WARNING : DISPLACEMENT DX AT NODE NO. 21 IS ABNORMAL. WARNING : DISPLACEMENT DY AT NODE NO. 21 IS ABNORMAL. WARNING : DISPLACEMENT DZ AT NODE NO. 21 IS ABNORMAL. WARNING : DISPLACEMENT RX AT NODE NO. 21 IS ABNORMAL. WARNING : DISPLACEMENT RY AT NODE NO. 21 IS ABNORMAL. ERROR NORM IS NaN or INFINITE THE PROGRAM IS ABORTED 请问这个问题怎么解决啊 大佬