脆性弯曲断裂试验中的稳定加载条件

Stable Loading Condition of Brittle Bending-Fracture Test

通过对含裂纹试样与加载机构共同作用系统的分析,得到了试验机的稳定加载条件为试验机-试样系统的能量输入率T>0。此T判据的等价条件为试验机的刚度K_n和含裂纹试样荷载-挠度(F-Δ)曲线的斜率K_s满足不等式K_m+K_s>0。T判据可以推广到含裂纹体结构物系统的稳定性分析。结果表明,其稳定性不仅取决于含裂纹构件的刚度性质,而且也取决于与构件相连的结构物的刚度性质。

Based on a discussion on the interaction system including both the cracked specimen and loading device, the stable Loading condition of a testing machine is given, i.e. T>0, where T is the rate of energy input of the system. As a criterion, T>0 is equivalent to that the rigidity of testing machine Km and the slope of load-deflection curve Ka must satisfy the inequality Km+Ka>0. Criterion T can also be generalized to analyze the stability of a system including members of cracked structure. The result shows that the stability depends not only on the rigidity of such cracked members but also on the rigidity of others connected to the former.