Showing papers on "Vehicle engineering published in 2003"

Dynamic Stress Analysis of Vehicle Frame Using a Nonlinear Finite Element Method

Abstract: Structural integrity of either a passenger car or a light truck is one of the basic requirements for a full vehicle engineering and development program. The results of the vehicle product performance are measured in terms of durability, noise/vibration/harshness (NVH), crashworthiness and passenger safety. The level of performance of a vehicle directly affects the marketability, profitability and, most importantly, the future of the automobile manufacturer. In this study, we used the Virtual Proving Ground (VPG) approach for obtaining the dynamic stress or strain history and distribution. The VPG uses a nonlinear, dynamic, finite element code (LS-DYNA) which expands the application boundary outside classic linear, static assumptions. The VPG approach also uses realistic boundary conditions of tire/road surface interactions. To verify the predicted dynamic stress and fatigue critical region, a single bump run test, road load simulation, and field test have been performed. The prediction results were compared with experimental results, and the feasibility of the integrated life prediction methodology was verified.

Dynamics and Control of Microwave-propelled Sails

Abstract: This paper is concerned with the stability of carbon ber sail structures that are being studied in a series of experiments at the Jet Propulsion Laboratory (JPL) by a team led by Microwave Sciences, Inc. The passive dynamic stability in the one-dimensional (1-D) case is most easily understood in terms of the xed points of the trajectories for the governing equations of motion. A more elaborate attempt at studying the three-dimensional (3-D) stability of rigid sail con gurations with a distributed mass and accounting for sail spin is also being performed using a code developed at JPL. The simple 1-D model introduces the possibility of controlling a microwave-propelled sail using various nonlinear control strategies. This work will be extended in the future to control the full 3-D case. We present results of studies in both the 1-D and 3-D analyses. In addition to providing guidance to future proof-of-principle experiments, this work will lead to novel strategies for enabling a feedback power controller to steer a sail to a desired altitude.

Vehicle Dynamic Analysis Using Virtual Proving Ground Approach

Abstract: Structural integrity of either a passenger car or a light truck is one of the basic requirements for a full vehicle engineering and development program. The results of the vehicle product performance are measured in terms of ride and handling, durability, noise/vibration/harshness (NVH), crashworthiness and occupant safety. The level of performance of a vehicle directly affects the marketability, profitability and, most importantly, the future of the automobile manufacturer. In this study, we used the virtual proving ground (VPG) approach for obtaining the dynamic characteristics. The VPG approach uses a nonlinear dynamic finite element code (LS-DYNA3D) which expands the application boundary outside the classic linear static assumptions. The VPG approach also uses realistic boundary conditions of tire/road surface interactions. To verify the predicted dynamic results, a single lane change test has been performed. The prediction results were compared with the experimental results, and the feasibility of the integrated CAE analysis methodology was verified.

Linking analytical target cascading to engineering information systems for simulation-based optimal vehicle design

Abstract: An environment for simulation-based analysis, design, and product development is presented in this article. Specifically, we integrate the analytical target cascading (ATC) methodology for optimal design with the Active Mediator Object System (AMOS) II information management tool to represent and exchange engineering data in distributed and heterogeneous environments. The ATC process is applied to the design optimization problem of a vehicle model with many design variables. The vehicle model is decomposed into system models, and vehicle design targets are translated to system specifications. The ADAMS software is used to develop the necessary simulation models. AMOS II is used to enable the data exchange among the vehicle dynamics simulation software that is distributed on different computers connected by a network.

Comprehensive approach to increased pedestrian safety in pedestrian-to-car accidents

Abstract: At the Ford Forschungszentrum Aachen a finite element pedestrian humanoid model for use in pedestrian accident simulations was constructed that is capable of being used as vehicle engineering development tool. To further improve the understanding of the kinematics of pedestrian accidents and to optimise the computer simulation program it is necessary to collect a set of highly detailed real world data. At present that data is either unavailable, or not sufficiently accurate for this purpose. To meet these targets an interdisciplinary study has been established. In parallel a demonstrator vehicle has been build to show future technologies in pedestrian safety.

Welded repair and maintenance in the space environment

Abstract: The feasibility of using earth bounded welding techniques in the space environment has been investigated. A literature survey on welding in space reveals numerous aspects about the work done in different countries. The survey indicates the need of a more detailed focus, since no welding experiments have been performed in space since July 1984 (Salyut-7). Addressing the peculiarities of different welding processes, such as environmental restrictions, helped in evaluating and analyzing the selected processes. In order to study the use of a welding process, one should also analyze the ways to test the welds produced. Consequently, non-destructive testing (NDT) techniques with potential use in the space environment were evaluated. A comparison of the various NDT techniques showed parameters, which had not been previously considered, for instance materials to be welded and type of welding processes to be used. The most probable candidates for use in the space environment were ultrasonic, radiographic and eddy current techniques. Even though mathematical modeling is not the main part of the thesis, an existing model was used in order to examine the impact of gravity on defect formation, and humping in particular, in the welding pool. Different results were generated for the Earth environment as well as the simulated space environment inside a spacecraft. Thesis Supervisor: Koichi Masubuchi Title: Professor of Ocean Engineering and Materials Science Emeritus Thesis Supervisor: Patricio F. Mendez, Ph.D. Title: Research Affiliate Thesis Reader: Thomas W. Eagar Title: Professor of Materials Science and Engineering

Litteraturöversikt Skadehändelser relaterade till busstrafik : Buss-OLA - en trafiksäker bussfärd

Abstract: The aim of this literature review was to describe the pattern of injuries and fatalities related to bus traffic. Furthermore, the aim was to identify possible future measurements for improvement of ...

Computing trimmable angle of attack for aircraft with control failures

Abstract: A method is presented for computing the range of angle of attack for which an air vehicle can be rotationally trimmed when experiencing control effector failures. The algorithms are applied to an unpowered reentry vehicle as an example. Types of failures considered include floating effectors that do not contribute to the aerodynamic forces and moments and also to cases where effectors are locked at a given position within the effector displacement range. The algorithm can provide critical information to online trajectory generators and path planners for autonomous air vehicles.

Training effective systems engineers

Abstract: An experiential systems engineering training program developed for customers of the California Institute of Technology Industrial Relations Center (IRC) was described in a previous paper (Fisher 2001). This program has now been modified and is being jointly sponsored by the IRC and the Aerospace Corporation’s trainiig organization, the Aerospace Institute, to provide systems engineering training for Air Force personnel kom the Space and Missile Systems Command. The course now includes eight class meetings over a period of 14 weeks with an instructor-defmed class-long exercise requiring the design of a satellite system. Two courses are being conducted in parallel, offset by one week. Each class of 24 students is divided into two teams. The exercise requires each team to develop a system with a number of pre-defined steps that are described by the instructor tutorials. The exercise originates with an instructor-prepared system requirements document and culminates with a student-prepared Preliminary Design Review, life cycle cost estimate and risk management plan. The tutorial material prepares the students for each step in the system development process. Each 8-hour class meeting involves a tutorial hy the faculty as well as student team reports describing their progress with the exercise. Modifications to the earlier program include the addition of a class meeting utilizing the facilities of the Aerospace Concept Design Center (CDC). The CDC provides the capability to derive space system characteristics with computer-based mathematical models. This allows the students to conduct a tradeoff analysis to select a system design concept from the possible alternatives.