密肋复合墙体温度应力数值分析

在密肋复合墙板的生产过程中,由于普通混凝土较蒸压加气混凝土的材料性质有较大差别,在变化的环境温度下,两者接触界面存在相互约束、变形互不协调而出现开裂问题。为探讨密肋复合墙体温度裂缝机理,采用三维有限元方法模拟墙板的生产过程中温度场的变化,进行温度应力仿真分析,重点探讨墙体温度应力与环境温度变化之间的关系。计算结果表明:建立的有限元模型符合实际情况,温度陡降是构件表面拉应力突升的直接原因;构件表面对温度反应敏感,构件表面处的温度梯度大于内部;构件表面处界面是其薄弱环节。预留缝方式处理界面表面温度裂缝问题是一种方便有效措施。

NUMERICAL ANALYSIS OF THERMAL STRESSES OF MULTI-RIBBED COMPOSITE WALL

In the production process of multi-ribbed composite wall,cracks will occur on the contact interface between RC ribbed-frame and AAC blocks under temperature action because of the large difference of material property between concrete and AAC. To discuss the mechanism of the thermal crack of MRCW,the 3D FEM is adopted to simulate temperature field transformation and the analysis of thermal stress is carried out.The relationship between thermal stress and temperature field transformation is presented.The results show that the FE model in this paper accords with engineering practices,and dramatic temperature-decline is the primary reason of increasing abruptly tension stress on surface.The component surface is highly sensitive to any temperature changes.And the temperature gradient of the surface is higher than that of the inner of the component.So,the weakness part is at the component surface.It is suggested that a gap should be set on the contact interface,which would effectively avoid the crack caused by thermal stresses.