Impact of crack growth behavior on high strength steel and sandwich metal panel using the constant stress ratio, frequency and thickness

Abstract

The armoured vehicle uses a special solid steel that has a heavy vehicle ratio which causes the performance to decrease after being triggered by high velocity impact bullet on rescue missions thus experiencing the phenomenon of fatigue and unstable crack growth flow. In this study, an investigation on crack growth behaviour was carried out for sandwich metal panel and solid High Strength Steel (HSS) which has high ability in terms of residual life. Meanwhile, sandwiched metal panel contains HSS as face sheets and lightweight material as a solid core. The main objective of this study was to determine the crack growth behaviour on two types of structural material by applied frequency (f=10 Hz), stress ratio (R=0.1), and thickness (10 mm) as a constant parameter. The crack growth experiment used compact tension (CT) specimen as followed the ASTM E647 standard. The benchmark for establishing the crack growth behaviour is the (a-N) graph and the Paris law regime, da/dN against stress intensity in order to determine Paris constant (C and m). Based on the results, the sandwich metal panel is more applicable with the number cycle of N = 23300 with an increase in about 27% compared to solid HSS. It can be concluded that the sandwich metal is most practicable and affordable for using higher level of threat for hard armour vehicle panel.