This study concerned about the sandwiched metal panel on the fatigue crack growth of mild steel and aluminium. The fatigue crack growth consists of 3 layer of metal sheet or panel that bonded together using adhesive of epoxy resin by hand lay-up technique. The 3 layers are consisting of 2 face metal sheets and 1 metal sheet as a core for the sandwiched; sandwiched of aluminium with mild steel panel (SAMSP) and sandwiched of mild steel panel (SMSP). The specimen was cut using Electrical Discharge Machine Wire Cut (EDM-wire cut) to get tensile test specimen based on American Standard Testing Method (ASTM) E8 before tested with speed rate of 3mm/min using Universal Testing Machine Instron 5569A (UTM). The stress strain curve was plotted in order to analyse the yield strength, Ultimate Tensile Strength (UTS) and the Young's Modulus of the sandwiched. UTS value is used for the fatigue test in the maximum stress applied between 0.50%, 0.60%, 0.70%, 0.80% and 0.90% of UTS. The fatigue test was conducted under ASTM E647 compact tension C(T) standard using Instron 8801 Fatigue Machine with constant frequency of 20Hz and subjected to 1 million cyclic loading to reach failure. The crack growth behaviour of the specimen were discover that indicate the fatigue life, (a-N), fatigue crack growth and failure of the structure by the initial notch. The sandwiched of mild steel panel (SMSP) is compared with the sandwiched of aluminium with mild steel panel (SAMSP) to observe the crack growth behaviour and mechanical properties of the specimen in this study. It can be determined that SAMSP has two times better crack growth behaviour that improve the structure properties compare to the SMSP.

This paper presents the efficient energy absorption of magnesium alloy AZ31B with reinforcement carbon nanotubes (CNT) and lead (Pb). The high specific energy absorption demonstrated by CNT compared to metals is one of the criteria to improve the AZ31B performance against ballistic penetration. More ductility by adding Pb in the alloy also plays a vital role to increase the energy absorption capability. Four-cylinder shape AZ31B-based specimens are tested dynamically by using compression Split Hopkinson Pressure Bar (SHPB). The diameter and thickness of the specimen is 18 mm and 12.5 mm respectively. The striking velocity used in this work is 20 m/s. By equation of 1D wave propagation, stress-strain curve is plotted and the area under the curve is equivalent to energy absorption. The highest energy absorption is about 270 kJ with the increment of 47% compared to original AZ31B. This increment is consistent with the higher strain rate experienced by the specimen during the test. The strain rate determined from the study is 1300 per second compared to original AZ31B of 850 per second. The finding of this paper is the presence of CNT and lead could improve the energy absorption performance as the strain rate of the specimen also increased.

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This study concerns the behaviors of stresses distributed on a sandwich metal panel using high-strength steel (HSS) as faces and magnesium alloy (AZ31B) as core materials via simulation analysis. The combination of the sandwich metal panel offered good potential to reduce the vehicle weight, reduce the excessive fractures, and improve the energy absorption better than monotonic material. In this comparison analysis, there were two main types of materials used which is sandwich metal panel material and solid material. The tensile experiment was set in the tensile specimen by follow ASTM E8 standard test methods, while for simulation, the three-dimensional and meshing process between tensile and compact tension (CT) models was developed in the simulation analysis software. The mesh element size and tolerance values were 1.0 mm and 0.05 mm, respectively. It was subjected to evaluate the ultimate tensile strength and yield strength of the solid material, HSS and AZ31B between experiment and simulation. The stress behavior on both CT specimens only evaluates the energy absorption using simulation with the 90% of yield strength HSS value from tensile simulation. This tensile test was convinced by comparing the result of experimental and simulation with the coefficient value of determination (R2) of more than 0.85. Consequently, the results obtained by simulation analysis show that sandwich metal panel is most practicable with the increment about more than 70% for future improvements in new material development, especially in light armored vehicle applications.