【摘要】 T应力是存在于裂纹尖端平行于裂纹方向的应力,是裂纹尖端应力级数展开式中的常数项,它对裂缝尖端应力场的贡献不容忽视。三点弯曲梁是普通实验室中用来测定试件断裂性能的基本几何形式,为保证这些断裂参数确定的有效性,必须首先确定裂纹尖端T应力的大小,才能明确T应力对断裂参数的影响程度。该文通过有限元数值模拟得到跨高比为4的三点弯曲缺口梁和纯弯作用下单边裂纹尖端的T应力大小,与已有文献的比较验证了有限元计算的有效性。在此基础上根据圣维南原理,由跨高比为4和纯弯作用这两种情况下的T应力推导出一般跨高比情况下裂纹尖端的T应力表达式,并以跨高比为6、8和10三种情况为例,进行了计算并与该文的有限元计算结果进行比较,验证了该文提出的T应力计算公式的可靠性。更多还原

【Abstract】 The T-stress which acts parallel to a crack,which corresponds to the constant term in the stress series at the crack tip,and its influence on the stress field can not be ignored.Three-point bending beam is generally used for testing fracture parameters in ordinary laboratories.Under this circumstance,T-stress at the crack tip must be determined first to see whether its value would influence the fracture parameters.In this paper,finite element program Abaqus is used to derive the T-stress for a three-point bending beam with a span-to-depth ratio of 4 and a single-edge notched beam subjected to pure bending.Thereafter,a general expression for T-stress of three-point bending beams of arbitrary span-to-depth ratio is presented based on St.Venant Principle.T-stress of three-point bending beams with span-to-depth ratio of 6,8 and 10 is calculated using the proposed expression,and reasonable agreement is observed with the finite element analysis.更多还原