Derivation of Extreme Static Durability Load Cases for FEA Based Vehicle Strength Evaluation

Validation of vehicle structure by use of finite element analysis is at the core of reduction of product development time. In the early phase of validation it is required to evaluate the strength of the vehicle structure to account for the loading during physical validation and service loading. In service the vehicle is subjected to variable loads. These act upon the components that originate from road roughness, maneuvers and power train loads. All systems in the vehicle represent more or less complicated elastic structures subjected to time varying loads.

A time domain dynamic assessment of the vehicle structure is time consuming and expensive. Also in the early phase of design wherein several design iterations need to be carried out for design validation, it is practically impossible to conduct a dynamic analysis and fatigue life assessment. Extreme static load cases are traditionally being used for this process. This paper describes the methodology based on measured road loads to derive extreme load cases which can be used for the strength analysis in the initial phase of the vehicle development program as against the traditional 321g load cases. Also a systematic approach to assess vehicle strength and later evaluate vehicle structure durability is presented.