Research Article

Experimental Investigation of Sandstone under Cyclic Loading: Damage Assessment Using Ultrasonic Wave Velocities and Changes in Elastic Modulus

Figure 9

P- and S-wave velocities versus axial stress for Type 2 tests. (a) Loading stage P-wave velocities, (b) unloading stage P-wave velocities, (c) loading stage S-wave velocities, (d) and unloading stage S-wave velocities.
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