图示结构原始刚度矩阵为：（） <br/> <img src="http://jgxm-question.oss-cn-beijing.aliyuncs.com/psst/files/b2696c25557f4914a7a2493f9ae1925b.png?x-oss-process=image/sharpen,200"/><br/> 已知各单元的整体坐标的单元刚度矩阵为：<img src="http://jgxm-question.oss-cn-beijing.aliyuncs.com/psst/files/1b7533effb144e2cbe4c1cc9f379f025.png?x-oss-process=image/sharpen,200"/>