Shahrood University of Technology Journal of Solid and Fluid Mechanics 2251-9475 7 3 2017 09 23 Comparison of energy absorption performance of multi-walled square and circular structures using COPRAS method and optimization of circular structures using RSM Comparison of energy absorption performance of multi-walled square and circular structures using COPRAS method and optimization of circular structures using RSM 133 147 1102 10.22044/jsfm.2017.5283.2302 FA S. Pirmohammad S. Esmaeili Marzdashti Journal Article 2017 01 13 In this paper, the energy absorption performance of double-walled structures with reinforcements that joint the inner and outer members together were studied under axial and oblique quasi-static loading. These structures were assumed to have square and circular cross-sections. In the first step of this research, the finite element simulations performed in LS-DYNA were validated by comparing with experimental results. This validated code was then used to simulate energy absorption behavior of the double-walled square and circular structures with different scales (0, 0.25, 0.5, 0.75, and 1) under different axial and oblique quasi-static loading. In the second step, a multi-criteria decision-making method namely complex proportional assessment (COPRAS) was employed to select the best possible structure in view point of crashworthiness. The results demonstrated that the cross-sections with the scale of 0.5 were the best energy absorbers. Moreover, the circular cross-section was found to be the best energy absorber due to having higher number of sides. In addition, both energy absorption and peak crushing force reduced by increasing the loading angles. Finally, the response surface (RSM) and central composite design methods were used to optimize the design parameters including the thickness and radius of the double-walled circular structure. In this paper, the energy absorption performance of double-walled structures with reinforcements that joint the inner and outer members together were studied under axial and oblique quasi-static loading. These structures were assumed to have square and circular cross-sections. In the first step of this research, the finite element simulations performed in LS-DYNA were validated by comparing with experimental results. This validated code was then used to simulate energy absorption behavior of the double-walled square and circular structures with different scales (0, 0.25, 0.5, 0.75, and 1) under different axial and oblique quasi-static loading. In the second step, a multi-criteria decision-making method namely complex proportional assessment (COPRAS) was employed to select the best possible structure in view point of crashworthiness. The results demonstrated that the cross-sections with the scale of 0.5 were the best energy absorbers. Moreover, the circular cross-section was found to be the best energy absorber due to having higher number of sides. In addition, both energy absorption and peak crushing force reduced by increasing the loading angles. Finally, the response surface (RSM) and central composite design methods were used to optimize the design parameters including the thickness and radius of the double-walled circular structure. https://jsfm.shahroodut.ac.ir/article_1102_5def5d5523fa51ff99f5ebe68ab23b8d.pdf