same panel thickness, chiefly because of the door openings and the thinness and curved shape of the body panels. It is concluded that it should be possible to reduce the weight of the average car of today by approximately 100 lb, still maintaining its riding and quietness qualities, by substituting a unit construction for a separate frame. It is emphasized, however, that the unit-construction car probably will cost more and will require considerable time for development and alterations. A new frame design to replace the X-member frame is promised that will improve car performance. Major phases of the problem are grouped under the following headings: The Experimental Background, General Viewpoints, The Ride Problem, The Structure's Effect on the Ride, The Car Body as a Structural Member, and Road Noise.

SHERMAN, D. W.

Aspects of Frameless Car Design

3901841/1/1939

MR. APPEL defines a frameless car as one in which the body is used as a structural member and in which the axles, engine, and steering gear are attached to the body, instead of having that unit used merely as a shell for passengers. The chief differences between frameless and conventional cars are summarized by stating that frameless cars: 1. weigh about 2% less; 2. cost less by somewhat more than 2% - where sufficient quantities are involved; 3. are definitely more rigid; 4. are necessary to obtain the lowest floor height; 5. cost no more to service; 6. are just as quiet on the road; and 7. do not involve higher insurance rates than conventional cars. Design effects brought by the frameless construction are listed as including: 1. elimination of the outside coach builder, even in Europe; 2. there can be no shifting of blame between body and chassis designers for body squeaks, rattles, and so on - the body and the chassis engineer become the same person; 3. because spring brackets, shock absorbers, bumpers, front frame extensions, and so on, are attached directly to thin sheet metal, particular care must be taken in providing local reinforcements to distribute the stress; 4. considerably greater rigidity in the underbody is required for convertible models.

Appel, W. D.

BODY AND CHASSIS DEVELOPMENT

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