Strain incompatibility as a source of residual stress in welding and additive manufacturing

TL;DR

This paper presents a 1.5D analytical model demonstrating how strain incompatibility from thermal expansion during welding and additive manufacturing causes residual stresses, influenced by the heat source velocity.

Contribution

It introduces a transparent analytical model linking strain incompatibility to residual stress formation, emphasizing the role of construction history and heat source velocity.

Findings

Residual stresses originate from strain incompatibility due to thermal expansion.

The model captures the evolution of residual stresses during cooling.

Heat source velocity significantly affects residual stress development.

Abstract

The accumulation of residual stress during welding and additive manufacturing is an important effect that can significantly anticipate the workpiece failure. In this work we exploit the physical and analytical transparency of a 1.5D model to show that the deposition of thermally expanded material onto an elastic substrate leads to the accumulation of strain incompatibility. This field, which is the source of residual stress in the system, introduces memory of the construction history even in the absence of plastic deformations. The model is then applied to describe the onset and the progression of residual stresses during deposition, their evolution upon cooling, and the fundamental role played by the velocity of the moving heat source.