NONLINEAR DYNAMIC RESPONSE OF MARBLE TO REPEATED SHOCK WAVE
XI Jun1，YU Yong2，XI Daoying2
(1. School of Mechanical Engineering，Beijing Institute of Petrochemical Technology，Beijing 102617，China；
2. School of Earth and Space Science，University of Science and Technology of China，Hefei，Anhui 230026，China)
Abstract：The experimental research on the propagation of repeated shock wave through dry and water saturated marble has been performed by means of Hopkinson bar. The results suggest that impact modulus varies with stress and strain. When repeated shock stress in dry marble is less than yield stress，the dynamic modulus reduces with the increase in distance or time of wave propagation. Due to the modulus of unloading is larger than one of loading，the unloading wave pursues the loading wave，resulting in the narrowing of stress wave and the amplitude decreasing continuously. With the increase in the number of shock，the modulus of dry marble becomes larger，dispersion and amplitude of attenuation decrease，stress wave gets narrow and the impact compaction effect appears. When the shock stress in water saturated marble is larger than yield stress，the modulus and the properties of stress waveform are similar to ones of dry marble. With the increase in the number of shock，the experimental results show that waveform gets longer and scattered，the residual strain increases. These are inverse to the results in dry marble. It is because that shock exceeding yield stress causes crack growth and new crack initiation，volumetric expansion and modulus decrease in water saturated marble. All these results are helpful to the design and construction of large projects，especially for the defense engineering.
2011, Vol. 30 
