双K断裂模型失稳韧度KunIc的解析计算方法  

Analytical Calculation Method for Unstable Toughness of Double-K Fracture Model

作　　者：王占科 高洪波[1] 韩小燕 马鹏[1] WANG Zhan-ke;GAO Hong-bo;HAN Xiao-yan;MA Peng(School of Civil Engineering and Architecture,Hainan University,Haikou 570228,China;Guangxi Vocational College of Safety Engineering,Nanning 530100,China)

机构地区：[1]海南大学土木建筑工程学院,海口570228 [2]广西安全工程职业技术学院,南宁530100

出　　处：《长江科学院院报》2019年第6期106-109,115,共5页Journal of Changjiang River Scientific Research Institute

基　　金：国家自然科学基金项目(51268010)

摘　　要：为预估最大荷载Pmax和失稳韧度KIc^un,提出一种只需混凝土轴心抗压强度fc即可计算双K断裂模型失稳韧度KIc^un的解析计算方法。大量的试验数据表明,临界裂缝扩展量与韧带高度之比Δac/(h-a0)趋于常数。结合这一规律,基于虚拟裂缝的双线性本构关系,根据带切口的三点弯曲梁跨中截面的平衡条件,计算最大荷载Pmax,再将Pmax的计算值代入公式计算双K断裂模型的失稳韧度KIc^un。为检验计算精度,将最大荷载Pmax和失稳韧度KIc^un的计算值与试验值比较。结果表明:最大骨料粒径dmax≤40mm的较大尺寸三点弯曲梁试件,最大荷载Pmax及失稳韧度KIc^un的计算值与试验值吻合良好。An analytical method which merely needs the axial compressive strength f c of concrete to calculate the unstable toughness KIc^un of double-K fracture model is proposed in this paper. Massive experimental data indicate that the ratio of critical crack propagation length Δac to ligament length ( h-a0 ) tends to be a constant. According to this regularity and on the basis of the bilinear constitutive relationship of the fictitious crack model, the maximum load P max of three-point bending notched beam is calculated under equilibrium condition. Then the calculated result of Pmax is substituted to the formula and the unstable toughness KIc^un of double- K fracture model is calculated. The calculated results of P max and KIc^un are compared with those of test values to verify the accuracy of the method. Results conclude that the calculated results of Pmax and KIc^un agree well with test values for relatively big size concrete specimens with maximum aggregate size not greater than 40 mm. The maximum load Pmax and the unstable toughness KIc^un can be predicted by the proposed analytical method.

关 键 词：混凝土 最大荷载 失稳韧度 断裂力学 解析计算 双线性本构关系 双K断裂模型 

分 类 号：TV431[水利工程—水工结构工程]