In this study, Buckling Limit of Strain (B.L.S.) is introduced as one of the most important limiting factors in cold roll forming process. B.L.S. is calculated by the finite element procedure. Then for two particular processes with existing analysis and experimental results, B.L.S. has been determined and evaluated. LUSAS 12.3 is used for finite element analysis. The results show that when buck...

The presence of the delamination causes reductions in the bending stiffness which in turn leads to the undesirable loss in the compressive buckling and post-buckling strength. Thus, it is of chief importance to investigate the compressive behavior of composites with delaminations. Anastasiadis et al. analyzed the buckling and postbuckling behavior of delaminated composite laminates with a throu...

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...

An analytical investigation is conducted to predict the post-buckling strength of laminated composite stiffened panels under compressive loads. When a stiffened composite panel buckles, the skin would deform into a sinusoidal mode shape, and hence induces additional moments and forces near the skin-stiffener interface region. These induced loads would cause the existing small edge delamination ...

Two new "nitely deformed dynamical beam models are established for serious study on non-linear vibrations of thick beams subjected to arbitrarily given external loads. The total potentials of these beam models are non-convex with double-well structures, which can be used in post-buckling analysis and frictional contact problems. Dual extremum principles in unstable dynamic systems are developed...

This paper was to verify the STAGS (general shell, geometric and material nonlinear) code and the critical crack-tip-opening angle (CTOA) fracture criterion for predicting stable tearing in cracked panels that fail with severe out-of-plane buckling. Materials considered ranged from brittle to ductile behavior. Test data used in this study are reported elsewhere. The STAGS code was used to model...

Foam core sandwich composites are widely used in primary structural components of launch vehicles and spacecraft. These structures exhibit complex failure modes and are highly sensitive to butt-joints, core mismatches, impact damage, voids, and facesheet delaminations. 3D Fiber Reinforced Foam Cores (3DFRFC) represent a new class of core material designed to replace standard foam core in future...

Summary This article analyses static buckling of the so-called Gao beam nonlinear model. It considers pure problems in which vertical loads are omitted. The analysis, using minimisation energy and concept a modified Rayleigh quotient, leads to new results regarding critical load necessary for buckling, existence number post-buckling solutions. Computational provided cases with fixed axial loadi...

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....

It is empirically established that, due to a number of factors involved, a classical (linear) analysis of buckling pressure is impossible. Nonlinear theories of buckling are, therefore, required that involve effective factors such as imperfections and welding effects. In this study, models are developed which are as close to allowable standard deviations as possible. In the next stage, their bu...