Laser cutting of sharp edge: Thermal stress analysis

• Published in: Optics and lasers in engineering Vol. 48; no. 1; pp. 10 - 19
• Main Authors: Yilbas, B.S., Arif, A.F.M., Abdul Aleem, B.J.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 2010; Elsevier
• Subjects: Biological and medical applications; Cutting; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Industrial applications; Laser; Optics; Physics; Sheet metal; Thermal stress; Thermal stress; Cutting; Sheet metal; Laser; Scanning electron microscopy; Stress analysis; Laser assisted processing; Laser cutting; Theoretical study; Residual stresses; XRD; Laser beam applications; Laser beams; Finite element method; Optical microscopy; Steels; Thermal stresses
• ISSN: 0143-8166; 1873-0302
• DOI: 10.1016/j.optlaseng.2009.03.006

Laser cutting of sharp edge and thermal stress development in the cutting section is examined. The finite element method is used to predict temperature and stress fields while the X-ray diffraction (XRD) technique is used to measure the residual stress around the cut edges. A mild steel sheet with 5 mm thickness is used in the simulations and the experiment. The morphological and metallurgical changes around the edges are examined using the optical microscopy and scanning electron microscopy (SEM). It is found that temperature remains high at the sharp edge when the laser beam is located in this region. This, in turn, lowers the cooling rate and reduces von Mises stress in this region. The magnitude of the residual stress is about 90 MPa at the sharp corner while the maximum von Mises stress is in the order of 280 MPa, which occurs away from sharp corner. In addition, the residual stress predicted agrees with the experimental data.