【摘要】 针对基于虚拟裂缝扩展粘聚力的解析方法确定双K断裂参数时 ,起裂韧度 KiniIc和选定的混凝土软化本构曲线形状有关的问题 ,指出对于双线性软化本构曲线而言 ,其拐点坐标 (ws,σs)的取值大小对 KiniIc有一定影响。当取 ws等于临界裂缝尖端张开位移 ,并引入一个反映混凝土变形性能的参量λ时 ,λ的大小将直接影响 KiniIc的确定。通过将三点弯曲梁断裂试验取得的 KiniIc实测结果与选择不同混凝土软化本构曲线形状得到的解析解进行对比 ,得到了使两者吻合的参量 λ和软化本构曲线形状 ,为确定双 K断裂参数中的起裂韧度 KiniIc提供了适合的双线性软化本构曲线。更多还原

【Abstract】 Aimed at the problem that the initial fracture toughness K ini Ic depends on the shape of softening traction separation law used in the calculation, this paper point out that, the values of w s and σ s at the breaking point on the bilinear softening traction separation curve will influence on the K ini Ic . Under the condition of w s being equal to critical crack tip opening displacement and introducing a parameter named λ which is associated with the deformation property of concrete, the determination of K ini Ic will directly depend on the value of λ . To compare the results of K ini Ic evaluated with different shapes of softening traction separation law with that measured from the experiment on three point bending notched beams, the shape of softening traction separation law which makes the above two results agree well can be obtained to evaluate the K ini Ic . Thus the suitable bilinear softening traction separation law is presented for determining the double K fracture parameters.更多还原