Research On Fatigue Life Prediction Of Laminated Composites With A Hole Under Elevated Temperature

Due to the excellent mechanical properties and strong designability,resin matrix composites are highly favored.The national key projects in the development of related composite materials with domestic aircraft,gas turbines,etc.In order to be able to apply composite materials more widely and to make it easier for engineers to design safe and reliable components,in particular,to reliably evaluate the fatigue properties of composites in a temperature environment.This paper focuses on the study of fatigue behavior and fatigue prediction of laminated structures of carbon fiber reinforced resin-based composite under temperature environment,which can widen the application of composite laminated structure in temperature conditions.The main work is completed as follows:(1)A finite element analysis method of the strength and fatigue life of fiber reinforced composite laminated plates was established for the laminated structure considering the influence of temperature and fiber volume fraction.Based on the theory of unidirectional ply and the method of gradual damage analysis,this method generalized the hashin failure criteria to determine the strength and fatigue failure under the conditions of temperature and fiber volume fraction.At the same time,the fatigue model considering residual stiffness and residual strength of the temperature and fiber volume fraction was introduced as the damage judgment of the gradual decline of fatigue performance.In this method,based on the ANSYS software platform and the APDL parametric language,the corresponding program of predicting and analyzing the static strength and fatigue life of the composite material with holes in the temperature environment has been developed.(2)Based on the T300-3K carbon fiber,QY8911-IV bismaleimide resin matrix composites with holes,the static tensile and fatigue tests were carried out at room temperature,150℃,and 200℃.Tests included static tensile and fatigue tests with the same size test pieces at different temperatures,and with the same temperature and wide-hole ratio under the different aperture conditions.By comparing the experimental data,the influence of temperature,pore size and fiber volume fraction on the strength and fatigue was studied.(3)Combined with the experimental data of unidirectional ply,this paper compared the theoretical predictions with the results of other authors and experiments in this paper,based on the established method of strength and fatigue life analysis of laminates with the hole,and verified the reliability of the program.Furthermore,the strength and fatigue predictions of laminates with the hole at different conditions of the temperature,pore size,and fiber volume fraction were conducted.The effects of temperature,pore size and fiber volume fraction on the static strength and fatigue life of laminates with the hole were analyzed and discussed.It provides a strong basis for the research of laminated composite structure with holes in temperature conditions.