基于态型近场动力学的淬火陶瓷破坏过程分析

Analysis on failure of quenching ceramics using state-based peridynamics

基于态型近场动力学理论进行复合陶瓷板淬火破坏过程力学建模与分析。引入热膨胀项反映材料的热致变形,基于物质点对的断裂定义损伤,构建三维非局部常规态型近场动力学热弹脆性模型,结合多速率显式积分法计算热-力耦合,实现热冲击荷载作用下陶瓷板起裂和裂纹扩展全过程的模拟。通过模拟典型淬火Al_(2)O_(3)陶瓷板的破坏过程,并与实验和其他数值结果对比,验证了该模型和方法。使用该模型研究了含不同α-Al_(2)O_(3)纤维掺杂比率的Al_(2)O_(3)复合陶瓷板淬火破坏过程,结果表明,断裂韧性的提高显著减少了裂纹数量并延后起裂时间;含5%α-Al_(2)O_(3)纤维掺杂比率的复合陶瓷材料综合力学性能最优,能够有效提升构件抵抗热冲击荷载能力。

The failure process of quenching ceramics is investigated based on state-based peridynamic theory.A three-dimensional nonlocal thermoelastic brittle peridynamic model is proposed,in which a thermal expansion term is introduced to reflect thermal deformation and the damage is defined on material-point bond scale.With multirate integration method for thermal-mechanical coupling calculation,the proposed model is employed to simulate the crack initiation and propagation process of quenching Al_(2)O_(3) ceramic plates,and its validation is established by comparing the simulation results with available experimental and other numerical results.Further investigations into the damage of Al_(2)O_(3) composite ceramic plates with differentα-Al_(2)O_(3) fiber ratio indicate that the increase of fracture toughness can reduce the number of cracks and delay crack initiation time significantly,and the composite with 5%α-Al_(2)O_(3) fiber ratio shows excellent comprehensive mechanical properties to improve the strength of ceramic components under thermal shock loading.