Tightening torque and washer size effects on bearing strength of fiber metal laminate bolted-joints

Shiming Zu,Zhengong Zhou,Jiazhen Zhang,Lu Che,Yanfeng Zhang,H.F Abdul Amir,P.S Khiew

doi:10.1051/matecconf/201710801010

Abstract

The study investigated the effect of tightening torque and washer size on the mechanical properties of double-lap, single bolt fiber metal laminate (FML) joints. The tightening torque under the examination was 0.1Nm, 3 Nm, 5 Nm, 10 Nm and 15 Nm, and the washer size was changed by varying the value of outer diameter of washer (Dwo=11mm, Dwo=13mm, Dwo=15mm, Dwo=17mm and Dwo=19mm). A three-dimensional (3D) failure finite element model was used to predict the bearing behaviour of FML joints. The comparison between simulation and experimental results showed a good agreement in strength. The results showed that the effect of bolt tightening torque on the failure loads of bolt-loaded FML joints was obvious, and the effect of washer size on the load-bearing capacity was not sensitive. The present work provided supporting information for the design of FML joints.

Highlights

Composite materials have been widely used in aircraft industry due to the high strength and stiffness-to-weight ratios
This paper aims to investigate the effect of tightening torque and washer size on bearing strength of bolt-loaded Fiber metal laminate (FML) joints by a three-dimensional (3D) damage model
The specimen geometry was based on the ratios of width-to-diameter ratio (W/D)=4 and edge distance-to-diameter ratio (E/D)=4

Summary

Introduction

Composite materials have been widely used in aircraft industry due to the high strength and stiffness-to-weight ratios. Fiber metal laminate (FML) is a special kind of composite material which originated at Fokker/TU Delft in the Netherlands[1]. FML is a class of hybrid composites consisting of alternating layers of thin metal sheets and polymer matrix composite. Incorporating composite layers into a metal sheets system greatly enhances the overall performance of the FML which combines the advantages of both conventional composites and metals. FML has been proved to have many excellent mechanical properties such as outstanding fatigue resistance, high specific static properties, superior impact resistance, good residual and blunt notch strength, better bearing strength, fire resistance and corrosion properties [2]. Glass-reinforced aluminium laminate (GLARE) has been selected for the upper fuselage skin structures of Airbus A380, as shown in Figure 1 [3]

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