万能杆件塔架稳定分析

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1、万能杆件塔架稳定分析北京迈达斯技术有限公司目录1、工程概况····························································································22、定义材料和截面················································································2定义钢材的材料特性·········································································

2、······2定义截面··································································································23、建模····································································································3建立第一根竖杆：·······································································

3、···········3建立余下三根竖杆：···············································································4建立横向支撑和斜撑单元：···································································5建立其余三根竖杆间的支撑：·······························································6添加边界条件······························

4、··························································11添加荷载工况························································································12定义屈曲分析························································································134、查看结果····································

5、······················································14查看屈曲模态························································································14表格形式查看各模态的临界荷载·························································15万能杆件塔架稳定分析稳定分析是研究结构或构件的平衡状态是否稳定的问题。处于平衡位置的结构或构件，在任意微小外界扰动下，将偏离其平衡位置，当

6、外界扰动除去后，仍然自动回复到初始平衡位置时，则初始平衡状态是稳定的。如果不能回复到初始平衡位置，则初始平衡状态是不稳定的。结构或构件由于平衡形式的不稳定性，从初始平衡位置转变到另一平衡位置，称为屈曲，或称为失稳。研究稳定可以从小范围内观察，即在邻近原始状态的微小区域内进行研究。为揭示失稳的真谛，也可从大范围内进行研究。前者以小位移理论为基础，而后者建立在大位移非线性理论的基础上。引出了研究结构稳定问题的两种形式：第一类稳定，分支点失稳问题；和第二类稳定，极值点失稳问题。屈曲分析在数学上是一个求解特征值的问题。屈曲分析结果输出的特征值也就是屈曲荷载系数，而我们关心的是屈曲荷载值的大

7、小。求出屈曲荷载系数后，可以根据荷载情况计算出屈曲荷载值。第一种情况：输入自重（不变）和二期荷载（可变）进行屈曲分析，得到的屈曲荷载系数×二期荷载＋自重＝屈曲荷载值。第二种情况：输入自重（可变）和二期荷载（可变）进行屈曲分析，得到的屈曲荷载系数×（二期荷载＋自重）＝屈曲荷载值。由于屈曲分析数学上是一个求解特征值的问题，求出负数也是正常的，但这个结果在力学上没有物理意义，所以有些程序直接将他屏蔽掉了。midas/Civil2006中对于这些结果也可以屏蔽：另外需要注意的