用AWB分析一大型空間屋蓋結構，在求解時出現以下錯誤：

A solver pivot warning or error has been detected in the UX degree of freedom of node 4776 located in Geom-1_beams. This is usually a result of an ill conditioned matrix possibly due to unreasonable material properties, an under constrained model, or contact related issues.  Check results carefully. You may select the offending object and/or geometry via RMB on this warning in the Messages window.

*** ERROR ***                           CP =       2.062   TIME= 17:17:43
 There is at least 1 small equation solver pivot term (e.g., at the UX  
 degree of freedom of node 4776).  Please check for an insufficiently   
 constrained model.     

初步以為是桿件節點的連接有問題，但在Spaceclaim中檢查后各節點連接均沒有問題。改變多種約束方式依然提示上述錯誤。

以下是AWB工程文件（ANSYS 18版本），希望前輩們能夠指導下，十分感謝

TEST.rar