Acoustic Emission Experimental Research of the Damage Characteristics of Raw Coal under Different Loading and Unloading Rates

Figure 8

Corresponding curves of AE count time under different unloading rates. (a) 0.1 MPa/s unloading rate. (b) 0.2 MPa/s unloading rate. (c) 0.4 MPa/s unloading rate. (d) 0.6 MPa/s unloading rate.

(a)

(b)

(c)

(d)