Modelling and Characterisation of a Servo Self-Piercing Riveting (SPR) System

D Tang,M Evans,P Briskham,N Sims,L Susmel

doi:10.1088/1742-6596/1106/1/012021

D Tang, M Evans + Show 3 more

Open Access

https://doi.org/10.1088/1742-6596/1106/1/012021

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Abstract

SPR is a cold mechanical joining process in which multiple sheets of material are riveted together without the need for a predrilled hole. It works by pushing a typically semi-tubular rivet into a target stack of material, during which the plastic deformation of the material and rivet are such that a mechanical lock is formed within the material stack. The process is used extensively in the automotive industry in car body construction, and is a competing technology to more established joining techniques such as resistance spot welding. As part of the ongoing development of the technique, there is a strong need to understand and simulate the dynamics of the process. In this work, a lumped parameter model of the SPR system with a non-parametric model of the joint is presented. Simulated results are compared with experimental data for a given joint configuration. Furthermore, the model is used to highlight the significance of the compliances within the system. It is shown that during rivet insertion, the stiffness of the C-frame structure is an influential factor in determining the dynamic response of the system. The results provide the basis for a more comprehensive sensitivity analysis into the factors which affect the quality of the resulting joint.

Highlights

Self-piercing riveting (SPR) is a cold mechanical joining process in which multiple sheets of material are riveted together without the need for a predrilled hole
The relative displacement represents the extent of rivet insertion into the material, and the relative velocity represents the rate of rivet insertion
The results strongly suggest that the dynamics of the C-frame dominate the response of the system at the riveting interface, and significantly influence the rivet insertion process

Summary

Introduction

Self-piercing riveting (SPR) is a cold mechanical joining process in which multiple sheets of material are riveted together without the need for a predrilled hole. In the servo SPR process, the upsetting force required to form the joint is provided by the C-frame structure. Studies which take a model-based approach to investigating the sensitivity of the process, such as [7] and [8], have focused solely on the interactions at the rivet-material level and do not account for the response of the overall SPR system.

Results

Conclusion