Dynamic Fracture and Energy Evolution Characterization of Naturally Fractured Granite Subjected to Multilevel Cyclic Loads

Table 1

Fitting relationships for , , , and the upper stress during the whole test.

Sample ID	Initial damage degree (%)	Type of strain energy (×100)	Fitting function	Correlation coefficient ()
NFG1	0.08%			0.9983
				0.9978
				0.9985
NFG3	0.12%			0.9994
				0.9921
				0.9887
NFG5	0.56%			0.9827
				0.9955
				0.9214
NFG7	2.11%			0.9694
				0.9798
				0.9862