Analysis For Bearing Capacity Of Y And K Joint Of Composite Materials Truss

Composite material joint is the main components of the aviation structure, the condition of stress and deformation in the joint part is very complicated. According to statistics, more than 70% damage of the aircraft structure is occurred in the joint part.Therefore, the research including design, analysis which is carried around the develpoment of composite material joint has important theoretical and practical significance, so it has become a mian research filed and development direction of new materials in aerospace field.The studies in this article can be divided into two parts. In the first part of this article, based on a series of numerical analysis of composite tubular Y-joint and K-joint of various geometric parameters, the effect of the various geometric parameters on stress distribution had been investigated. The various geometric parameters were consisted of auxiliary tube diameter, auxiliary tube thickness, competent thickness, angle between auxiliary tube and competent, distance between two auxiliary tubes. In the second part ,the effect of auxiliary tube diameter, auxiliary tube thickness, competent thickness on stress distribution of a special kind of Y-joint composite tubular (T-joint) under compression, bending, torsion and compression - bending - torsion load case combinations had been discussed.Finite element models for composite tubular Y-joint and K-joint of various geometric parameters were established with ANSYS software. The relationship curves between stress distribution of each group composite truss joints and various geometric parameters were obtained with finite element analysis of each group of tested samples.The results show that, the maximum stress of the four kinds truss joints appeared on the junction place of competent and auxiliary tube.This area is the most unsubstantial of the truss joint, it can be destroyed easily.Finite element models for composite tubular T-joint under different load conditions were developed. The relationship curves between stress distribution of composite tubular T-joint and various geometric parameters were also studied. According to the results, the junction place of competent and auxiliary tube is still the most unsafe area. The corresponding local enhancement should be provided during design and processing.