在分析某空间桁架架构时需要把部分beam杆件转换为link180单元，插入以下命令流：

et,matid,link180

SECTYPE, 1,link, ctube, , 0

SECDATA,44.5,48

用该命令流对结构单元进行修改后，分析时出现以下报错：

*** ERROR ***                           CP =       1.578   TIME= 13:59:38
 Beam element 1 references section 1 which is not a beam section.       

 *** ERROR ***                           CP =       1.578   TIME= 13:59:38
 Beam element 2 references section 1 which is not a beam section.       

 *** ERROR ***                           CP =       1.578   TIME= 13:59:38
 Beam element 3 references section 1 which is not a beam section.       

 *** ERROR ***                           CP =       1.578   TIME= 13:59:38
 Beam element 4 references section 1 which is not a beam section.       

 *** ERROR ***                           CP =       1.578   TIME= 13:59:38
 Beam element 5 references section 1 which is not a beam section.       

 *** ERROR ***                           CP =       1.578   TIME= 13:59:38
 Beam element 6 references section 1 which is not a beam section.       

 *** ERROR ***                           CP =       1.578   TIME= 13:59:38
 Beam element 7 references section 1 which is not a beam section.       

 *** ERROR ***                           CP =       1.578   TIME= 13:59:38
 Beam element 8 references section 1 which is not a beam section.       

 *** ERROR ***                           CP =       1.578   TIME= 13:59:38
 Beam element 9 references section 1 which is not a beam section.       

希望前辈们能指点后辈一下，十分感谢，以下是workbench分析文件。

test.rar