Predicting residual and flow stresses from surface topography created by laser cutting technology

Abstract

The paper deals with the engineering method for laser cutting technology that utilizes stress equations derived from surface topography for determining residual stresses. It presents an original method for residual stress assessment in a non-contact and non-destructive manner. The high temperature around cut edges results in the development of residual stresses during the cutting process, which decreases the quality of the end product. Surface topographical parameters themselves carry information on a concrete state of technological process in the concrete moment of its usage. This method for the assessment of residual stress in materials being cut by a laser beam provides sufficient information on the residual stress state evaluation with sufficient accuracy by applying an analytical and experimental approach. Experiments were conducted on three different materials, namely steel, aluminium alloy and titanium. It was necessary to check calculation by measuring the residual stress distribution in the vicinity of cut edge using the ultrasonic method. The novelty of the method for the determination of residual stresses in a workpiece lies in the physics-based approach focusing on the mechanical and stress-deformation parameters of the material being cut and on the mechanical equilibrium of the system: material properties—tool properties—deformation properties.