简谐激励下声学黑洞梁的疲劳裂纹扩展分析

Fatigue crack propagation analysis of acoustic black hole beam under harmonic excitation

针对含有裂纹的声学黑洞(ABH)梁,基于假设振型法建立振动力学方程,采用包含裂纹位置及深度信息的等效弯曲刚度模型描述裂纹对ABH梁振型的影响.利用Paris公式模拟疲劳裂纹的扩展速率,提出ABH梁的振动疲劳寿命预测流程图.MATLAB数值模拟与COMSOL有限元分析结果表明,基于等效弯曲刚度模型的数值模型与有限元仿真结果吻合.裂纹扩展分析表明,ABH梁特征频率的阶数与疲劳寿命没有内在关系.振动疲劳模拟表明ABH结构的特征参数会影响疲劳寿命分布.

Avibration equation of acoustic black hole(ABH)beam with cracks was established based on the hypothetical mode method.An equivalent bending stiffness model involving the information of crack location and depth was employed to describe the influence of a crack on the vibration mode.The fatigue crack propagation was simulated using the Pair's formula.A flowchart of vibration fatigue life prediction was proposed for the ABH beam.The results of MATLAB numerical simulations and COMSOL finite element analysis showed that the numerical model using the equivalent bending stiffness model was in good agreement with the finite element simulation results.The crack growth analysis showed that there was no intrinsic relationship between the order of the ABH beam eigen frequencies and the fatigue life.The vibration fatigue simulations showed that the characteristic parameters of ABH structure affected the fatigue life distribution.