基于态基近场动力学的碳化硅陶瓷圆柱壳体断裂损伤分析
FRACTURE DAMAGE ANALYSIS OF SILICON CARBIDE CERAMIC CYLINDRICAL SHELLS BASED ON STATE-BASED PERIDYNAMICS
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摘要: 碳化硅(SiC)陶瓷材料具有优异的力学性能, 广泛应用于各种工程部件中. 然而, 陶瓷是脆性材料, 当发生脆断时会造成巨大的危害. 因此对其断裂行为的准确预测显得极为重要. 为了研究SiC陶瓷壳体在外载荷作用下的断裂损伤机理, 首先通过准静态拉伸和压缩实验获得SiC陶瓷的临界能量释放率, 建立了适用于拉伸和压缩损伤分析的常规态基近场动力学模型. 然后, 采用Fortran语言编程实现了陶瓷壳体在线性递增外载荷作用下断裂损伤行为的数值仿真, 并将所获得的仿真值与理论预测值进行对比, 验证了所建模型的准确性. 最后, 对仿真结果进行详细分析, 揭示了壳体结构的损伤扩展演化规律. 仿真结果表明: 初始损伤区源于壳体内壁面的压缩断裂, 且沿环向呈90°均匀分布. 随着载荷的逐渐增加, 壳体外壁面出现拉伸断裂损伤区, 内外壁面的损伤区先沿着周向扩展, 再向着壳体中面缓慢延伸, 并在厚度方向贯穿整个壳体. 随后, 在壳体轴线方向出现拉-压损伤混合区, 该损伤区沿着轴向扩展, 最终将壳体分成4个断裂区. 所建模型能够有效地描述复杂载荷作用下SiC陶瓷结构的断裂损伤演化过程, 同时弥补了态基近场动力学在断裂分析方面的不足.Abstract: Silicon carbide (SiC) ceramic material have excellent mechanical properties and is widely used in various engineering components. However, SiC ceramic is an inherently fragile material that can cause tremendous hazards when brittle fracture occurs. Therefore, accurate prediction of its fracture behavior is extremely important. In order to investigate the fracture damage mechanism of SiC ceramic shells subjected to external loads, this paper firstly obtained the critical energy release rate of SiC ceramic through quasi-static tensile and compression experiments, and an ordinary state-based peridynamic model that is appropriate for tensile and compression damage analysis is established. Then, the numerical simulation of the fracture damage behavior of ceramic shells under linearly increasing external loads is implemented by programming in Fortran language, the correctness of the constructed model is confirmed by comparing the simulation value that is achieved with the theoretical predicted value. At last, the fracture damage propagation evolution process of the shells is revealed in detail. The simulation results show that the initial damage zones originate from the compression fracture of the inner surface of the shell, and uniformly distributed at 90° along the circumferential direction. With the gradual increase of the external loads, the tensile fracture damage zones appear on the external surface of cylinder, and the damage zones on the inner and outer surfaces first extend along the circumferential direction, then slowly propagate to the middle surface of the shell, and penetrate the whole cylinder in the thickness direction. Following that, two mixed zones of tensile-compressive damage appear in the axial direction of the shell, which extend along the axial direction and ultimately divide the shell into four fracture zones. The constructed model can successfully describe the fracture damage evolution process of the SiC ceramic structures under intricate loads, while compensating for the drawbacks of state-based peridynamics in damage analysis.