Vibrations of beams containing cracks are usually investigated by using open or breathing crack models. Neither one of these approaches considers the plasticity induced crack closure (PICC) phenomena which occurs in fatigue crack growth. In this study, PICC is integrated into the vibration analysis of a cracked beam. First, fatigue crack growth at a notch is simulated with elastoplastic finite element analysis. Residual deformations, stresses and the contact pressures on crack faces are obtained. In the second phase, the model which includes these quantities is used for forced vibration analysis under harmonic loading by using implicit finite element method. For comparison, analyses are also running without PICC. Simulation results indicate that PICC has a significant effect on vibrations of cracked beams. For low load amplitude levels, cracked beam behaves like an intact beam. Nonlinear behavior appears only at rather high amplitude levels. It is concluded that PICC could suppress the crack breathing behavior and this could make it difficult to detect a fatigue crack in a beam from its nonlinear vibration response.

中文翻译：

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裂纹闭合效应对裂纹梁振动的模拟

通常使用开放或呼吸裂纹模型来研究包含裂纹的梁的振动。这些方法都没有考虑疲劳裂纹扩展中发生的塑性诱导裂纹闭合 (PICC) 现象。在本研究中，PICC 被集成到裂纹梁的振动分析中。首先，通过弹塑性有限元分析模拟缺口处的疲劳裂纹扩展。获得裂纹面上的残余变形、应力和接触压力。在第二阶段，包含这些量的模型通过隐式有限元方法进行谐波载荷下的受迫振动分析。为了进行比较，分析也在没有 PICC 的情况下进行。仿真结果表明PICC对裂纹梁的振动有显着影响。对于低载荷幅度水平，裂纹梁的行为类似于完整的梁。非线性行为仅出现在相当高的幅度水平上。结论是，PICC 可以抑制裂纹呼吸行为，这可能使得从梁的非线性振动响应中检测疲劳裂纹变得困难。