Effects of Hole Perpendicularity Error on Mechanical Performance of Single-Lap Double-Bolt Composite Joints

Xueshu Liu,Yongjie Bao,Yiqi Wang,Yuxing Yang,Hang Gao

doi:10.1155/2017/2790198

Xueshu Liu, Yongjie Bao + Show 3 more

Open Access

https://doi.org/10.1155/2017/2790198

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Abstract

Static tensile experiments and numerical simulations were carried out to study effects of hole perpendicularity error on mechanical performance of single-lap double-bolt composite joints. Hole tilting angle, varying from 1 to 4 degrees, and hole tilting direction to account for anisotropic properties of composite material were investigated. Progressive damage model (PDM) based on Chang-Lessard type criterion with an extension by Olmedo was created, which involved seven failure modes and made material properties be a direct function of predefined field variables. The model was implemented in ABAQUS/Standard using a UMAT subroutine. Good agreement was found when comparing numerical simulation results with experimental outcomes. In addition, the results demonstrate that, with increasing of hole tilting angle, damage is prone to arise and the load path of the composite bolted joints alters with changing of hole tilting direction, which result in severe stress concentration around the edge of hole and joint failure in advance.

Highlights

Designable combinations of fiber and matrix make the composite a versatile material
It is essential to machine the composite laminates with the utilization of, for example, drills, and the structure integrity of composite laminate is broken, which results in stress concentration around the edge of hole and a significant reduction of the load-carrying capacity
Hole perpendicularity error is a kind of manufacturing defects, which results in stress concentration around hole edge area

Summary

Introduction

Designable combinations of fiber and matrix make the composite a versatile material Their high strength coupled with light weight leads to their use wherever structural efficiency is at a premium. When load-carrying capacity is concerned, bolted joints are the most important methods of composite assembling especially in aerospace industry because of their high loadcarrying capacity and facility to assemble, disassemble, and repair. For such a joint, it is essential to machine the composite laminates with the utilization of, for example, drills, and the structure integrity of composite laminate is broken, which results in stress concentration around the edge of hole and a significant reduction of the load-carrying capacity. Finite element analysis (FEA) and experiments were carried out and compared to assess the mechanical performance of composite joints

Problem Description

Methodology

Section A

Results

Conclusions