小冲孔试样高温蠕变损伤的有限元分析

FINITE ELEMENT ANALYSIS OF CREEP DAMAGE OF SMALL PUNCH TEST SPECIMEN AT ELEVATED TEMPERATURE

基于小冲孔蠕变试验 ,建立 1Cr0 .5Mo耐热钢小冲孔蠕变试样的有限元模型。应用改进的K R蠕变损伤本构方程 ,分析在 5 5 0℃、恒载荷条件下的试样中心挠度、应变等随时间的变化规律以及试样蠕变损伤的发展与断裂过程。计算结果表明 ,整个试样的损伤在中心位置比较严重 ,且呈现明显的局部化特征 ;试样的失效首先发生在下表面上 ,离试样下表面中心约 0 .8mm 。

The finite element model of a small punch test specimen of 1Cr0.5Mo steel is established. Modified K-R(Kachanov-Rabotnov) creep damage constitutive equations are used to analyze variation of central deflection and creep strain with time and the evolution of creep damage subjected to constant forces. The numerical results show that the creep damage at the central part is high, and localization of damage is obvious. Initial failure occurs at the bottom surface, 0.8 mm away from the center which agrees well with the observation from the test.