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采用冲击改性的高聚物对材料的断裂能在近瑞利波速C,时减小的断裂行为进行了研究.设计了基于条带几何形状的实验装置用以探索这些高聚物在快速裂纹传播(RCP)时的脆性行为.发现沿着橡胶增韧聚甲基丙烯酸甲酯(RT-PMMA)的整个试样,尽管有的出现裂纹分叉甚至裂纹俘获静止,其宏观裂纹速度几乎恒定.当材料行为趋于加速裂纹时,临近Cr时断裂能减少,而当由于分叉使力学惯性效应趋于限制裂纹传播速率时,宏观裂纹速度稳定在大约amb=0.6 cr,其是RT-PMMA的宏观裂纹分叉速度.因此,对这种材料在宏观裂纹分叉速度时,实验断裂表面能及断裂表面韧性没有单一值.实际上,其宏观断裂表面能值随着失稳形态数目或无效裂纹分叉而增加.
The impact-modified polymers were used to study the fracture behavior of the material at near Rayleigh wave velocity C, and to study the fracture behavior of the material.A experimental apparatus based on strip geometry was designed to explore the effect of these polymers on the rapid crack propagation Brittle behavior at propagation (RCP), it was found that the macroscopic crack velocity was nearly constant along the entire sample of rubber-toughened polymethylmethacrylate (RT-PMMA), despite the occurrence of crack bifurcation and even crack arrest. When material behavior tends to accelerate cracking, the fracture energy decreases near Cr, and when the mechanical inertial effect tends to limit the crack propagation rate due to furcation, the macro-crack velocity stabilizes at about amb = 0.6 cr, which is the value of RT-PMMA Macroscopic crack bifurcation velocity.Therefore, there is no single value for the experimental fracture surface energy and the fracture surface toughness for this kind of material at the macroscopic crack bifurcation speed.In fact, the macroscopic fracture surface energy value increases with the number of instability modes or invalid crack Bifurcation increases.