Simulation of Spot Welded Assemblies Using Nonlinear Shell Theory

Other conference contribution, 2025

All manufacturing processes exhibit variations from nominal settings. These variations may arise from differences in material properties, leading to geometric deviations in manufactured parts. Additionally, part variation, along with inconsistencies in fixturing and tooling, contributes to deviations in the assembly process. Such geometric deviations can cause issues during assembly or result in a decline in the functional and aesthetic quality of the final product.

Geometry assurance (GA) encompasses a series of activities throughout the product lifecycle aimed at ensuring the geometric quality of the manufacturing process.

During the concept phase, design proposals are developed and evaluated in conjunction with manufacturing systems. This phase is followed by a verification stage, where inspection routines are established alongside virtual matching simulations. Finally, in the production stage, the focus shifts to process monitoring, deviation identification, and root cause analysis.

The time and cost associated with design changes increase significantly as more product and manufacturing process decisions become finalized. Therefore, it is crucial to ensure that the product is highly likely to meet requirements and that those requirements are correctly defined from the beginning.

In this paper, we have developed a model to simulate spot welding without using the standard MIC, often referred to as Direct-FEM. Using this model, we have investigated the consequences of assuming geometric linearity.

The shell model employed is based on the shell proposed by Ibrahimbegovic and includes 6 degrees of freedom per node, including drilling rotation. The findings are used to provide recommendations on how to apply variation simulation to spot welding.