高温结构的材料本构模型和有限元分析方法

MATEKIAL CONSTITUTIVE MODEL AND FINITE ELEMENT ANALYSIS METHOD OF HIGH-TEMPERATURE STRUCTURES

考虑到对大量工作于高温和循环热—机械载荷作用下的机械结构进行实际而有效的热弹塑性—蠕变分析，并进行合理的设计和寿命估计的需要，本文建立并完善了用于高温非弹性分析的修正分离型本构模型。此模型能描述材料循环弹塑性和蠕变行为以及它们之间的相互作用。发展了用于高温非弹性有限元分析的数值方案，此方案在算法上是无条件稳定的，并有较高的精度和效率。多种算例证实了上述方案的有效性和对于工程分析的实用性。

In industries,a large number of structures or cornponents are working at elevated ternperature andsubjected to cyclic thermo-mechanical loadings.In order to predict their inelastic deforrnations and damages andevaluate their lives,the thermo-elastic-plastic and creep analysis must be first performed. In this paper,first,amodified superposition constitutive model for high temperature inelastic analysis is developed. The interactionbetween creep and plasticity is considered by introducing two interactiqn factors,Second,based on the initial elasticstiffness rnatrix rnethod and accelerating convergence,an iterative scheme is proposed for inelastic analysis,and ahigh accracy schen1e for integrating the constitutive equations is developed.Numerical examples demonstrate thestability,accuracy and applicability of the procedure.