Modeling the Strength Degradation and Fatigue of Carbon Fiber Rein-forced Composites

Pasquale Verde

doi:10.2174/1874088x01206010077

Abstract

Static and fatigue data available in literature concerning carbon fiber reinforced composite laminates subjected tension-tension fatigue were re-elaborated in the framework of a two-parameter fatigue model explicitly accounting for the cyclic as well as the mean stress. The data were used to obtain the model parameters by best fitting procedures. A primitive statistical implementation of the model was based on the hypothesis that the monotonic tensile strength follows a two-parameter Weibull distribution. The model has the potential of being predictive indicating that the fatigue character-ization of given laminate can be achieved with a minimum of experimental tests. The model reliability and its applicabil-ity limits are discussed.

Highlights

Carbon fiber reinforced polymer based composites have emerged as superior engineering materials due to attributes that are not attainable with existing engineering materials
This paper presents a re-elaboration of static and fatigue data available in literature [37, 38] concerning carbon fiber reinforced laminates
Modeling the Strength Degradation and Fatigue of Carbon Fiber reinforced plastics are different from those observed in graphite/epoxy laminates, where matrix splitting accumulation and delamination play an important role in determining the final collapse

Summary

Introduction

Carbon fiber reinforced polymer based composites have emerged as superior engineering materials due to attributes that are not attainable with existing engineering materials. Further the fatigue lifetime of composite materials is influenced primarily from the matrix and fibers type, the geometry of reinforcement (unidirectional, mat, fabric, braiding), the laminate stacking sequence, the environmental conditions (mainly temperature and moisture), the loading history (stress ratio, R, cyclic frequency..) and boundary conditions. According to equation 2, the evolution of strength degradation with fatigue cycling can be calculated, provided the constants and (with =1-b), only dependent on the material and loading conditions, are known.

Results

Conclusion