请教大神，这个问题该怎么解决？

mgdtumu2015

Three factorizations in a row failed. Check the model. It is possible that the model contains the kinematic coupling definition set up in a way that a degree of freedom has neither mass nor stiffness.
一排三个分解失败。检查模型。该模型包含了一个自由度既没有质量也没有刚度的运动耦合定义。在用弹簧接触的模拟中出了这个错误，该怎么解决呢？