A mixed PGD-a priori time basis strategy for the simulation of cyclic transient thermal behavior

Ahmad Al Takash,Mohammad Hammoud,Marianne Beringhier,Jean-Claude Grandidier

doi:10.1051/meca/2020082

Abstract

The knowledge of the service life of polymers under cyclic loading, widely used in industrial applications, is required and usually based on the use of methods necessitating an accurate prediction of the stabilized cycle. This implies a large computation time using the Finite Element Method (FEM) since it requires a large number of cycles for polymers. To alleviate this difficulty, a model order reduction method can be used. In this paper, a mixed strategy is investigated. Through the Proper Generalized Decomposition Method (PGD) framework, this strategy combines the Fast Fourier Transform (FFT) to create a priori time basis and the FEM to compute the related spatial modes. The method is applied to 3D thermal problems under cyclic loadings. The robustness of the proposed strategy is discussed for various boundary conditions, multi-times, and different cyclic loadings. A large time saving is obtained proving the interest of this alternative strategy to deal with fatigue simulations.

Highlights

Polymers are widely used in industrial applications such as aerodynamics, internal-combustion engine, turbines, biomechanics, etc [1,2]
The results show that for loads with different cycle times and amplitudes, different time bases are generated by changing the cycle time of the analytical expressions
Let us note that we here assume that the analytical expressions are valid for large time domains, larger than the fitting time domain

Summary

Introduction

Polymers are widely used in industrial applications such as aerodynamics, internal-combustion engine, turbines, biomechanics, etc [1,2]. Parking phases under the sun generating high temperature with constant loads (weight) alternate with vibratory phases at very high temperature generated by the engine. In such a context, structural parts must fulfill their functions throughout the life of an automobile. Numerical tools are a mandatory step for engineers They are confronted with numerical calculations of thermomechanical problems cycled over a large number of cycles with an additional difficulty in the case of polymers or metallic parts under high temperature [3] for example, which do not present real stabilized cycles, thermocreep being always active throughout the

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Discussion

Conclusion