The aim of this paper is to carry out extensive numerical investigations about the effect of various parameters on both buckling loads and ultimate behavior of continuous partially composite castellated beams under vertical loads. Efficient nonlinear 3D Finite Element Model using ABAQUS software is developed. The initial geometric imperfection and material nonlinearities were carefully consider...

A variational principle for microtubules subject to a buckling load is derived by semi-inverse method. The microtubule is modeled as an orthotropic shell with the constitutive equations based on nonlocal elastic theory and the effect of filament network taken into account as an elastic surrounding. Microtubules can carry large compressive forces by virtue of the mechanical coupling between the ...

In this article, the effect of size-dependent on the buckling and vibration analysis of functionally graded (FG) double-layer boron nitride plate based on classical plate theory (CPT) under electro-thermo-mechanical loadings which is surrounded by elastic foundation is examined. This subject is developed using modified couple stress theory. Using Hamilton's principle, the governing equations of...

Cylindrical thin-walled tubes due to construction and easy installation, high energy absorption capacity are used in the automotive industry as an impact energy absorber. However, the main weakness of cylindrical tubes is in the high initial peak load. Therefore, in this paper, to overcome this weakness, a buckling initiator is used at the top of the tube. This buckling initiator is a steel rod...

This paper describes the application of refined plate theory to investigate free vibration and buckling analyses of functionally graded nanocomposite plates reinforced by aggregated carbon nanotube (CNT). The refined shear deformation plate theory (RSDT) uses four independent unknowns and accounts for a quadratic variation of the transverse shear strains across the thickness, satisfying the zer...

Elastic stability of ring and stringer-stiffened cylindrical shells under axial, internal and external pressures is studied using Ritz method. The stiffeners are rings, stringers and their different arrangements at the inner and outer surfaces of the shell. Critical buckling loads are obtained using Ritz method. It has been found that the cylindrical shells with outside rings are more stable th...

We discuss the stability of icosadeltahedral shells subjected to a uniform external load in the form of an isotropic pressure. We demonstrate that there exists a universal critical buckling pressure scaling form that defines a locus of buckling instabilities. The parameter that uniquely determines this scaling form is shown to be the Föppl-von Karman number of nonpressurized shells. Numerical r...

With dynamic loading like landing impact a distinction should be made between relatively short and long, quasistatic loading durations, and loadings the durations of which are in the order of the longest lateral period (lowest eigenfrequency) of the structure. A particular problem is to be expected under the later loadings where the interaction of loading dynamics with the dynamics of the buckl...

Background: Scaling laws for cylindrical column buckling are reviewed, applicable to the cardio-vascular system arteries or veins of various thicknesses to diameter ratios. Methods: Critical buckling load scales as (hr/L^2) for axial loads, (h/r)^3 for compressive circumferential loads, and ( h/r)^0.5 for pulse wave velocity. Results: Arteries and veins are most susceptible to buckling failure ...

The present research deals with the flexural-torsional buckling analysis of sandwich web and/or flanges tapered doubly-symmetric I-beam. All section walls are composed of two metal face layers and a functionally graded (FG) porous core. It is assumed that the material properties of the porous core vary gradually in the longitudinal direction according to the simple power-law function considerin...