Size Effect in Blunt Fracture: Concrete, Rock, Metal
Size Effect in Blunt Fracture: Concrete, Rock, Metal
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DOI：
10.1061/(asce)0733-9399(1984)110:4(518
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发表时间：
1984-04
期刊：
影响因子：
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通讯作者：
Z. Bažant
中科院分区：
文献类型：
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作者：
Z. Bažant
混凝土和岩石中的断裂前缘被微裂纹区钝化，而韧性金属中的断裂前缘被屈服区钝化。这种钝化导致偏离线弹性断裂力学（LEFM）已知的结构尺寸效应。首先研究混凝土或岩石结构的尺寸效应，使用量纲分析和例证。断裂被认为是由裂纹带的扩展引起的，该裂纹带在其前部相对于骨料尺寸具有固定的宽度。分析基于断裂引起的能量释放取决于裂纹带的长度和面积的假设。结果表明，尺寸效应存在于从小尺寸强度准则到大尺寸LEFM准则的平滑过渡中，失效时的名义应力σN按（1+λ/λ0）-1/2下降，其中λ0为常数，λ为相对结构尺寸。该函数得到了沃尔什测试数据的验证。如果在断裂前缘有加强物，并且表现出弹性，……
The fracture front in concrete, as well as rock, is blunted by a zone of microcracking, and in ductile metals by a zone of yielding. This blunting causes deviations from the structural size effect known from linear elastic fracture mechanics (LEFM). The size effect is studied first for concrete or rock structures, using dimensional analysis and illustrative examples. Fracture is considered to be caused by propagation of a crack band that has a fixed width at its front relative to the aggregate size. The analysis rests on the hypothesis that the energy release caused by fracture depends on both the length and the area of the crack band. The size effect is shown to consist in a smooth transition from the strength criterion for small sizes to LEFM for large sizes, and the nominal stress σN at failure is found to decline as (1+λ/λ0)-1/2 in which λ0=constant and λ=relative structure size. This function is verified by Walsh's test data. If reinforcement is present at the fracture front and behaves elastically, ...