A parametric study of laser spot size and coverage on the laser shock peening induced residual stress in thin aluminium samples

The Journal of Engineering

J. Rebelo-Kornmeier¹  M. Klaus²  M. Meixer²  N. Huber³  P. Staron³  N. Kashaev³  M. Sticchi³  Y. Sano⁴ 

[1] Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Lichtenbergstr. 1, 85748 Garching, Germany;Helmholtz-Zentrum Berlin, Department of Microstructure and Residual Stress Analysis, Hahn-Meitner-Platz 1, D-14109 Berlin, Germany;Helmholtz-Zentrum Geesthacht, Institute of Materials Research, Max-Planck-Straße 1, D-21502 Geesthacht, Germany;Toshiba Corporation, Power and Industrial Systems Research and Development Center, 8 Shinsugita-cho, Isogo-ku, 235-8523 Yokohama, Japan

关键词: peen size;    HEL value;    spot size;    fatigue enhancement treatment;    outer layers;    stress field;    analytical analysis;    AA2139-T3 aluminium alloy;    numerical analysis;    under-water-LSP;    compression field;    laser energy;    compressive residual stresses;    RS-field;    induced stress magnitude;    surface compressive stresses;    laser shock peening induced residual stress;    AA7050-T76 aluminium alloy;    electronic speckle pattern interferometry;    AA2024-T351 aluminium alloy;    metallic components;    RS measurement;    thin-aluminium metal;    AA7075-T6 aluminium alloy;    zero-depth value;    2D-axisymmetrical finite element model;    Hugoniot elastic limit;    X-ray diffraction;    compressive stress;    hole drilling;    laser spot size;   

DOI  :  10.1049/joe.2015.0106

学科分类：工程和技术（综合）

来源: IET

【 摘 要 】

Laser Shock Peening is a fatigue enhancement treatment using laser energy to induce compressive Residual Stresses (RS) in the outer layers of metallic components. This work describes the variations of introduced RS-field with peen size and coverage for thin metal samples treated with under-water-LSP. The specimens under investigation were of aluminium alloy AA2024-T351, AA2139-T3, AA7050-T76 and AA7075-T6, with thickness 1.9 mm. The RS were measured by using Hole Drilling with Electronic Speckle Pattern Interferometry and X-ray Diffraction. Of particular interest are the effects of the above mentioned parameters on the zero-depth value, which gives indication of the amount of RS through the thickness, and on the value of the surface compressive stresses, which indicates the magnitude of induced stresses. A 2D-axisymmetrical Finite Element model was created for a preliminary estimation of the stress field trend. From experimental results, correlated with numerical and analytical analysis, the following conclusions can be drawn: increasing the spot size the zero-depth value increases with no significant change of the maximum compressive stress; the increase of coverage leads to significant increase of the compressive stress; thin samples of Al-alloy with low Hugoniot Elastic Limit (HEL) reveal deeper compression field than alloy with higher HEL value.

【 授权许可】

CC BY