ansys求解时出现错误，求教

水中谐响应求解时出现如下错误：

property sons of material 4 referenced by element 1 was set to 0 which cannot be negative or extremely small.

property sons of material 3 referenced by element 76801 was set to 0 which cannot be negative or extremely small.

property sons of material 5 referenced by element 204001 was set to 0 which cannot be negative or extremely small.

其中材料3、4、5分别为近场水，远场水，边界水；不知是材料设置的问题还是网格划分的问题，还是什么其他问题？？求大神给小弟指教，谢谢！！！