组合梁几何非线性与长期效应的同步算法

首先根据建立的随转坐标系下考虑滑移组合梁单元平衡方程,结合初应变法得到组合梁收缩徐变等效节点力有限元列式.然后基于随转列式全量法,利用总体坐标系与随转坐标系下变量间转换矩阵,获得界面滑移平面组合梁单元收缩徐变与几何非线性同步考虑的实用算法.该方法的优点是可实现几何非线性与收缩徐变材料非线性算法上的分离,收缩徐变仅在随转坐标系下考虑,几何非线性通过转换矩阵考虑.最后,结合算例说明考虑滑移的组合梁几何非线性与收缩徐变之间存在着耦合作用.

Algorithm of Composite Beam Synchronously Considering Geometrical Nonlinearity and Long Term Effects

The interlayer slip, geometric nonlinearity, concrete shrinkage and creep may coexist in long-span flexible composite structures such as composite cable-stayed bridges. Firstly, balance equation of composite beam element with interlayer slips under corotational coordinate system was deduced. Combining initial strain method,equivalent nodal force formulation of shrinkage and creep was obtained. Based on the corotational method, using the transformation matrices relating local and global quantities, a practical algorithm for analysis of composite beam with interlayer slips considering geometric nonlinearity, concrete shrinkage and creep synchronously was put forward. The advantage of this approach is that it leads to the separation of geometrical and material non-linearities such as shrinkage and creep. The shrinkage and creep is only present at the level of the local element, whereas the geometrical non-linearity is included in the transformation matrices. Finally, it was illustrated that the geometric nonlinearity is coupled with shrinkage and creep for composite beam with interlayer slip by an example.