Evaluate the Fatigue Life of CFRC Subjected to Coupled Thermo-Mechanical Loading.

Junjie Ye,Xuefeng Chen,Zhi Zhai,Yiwei Wang,Yang Shi,Gaigai Cai,Wangpeng He

doi:10.3390/ma12182886

Abstract

Mechanical properties of composites manufactured by high-temperature polymer polyether ether ketone (PEEK) with continuous reinforced fibers are closely dependent on ambient temperature variations. In order to effectively study fatigue failure behaviors of composites under the coupled thermo–mechanical loading, a well-established microscopic model based on a representative volume element (RVE) is proposed in this paper. Stiffness degradation behaviors of the composite laminates at room and elevated temperatures are firstly investigated, and their failure strengths are compared with experimental data. To describe the fatigue behaviors of composites with respect to complex external loading and ambient temperature variations, a new fatigue equation is proposed. A good consistency between theoretical results and experimental data was found in the cases. On this basis, the temperature cycling effects on the service life of composites are also discussed. Microscopic stress distributions of the RVE are also discussed to reveal their fatigue failure mechanisms.

Highlights

Due to their excellent mechanical properties [1,2], such as fatigue resistance, good thermal stability, and fracture toughness [3,4], high-temperature polymer composites have been widely used in the aviation industry, and they are looking to replace metal materials in a variety of aircraft components, such as luggage racks and cable clips [5]
The experiment results indicate that the polyether ether ketone (PEEK) matrix at room and high temperatures presents high ductility
This study focused on the fatigue life of composite structures under coupled thermo–mechanical loading

Summary

Introduction

Due to their excellent mechanical properties [1,2], such as fatigue resistance, good thermal stability, and fracture toughness [3,4], high-temperature polymer composites have been widely used in the aviation industry, and they are looking to replace metal materials in a variety of aircraft components, such as luggage racks and cable clips [5]. Thousands of researchers have devoted themselves to deeply investigating the fatigue properties of composites by using experimental or theoretical methods [7,8,9,10]. Li [8] established a model to investigate fatigue crack growth in composite structures. Carvalho et al [8] studied the influence of reinforcement mechanisms of carbon nanotubes on wear, as well as fatigue tests on an aluminum–silicon composites. Huang et al [10] employed the experimental method to study crack bridging in engineered cementitious composites under fatigue tensile loading

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