陶瓷材料相变增韧尺寸效应的力学分析

ANALYSIS OF SIZE EFFECT ON TRANSFORMATION TOUGHENING IN CERAMICS

利用计及相变剪切效应的陶瓷材料本构关系和裂尖场的双参数表达式，对平面应变Ⅰ型裂纹定常扩展过程进行渐近分析．基于渐近场和能量积分，得到韧性增值的估算公式，并且根据数值结果和实验现象进一步讨论相变剪切塑性和应力非奇异项的影响．

Based on the constitutive taw including the shear effect of transformation and twoterm expansion of near-tip fields, the asymptotic analysis is carried out for plane-strain mode Ⅰsteadily-growing crack problems in ceramics. The equation for evaluating toughness enhancement is obtained by means of asymptotic fields and the energy balance. Furthermore, the effects of shear deformation and non-singular stress on the toughening are discussed on the basis of numerical results and experimental observation.