Numerical impact strain response of multi-layered steel-aluminium plate using signal processing

This paper investigates the impact strain response resulting from the numerical Charpy impact test of double- and triple-layered steel-aluminium plate employing time-frequency analysis. The potential of the laminated steel-aluminium plate in weight reduction is evaluated using a single-layered specimen as a reference. The signal processing technique in the time-frequency domain is capable of revealing the behaviour and strength of the laminated plate. The time domain signal from the numerical Charpy impact test is transformed into the frequency domain using the power spectrum density and time-frequency domain by the Hilbert-Huang spectrum. The relationship of strain energy from the finite element method and the power spectrum density showed the R-2 value of 0.8899, indicating that the power spectrum density can be used as an alternative in calculating the strain energy. In this study, the frequency distribution in the power spectrum density was compared with the Hilbert-Huang spectrum. The triple-layered specimen was found to show better performance with 23% higher maximum strain and 11% more strain energy to fracture, compared to the double-layered specimen. Therefore, the analysis in both frequency and time-frequency domains provide a better understanding of the impact behaviour of the double- and triple-layered plate.