三维耦合热裂纹体的时域边界元解及其收敛性

将现有耦合准静态热弹性问题的时域边界元法进一步扩展应用到三维裂纹问题的分析中，时间采用常数插值，空间采用二次等参单元插值，并用奇性元模拟了三维裂纹前沿的应力奇异性，获得了几个典型的三维裂纹体在热冲击工况下的热动态应力强度因子；着重考察了这种时域方法解的精度和收敛性，计算结果表明：随着离散网格的细分，计算结果迅速收敛；随着时间步长的细分，时域边界元法的累积误差减小，精度提高，所以，耦合热弹性问题的时域边界元法在解三维裂纹问题时具有较高的精度。

Time-Domain Boundary Element Solutions and Convergence Analysis for 3-D Coupled Thermoelastic Crack Bodies

The time domain boundary element method in coupled quasi static thermoelasticity was developed for 3 D thermoelastic crack problems. The temporal interpolation is chosen constant and the spatial interpolation is chosen quadratic isoparametric. Singular elements are used to simulate the stress singularity along the front of a crack. The thermal dynamic stress intensity factor for several typical 3 D crack bodies subjected to transient thermal shock was calculated, especially the precision and convergence were investigated. The main conclusion is that the result is rapidly converged with the discretization mesh subdivision, while the accumulative error is decreased and the precision is improved with the time step subdivision. Hence, the accuracy of time domain boundary element method for 3 D coupled thermoelastic crack problems is demonstrated.