abaqus仿真时遇到错误，求大神解

好像意思是刚体上的参考点没有转动惯量约束，求大神解The rigid bodies with the reference nodes contained in node set ErrNodeRefNodeNoRotInert have no rotary inertia associated with them and the rotational degree of freedom of the reference nodes is not restrained. Either rotary inertia must be defined at the reference node or the rotational degree of freedom of the reference nodes must be constrained. See the status file for further details.