PSI - Issue 36

Valeriy Kharchenko et al. / Procedia Structural Integrity 36 (2022) 137–144 Valeriy Kharchenko, Eugene Kondryakov, Oleg Katok et al. / Structural Integrity Procedia 00 (2021) 000 – 000

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resistance, which requires the use of high-strength and armored steels Fras et al. (2018), Dey et al. (2004). Investigation of the strain rate effect on the mechanical characteristics of the material and its behavior under various types of loading is a vital task. Different experimental and calculation techniques are used to solve it. The method of static and dynamic perforation of thin plates is employed to investigate the strain rate effect on the mechanical characteristics of high-strength steels. It makes it possible to perform tests with low and medium loading rates. Moreover, it allows one to get more information as compared with high-speed penetration tests, Koubaa et al. (2017), Popławski et al. (2020) . It is necessary to consider the influence of such factors as deformation hardening, complex stress state, temperature, strain rate along with standard mechanical characteristics for different deformation models and criteria of metal fracture. Due to the experimental investigation complexity of high-speed penetration processes, numerical simulations are carried out using different materials deformation and fracture models. The most well-known materials deformation models that are used to simulate perforation processes are the Cooper-Symonds, Cowper et al. (1957), Johnson Cook, Johnson et al. (1985), and GTN models, Tvergaard et al. (1986). But the major problem of these models is determining their parameters and considering all the features of materials deformation and fracture under various loading conditions Choudhary et al. (2020). 2. FE Models Numerical modeling of static and dynamic perforation was carried out by the FE method using the Johnson-Cook material deformation model for the plate-shaped specimen considering the strain rate effect. Armox 500T steel is selected for the investigations. Armox steels are martensitic steels that are made via a specific production process and end with rolling, quenching, and tempering. This treatment results in excellent mechanical properties of Armox such as high hardness, tensile strength, and good toughness, which allows one to use this steel for civil and military ballistic applications, Tenggren (2014). The Johnson-Cook material model parameters for Armox 500T were taken from the literature data, Iqbal et al. (2016). Table 1 lists their values.

Table 1. Material Parameters of Armox 500T Steel. Description Notation

Numerical value

Modulus of elasticity

E, Pa

2.01  10 11

Poisson’s ratio

µ

0.33 7850

Density

ρ, kg/ m 3

Yield stress constant

А, Pa В, Pа

1387 × 10 6 835 × 10 6

Strain hardening constant

n

0.25 0.07

Viscous effect

С m

̇ 0 , s -1

Thermal sensitivity Reference strain rate

1 1

Fracture parameters D1

0.04289 2.1521 -2.7575 -0.0066

D2 D3 D4 D5

0