Research On Strength And Fatigue Life Of Composite Bolted Joint Under Hygrothermal Conditions

As the most mainly connection type in composite materials structures, bolted connection is moreand more used in aircraft structure and aircraft engine. Hygrothermal conditions make some impact onthe mechanical properties of the composite bolted joint. This paper is to study the influence ofhygrothermal conditions on the strength and the fatigue life of the composite bolted joint, and to getthe prediction method of the strength and the fatigue life of the composite bolted joint under thehygrothermal conditions based on the hygrothermal effects of composite laminates and theprogressive damage analysis method of the composite bolted joint.The strength and fatigue performance of the composite bolted joint under the room temperaturedry conditions and the hygrothermal conditions have been studied in this paper, which are mainlyincluding the followings:(1) The strength test and fatigue test of the composite bolted joint under the room temperaturedry conditions were carried out. The strength and the fatigue life curve of the composite bolted jointwere gotten from the test data.(2) The strength test and fatigue test of the composite bolted joint under the hygrothermalconditions were carried out. The influence of hygrothermal conditions to the strength and the fatiguelife of the composite bolted joint was analyzed.(3) The strength and fatigue life prediction method of the composite bolted joint under thehygrothermal conditions was established basing on the hygrothermal effects of composite laminatesand the progressive damage analysis method which includes failure criterions, material propertydegradation and finally failure criterions.(4) A strength and fatigue life prediction programm for composite bolted joint under thehygrothermal conditions has been developed by using APDL of the ANSYS software. The strengthand fatigue life of composite bolted joint under the room temperature dry conditions andhygrothermal conditions was predicted using the prediction method, and the feasibility of theestablished prediction method has been proved through comparing with the experimental data.