在Optistruct里如何设定revolute joint?

目前在optistruct以简单模型设定revolute joint

并给予重力条件进行模拟，但结果会一直错误

错误为

** ERROR # 153 ***

 Exactly zero pivoting encountered during Numerical Factorization;

 the model may have rigid body mode.

  Solver error no. =   -503 

        spc set id = 3 

             index =      1 

 Possible reasons are:

 1) insufficiently constrained model,

 2) having rigid body mechanisms within the model,

 3) extremely ill-conditioned rigid element sets,

 4) extremely thin shells (as used for skinning) that have MID2/MID3,

 5) gap elements with extremely high stiffness (KA, especially KT or MU).

 Check the model and rerun the problem.

 (MECHCHECK may be used to find the rigid body modes.  To do so,

  change the input to be an eigenvalue analysis and add MECHCHECK.)

 (WARNING: results obtained with MECHCHECK cannot be used because

          the model is changed internally.)

 This error was detected in subroutine bcsmtxfct.

目前在里面joint的设定为图所示

这边也想请教MPC和FE实际意义差在哪

目前都是已FE去进行设定

这边有附上模型(FE)，有去找到有些文章是说这是约束不足

但有假设一些约束条件，这个错误还是会出现

8.rar