等效线性粘弹性模型UMAT子程序编写，用粘弹性Kelvin模型来反映土体在周期荷载下的滞回性。(The UMAT subprogram of the equivalent linear viscoelastic model is written, and the viscoelastic Kelvin model is used to reflect the hysteretic behavior of the soil under p

等效粘弹性模型UMAT子程序，适合准备编程学习的朋友(Equivalent viscoelastic model -- UMAT subroutine)