Introducing buckling pattern into straight-walled lattice structure, anovel inspired meta-structure (BILM) was designed and fabricated using polylactic acid (PLA) by three-dimensional (3D) printing technology. The square structure with positive Poisson’s ratio (PPR) is transformed negative (NPR) induction. Curved struts decrease the maximum strain, prohibit strut fracture, increase contact indu...

The aim of this paper is to investigate the energy absorption behavior some reticulated tubes with different auxetic and non-auxetic wall grid patterns. Re-entrant, arrow-head anti-tetrachiral were three types cellular patterns for tubes, conventional honeycomb pattern was used tubes. All designed specimens fabricated by laser rotary cutting machine on steel crushing tests performed a universal...

This article investigates the collapse characteristics of thin-walled tubes with octagonal cross sections during axial crushing. The tubes’ axial crushing resistance (the relationship between crushing force and axial deformation) is described with a series of mathematical equations, which are derived applying global energy equilibrium theory. The derived axial crushing resistance is then used f...

In this study, the wavy honeycomb's initial peak crushing force (IPCF) and energy absorption (EA) were estimated using decision tree algorithm. First, experimental results, Ls-Dyna models of honeycombs verified. way, stress-strain curves shapes compatible. Secondly, effect parameters was examined. Waves contribute significantly to values. particular, for with same geometric properties, when wav...

In this paper, crashworthiness characteristics of conical steel tubes stiffened by annular rings and rigid polyurethane foam are investigated. For this purpose, wide circumferential rings are created from the outer surface of the conical tube at some determined areas along tube length. In fact, this method divides a long conical tube into several tubes of shorter length. When this structure is ...

objectives: foot and ankle problems are common complications in rheumatoid arthritis disease. gait pattern such as normal foot and ankle rocker is impaired in patients with rheumatoid arthritis. rocker sole as an external shoe modification is commonly prescribed in this pathology. the aim of this study was to investigate the effect of rocker shoe on vertical ground reaction force parameters dur...