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It is presented in this study a methodology based on numerical simulation by means of the computational fluid dynamics for the analysis of air flow inside the engine tunnel for commercial vehicles, aiming primarily at the performance of the cooling system. The simulations have been carried out with the software Ansys CFX v12.1. Starting from the geometries of the water and engine charge air radiators, a 3D finite volume model is automatically generated for this system by means of a macro written with Excel, taking into account the dimensions, forms and quantity of tubes, as well as the fluid inside them, in order to represent the heat exchanges which occur on the water and air radiators.

The purpose of this work is to present a methodology for the structural analysis of commercial vehicle components, through the finite element method, by considering dynamic load simulations of test track. This methodology consists on the substructuring of complete models for the simulation of dynamic loads, by using modal superposition with the addition of static modes of the component in study. Example cases are presented with the indication of percentage variations between dynamic stresses of the complete model and the values obtained from the isolated model. The latter is calculated with the imposition of the displacement history on the connection points with the complete model. With this methodology one pursues the reduction of time per analysis cycle, during the development of new vehicle components.

This paper describes the application of structural and dynamic analysis of a new articulated bus developed by Daimler-Chrysler do Brasil. Structural analysis is carried out using both static and dynamic finite element analysis. The simulation of the vehicle running on a road track gives input for structural dynamic analysis that is followed by durability calculation. Dynamics analyses are carried out using the multibody dynamic methodology and the software Adams/View. Initially, a detailed numerical model is developed, including all the major non-linearities of the actual vehicle, such as air spring and shock absorber curves, suspension bump stops and tire model. Also the representation of the suspension geometry and articulation properties is introduced. Using this model, the first dynamic analysis performed is the calculation of forces acting on suspension elements when the bus is running on a road track with severe profile.

The main truck cabin or car body parts needs a precise design due its importance to occupant safety. In the last years and in the present these parts are commonly designed using sheet material nominal properties and the influence of the forming process (thickness reduction, plastic strain and residual stress) was not take in account. This procedure hidden some spurious answers of the structures and sacrifice in some cases the vehicle safety. Other consequences are a bigger cost of test of prototypes and delays in the launching of new products. To minimize this problem, it becomes necessary to introduce the effect of the forming process in the structural sizing and the analyses of the occupant safety (Crashworthiness) of new cabins and body cars. It is also known that the Sheet Forming Simulation reached precision and trustworthiness enough to supply the geometric and material changes to Crashworthiness analysis.

In the automated design of mechanical systems by means of structural synthesis techniques, two cathegories of procedures, namely shape and sizing optimization, play different but equally important roles: the former is usually applied to the synthesis of solid modelled (in the finite element method sense) structures, by finding optimum positions for the model's nodes, and the later is often used to optimize direct finite element properties (shell thicknesses and bar areas, for instance). Besides the nature of the finite element model (plane or solid) is mainly a consequence of the system's inherent features, not so seldom, the engineer can be faced with structures that allow both types of approaches and, for optimization purposes, the two aforementioned alternatives arise. Thus, in such situations, the choice for the type of finite element model to be built is also driven by which kind of structural synthesis (shape or sizing) would lead to better results.

This paper presents a general methodology to study the dynamical behavior of vehicles: the equations of motion are obtained using Lagrange's equation and the elasticity of structural elements are considered. Symbolic computation is used to handle long energy equations. The equations of motion are integrated using traditional numerical algorithms. The dynamical behavior of the vehicle can be improved using optimization techniques. In this paper the design of a simple vehicle model is optimized.