Issue 37

Q. Like et alii, Frattura ed Integrità Strutturale, 37 (2016) 342-351; DOI: 10.3221/IGF-ESIS.37.45

(a) SEM image of galena ore

(b) computed model of ore

Figure 2 : Geometric plot of computed model. Density (ρ), elasticity modulus (E), Poisson’s ratio (μ), and tensile strength (T) of galena and calcite are listed in Tab. 1 [27, 28].

ρ (kg/m 3 )

E (GPa)

μ

T (MPa)

Calcite Galena

2712 5016

83.8 272

0.31 0.16

12 12

Table 1 Mechanical properties of the discs

The PFC model parameters include minimum disk radius R min =1.66, and the total number of disks (6046). The other parameters that define a parallel-bonded material in PFC include solid density ρ b , Young’s modulus at each particle-particle contact E c , ratio of particle normal to shear stiffness k n /k s , particle friction coefficient u , radius multiplier used to set the parallel-bond radii  , Young’s modulus of each parallel-bond c E , ratio of parallel-bond normal to shear stiffness / n n k k , normal strength of the cement c  , and shear strength of the cement c  . The biaxial and Brazilian tests were employed for parameter calibration (Tabs. 2 and 3). =0.02 mm, disk size ratio R max /R min

ρ b

E c

U

(kg/m 3 )

(GPa)

k n

/k s

Calcite Galena

3228.6

91 73

5 3

0.5 0.5

9044

Table 2 : Mechanical properties of the discs.

  (MPa)

/ n n

c 

c E (GPa)

k k



c

Calcite Galena

1 1

91 73

5 3

49±10 49±10

Table 3 : Mechanical properties of the cement.

The thermal conductivity and specific heat capacity of galena and calcite are shown in Tab. 4, while their thermal expansion coefficients are presented in Tab. 5 [27, 28].

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