Fatigue Modeling and Numerical Analysis of Re-Filling Probe Hole of Friction Stir Spot Welded Joints in Aluminum Alloys.

Armin Yousefi,Reza Hedayati,Ahmad Serjouei,Mahdi Bodaghi

doi:10.3390/ma14092171

Armin Yousefi, Reza Hedayati + Show 2 more

Open Access

https://doi.org/10.3390/ma14092171

Copy DOI

Abstract

In the present study, the fatigue behavior and tensile strength of A6061-T4 aluminum alloy, joined by friction stir spot welding (FSSW), are numerically investigated. The 3D finite element model (FEM) is used to analyze the FSSW joint by means of Abaqus software. The tensile strength is determined for FSSW joints with both a probe hole and a refilled probe hole. In order to calculate the fatigue life of FSSW joints, the hysteresis loop is first determined, and then the plastic strain amplitude is calculated. Finally, by using the Coffin-Manson equation, fatigue life is predicted. The results were verified against available experimental data from other literature, and a good agreement was observed between the FEM results and experimental data. The results showed that the joint’s tensile strength without a probe hole (refilled hole) is higher than the joint with a probe hole. Therefore, re-filling the probe hole is an effective method for structures jointed by FSSW subjected to a static load. The fatigue strength of the joint with a re-filled probe hole was nearly the same as the structure with a probe hole at low applied loads. Additionally, at a high applied load, the fatigue strength of joints with a refilled probe hole was slightly lower than the joint with a probe hole.

Highlights

Lightweight metals such as aluminum alloys are widely used in the automobile and aerospace industries
Friction stir welding (FSW) is a revolutionary joining method developed by TWI (Cambridge, UK) in 1991
The sheets used in this study were made of A6061-T4 aluminum alloy with a thickness of 2 mm

Summary

Introduction

Lightweight metals such as aluminum alloys are widely used in the automobile and aerospace industries. Assembling such metal structures is a challenging process in the industry. Resistance spot welding (RSW), laser spot welding, and riveting are widely used to assemble aluminum alloy panels. A new method is required for joining aluminum panels in order to overcome these shortcomings. Friction stir welding (FSW) is a revolutionary joining method developed by TWI (Cambridge, UK) in 1991. This method has various advantages, such as small thermal deformation, high-quality welds with superior mechanical properties, fine and uniform weld microstructures, and high welding efficiency [1]

Methods

Results

Conclusion