Influence of gap filling on mechanical properties of composite-aluminum single-lap single-bolt hybrid joints

Xuande Yue,Luling An,Chufan Wang,Yuebo Cai,Zengtao Chen,Ruiheng Xiao

doi:10.1177/1687814021989506

Xuande Yue, Luling An + Show 4 more

Open Access

https://doi.org/10.1177/1687814021989506

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Abstract

Composite-aluminum structures exist in aircraft structures generally. It is easy to cause gap between mating surfaces in composite-aluminum assembled structures with the curing deformation of composite. The composite-aluminum, single-lap, single-bolt joints were utilized to investigate the influence of forced assembly, liquid shim and peelable fiberglass shim on the mechanical properties of assembled structures. A steel gasket that removed the middle part was used in the joint to make a gap. The 3D Digital Imagine Correlation (3D-DIC) system was utilized to measure the strain field of specimens and the progressive damage model was created in ABAQUS. The results show that the shim filling can significantly increase the tension stiffness and peak load of the joint compare with forced assembly. As the shim thickness changes, the effects of the liquid shim and the peelable fiberglass shim on the tensile stiffness and peak load shows different. The liquid or peelable fiberglass shim can reduce the strain value around the hole and the peelable fiberglass shim has a better result than liquid shim. The squeeze between the bolt and composite laminate has a greater impact on matrix damage and fiber-matrix shear damage, while the secondary bending has a greater impact on matrix damage and fiber damage.

Highlights

Composite materials have been widely used in aircraft manufacturing with excellent mechanical properties
The progressive damage-based finite element model was established by using the USDFLD subroutine provided in ABAQUS
Following conclusions have been drawn from the present work: (1) In the case of forced assembly, the tensile stiffness and peak load of the specimen continue to decrease as the gap increases

Summary

Introduction

Composite materials have been widely used in aircraft manufacturing with excellent mechanical properties. It can be seen from the liquid shim filling results that the tensile stiffness and peak load of the specimens are higher than those of forced assembly.

Results

Conclusion