请问如下问题如何解决？谢谢
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我将模型导入ansys中计算时，遇到如下问题，请问怎么解决？
811 small pivots encountered in system matrix. Check for an
unconstrained model.
Small negative pivot equal to -2.03822911E-49 is found. Check for
unconstrained model.
Sparse solver maximum pivot= 1.309636918E+31 at node 259771 UY.
Sparse solver minimum pivot= -3.783789506E+23 at node 181547 UY.
Sparse solver minimum pivot in absolute value= 0 at node 84752 UZ.
811 small pivots encountered in system matrix. Check for an
unconstrained model.
Small negative pivot equal to -2.03822911E-49 is found. Check for
unconstrained model.
Sparse solver maximum pivot= 1.309636918E+31 at node 259771 UY.
Sparse solver minimum pivot= -3.783789506E+23 at node 181547 UY.
Sparse solver minimum pivot in absolute value= 0 at node 84752 UZ.
模型约束不够啊！