MULTI-SCALE MODELING OF THE HIGH CYCLE FATIGUE BEHAVIOR OF CHOPPED AND CONTINUOUS FIBER COMPOSITES FOR THE AERONAUTICAL AND AUTOMOTIVE INDUSTRIES

摘要

Today, the design of high quality, light and energy efficient vehicles is crucial for success in theautomotive and aerospace industries. Optimal designs suited for this new environment can beachieved using predictive CAE and advanced material modeling tools.As composites are used more and more in load bearing applications, understanding thedevelopment of damage over their service lifetime is increasingly important. The development ofaccurate predictive CAE tools is necessary to build confidence in the ability to replace partstraditionally made from metals. Efficient fatigue analysis for metals was developed from theunderstanding of microscopic behavior (crack initiation and growth) and extended to themacroscopic level through corresponding test data (S-N curves, etc). Similarly, multi-scalemicromechanical approaches are being developed for chopped and continuous fiber reinforcedcomposite materials.This paper presents a physics-based approach to accurately predict the high cycle fatigue life ofcomposite structures implemented in the software package DIGIMAT?. This solution iselaborated from mean-field homogenization techniques to compute the fatigue life of anyanisotropic composite material, accounting for its local microstructure. A combination of S-Ncurves as well as quasi-static coupon tests yields the necessary input data for this solution. Ademonstration of the methodology will come through an analysis of the fatigue properties of ashort fiber reinforced polymer.