Automotive Science and Engineering

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In the present work, the energy absorption study of warm-rolled LZ71 sheet is done for the first time. To do so, Lithium (7% Wt), Zinc (1% Wt) and Magnesium are cast in 770⁰C. After that, the billet has been warm-rolled at 350⁰C and its thickness reduced by 80%. Then, two different heat treatment situations are studied to reach an isotropic plate. Afterward, microstructures of the specimens have been studied using an optical microscope. Tensile tests of the samples are derived to study the mechanical properties and isotropy of the sheets. Moreover, the results of tensile tests applied for crushing simulations. Energy absorption study of the alloy is also done using ABAQUS/Explicit commercial code. The results of simulations are validated using experimental tests of A6082 and completely acceptable performance of simulations is observed. Then, the mechanical properties of LZ71 are used to study the crashworthiness behavior of the mentioned alloy. Crash absorption parameters, namely peak crush force (F_Max), mean crush force (F_Mean), Total Energy Absorption (TAE), Crush Force Efficiency (CFE), Specific Energy Absorption (SEA) and Total Efficiency (TE) of LZ71 and A6082 are compared which are shown that the performance of LZ71 is considerably more efficient than A6082. Lastly, by the help of Artificial Neural Network (ANN) and Taguchi Method, the effects of dimensional parameters of tube, namely diameter, length and thickness, on F_Max, F_Mean and TAE and also the influences of dimensionless geometrical ratios, namely L/D and D/t on CFE, SEA and TE are surveyed comprehensively.

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A trapezoidal sandwich panel with a mild steel honeycomb core was modeled under high-velocity impact loading generated by high-energy materials. Numerical simulations were performed at three impact energy levels for five sandwich panel configurations and an equivalent square plate of the same mass, for use in certain special vehicles. The deformation response of the sandwich panels and the equivalent square plate was comparatively evaluated. The results showed that the equivalent square plate exhibits the lowest specific energy absorption and the highest peak transmitted load among all the tested configurations. Panel P3, with approximately 145% higher energy absorption and about 190% lower peak transmitted force compared with the equivalent square plate, was identified as the most efficient design for impact energy dissipation. Therefore, this panel can be proposed as a cost-effective and efficient energy absorber for protecting equipment and occupants in various industrial applications.