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A theoretical (semi-analytical) approach was proposed to estimate the dynamic in-plane response of corrugated core sandwich columns against suddenly applied loads with a compression rate less than 5m/s. The model has been constructed so as to effectively include various dynamic effects such as stress wave propagation, material rate dependence and lateral inertia. The practical and theoretical complexities caused from the dynamic phenomena and the established governing equations (e.g. coupled non-uniform axial force distribution) have been resolved by employing Galerkin's method. The proposed approach was validated by comparing the calculations from the theoretical model and Finite Element Method (FEM): the load history and deformation shape of extruded Al6061-T6 corrugated core sandwich columns and bending/brazed SS304 corrugated core sandwich columns. The model successfully yielded the imperfection-sensitive, velocity-dependent dynamic response and appearance of higher buckling modes. In addition, it has been demonstrated that the sandwich columns with periodic cellular metals outperform their weight-equivalents, monolithic solid columns, under dynamic conditions. The proposed approach as an efficient tool to explore the dynamic global buckling response in design space can make preliminary studies of weight minimization for dynamic applications. [ABSTRACT FROM AUTHOR]

Abstract: The lateral buckling and helical buckling problem of a circular cylinder constrained by an inclined circular cylinder under a compressive force, torsion, and its own weight is complicated and difficult to obtain an exact analytical solution. Thus, the non-linear differential equation is solved incrementally using the discrete singular convolution (DSC) algorithm together with the Newton–Raphson method. Detailed formulations are worked out. A simple way to numerically simulate the helical buckling is proposed and solution procedures are given. Four examples with various inclined angles, weights per unit length of the inner cylinder, axial applied loads, and boundary conditions are investigated. To verify the formulations and solution procedures, comparisons are firstly made with data obtained using the finite element method. It is verified that under certain circumstance, only lateral or helical buckling alone will occur. On some other circumstance, both lateral buckling and helical buckling may occur and the critical helical buckling loads are higher than the critical lateral buckling loads if frictions are not considered. Some conclusions are made based on the results presented herein. [Copyright &y& Elsevier]

In this article, post-buckling and non-linear bending analysis of functionally graded annular sector plates based on three dimensional theory of elasticity in conjunction with non-linear Green strain tensor is considered. In-plane normal compressive loads have been applied to either radial, circumferential, or all edges of annular sector plates. Material properties are graded in the thickness direction according to a simple power law distribution in terms of the volume fractions of constituents while Poisson׳s ratio is assumed to be constant. The governing equations are developed based on the principle of minimum total potential energy and solved based on graded finite element method. Non-linear equilibrium equations are solved based on iterative Newton–Raphson method. The effects of material gradient exponent, different sector angles, thickness ratio, loading condition and two different boundary conditions on the post-buckling behavior of FGM annular sector plates have been investigated. Results denote that due to the stretching–bending coupling effects of the FGMs, the post-buckling behavior of movable simply supported FGM plates is not of the bifurcation-type buckling. Moreover, FGM annular sector plates subjected to uniaxial compression at radial edges show a non-linear bending behavior with unique and stable equilibrium paths following a flattening feature. [ABSTRACT FROM AUTHOR]

Abstract: In the present work a model able to predict the buckling behavior of thin, orthotropic, stiffened plates and shells subject to axial compression is proposed. In the context of the Kirchhoff-Love plate theory and making use of different strain-displacement models – namely the von Kármán model, the Koiter–Sanders shell model, an enhanced von Kármán model and a spurious model commonly adopted in literature – the equilibrium equations have been solved by the Levy-type approach. The results obtained highlight the influence of each non-linear strain-displacement term and show that the von Kármán model can noticeably overestimate the buckling load when the critical mode involves significant in-plane displacements. [Copyright &y& Elsevier]

Abstract: The paper presents a procedure for the analysis of stability and initial post-buckling behaviour of spliced columns in sway and non-sway steel frames. The main assumptions are linear elasticity and geometrically perfect columns that are loaded by a compressive force which retains its direction as the column deflects. An energy-based formulation that includes a polynomial Rayleigh–Ritz approximation into the potential energy function, in combination with the Lagrange’s method of undetermined multipliers, has been found very convenient for this type of problem. The system is thus described by a set of kinematically admissible generalized coordinates and a single loading parameter. First, the critical state is characterized by means of linear eigenvalue analysis. A parametric study is implemented to assess the critical load. The numerical results are used to develop a relatively simple yet reasonably accurate engineering method for predicting the critical behaviour of spliced columns in sway and non-sway steel frames. The energy formulation is then applied to the search of post-buckling branches of bifurcation points. The approach embraces path-following methods based on perturbation schemes built on a Newton type iterative procedure. This is illustrated in the application to post-bifurcation in columns with different splice mechanical characteristics. The findings suggest that the splice tangent stiffness has a major influence on the overall column behaviour. [Copyright &y& Elsevier]

Abstract: The buckling of nanostructures including as a nanobeam, nanorod, and nanotube in a temperature field is investigated based on the non-local elasticity field theory with non-linear strain gradients first proposed by Eringen. New higher-order governing differential equations both in transverse and axial direction for buckling of such nanostructures are derived based on the exact variational principle approach with corresponding higher-order non-local boundary conditions. Based on these new governing equations and boundary conditions, new analytical solutions for some practical examples on buckling of nanostructures are presented and analyzed in detail. Subsequently, the effects of non-local nanoscale and temperature change on critical buckling load are analyzed and discussed. It is observed that those factors have great influence on the critical buckling load of the nanostructures. In particular, the non-local stress very much affects the stiffness of nanostructures and the critical buckling load is significantly increased in the presence of non-local stress. The paper concludes that at low and room temperature the critical buckling load of nanostructures increases with increasing temperature change, while at high temperature the critical buckling load decreases with increasing temperature change. A critical temperature change which causes buckling without external load is also derived and discussed. [Copyright &y& Elsevier]

Abstract: The in-plane elastic buckling of a steel column with load-dependent supports under thermal loading is investigated. Two elastic rotational springs at the column ends are used to model the restraints which are provided by adjacent structural members or elastic foundations. The temperature is assumed to be linearly distributed across the section. Based on a nonlinear strain–displacement relationship, both the equilibrium and buckling equations are obtained by using the energy method. Then the limits for different buckling modes and the critical temperature of columns with different cases are studied. The results show that the proposed analytical solution can be used to predict the critical temperature for elastic buckling. The effect of thermal loading on the buckling of steel columns is significant. Furthermore, the thermal gradient plays a positive role in improving the stability of columns, and the effect of thermal gradients decreases while decreasing the modified slenderness ratios of columns. It can also be found that rotational restraints can significantly affect the column elastic buckling loads. Increasing the initial stiffness coefficient α or the stiffening rate β of thermal restraints will increase the critical temperature. [Copyright &y& Elsevier]

Abstract: The post-buckling behavior of the thin stiffened plates with uncertain initial deflection under uni-direction compression load is investigated based on Von-Karman large deflection theory. The uncertain initial deflections are considered to be unknown except that they belong to a given set in the interval range. Interval analysis model for computing the bounds of curves of the post-buckling deflection versus load of the plate is presented. Interval analysis model is compared with the stochastic model, which is taken as the benchmarks of accuracy for judgment. The results indicate that the non-probabilistic and stochastic methods will produce similar results for a large deviation of uncertainty. If the probabilistic information is unavailable, one should not propose the probabilistic method based on an arbitrary assumption on the distribution of the deflection coefficients. Rather, one should use the non-probabilistic method to uncertainty. [Copyright &y& Elsevier]

Abstract: This paper is concerned with an analytical study of the non-linear elastic in-plane behaviour and buckling of pinned–fixed shallow circular arches that are subjected to a central concentrated radial load. Because the boundary conditions provided by the pinned support and fixed support of a pinned–fixed arch are quite different from those of a pinned–pinned or a fixed–fixed arch, the non-linear behaviour of a pinned–fixed arch is more complicated than that of its pinned–pinned or fixed–fixed counterpart. Analytical solutions for the non-linear equilibrium path for shallow pinned–fixed circular arches are derived. The non-linear equilibrium path for a pinned–fixed arch may have one or three unstable equilibrium paths and may include two or four limit points. This is different from pinned–pinned and fixed–fixed arches that have only two limit points. The number of limit points in the non-linear equilibrium path of a pinned–fixed arch depends on the slenderness and the included angle of the arch. The switches in terms of an arch geometry parameter, which is introduced in the paper, are derived for distinguishing between arches with two limit points and those with four limit points and for distinguishing between a pinned–fixed arch and a beam curved in-elevation. It is also shown that a pinned–fixed arch under a central concentrated load can buckle in a limit point mode, but cannot buckle in a bifurcation mode. This contrasts with the buckling behaviour of pinned–pinned or fixed–fixed arches under a central concentrated load, which may buckle both in a bifurcation mode and in a limit point mode. An analytical solution for the limit point buckling load of shallow pinned–fixed circular arches is also derived. Comparisons with finite element results show that the analytical solutions can accurately predict the non-linear buckling and postbuckling behaviour of shallow pinned–fixed arches. Although the solutions are derived for shallow pinned–fixed arches, comparisons with the finite element results demonstrate that they can also provide reasonable predictions for the buckling load of deep pinned–fixed arches under a central concentrated load. [Copyright &y& Elsevier]

Abstract: The available accurate shell theories satisfy the interlaminar transverse stress continuity conditions based on linear strain–displacement relations. Furthermore, in majority of these theories, either influence of the transverse normal stress and strain or the transverse flexibility of the shell has been ignored. These effects remarkably influence the non-linear behavior of the shells especially in the postbuckling region. Furthermore, majority of the buckling analyses performed so far for the laminated composite and sandwich shells have been restricted to linear, static analysis of the perfect shells. Moreover, almost all the available shell theories have employed the Love–Timoshenko assumption, which may lead to remarkable errors for thick and relatively thick shells. In the present paper, a novel three-dimensional high-order global-local theory that satisfies all the kinematic and the interlaminar stress continuity conditions at the layer interfaces is developed for imperfect cylindrical shells subjected to thermo-mechanical loads. In comparison with the layerwise, mixed, and available global-local theories, the present theory has the advantages of: (1) suitability for non-linear analyses, (2) higher accuracy due to satisfying the complete interlaminar kinematic and transverse stress continuity conditions, considering the transverse flexibility, and releasing the Love–Timoshenko assumption, (3) less required computational time due to using the global-local technique and matrix formulations, and (4) capability of investigating the local phenomena. To enhance the accuracy of the results, compatible Hermitian quadrilateral elements are employed. The buckling loads are determined based on a criterion previously published by the author. [ABSTRACT FROM AUTHOR]

Abstract: An arch under a suddenly-applied load will oscillate about its equilibrium position. If the suddenly-applied load is sufficiently large, the oscillation may reach a position on the unstable equilibrium branch of the arch, triggering its dynamic buckling. In many cases, arches are supported by other structural members or by elastic foundations which provide elastic types of rotational restraints to the ends of the arch. When the rotational end restraints of an arch are not equal to each other, the in-plane non-linear equilibrium path of the arch may have multiple unstable branches, which will influence the dynamic buckling of the arch significantly. This paper investigates effects of multiple unstable equilibrium branches on the non-linear in-plane dynamic buckling of a shallow circular arch under a suddenly-applied central concentrated load. Two methods based on the energy approach are used to derive the dynamic buckling loads. It is found that the number and magnitude of dynamic buckling loads are influenced significantly by the number of unstable equilibrium branches, by the stiffness of the unequal rotational end restraints, and by the included angle and slenderness ratio of the arch. [Copyright &y& Elsevier]

Abstract: This paper presents an efficient mathematical model for studying the buckling behavior of geometrically perfect elastic two-layer composite columns with interlayer slip between the layers. The present analytical model is based on the linearized stability theory and is capable of predicting exact critical buckling loads. Based on the parametric analysis, the critical buckling loads are compared to those in the literature. It is shown that the discrepancy between the different methods can be up to approximately 22%. In addition, a combined and an individual effect of pre-buckling shortening and transverse shear deformation on the critical buckling loads is studied in detail. A comprehensive parametric analysis reveals that generally the effect of pre-buckling shortening can be neglected, while, on the other hand, the effect of transverse shear deformation can be significant. This effect can be up to 20% for timber composite columns, 40% for composite columns very flexible in shear (pyrolytic graphite), while for metal composite columns it is insignificant. [Copyright &y& Elsevier]

Curved structures, such as beams, arches, and panels are capable of exhibiting snap-through buckling behavior when loaded laterally, that is they can exhibit multiple stable equilibria, sometimes after any external loading is removed. This is a consequence of highly nonlinear force-deflection relations with perhaps multiple crossings of the zero-force axis for typical equilibrium paths. However, the propensity to maintain a stable snapped-through equilibrium position (in addition to the nominally unloaded equilibrium configuration) after the load is removed depends on certain geometric properties. A number of clamped arches are used to illustrate the relation between geometry (essentially the shape) and corresponding equilibrium configuration(s), and especially those conditions for which the initial equilibrium configuration is the only stable shape possible. Furthermore, related results are obtained when a change in the thermal environment may cause a system to exhibit a stable snapped-through equilibrium even when the system at ambient thermal conditions does not. Some representative examples are produced using a 3D printer for verification purposes. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents the theoretical developments of a high accuracy method for the post-buckling analysis of some channel section struts. In this method, the Von-Karman''s equilibrium equation is solved exactly to obtain the buckling loads and the corresponding form of out-of-plane buckling deflection modes. The investigation of channel section buckling behaviour is then extended to the post-buckling study with the assumption that the deflected form after the buckling is the combination of first, second and higher (if required) modes of buckling. Thus, the full-analytical post-buckling study is effectively a multi term analysis, which is attempted by utilizing the so-called semi-energy method. In this method the Von-Karman compatibility equation is used together with a consideration of the total strain energy of the strut. Through the solution of the compatibility equation, the in-plane displacement functions which are themselves related to the Airy stress function are developed in terms of the unknown coefficients in the assumed out-of-plane deflection function. The in-plane and out-of-plane deflection functions are substituted in the total strain energy expressions and the theorem of minimum total potential energy is applied to solve for the unknown coefficients. It is noted that the Classical Plate Theory (CPT) is applied throughout the theoretical developments. Through the comparison of the results and the appropriate discussion, the knowledge of the level of capability of the method is significantly promoted. [Copyright &y& Elsevier]

Abstract: This paper presents a thorough and comprehensive investigation of non-linear buckling and postbuckling analyses of pin-ended shallow circular arches subjected to a uniform radial load and which have equal elastic rotational end-restraints. The differential equations of equilibrium for non-linear buckling and postbuckling are established based on a virtual work approach. Exact solutions for the non-linear bifurcation, limit point and lowest buckling loads are obtained; in particular, exact solutions for the non-linear postbuckling equilibrium paths are derived. The criteria for switching between fundamental buckling and postbuckling modes are developed in terms of critical values of a geometric parameter for an arch, with exact solutions for these critical values of geometric parameter being obtained. Analytical solutions of non-linear buckling and postbuckling problems for arches with rotational end-restraints are of great interest, since they constitute one of the very few closed-form analyses of buckling and postbuckling behaviour of continuous structural systems. These exact solutions are a contribution to the non-linear structural mechanics of arches, as well as providing useful benchmark solutions for verifying non-linear numerical analyses. [Copyright &y& Elsevier]

Prestressed stayed columns are an innovative type of structural system where the compressive load-carrying capacity can be enhanced through prestressed external cable stays. A nonlinear analytical model for prestressed stayed columns with multiple crossarm systems along the column length, based on the Rayleigh–Ritz method, is presented that captures modal interactions for perfect geometries explicitly for the first time. It is demonstrated that the theoretical compressive strength enhancements under certain configurations can only be obtained at the expense of triggering a sequence of destabilizing bifurcations. This can give rise to dangerously unstable interactive post-buckling behaviour including so-called ‘mode jumping’ and ‘snaking’ phenomena. Parametric spaces where the system is most susceptible to the modal interactions are identified and it is for those configurations that the system is likely to be highly sensitive to initial imperfections. The model is validated using a nonlinear finite element model formulated within the commercial code ABAQUS and excellent comparisons are obtained. [ABSTRACT FROM AUTHOR]

Abstract: It is well established that certain structural buckling problems are extremely sensitive to small changes in configuration: geometric imperfections, load application, symmetry, boundary conditions, etc. This paper considers the behavior of a very shallow arch under lateral point loading, and specifically under the influence of changes in the thermal environment. In some ways the system under study is especially sensitive since small changes influence whether the arch ‘snaps-through’ or not. The experimental results provide insight into the challenges of understanding the behavior of these types of structural components in a practical, and thus necessarily imperfect, situation. The focus is on static loading or at least quasi-static loading, in which loading occurs on a slow time scale. This study also acts as a back-drop for studying the dynamic behavior of shallow arches, an area of concern in the context of aerospace structural components. [Copyright &y& Elsevier]

This paper presents the results of a combined experimental and analytical study on one-dimensional slender elements of monolithic glass subjected to simultaneous compression and bending, which progressively increased up to the collapse. The experiments were performed on 32 quintuplets; each quintuplet was composed of five identical specimens, while the quintuplets differed from each other in the geometry and glass of the specimens. The load and restraints applied to a specimen of a quintuplet were different from those applied to the other specimens of the same quintuplet; hence, five different types of tests were performed on the 160 specimens. In each test, the load and the displacements were measured continuously. The collapse, which occurred when the maximum tensile stress reached glass tensile strength (first cracking), exhibited large deflections. Cracking always initiated away from the edges, since the tests had been designed to avoid edge effects. The results proved that geometric non-linear behavior of glass members cannot be described using the same model as steel structures. An analytical model was then constructed to describe the behavior of glass members subjected to combined compression and bending, which predicts the load-carrying capacity and allows safety to be assessed. [ABSTRACT FROM AUTHOR]

Recent investigations have shown that the presence of weak cross sections can deeply modify flutter and divergence instability of a cantilever beam-column. Position, intensity of weakness and degree of non-conservativeness not only can alter the value of the critical load of the healthy column but can also produce a modification of the type of instability. In this paper, issues involved in the influence of an elastic end support on flutter and buckling instability of the Beck׳s column in presence of an arbitrary number of weak sections is investigated. In the literature, a numerical study, restricted to the case of a single weak section only, has been presented. The study here proposed has been motivated by an extension to the case of multiple weak sections by means of a model that does not require continuity conditions to be enforced. On the other hand, the latter extension has led to a surprising contradiction of the results previously divulgated for the propped Beck׳s column with a single weak section. The exact solution, in terms of mode shapes and characteristic eigen-value equation of the weakened propped cantilever has been obtained in an explicit suitable form, through the use of generalised functions. The extensive numerical applications aim at the investigation of the effect of different debilitation scenarios in the flutter and buckling instability of the propped cantilever. In particular, the results relative to the case of single-weak section propped column, already investigated in the literature, are discussed in this work and they are shown that do not match those obtained by other authors. The latter incongruence is duly highlighted and discussed to infer the specific motivation. [ABSTRACT FROM AUTHOR]

Polymer nanocomposites reinforced by boron nitride nanotubes (BNNTs) have great potential for use in a wide variety of thermal environments. A closed-form solution for nonlinear bending and thermal-postbuckling behavior of BNNT-reinforced nanocomposite beams under arbitrary temperature gradient in the thickness and length directions is presented for the first time. The uniform and functionally graded (FG) distributions of BNNTs through the thickness of macro-or micro-sized beams are considered. For constant temperature or constant heat flux conditions at two ends of the beam, thermal analysis is carried out to obtain temperature field Δ T x , z using the two-dimensional heat conduction equation and the assumption of arbitrary variation in the z direction. The governing equations of modified couple stress Timoshenko beam theory with von Kármán geometric nonlinearity are derived for BNNT-RC beams subjected to thermomechanical loads. Applying change of variable technique, the governing equations are exactly solved to develop closed-form expression for nonlinear transverse deflection. Finally, parametric study is performed to investigate the effects of length scale parameter, aspect ratio (L / h) , distribution of BNNTs, and temperature gradient on the nonlinear bending and postbuckling equilibrium paths. It is shown that the thermal-buckling behavior of clamped and cantilever beams is completely different. Under thermomechanical loading, an initial snap-through buckling behavior is observed in the cantilever beam, while there exist both stable and unstable configurations in the static equilibrium path of clamped beam. Moreover, it is found that the assumption of parabolic variation of temperature through thickness is not compatible with real situations, since the temperature field is obtained as harmonic functions with very short wavelengths in the length direction. • The effect of arbitrary temperature gradient on nonlinear bending and thermal-postbuckling behavior of BNNT-reinforced nanocomposite beams is investigated. • The closed-form solution of thermomechanical equilibrium paths is developed by applying change of variable technique. • Thermal analysis is presented to obtain temperature distribution Δ T (x , z) based on the two-dimensional heat conduction equation. • For clamped beams under thermomechanical loading, both stable and unstable paths may be occurred in the w m a x / h − q 0 curves. • For cantilever BNNT-RC beams under thermal loading, a slope change in static equilibrium paths is seen for the beginning point of thermal-postbuckling behavior. [ABSTRACT FROM AUTHOR]

The paper studies the effect of the inter-laminar contact and its temporal variation on the behavior of FRP strengthened walls with delaminated regions. The paper adopts an analytical approach that unifies the displacement and stress fields of sub-regions where the delaminated faces are in contact with ones where the layers are free of contact. This is achieved by means of a Robin type of condition at the delaminated interface and a 2D time dependent Heaviside function that automatically switches between contact states. The model is converted into a finite element form that utilizes the high order displacement fields, overcomes the obstacles due to the scatter of geometric scales, avoids the need to mesh through the thickness of the layers, and simplifies the implementation in a broader finite element framework. The role of the inter-laminar contact non-linearity is demonstrated through the study of the dynamic behavior triggered by the geometrically non-linear snap-out of a delaminated layer in a shear wall strengthened with FRP. The analysis quantifies the impact of the 2D time dependent contact map on the snap-out load, the dynamic post-buckling behavior, and the interfacial stresses. The paper closes with conclusion regarding the delaminated wall as well as many other laminated, adhesively bonded, or sandwich structural forms that are prone to delamination, dynamic instabilities, and the combination of the two. [ABSTRACT FROM AUTHOR]

Abstract: Geometrical non-linear analyses of a sandwich panel with a prescribed debond within one of the face sheets where the core is either incompressible (stiff) or compressible (compliant) are presented. A loading scheme of thermal or mechanical loads independently or combined thermo-mechanical load is considered. The debond, in one of the face sheets, consists of a through-the-width crack that divides it into two layers, one with a free surface (upper or lower) and the other attached to the core. The interfaces of the debonded crack are free of shear stresses but can only accommodate vertical normal compressive stresses. In the case of a compliant core the high-order sandwich panel (HSAPT) model is adopted and in case of an incompressible core the ordinary beam theory (OBT) and the first-order shear deformable theory (FOSDT) (equivalent single layer, ESL) are used. The mathematical formulation outlines the field equations along with the stress and displacements fields for the cases where the core (stiff or compliant) properties are either temperature independent (TI) or dependent (TD). The governing equations along with the appropriate boundary and continuity conditions are derived using variational principles following the principles of the HSAPT or ESL models. The non-linear analysis includes geometrical non-linearities in the face sheets caused by rotation of the face cross sections and high-order effects that are the result of the compliant core. The core stress and displacements fields with temperature-dependent (TD) mechanical properties are determined in a closed form using properties that are vertically coordinate dependent. The numerical study looks into the effect of the thickness (thin, moderate and very thick) of the debonded layer that is not attached to the core in the presence of mechanical and thermal loads on the non-linear response. An inner delamination is considered, around mid-span, for specific lengths with TI or TD mechanical properties. The results reveal that the ESL models cannot be used to predict the non-linear response of a sandwich panel with a compliant core. In addition, the existence of a debond crack nearby the face–core interface (very thick layer) may be associated with local buckling of the thin layer that is bonded to the core. [Copyright &y& Elsevier]

Abstract: The present literature review focuses on geometrically non-linear free and forced vibrations of shells made of traditional and advanced materials. Flat and imperfect plates and membranes are excluded. Closed shells and curved panels made of isotropic, laminated composite, piezoelectric, functionally graded and hyperelastic materials are reviewed and great attention is given to non-linear vibrations of shells subjected to normal and in-plane excitations. Theoretical, numerical and experimental studies dealing with particular dynamical problems involving parametric vibrations, stability, dynamic buckling, non-stationary vibrations and chaotic vibrations are also addressed. Moreover, several original aspects of non-linear vibrations of shells and panels, including (i) fluid–structure interactions, (ii) geometric imperfections, (iii) effect of geometry and boundary conditions, (iv) thermal loads, (v) electrical loads and (vi) reduced-order models and their accuracy including perturbation techniques, proper orthogonal decomposition, non-linear normal modes and meshless methods are reviewed in depth. [Copyright &y& Elsevier]

Abstract: Researches on the collapse behavior of a 3×3×0.7m tensegrity grid have been conducted with the aim of examining the accuracy of the proposed numerical procedure for investigating the localization or propagation of collapse in these systems. The experimental program consists of tests on the constituent elements and collapse test on the whole system. In the current study, two types of collapse due to sudden rupture of a cable element and buckling of a strut were examined in the studied tensegrity model under load control. It was found that the most important factors that influence the collapse behavior of the tensegrity model are the imperfection amplitude, damping factors and residual stresses of the buckled struts. Based on the obtained results, the finite element model were adjusted, compared and validated with the experimental results until reliable and robust numerical model were achieved. [Copyright &y& Elsevier]

Abstract: This paper deals with the large amplitude vibration, non-linear bending and postbuckling of fiber reinforced composite laminated plates resting on an elastic foundation in hygrothermal environments. Two kinds of fiber reinforced laminated plates, namely, uniformly distributed and functionally graded reinforcements, are considered. The material properties of fiber reinforced laminated plates are estimated through a micromechanical model and are assumed to be temperature-dependent and moisture-dependent. The motion equations are based on a higher order shear deformation plate theory that includes plate-foundation interaction and the hygrothermal effect. A two-step perturbation technique is employed to determine the non-linear to linear frequency ratios of plate vibration, the load-deflection and load-bending moment curves of plate bending, and postbuckling equilibrium paths of laminated plates. [Copyright &y& Elsevier]