时间自适应在海洋平台桩靴上拔模拟中的应用

该文通过模型试验和时间自适应有限元分析的方法模拟了海洋平台桩靴的上拔过程。在有限元数值分析中引入了启发式和基于误差评估的两种时间自适应方法,有效解决了因时间步长的选取而引起的不收敛和计算效率低等问题。启发式算法通过控制收敛速度调整时间步长,有效预防了不收敛或收敛过慢,但时步调整较为粗糙。基于误差评估的时间自适应有效控制了计算误差,能够平滑地调整时间步长,相比于启发式算法更具有精确性和稳定性。通过试验和数值方法得出海洋平台在上拔桩靴时需克服海床土体吸附力,采用时间自适应方法可以高效模拟桩靴位移时程的非线性问题。

APPLICATION OF AUTOMATIC TIME STEPPING METHOD IN SIMULATION OF PLATFORM’S LEG PULLOUT PROCESS

Using model test and numerical method, the pullout process of mobile platform’s leg is simulated. In the finite element simulation, two time stepping methods are implemented to adjust the time step size. One is based on the velocity of convergence; the other is based on the truncation error estimation in temporal discretization. The results show that the displacement of the platform’s leg nonlinearly increases. To effeciently deal with this nonlinearity, the step size is reasonably arranged during the whole calculation time by the two methods. Compared with the fixed time step method, automatic time stepping method can improve the calculation efficiency and the solution accuracy.