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提出了一种用于模拟带基体裂纹损伤的陶瓷基复合材料(CMC)杆动力学响应的多尺度方法。在宏观尺度采用有限元法模拟CMC杆的动力学响应。在细观尺度,采用多尺度力学模型计算材料的应力应变响应。建立了分布式计算系统加速模拟过程。通过算例分析计算了Nicalon/CAS-Ⅱ杆在轴向简谐载荷下的动力学响应。结果表明CMC在拉伸和压缩载荷下的应力应变响应都表现出明显的非线性特征。这导致CMC杆在简谐载荷作用下的动力学响应与弹性杆不同:(1)CMC杆的位移响应不再关于u=0对称;(2)由于非线性阻尼的作用,当外载荷频率达到一阶固有频率时,如果外载荷的幅值不是太大,CMC杆的位移响应被限制在一定的范围内,而不产生发散;(3)减小基体裂纹间距会增加杆的位移响应幅值。
A multi-scale method is proposed for simulating the dynamic response of ceramic matrix composite (CMC) rods with crack damage. The dynamic response of CMC rod was modeled by the finite element method at the macro scale. At the meso-scale, a multi-scale mechanical model is used to calculate the material’s stress-strain response. Established a distributed computing system to speed up the simulation process. The dynamic response of Nicalon / CAS-Ⅱ rod under axial simple harmonic load was calculated and analyzed by a numerical example. The results show that the stress-strain response of CMC under tensile and compressive loads shows obvious nonlinear characteristics. This results in the difference of the dynamic response of CMC rod under the simple harmonic load: (1) the displacement response of CMC rod is no longer symmetrical about u = 0; (2) due to the effect of nonlinear damping, when the external load frequency reaches For the first-order natural frequency, if the amplitude of the external load is not too large, the displacement response of the CMC rod is limited within a certain range without divergence. (3) Reducing the matrix crack spacing will increase the displacement response amplitude of the rod .