Papers by Author: Jiang Xu

Abstract: To explore the regularity of deformation and gas migration of coal seam, the author transmits signal of strain foil on coal samples in all directions by transforming oil plug, oil plug seal, heat shrink tubing and wire seal, based on the existing triaxial seepage device. We can complete coal deformation and gas seepage test with this device under different temperature, different stress, different gas stress and so on.

Abstract: The damage process is accompanied by the acoustic emission (AE) for brittle materials such as rocks. An AE experimental research was investigated based on different loading velocity, moisture content and rock structure. The research shows that Increasing loading velocity makes the duration of obvious AE longer, average AE rate improved, the strain values of obvious AE decreased; More moisture content delays the time of obvious AE, reduces the values of AE, increases the strain values of obvious AE; inferior structure rock has little AE, and appears discretely; The main reason of AE difference is the different rock structure.

Abstract: The related components of material testing machine (e.g., pressure plate, pressure head, compression bar, etc.) produce distortion in the experiment. It is obviously irrational to use the stroke to replace the specimen displacement, which can’t be measured directly by the extensometer in the destructive test. Therefore, the evolution of specimen displacement, machine displacement and stroke of 45 steel, duralumin alloy and sandstone was analyzed under uniaxial monotonic loading and uniaxial cyclic loading. The results show that the deformation of the related components of universal testing machine, which increases/decreases along with the increase/ decrease of load, can’t be ignored. And there is a good one-to-one correspondence between the machine displacement and the load. It also has nothing to do with the types of specimen materials and the experiments. The relationship of machine displacement and the load can be used to determine the specimen displacement indirectly.