求助：USER FATAL MESSAGE 9117(XREAD)

sqlm0720

^^^ USER FATAL MESSAGE 9117 (XREAD)
^^^ MASSLESS MECHANISMS MAY BE PRESENT IN THE MODEL BUT PARAM,MECHFIX,NO HAS BEEN SPECIFIED.
^^^ USER ACTION: USE THE DEFAULT VALUE FOR PARAM,MECHFIX TO AUTOMATICALLY CONSTRAIN MASSLESS MECHANISMS.
这种错误怎么回事啊，跪求大侠赐教，困扰很久了◎◎

sqlm0720

就没人遇到过这种错误吗？

eric4pft

模态分析没有定义质量？