Thin-Walled Struct Research Articles

Energy absorption characteristics analysis of multicellular columns based on the origami centripetal folding method

In order to improve the crashworthiness of traditional Thin-Walled Struct, a new method for designing multicellular tubes is presented in this paper. In this work, multicellular columns based on origami centripetal folding method (MCOCFM) are proposed. The cross section of MCOCFM is designed in the way of origami. The mechanical properties of MCOCFM under uniaxial compression are analyzed by numerical simulation. Studies have shown that increased levels and wall thickness facilitate energy absorption. In addition, the theoretical prediction of MCF is in good agreement with the simulation results. Compared with some existing structures, MCOCFM has better crashworthiness.

Reply to “A comment on buckling and postbuckling response of nonlocal strain gradient porous functionally graded micro/nano-plates via NURBS-based isogeometric analysis” [Thin-Walled Struct. 184 (2023) 110505

The comment published by Dehrouyeh-Semnani (2023) is based on an incorrect assumption which results in completely erroneous conclusions. In the present paper, the invalidity of claims given by that comment are proved clearly to avoid any possible mistake for readers.

A comment on “Buckling and postbuckling response of nonlocal strain gradient porous functionally graded micro/nano-plates via NURBS-based isogeometric analysis” [Thin-Walled Struct. 159 (2021) 107231

The reported results by Fan et al. (2021) show that the size-dependent and -independent porous functionally graded (PFG) small-scale plate with unsymmetrical material distribution, under fully simply supported boundary conditions, and subject to uniaxial uniform compressive load remains flat and then loses its stability at a critical buckling load. In the present comment, it is proved that the above-mentioned small-scale plate does not remain flat, no matter how small are the in-plane load, at the beginning of in-plane loading, the small-scale plate undergoes lateral deformation. Consequently, the buckling and post-buckling responses predicted by Fan et al. (2021) do not occur for the small-scale plate. It should be pointed out that Aydogdu (2008) utilized the method proposed by Leissa (1986) for the unsymmetrically laminated plate under in-plane load to prove that the functionally graded plate with unsymmetrical material distribution and fully simply supported boundary conditions does not remain flat when it is exposed to an in-plane load. The work presented by Aydogdu (2008) was not reviewed and discussed by Fan et al. (2021).

Analysis of fire-induced progressive collapse for topside structures of a VLCC-class ship-shaped offshore installation

ABSTRACT This study extends the authors’ previous numerical and experimental studies simulating the progressive collapse of steel stiffened-plate structures in fire events (Paik JK, Ryu MG, He KH, Lee DH, Lee SY, Park DK, Thomas G. 2021a. Full-scale fire testing to collapse of steel stiffened plate structures under lateral patch loading (part 1) – without passive fire protection. Ships Offsh Struct. 16(3):227–242; Paik JK, Ryu MG, He KH, Lee DH, Lee SY, Park DK, Thomas G. 2021b. Full-scale fire testing to collapse of steel stiffened plate structures under lateral patch loading (part 2) – with passive fire protection. Ships Offsh Struct. 16(3):243–254; Ryu MG, He KH, Lee DH, Park SI, Thomas G, Paik JK. 2021. Finite element modeling for the progressive collapse analysis of steel stiffened-plate structures in fires. Thin-Walled Struct. 159:107262). Specifically, this study demonstrates that the computational models developed in the earlier studies can be applied to the analysis of the heat transfer and fire-induced progressive collapse behaviour of the topside structures of a ship-shaped offshore installation. To this end, a hypothetical VLCC-class floating, production, storage and offloading (FPSO) unit hull structure is considered, and transient thermal elastic-plastic large-deformation finite element models are used. The novelty of this study and its contribution to industry are the development of a practical procedure to ensure the fire safety of large-scale steel-plated structures with complex geometries.

Corrigendum to “Experimental and numerical investigation on local–overall interactive buckling behavior of welded I-section steel columns” [Thin-Walled Struct. 151 (2020) 106763

Corrigendum to “Experimental and numerical investigation on local–overall interactive buckling behavior of welded I-section steel columns” [Thin-Walled Struct. 151 (2020) 106763

Corrigendum to “Influence of plain end-cap on the energy absorption characteristics of cylindrical tubular structures for lateral impact vehicle collisions”[Thin-Walled Struct. Vol 138 (2019) 32–45

Corrigendum to “Influence of plain end-cap on the energy absorption characteristics of cylindrical tubular structures for lateral impact vehicle collisions”[Thin-Walled Struct. Vol 138 (2019) 32–45

Corrigendum to “Experimental and numerical investigation of SHS truss T-joints reinforced with sidewall plates” [Thin-Walled Struct. 145 (2019) 1–16

Corrigendum to “Experimental and numerical investigation of SHS truss T-joints reinforced with sidewall plates” [Thin-Walled Struct. 145 (2019) 1–16

Open cross-section beams under pure bending II. Finite element simulation

Starting from the set of bending tests of U sections performed in our laboratory and described in Part I. Experimental investigations [Pastor MM, Roure F. Open cross-section beams under pure bending. I. Experimental investigations. Thin-Walled Struct 2008;46(5):476–483.], a numerical model has been developed. It reproduces the actual testing conditions and also the building of hinges in pure bending, as well as producing the moment–rotation curves of the section and a complete information about the stresses and strains of the beam along the whole loading process. Once the model has been validated, a parametric study has been done for the U sections. The influence of several parameters on the ultimate strength in bending of the section has been analysed: thickness ( t), width ( b), depth ( c w) and position of the point of application of the load ( y).

Nonlinear finite element method models for ultimate strength analysis of steel stiffened-plate structures under combined biaxial compression and lateral pressure actions—Part II: Stiffened panels

The present paper (Part II) is a sequel to the previous paper (Part I) [Paik JK, Seo JK. Nonlinear finite element method models for ultimate strength analysis of steel stiffened-plate structures under combined biaxial compression and lateral pressure actions—Part I: Plate elements. Thin-Walled Struct 2008, this issue, doi:10.1016/j.tws.2008.08.005.] on the application of nonlinear finite element methods for ultimate strength analysis of steel stiffened-plate structures under combined biaxial compression and lateral pressure actions. In contrast to Part I dealing with plate elements, the present paper (Part II) treats stiffened panels surrounded by strong support members such as longitudinal girders and transverse frames. In similar to Part I, some important factors of influence such as structural dimensions, initial imperfections, loading types and computational techniques in association with ultimate limit states are studied. Some useful insights in terms of nonlinear finite element method modeling are developed using ANSYS code together with the ALPS/ULSAP semi-analytical method, the latter being for the purpose of a comparison.

Buckling, post-buckling and delamination propagation in debonded composite laminates

Abstract A new mechanical and computational model is presented in this part 1 of the paper for bucking, post-buckling and delamination propagation in debonded composite laminates. The layer-wise plate theory of Reddy [Reddy JN. A generalization of two-dimensional theories of laminated composite plates. Commun Appl Numer Methods 1987; 3: 173–80] is extended to account for delamination kinematics. The possible displacement jumps across delamination interfaces are incorporated in the assumed displacement field with step function supplements. The geometric non-linearity is included through the use of von Karman’s non-linear strain–displacement relationships. For computational efficiency and modelling effectiveness of delamination, both point and distributed interface spring models are developed. In order to predict the delamination propagation, the energy release rate at the delamination front is computed by means of the crack closure method. B-spline finite strip methods [Wang S, Dawe DJ. Spline FSM postbuckling analysis of shear-deformable rectangular laminates. Thin-Walled Struct 1999; 34: 163–78; Wang S, Zhang Y. Vibration analysis of composite laminated plates using layer-wise B-spline finite strip method. Comp Struct 2005; 68: 349–58, [30] ] are extended to develop the computational model through the enrichment of displacement field by step functions.

Experimental investigations on combined resistance of corrugated sheets with strengthened cross-sections under bending and concentrated load

Multi-span corrugated sheets have lower resistance from single-span beams. This effect results from the combined bending moment and bearing load acting at the internal supports. It is a possibility to increase the resistance by means of local strengthening of critical cross-sections over the internal supports. The strengthening can be achieved by doubling of cross-sections (lap connection, applying an additional corrugated sheet). At present there is a lack of knowledge about the resistance of doubled cross-sections of corrugated sheets under concentrated load, bending moment or combined concentrated load and bending moment acting at the strengthened cross-section. The results of experimental investigations on combined M–F relationship for corrugated sheets with doubled cross-section have been presented. For 35 tested models the following parameters have been changed: the length of strengthening a, span distance l, the way of a profile placement, the structure of strengthening, the number and placement of connectors. Obtained results have been compared with those received experimentally for unstrengthened models [Biegus A, Czepiżak D. Research on the interactive resistance of corrugated sheets under combined bending and contact pressure, Thin-Walled Struct 2006;44:825–831]. The conclusions leading to the optimal parameters of strengthening of corrugated sheets have been given.

Bifurcation of locally buckled point symmetric columns—Experimental investigations

The bifurcation equations for locally buckled point symmetric sections are derived in a companion paper [Rasmussen KJR. Bifurcation of locally buckled point symmetric columns—analytical developments. Thin-walled Struct, submitted for publication]. In the present paper, two series of experiments are reported, one on narrow flange Z-sections and one on wide flange Z-sections. The main objective of the tests was to validate the bifurcation load predictions derived in [Rasmussen KJR. Bifurcation of locally buckled point symmetric columns—analytical developments. Thin-walled Struct, submitted for publication] against experimental values. A further objective of the tests on narrow flange sections was to investigate the change in the direction of overall buckling, as predicted by the theory, from principal axis directions to non-principal directions. A further objective of the tests on wide flange sections was to investigate the possible change of the critical overall buckling mode from a flexural mode to a torsional mode as a result of local buckling. Agreement is generally found between analytical and experimental results.

Research on the interactive resistance of corrugated sheets under combined bending and contact pressure

During designing, the interactive resistance M– F of trapezoidal cross-sections can be assessed from equations proposed in [PN-B-03207: 2002. Steel structures. Cold-formed profiles and corrugated sheets (Polish standard); EN1993-1-3:20xx:2002. General rules. Supplementary for cold-formed thin gauge members and sheeting; DIN 18807. Teil 1-3. Stahltrapezprofile; BS 5950-6: 1995. Structural use of steelwork in building. Part 6. Code of practice for design of light gauge profiled steel sheeting; AISI Specification for the design of cold-formed steel structural members 1996 ed]. From the comparison of M– F resistance obtained according to these standards, a significant discrepancy is observed. This paper aims to verify equations proposed in [the references above and Davies JM, Jiang C. Design procedures for profiled metal sheeting and decking. Thin-Walled Struct 1997;27:43–53] and to identify mode of failure of the steel sheeting subjected to the bending moment combined with a concentrated force. The experimental research of 19 models and numerical analysis (FEM) of 42 models have been carried out. The FEM analysis appears to be a very good scientific tool to identify the mechanism of the load transmission from a beam to the corrugated sheet. Moreover, analysis show that for used in practice wall thickness and support width of corrugated sheeting, EC3 [EN1993-1-3:20xx: 2002] and FEM give similar results of interactive resistance M– F to that obtained experimentally.

Rigid-link and FE models for first-generation sheet-section failure

First-generation sheet-sections, loaded by bending moment and a concentrated load, fail by three distinct post-failure modes, the rolling, yield arc, and yield eye post-failure modes. This article shows a new, systematic study of a sheet-section failing by the yield eye post-failure mode, using a rigid-link (RL) and a finite-element (FE) model for a specific set of imperfections. The rigid-link model explains the complex, i.e., snap-back behaviour of sheet-sections if loaded by a load bearing plate. This snap-back behaviour will result in an abrupt decrease in load if displacement control is used. The FE model predicts, besides the post-failure modes mentioned, additionally the roof post-failure mode [Mahendran M. Thin-walled Struct 1997; 27(3): 245–61]. This failure mode always goes together with an abrupt decrease in load, and sometimes results in convergence problems. If the results of the RL and the FE models are compared, it can be shown that the RL model cannot explain FE convergence problems, as was believed in the past [Hofmeyer H, Kerstens JGM, Snijder HH, Bakker MCM. J Constr Steel Res 2002; 58(12): 1509–29].

Application of direct strength method to axially loaded perforated cold-formed steel studs: Distortional and local buckling

A study to develop methods of analyzing perforated, axially loaded, cold-formed steel studs using the provisions of the Direct Strength Method [American Iron and Steel Institute (AISI). North American Specification for the Design of Cold-Formed Steel Structural Members 2001 Edition with Supplement 2004 (AISI/COFS/NASPEC 2004) and Commentary (AISI/COFS/NASPEC 2004), Washington, DC; 2004] was undertaken using the Finite Strip Method as the method for determining the elastic buckling stresses. Several different models were developed to represent the effect of the web perforations. The capacities predicted using the Direct Strength Method for the limit states of distortional and local buckling were compared to capacities calculated using the equations contained in the AISI Specification [American Iron and Steel Institute (AISI). North American Specification for the Design of Cold-Formed Steel Structural Members 2001 Edition with Supplement 2004 (AISI/COFS/NASPEC 2004) and Commentary (AISI/COFS/NASPEC 2004), Washington, DC; 2004]. The limit state of longwave buckling is considered in a companion paper [Sputo T, Tovar J. Application of direct strength method to axially loaded perforated cold-formed steel studs: Part 1. Longwave buckling. Thin Walled Struct, submitted for publication]. The validity of the results is discussed and recommendations are made for the use of the Direct Strength Method for these members.

A semi-analytical method for the elastic–plastic large deflection analysis of stiffened panels under combined biaxial compression/tension, biaxial in-plane bending, edge shear, and lateral pressure loads

In the earlier publications [Paik JK, Thayamballi AK, Lee SK, Kang SJ. A semi-analytical method for the elastic-plastic large deflection analysis of welded steel or aluminium plating under combined in-plane and lateral pressure loads. Thin-Walled Struct 2001;39;125–52; Paik JK, Thayamballi AK. Ultimate limit state design of steel-plated structures. Chichester: Wiley; January 2003], the author presented a semi-analytical method for the elastic–plastic large deflection analysis of unstiffened plates under biaxial loads, edge shear, biaxial in-plane bending and out-of-plane (lateral) pressure loads until the ultimate strength is reached. In the present paper, a similar method is applied to stiffened panels subjected to the same type of loading. The effect of initial imperfections in the form of initial deflection and welding residual stresses is accounted for in the calculations. The validity of the developed method is demonstrated by comparing with existing theoretical and numerical results where relevant. The present theory can be useful for ultimate strength analysis of plates and stiffened panels made of steel or aluminium alloys.

Deflections of highly inflated fabric tubes

Inflatable beams made of modern textile materials with important mechanical characteristics can be inflated at high pressure. The aim of the paper is to present experimental, analytical and numerical results on the deflections of highly inflated fabric tubes submitted to bending loads. Experiments are displayed and we show that tube behaviour looks like that of inflatable panels (Thin-Walled Struct. 40 (2002) 523–536). Equilibrium equations are once again written in the deformed state to take into account the geometrical stiffness and the following forces. The influence of the shear stress cannot be neglected and Timoshenko’s beam theory is used. A new inflatable tube theory is established and simple analytical formulas are given for a cantilever-inflated tube. Comparisons between analytical and experimental results are shown. A new inflatable finite tube element is constructed by use of algebraic operations, because the compliance matrix of the cantilever beam is not symmetric. Comparisons between experimental, analytical and numerical results prove the accuracy of this beam theory and on this new finite element for solving problems on the deflections of highly inflated tubes.

A nonlinear analysis of piezoelectric coated laminae

In relation to vibrations of piezoelectric materials subject to strong electric fields and large strains, a system of 2-D nonlinear laminae equations is derived by the use of Mindlins kinematic hypothesis for each layer. The laminae is coated completely with perfectly conducting electrodes on both its faces, and it may comprise any number of bonded layers, each with a distinct but uniform thickness and electromechanical properties. By use of a recent variational principle [Altay and Dokmeci, Thin Walled Struct. 39, 95–109 (2001)], the system of equations is consistently formulated in both invariant, differential and variational forms. The effects of elastic stiffnesses of, and the interactions between, layers of laminae are all taken into account. The system of equations governs the extensional, flexural, and thickness shear as well as coupled vibrations of piezoelectric laminae. Special types of vibrations, geometry, and material properties are recorded. Besides, the uniqueness is investigated in solutions of the initial-mixed boundary value problems defined by the linearized system of laminae equations. [Work supported in part by TUBA.]

Buckling of stretched strips

Flat plates subjected to tensile loads may buckle locally in the presence of geometric discontinuities such as cracks, holes or varying dimensions [Shaw D, Huang YH. Buckling behavior of a central cracked thin plate under tension. Engng Fract Mech 1990;35(6):1019–27; Gilabert A, et al. Buckling instability and pattern around holes or cracks in thin plates under tensile load. Eur J Mech A Solids 1992;11(1):65–89; Shimizu S, Yoshida S. Buckling of plates with a hole under tension. Thin-Walled Struct 1991;12:35–49; Tomita Y, Shindo A. Onset and growth of wrinkels in thin square plates subjected to diagonal tension. Int J Mech Sci 1988;30(12):921–31]. However, it appears to be surprising that even in the absence of any geometric discontinuity, buckling due to global tension occurs as a result of special boundary conditions. This effect can be observed during the stretching of thin strips, where high wave number buckling modes can affect large areas. In order to study this phenomenon and to find explanations, computational and analytical investigations were performed. A novel diagram for buckling coefficients is presented, enabling the determination of critical longitudinal stresses.

Vibrations of core walls with connecting beams

Vibrations of a singly symmetric core wall structure coupled with connecting beams is studied using Vlasov’s theory. Due to the presence of connecting beams, shear transfer occurs between the open edges of the core wall. The connecting beams are modeled as a continuum media with equivalent stiffness property. The results include warping effects and shearing deformations in the plane of the wall. Formulations for displacements and rotations at the top of the structure are given [cf. Ö. Sümer and G. Aşkar, Thin-Walled Struct. 14, 193–208 (1992)]. Results are compared with those of open core walls without connecting beams. [Work supported by TÜBITAK.]