Mesh sensitivity analysis in the fatigue life simulation based on the experimental load history

Resumo

Generally, in motorsport, loads are highly dependent on road conditions, with the wheels being sensitive
to oscillations on the road surface. In the case of off-road vehicles, these loads can be considerably unpredictable,
as they depend on the ground unevenness, dimensions of each ground element, speed, angle of attack, among other
several variables. In these cases, to predict the components behavior, experimental forms of analysis can take
place through techniques like extensometry in already existing vehicles, allowing the acquisition of real dynamic
loads and the creation of a database. The durability of many vehicles componets is affected by cyclical nature’s
failure, where there are dynamic stresses and variables as a function of time, in most cases with stresses below
the yield point and material rupture. For an analysis of fatigue life in vehicle structural components with variable
load in computational analysis, the experimental load history can be applied, considering the cumulative damage
effect. The analysis of resistance and durability is a crucial task in the dimensioning of automotive components
and, in complex geometries, the use of finite element software becomes advantageous. In these analysis, the mesh
parameters are directly related to the quality of the analysis, as it refers to a discretization of the model. In this
perspective, the present work presents an approach on the influence of the mesh parameters for the model in finite
elements, applied to the mechanical component most requested by the suspension of the prototype within the scope
of fatigue. Therefore, the load history acquired experimentally was considered for the excitation of the component,
while the interference of the main mesh parameters in the final results was verified. The fatigue tool from the
Ansys software was used to insert a variable gain in the load parameters. The load history was also incorporated
through files obtained experimentally. This history makes the nominal load applied to the component have variable
amplitude.