Influence of assembly preload on fatigue behavior of composite connector

Abstract

With the widespread application of composite materials in aviation, automotive and other fields, bolted connection, as the key focus in structural design, has always been a hot research topic for the scholars both at home and abroad. The pre tightening force of bolt assembly changes the loading situation at the hole edge of composite material connector and the overall load distribution of the structure, which can play a beneficial role in enhancing the strength and lifespan of the structure. This research took the deformation of bolt hole as the measurement standard for structural fatigue performance, the hydraulic fatigue machine was used to study the effect of assembly preload on the fatigue performance of composite material connector and the degradation of preload during the fatigue cycling. The results show that the magnitude and non-uniformity of the preload greatly affect the hole deformation and fatigue life of the structure. Within a certain range, the larger the assembly preload, the stronger the fatigue resistance of the structure. The degradation of pre tightening force of the bolt is influenced by various factors such as the initial pre tightening force, gasket type, and loading frequency. The smaller the initial pre tightening force, the more severe the degradation of structural pre tightening force.

Keywords

• composite materials
• preload
• preload degradation
• hole deformation