this study aims to numerically investigate on the crashworthiness of thin-walled square tubes by consideration of 3-d oblique loading. in this type of loading, direction of loading is defined by using two spatial angles relative to the position of the tube. to this aim, finite element (fe) analysis is employed to simulate the loading for 8 different numerical models with different loading orien...

Metallic single-walled carbon nanotubes have been proposed to be good one-dimensional conductors. However, the finite curvature of the graphene sheet that forms the nanotubes and the broken symmetry due to the local environment may modify their electronic properties. We used low-temperature atomically resolved scanning tunneling microscopy to investigate zigzag and armchair nanotubes, both thou...

In this article, based on the Euler-Bernoulli beam theory, the large-amplitude vibration of multiwalled carbon nanotubes embedded in an elastic medium is investigated. The method of incremental harmonic balance is implemented to solve the set of governing nonlinear equations coupled via the van der Waals (vdW) interlayer force. The influences of number of tube walls, the elastic medium, nanotub...

Thin-walled tube bending has common applications in the automobile and aerospace industries. The rotary-draw-bending method is a complex physical process with multi-factor interactive effects and is one of the advanced tube forming processes with high efficiency, high forming precision, low consumption and good flexibility for bending angle changes. However, it may cause a wrinkling phenomenon,...

Evidence for modified electronic structure in double-walled carbon nanotubes with respect to their individual inner and outer constituent single-walled nanotubes is provided by scanning tunneling microscopy and spectroscopy experiments. The contribution originating from the inner tube to the local density of states of the double-walled system was identified in agreement with previous theoretica...

Aqueous suspensions of length selected single-walled carbon nanotubes were studied by atomic force microscopy (AFM) in order to probe the influence of sonication on nanotube scission. The maximum of the tube length distribution, lM, initially exhibits a power law dependence on the sonication time, t - roughly as lM approximately t(-0.5). This and the limiting behavior observed at longer times c...

We show that the number of concentric graphene cylinders forming a carbon nanotube can be found by squeezing the tube between an atomic force microscope tip and a silicon substrate. The compressed height of a single-walled nanotube (double-walled nanotube) is approximately two (four) times the interlayer spacing of graphite. Measured compression forces are consistent with the predicted bending ...

In modern offshore installations, thin walled columns are used for energy absorption in accident situation. When this advanced offshore shock absorber is subjected to axial compressive load, plastic hinges are developed on the sides of column and the column crushes with repeatable patterns. It can absorb considerable impact energy due to large and continuous plastic deformation. This paper deve...

Thin-walled tubes are widely used as energy absorbers due to their high crashworthiness performance. This study aims evaluate the effect of plastic forming history carried out for thickness optimization on performance thin-walled square tube (TWST). Within scope study, a series numerical analyzes were conducted TWST using commercial finite element (FE) software. In order determine individual op...