小妹最近在分析一个空间桁架,求解应力及位移,建模过程应该不存在什么问题了,但总出现这样的错误
*** ERROR *** CP= 50.984 TIME= 16:27:57
At least 1 number of ZERO PIVOT is in Eqn. Matrix system.
*** ERROR *** CP= 51.031 TIME= 16:27:58
There are 1 negative pivot terms encountered in Sparse Direct Solver.
Check for an insufficiently constrained model.
*** ERROR *** CP= 51.078 TIME= 16:27:59
Bisection may be activated if it is a nonlinear analysis.
请教一下,可能是什么原因??
我实在是连错误都看不懂,还是菜鸟一只!!多谢各位拉!