A complete investigation on the free vibration and stability analysis of beams made of functionally graded materials (FGMs) containing open edge cracks utilizing four beam theories, Euler-Bernoulli, Rayleigh, shear and Timoshenko, is performed in this research. It is assumed that the material properties vary along the beam thickness exponentially and the cracked beam is modeled as two segments ...

The buckling and postbuckling behaviors of a composite beam with single delamination are investigated. A three-dimensional finite element model using the commercial code ANSYS is employed for this purpose. The finite elements analyses have been performed using a linear buckling model based on the solution of the eigenvalues problem, and a non-linear one based on an incremental-iterative method....

Ranges of validity for the continuum-beam model, the length-scale effects and continuum assumptions are analyzed in the framework of scaling analysis of NT structure. Two coupled criteria for the applicability of the continuum model are presented. Scaling analysis of NT buckling and geometric parameters (e.g., diameter and length) is carried out to determine the key non-dimensional parameters t...

background: laser-tissue interaction on low-level laser therapy (lllt) has widespread medical applications (e.g., improved wound healing). the tensile strength of radiated tissue by lllt is known to be increased mainly because of cross collagen bands developed after radiation. objective: in this work, we studied the instantaneous effect of radiation of polarized laser beam on the viscoelastic t...

A thin elastic rod embedded in an elastic medium buckles into an exponentially decaying short wavelength profile under compressive loading beyond a critical value. In this study, we report a combined experimental and theoretical investigation of the buckling profile of a thin elastic rod embedded in an elastic gelatin biopolymer network when fracture of the network happens. Prior models have pr...

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...

geometrically nonlinear governing equations for a plate with linear viscoelastic material are derived. the material model is of boltzmann superposi¬tion principle type. a third-order displacement field is used to model the shear deformation effects. for the solution of the nonlinear governing equations the dynamic relaxation (dr) iterative method together with the finite difference discretizati...

The present study investigates buckling characteristics of both nonlinear symmetric power and sigmoid functionally graded (FG) beams. The volume fractions of metal and ceramic are assumed to be distributed through a beam thickness by the sigmoid-law distribution (S-FGM), and the symmetric power function (SP-FGM). These functions have smooth variation of properties across the boundary rather tha...

The phenomenon of buckling in compression of an elastic inhomogeneous medium under initial stress is well known. It is illustrated by the instability of a longitudinally compressed ‘elastic plate embedded in a medium of lower rigidity. Under a critical load buckling appears suddenly in the form of a sinusoidal folding of a certain wave-length. Such sudden buckling ,will, of course, not occur in...