This study aims to evaluate coating adhesion durability using the laser shock-wave adhesion test (LaSAT). In particular, the interfacial strength with respect to the applied loading cycle is evaluated quantitatively. This method uses strong elastic waves induced by pulsed laser irradiation, as interfacial fracture of the coating occurs due to a strong wave. The coating delamination can be identified from changes in the out-of-plane displacement waveform, yielding a critical laser energy for coating delamination. Subsequently, computation of elastic wave propagation using the finite difference time domain (FDTD) method was carried out to estimate the tensile stress developed at the coating/substrate interface, yielding the interfacial strength. In addition, the durability of interfacial adhesion was investigated by repeated LaSATs. Repetitive lower stress loading was applied to the interface using repeated laser irradiations. It was found that repetitive loading encourages interfacial fracture, which has a stress level lower than that of single (monotonic) laser irradiation. For various levels of irradiation laser energy, the interfacial adhesion durability was investigated. This result may be useful for evaluating adhesion durability when a coating/film is used under cyclic loading over a long-time duration.

中文翻译：

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使用重复激光冲击波粘附试验评估表面涂层粘附耐久性的发展

本研究旨在使用激光冲击波附着力测试 (LaSAT) 评估涂层附着力的耐久性。特别是，定量评估相对于施加的加载循环的界面强度。这种方法使用由脉冲激光照射引起的强弹性波，因为强波会导致涂层的界面断裂。涂层分层可以从平面外位移波形的变化中识别出来，从而产生涂层分层的关键激光能量。随后，使用有限差分时域 (FDTD) 方法计算弹性波传播，以估计涂层/基材界面处产生的拉伸应力，从而产生界面强度。此外，通过重复的 LaSAT 研究了界面粘附的耐久性。使用重复的激光照射对界面施加重复的较低应力载荷。发现重复加载会促进界面断裂，其应力水平低于单次（单调）激光照射的应力水平。对于不同水平的照射激光能量，研究了界面粘附耐久性。当涂层/薄膜在长期循环负载下使用时，该结果可用于评估粘附耐久性。