Carbon nanotubes (CNTs) were first discovered by Iijima in 1991 [1]. CNTs have sparked great interest in many scientific fields such as physics, chemistry, and electrical engineering [2, 3]. CNTs are composed of graphene sheets rolled into closed concentric cylinders with diameter of the order of nanometers and length of micrometers. CNTs are in two kinds, based on number of walls, the single-w...

Abstract In this research work, the finite element software, ABAQUS is used to study by simulations influence of form defect on mechanical behavior a shrink-fitted assembly presenting internal radial cracks. Under action contact pressure induced tightening between two cylinders, these cracks resulting from incorrect operations or materials elaboration defect, can be harmful assembly. Various we...

Introduction. Cylindrical and spherical shells are extensively used in engineering. They face internal and/or external pressure heat. Stresses strains distribution elastoplastic has been studied by many scientists. Numerous works involve the use of von Mises yield conditions, maximum shear stress, reduced stress. These condi- tions do not include dependence on first invariant stress tensor sign...

in this paper, the problem of calculating the stress intensity factor (sif) for an orthotropic thick-walled cylinder with a small radial crack subject to internal pressure is considered. the crack is assumed to be an edge crack on the external radius of the cylinder. the stress intensity factor is calculated by superposition of an uncracked cylinder with uniform stress distribution and a cylind...

one of the new research fields in plasticity is related to choosing a proper non-associated flow rule (nafr), instead of the associated one (afr), to predict the experimental results more accurately. the idea of the current research is derived from combining von mises and tresca criteria in the places of yield and plastic potential surfaces in rate-independent plasticity.  this idea is implemen...

In various fields of engineering, such structural elements are widely used that, from the point view their strength calculation, can be referred to thin shells (tanks, reservoirs, cylinders, etc.). When calculating thin-walled shells, a number hypotheses adopted simplify solution problem. The problem is most simply solved within framework momentless theory according which only force normal sect...

Solutions of stress intensity factors for external and internal unpressurized and pressurized surface cracks in internally pressurized thick-walled reactor pressure vessels are determined directly by a three-dimensional displacement-hybrid finite element method. The finite element method is based on a rigorous modified variational principle of the total potential energy, with arbitrary element ...

In contrast to our previous study (Barth & Marx, 2008) dealing with a currently decreasing research field (high-temperature superconductors) we analyzed here a topic which has raised a strongly increasing interest among researchers: research activities around carbon nanotubes (CNTs or NTs). Carbon nanotubes (often named only nanotubes) are graphite sheets rolled up into cylinders with diameters...

In the present article a numerical procedure is developed for dynamic analysis of single and double autofrettage of thick–walled FG cylinders under transient loading. The governing differential equations are discretized and presented in explicit Lagrangian formalism. The explicit transient solution of discrete equations are obtained on the meshed region and results for stress and strain distrib...

A laboratory study was conducted to investigate the borehole deformation of poorly cemented sandstone rocks with Uniaxial Compressive Strength (UCS) less than 10 MPa under different stress path regimes by using a convergence measuring device (CMD). Synthetic thick-walled hollow cylinders (TWHCs) comprised sand grains, Portland cement and water were prepared for this study. series mechanical tes...