Study on the temperature field loaded by a shaped laser beam on the top surface of a cylinder head for thermal fatigue test

Abstract

In thermal fatigue test, the key point is whether the temperature field on the top surface of cylinder head induced by the heat source can well match it in real service. In order to produce the target temperature field in service which is measured by thermocouples, shaped laser beam generated by diffractive optics element (DOE) is chosen as the heat source to irradiate on the top surface of cylinder head. The DOE is designed based on the Gerchberg-Saxton (GS) algorithm and the simulated temperature field is calculated by finite element model (FEM). The results show that the simulated and experimental temperature field can well match the target one which demonstrates that this method is feasible to produce the target temperature field and can be used in thermal fatigue test.

Design and analysis of a spatially shaped laser beam used for temperature field simulation

“…Because of the ability to freely modulate the irradiance and phase profile of laser beam by the surface relief microstructure, diffractive optical elements (DOEs) have been widely used in laser beam shaping technology [7][8][9][10]. Based on the spatial shaping technology and DOE, some studies [11][12] have shown that, in thermal fatigue test of engine parts, it is possible to use a shaped laser beam for thermal loading to induce temperature field similar to the actual working condition. The spatial intensity distribution of the shaped laser beam can be modulated according to the temperature value of each position, so as to ensure the accuracy and reliability of thermal fatigue test.…”