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With the intent of attend the Annex 10 performance specifications of the Economic Commission for Europe (ECE-R13), translated on NBR 14354/1999, it was necessary to develop a load sense valve installation layout also to the 6×4 vehicles. This work shows the steps for the development of the load sense valve installation and calibration on 6×4 vehicles, considering the valve performance on the two traction axles and preventing brake locking under low friction track conditions, under empty conditions use or with low load. The design required a detailed layout in order to develop a load sense valve attachment system considering the movement of both traction axles, as well as respecting the vehicle initial project physical limits; adjusting it to one of the available valve cams in the market; intending to develop a durable design and at the same time of low variable cost, with low tooling costs and that does not add much complexity to the production line.

Triggered explosions are increasingly becoming common in the world today leading to the loss of precious lives under the most unexpected circumstances. In most scenarios, ordinary citizens are the targets of such attacks, making it essential to design countermeasures in open areas as well as in mobility systems to minimize the destructive effects of such explosive-induced blasts. It would be rather difficult and to an extent risky to carry out physical experiments mimicking blasts in real world scenarios. In terms of mechanics, the problem is essentially one of fluid-structure interaction in which pressure waves in the surrounding air are generated by detonating an explosive charge which then have the potential to cause severe damage to any obstacle on the path of these high-energy waves.

Designing a vehicle for superior crash safety performance in consumer rating tests such as US-NCAP is a compelling target in the design of passenger vehicles. In today’s context, there is also a high emphasis on making a vehicle as lightweight as possible which calls for an efficient design. In modern vehicle design, these objectives can only be achieved through Computer-Aided Engineering (CAE) for which a detailed CAD (Computer-Aided Design) model of a vehicle is a pre-requisite. In the absence of the latter (i.e. a matured CAD model) at the initial and perhaps the most crucial phase of vehicle body design, a rational approach to design would be to resort to a knowledge-based methodology which can enable crash safety assessment of an assumed design using artificial intelligence techniques such as neural networks.

As part of the joint government/industry Partnership for a New Generation Vehicle (PNGV), Ford Motor Company, with the support of Alcan Aluminum Corporation and The Budd Company, conducted a feasibility study of the design and high volume manufacturing of a lightweight aluminum sport utility vehicle frame. The specific objective of the study was to assess the capability of an aluminum frame to achieve equivalent performance to the 2002 Ford Explorer frame, but at a 40% weight reduction. Using Finite Element Analysis (FEA), it was determined that if a design was constrained to the same section size as the production steel frame, the maximum weight savings that can be realized by use of aluminum is approximately 20%.

In this study, a finite element analysis method is developed for simulating a camshaft cap punching bench test. Stiffness results of simulated camshaft cap component are correlated with test data and used to validate the model accuracy in terms of material and boundary conditions. Next, the method is used for verification of cap design and durability performance improvement. In order to improve the computational efficiency of the finite element analysis, the punch is replaced by equivalent trigonometric distributed loads. The sensitivity of the finite element predicted strains for different trigonometric pressure distribution functions is also investigated and compared to strain gage measured values. A number of equivalent stress criteria are also used for fatigue safety factor calculations.

In this study the finite element method is used to simulate a light truck multi-leaf spring system and its interaction with a driven axle, u-bolts, and interface brackets. In the first part of the study, a detailed 3-D FE model is statically loaded by fastener pre-tension to determine stress, strain, and contact pressure. The FE results are then compared and correlated to both strain gage and interface pressure measurements from vehicle hardware test. Irregular contact conditions between the axle seat and leaf spring are investigated using a design of experiments (DOE) approach for both convex and discrete step geometries. In the second part of the study, the system FE model is loaded by both fastener pre-tension and external wheel end loads in order to obtain the twist motion response. Torsional deflection, slip onset, and subsequent slip motion at the critical contact plane are calculated as a function of external load over a range of Coulomb friction coefficients.

The use of finite element modeling (FEM) tools is part of the most of the current product development projects of the automotive industry companies, replacing an important part of the physical tests with lower costs, higher speed and with increasing accuracy by each day. In addition to this, computer-aided engineering (CAE) tools can be either used after the product is released, at any moment of the product life, in many different situation as a new feature release, to validate a more cost-efficient design proposal or to help on solving some manufacturing problem or even a vehicular field issue. Different from the phase where the product is still under development, when standard virtual test procedures are performed in order to validate the vehicle project, in this case, where engineers expertise plays a very important role, before to proceed with any standard test it is fundamental to understand the physics of the phenomena that is causing the unexpected behavior.

In December 2015, the National Highway Traffic Safety Administration (NHTSA) published a Request for Comments on proposed changes to the New Car Assessment Program (NCAP). One potential change is the addition of a frontal oblique impact (OI) crash test using the Test Device for Human Occupant Restraint (THOR). The resultant acetabulum force, which is a unique and specifically defined in the THOR dummy, will be considered as a new injury metric. In this study, the results of ten OI tests conducted by NHTSA on current production mid-sized vehicles were investigated. Specifically, the test data was used to study the lower extremity kinematics for the driver and front passenger THOR dummies. It was found that the acetabulum force patterns varied between the driver and passenger and between the left leg and the right leg of the occupants. The maximum acetabulum force can occur either on the left side or right side of a driver or a front passenger in an OI event.

This paper summarizes the design features of the Aerostar aluminum driveshaft and the analytical techniques used in its development. The Aerostar aluminum driveshaft was designed for lightweight and smooth operation. The aluminum driveshaft uses magnetic impulse metal forming to attach the tube yokes to the tube. This process does not produce a significant amount of heat preserving tube's mechanical properties. Computer aided design techniques were used to optimize the design of driveshaft components and driveline geometry. Finite element analysis was used to refine the tube yoke design for minimum weight within the torque requirement. Finite element analysis was also used to determine resonant frequencies of the powertrain.

The unitized construction Aerostar compact van and wagon models have been engineered to meet a variety of consumer transportation needs. The broad range of functional and image objectives have been attained by traditional design and development programs augmented by new developmental methods and isolation components. State-of-the-art development methodologies applied early in the Aerostar program enabled prediction of the effects of design revisions intended to improve subsystem response characteristics and isolation. Developmental methods used included finite element analysis, modal analysis and synthesis, transmissibility measurements, torsional powertrain measurements, continuous wave laser holography, acoustical mode determination, acoustical intensity mapping and sensitivity studies used to project production ranges of quality.

Finite Element Analysis (FEA) models are routinely being adopted as a means of up-front design for automotive body structure design. FEA models play two important functions: first as a means of assessing design versus an absolute target; secondly they are used to assess the performance of design alternatives required to meet targets. Means of assessing model capability versus task is required to feed appropriate information into the design process. Being able to document model capability improves the credibility of the FEA model information. A prior paper addressed assessing the absolute performance of model technology using a metric based on a statistical hypotheses test that determines membership in a reference set. This paper extends the use of quality technology to determining the capability of the FEA model to span the design space using Designed Experiments.

Metal binderjetting (MBJ) and bound metal deposition (BMD) are high throughput additive manufacturing process that have the potential to meet the needs of automotive volume production. In many cases, these processes require a sintering post-process to meet final dimensions. Because the sintering stage is performed free standing (i.e. without the use of tooling) and can involve up to a 20% dimensional change from green part to the final part shape, part distortion can be a concern. In this study, the sintering stage of a bridge geometry was simulated under different parameter settings using a Finite Element Analysis. The sensitivity of the simulation to various process parameter inputs was examined. Physical parts were then produced in 316L using a bound metal deposition and sintering process and compared to prediction. The sintering simulation indicated good agreement with experiment for some dimensions but highlighted the need for additional analysis.

Accident statistics have shown that older and obese occupants are less adaptable to existing vehicle occupant restraint systems than ordinary middle-aged male occupants, and tend to have higher injury risk in vehicle crashes. However, the current research on injury mechanism of aging and obese occupants in vehicle frontal impacts is scarce. This paper focuses on the optimization design method of occupant restraint system parameters for specific body type characteristics. Three parameters, namely the force limit value of the force limiter in the seat belt, pretensioner preload of the seat belt and the proportionality coefficient of mass flow rate of the inflator were used for optimization. The objective was to minimize the injury risk probability subjected to constraints of occupant injury indicator values for various body regions as specified in US-NCAP frontal impact tests requirements.

There are a wide variety of approaches to model the automotive seat and occupant interaction. This paper traces the studies conducted for simulating the occupant to seat interaction in frontal and/or rear crash events. Starting with an initial MADYMO model, a MADYMO-LS/DYNA coupled model was developed. Subsequently, a full Finite Element Analysis model using LS/DYNA was studied. The main objective of the studies was to improve the accuracy and efficiency of CAE models for predicting the dummy kinematics and structural deformations at the restraint attachment locations in laboratory tests. The occupant and seat interaction was identified as one of the important factors that needed to be accurately simulated. Quasi-static and dynamic component tests were conducted to obtain the foam properties that were input into the model. Foam specimens and the test setup are discussed. Different material models in LS/DYNA were evaluated for simulating automotive seat foam.

Build variation is an important aspect of vehicle assembly. However traditional variation analysis assumes parts are rigid, leading to overestimation of variations. A finite element analysis procedure to estimate the build variation due to variations of shape, size and mechanical properties of flexible parts is presented. In addition to the part deformation, assembly force and stress can also be calculated by this method. This procedure is illustrated with an example problem.

In order to ensure the safety of a structure, adequate strength for structural elements must be provided. Moreover, catastrophic deformations such as buckling must be prevented. Using the linear finite element method, deterministic buckling analysis is completed in two main steps. First, a static analysis is performed using an arbitrary ordinate applied loading pattern. Using the obtained element axial forces, the geometric stiffness of the structure is assembled. Second, an eigenvalue problem is performed between structure's elastic and geometric stiffness matrices, yielding the structure's critical buckling loads. However, these deterministic approaches do not consider uncertainty the structure's material and geometric properties. In this work, a new method for finite element based buckling analysis of a structure with uncertainty is developed. An imprecise probability formulation is used to quantify the uncertainty present in the mechanical characteristics of the structure.

The development of numerical control, interactive computer graphics and finite element analysis has spawned an overabundance of new acronyms to describe the application of computers in the engineering and manufacturing environment. The purpose of this paper is to provide an overview of these technologies and describe how greater productivity improvement can be achieved via the synergistic benefits of integrating these diverse systems. Discussions will be based largely on the Ford Motor engineering and manufacturing environment which includes not only the internally developed Ford graphics systems, but systems provided by every major turn-key graphics vendor. Evaluation of the Initial Graphics Exchange Specification (IGES) and communication of computer graphics data to Ford suppliers will also be discussed.

Finite element based stress analysis and fatigue predictions are practiced routinely in automotive body structural design and development. The accuracy of these simulation results is not fully understood or at least not well documented. Automotive body structures have many kinds of notches, metal thinning due to stamping and cold working etc. Modern fatigue assessment tools do take into account many of these complexities by Neuber corrections, mean-stress correction, critical plane selection, etc. Other challenges exist in the sensitivity to element quality, including warpage, size, element type, interpretation of results, etc. This case study is based on static loading and accelerated fatigue test conducted on a front-end body buck. The stress and fatigue correlations are designed to build confidence in the model and load inputs. The fatigue results are intended to reproduce durability issues that developed during a proving ground test and were then used to verify potential fixes.

Automotive vehicles equipped with Cardan joints may experience low frequency vehicle launch shudder vibration (5-30Hz) and high frequency driveline moan vibration (80-200Hz) under working angles and speeds. The Cardan joint introduces a 2nd order driveshaft speed variation and a 4th order joint articulation torque (JAT) causing the vehicle shudder and moan NVH issues. Research on the Cardan joint induced low frequency vehicle shudder using a Multi-Body System (MBS) method has been attempted. A comprehensive MBS method to predict Cardan joint induced high frequency driveline moan vibration is yet to be developed. This paper presents a hybrid MBS and Finite Element Analysis (FEA) approach to predict Cardan joint induced high frequency driveshaft moan vibration. The CAE method considers the elastically coupled driveshaft bending and engine block vibration due to Cardan joint excitation.

Material stress strain relations of cast aluminum are both temperature and strain rate dependent when used for themomechanical fatigue analysis. In the present paper, A unified visco-plasticity relation and several classical plasticity relations available in commercial finite element code ABAQUS are compared in their capability and computation efficiency for high temperature cyclic material stress analysis. The unified viscoplasticity considers simultaneously plasticity and creep offers the best, most accurate approach for a description of the stress and strain behavior. For certain applications, when the needs of a speedy computation weighs more than accuracy, classical plasticity can be used to approximate the viscoplastic behavior. In such situations, it is shown that combined hardening model is most promising in capturing observed phenomena.