PSI - Issue 64

6

Amrita Milling et al. / Procedia Structural Integrity 64 (2024) 1009–1016 Milling/ Structural Integrity Procedia 00 (2024) 000 – 000

1014

(a)

(i)

(ii)

(b)

(i)

(ii)

Fig.3.Comparison of Quasi-static and Dynamic tensile behaviour (a) QS-0.0069/s (b) D-9.04/s : (i) stress-strain response (ii) image of crack formation at different times.

Table 3: Effect of strain rate on the average tangent modulus of each Stage. Strain rate [1/s]

Average Tangent Modulus [GPa] (COV)

0.005 < ̇ ≤ 0.01 0.5 < ̇ ≤ 1 ̇ ≈2 6< ̇ ≤10

Stage I

Stage II

Stage III

3527 (26.8%) 6571 (89.7%) 10924 (51.3%) 11416 (27.0%)

17 (32.1%) 32.7 (20.3%) 49.7 (16.1%) 30.6 (26.9%)

23.1 (28.7%)

- - -

3.2. Effect of strain rate on tensile parameters In the dynamic loading range of 0.59/s to 9.04/s, the ultimate tensile strength, ultimate strain, and toughness varied from 1632 to 2186 MPa, 2.58 to 4.11% and 37.6 to 59.1 MPa, respectively. In comparison, the average quasi-static tensile strength, ultimate strain, and toughness were 1522 MPa (COV=8.6%), 2.78% (COV=12.8%), and 31.2 MPa (COV=19.3%), respectively. Fig.4 shows the dynamic increase factors for the tensile parameters. The tensile strength increased by a factor of 1.1 to 1.4, and the tensile strain increased by 1.1 to 1.5 times, except in the case of specimens D-2.22/s and D-9.04/s (circled in red), where the strain was less than the static value. Moreover, toughness increased