PSI - Issue 47

Ezio Cadoni et al. / Procedia Structural Integrity 47 (2023) 268–273

269

2

Author name / Structural Integrity Procedia 00 (2023) 000–000

a)

b)

Fig. 1. Smooth (a) and notched (b) specimen geometry used.

Nomenclature

density of the material

ρ

incident pulse reflected pulse

I

R T

transmitted pulse C 0 elastic wave speed in the bar E 0 elastic modulus of the bar A 0 cross section of the input and output bars A cross section of the specimen L specimen gauge length ˙ strain-rate

2. Material and specimens

An alloy of commercial tungsten with high density ( ρ = 16’925kg / m 3 ) was used in this study. It is composed of C (4.20%), O (2.59%), Co (3.79%), Ni (7.98%), and W (81.43%). Testing was conducted on smooth round specimens of 2mm diameter and 5mm gauge length (Fig. 1a). A three-notch configuration was used to evaluate the e ff ects of di ff erent triaxiality conditions on stress-strain (R = 0.4mm;R = 0.8mm;R = 2.0mm) keeping a constant net cross-section of 2mm in diameter (Fig. 1b). To connect the specimen ends to the testing machines, they had an M5 fillet. The quasi-static results are resumed in Table 1.

Table 1. Quasi-static results. E ( GPa ) f p , 0 . 2 ( MPa )

3 )

3 )

f u ( MPa )

u ( % )

f f ( MPa )

f ( % )

Z (%)

W u ( MJ / m

W

f ( MJ / m

307 (40)

1567 (81)

1761 (10)

0.74 (0.03)

1607 (13)

5.09 (0.84)

13.01 (1.38)

8.54 (0.27)

81.2 (14.1)

3. Experimental technique

The dynamic response of this commercial Tungsten alloy at high strain-rate was investigated by using a Split Hopkinson Tensile Bar (SHTB) [Cadoni et al. (2015); Cadoni and Forni (2015)] installed at the DynaMat SUPSI