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Proceedings Paper

Thermal elasto-plastic stress analysis during laser heating of a metal plate
Author(s): Yanbei Chen; Jian Lu; Xiaowu Ni
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Paper Abstract

During laser heating of a metal material, the continuity of material confines its free expansion, thermal stresses arise. On one hand the thermal expansion of the heated zone of the material increases with the increase of temperature, the thermal stress level increases correspondingly; on the other hand the mechanical properties of the material will change with the increase of temperature, especially the elastic modulus, yield strength and tensile strength drop significantly, which is the so-called thermal softening problem. Due to the effect of the two factors, as the heating time or the intensity of the laser beam increases, it is possible that the stress levels of the heated zone of the material exceed the yield strength, which leads the material to come into a plastic stage. Thus, a thermal plastic problem occurs. In this study, thermal elasto-plastic stresses during laser heating of a metal plate are computed by the finite element method (FEM) based on thermal elasto-plastic constitutive theory. The mechanical behaviors of the metal material during the laser heating are analyzed. By the analysis of the results, it is found that thermal expansion leads to the increase of stress level early during the laser irradiating, and thermal softening causes the decrease of stress levels in the plastic zone and the slow growth and even decrease of stress levels in elastic zone later. The radial stresses are all compressive stresses, and the hoop stresses are compressive stresses within about the laser spot and are tensile stresses at other place. This work may be beneficial to the laser processing of metal materials.

Paper Details

Date Published: 4 January 2008
PDF: 9 pages
Proc. SPIE 6825, Lasers in Material Processing and Manufacturing III, 68251C (4 January 2008); doi: 10.1117/12.757854
Show Author Affiliations
Yanbei Chen, Nanjing Univ. of Science and Technology (China)
Jian Lu, Nanjing Univ. of Science and Technology (China)
Xiaowu Ni, Nanjing Univ. of Science and Technology (China)


Published in SPIE Proceedings Vol. 6825:
Lasers in Material Processing and Manufacturing III
ShuShen Deng; Akira Matsunawa; Xiao Zhu, Editor(s)

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