The phenomenon of stiffness deterioration (progressive damage) beyond the peak stress has been observed in cyclic loading tests of coals, rocks, concretes, soils and sands.
峰后的刚度劣化现象(渐进损伤)在多种煤、岩石、混凝土、土和砂子的循环加载实验中已被观察到。
3
Progressive cracking of granite plate under uniaxial compression had been investigated by using a loading frame, which could be well equipped with optical microscope and video recorder.