适用于数值流形法分析的混凝土徐变递推公式

Recursive Formulae of Concrete Creep Suitable for Numerical Manifold Method Analysis

目前大体积混凝土结构温度应力仿真计算主要采用有限元法。对于复杂结构,有限元法仿真计算存在计算规模大、前处理难度大等问题。数值流形法具有网格剖分和自适应分析方便等优点,可为温度应力仿真计算提供有力的分析手段。混凝土徐变可以松驰温度应力,在温度应力仿真计算中一般都要考虑徐变的影响。有限元法中采用的徐变递推公式是基于数值积分点的应力状态,但数值流形法的单元应力呈多项式函数分布,这种递推公式已不适用。为此,推导了适合于数值流形法的徐变递推公式及等效荷载计算公式,并编制了数值流形法仿真计算程序,通过数值算例验证了公式的正确性。

Currently,the thermal stress analysis simulating the construction process of mass concrete structures primarily adopts the finite element method（FEM）.But much computation is required and difficulties in mesh generation are encountered in conducting FEM analysis of complicated structures.For convenience in adaptive analysis and mesh division,the numerical manifold method（NMM） provides a new effective approach for the thermal stress analysis.The effects of the concrete creep should be generally considered in the thermal stress analysis as the concrete creep can reduce thermal stresses.The recursive formulae of the concrete creep widely used in FEM,which were derived based on the stresses at numerically integrated points of finite elements,are not suitable for NMM analysis due to the stresses of manifold elements are expressed in the polynomial form,especially in high-order NMM.According to the recursive formulae of concrete creep used in FEM,recursive formulae of concrete creep and formulae of corresponding equivalent loads suitable for NMM analysis are deduced.On the basis of the derived formulae,a program of high-order NMM for the thermal field and the thermal stress analysis is developed and verified by an example.