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Presents an alternative lower bound to the elastic buckling collapse of thin shells of revolution, in comparison with results from geometrically non‐linear elastic analysis. The numerical finite element method is based on axisymmetric rotational shell elements whose strain‐displacement relations are described by Koiter’s small finite deflection theory, with displacements expanded circumferentially using a Fourier series. First, compares the reduced stiffness linear analysis, based on the buckling equation without incremental linear in‐plane energy components corresponding to the lowest eigenmode (for a particular cylindrical shell under external pressure), with the results obtained by Batista and Croll. Second, the non‐linear astatic (quasi‐static) elastic analysis to clamped spherical caps under uniform external pressure is carried out in order to compare the results from a reduced stiffness analysis from viewpoints of not only buckling loads, but also total potential energy. Argues that the astatic buckling loads may relate to reductions due to a specific imperfection effect on elastic buckling collapses.

It is generally known that the perforated section such as the castellated section is good to sustain distributed loads but inadequate to sustain highly concentrated loads. Therefore, it is possible to design the opening in a different arrangement of web opening to achieve section efficiency, thus improving the strength and torsional behaviour of the section with web opening. This study aims to focus on the finite element analysis of I-beam with and without openings in steel section dominated to lateral-torsional buckling behaviour.

In this work, the analysis of different sizes, shapes and arrangements of web opening is performed by using LUSAS application to conduct numerical analysis on lateral-torsional buckling behaviour. This involves three diameter sizes of web opening, five types of opening shapes and two criteria of the model.

The section with c-hexagon web opening was placed about 200-mm centre to centre and 100-mm edge distance, contribute to 7.26% increase of buckling capacity. For the section with 150-mm centre to centre and 50-mm edge distance, the occurrence of local buckling contributes to decrease of lateral buckling section capacity to 19.943 kNm, where pure lateral-torsional buckling mostly occurred because of prevented section. Besides that, the web opening diameter was also analysed. The web crippling was observed because of the increase of opening diameter from 0.67 to 0.80 D.

This contributes to a decrease in buckling capacity as figured in the contour of the deformed shape. For Model 1, an increase of buckling capacity (31.46%) is observed when the opening diameter are changed from 0.67 to 0.80 D.

Several experimental and numerical studies were performed in the past to estimate buckling capacity of corroded tubular members. However, the effect of initial imperfections has not been properly considered in most of these earlier proposed formulas. Therefore, the main objective of this paper is to propose an accurate analytical formula to determine the buckling capacity of patched corroded tubular members.

Tubular members with initial geometrical imperfections can be regarded as beam-columns because of the combination of axial load and bending moment. The proposed formula is derived for a rectangular corrosion patch. The proposed formula is verified with results from finite element analysis of corroded tubular members and experimental results. The formula is also applied to an existing offshore jacket structure to highlight its significance and applicability. It is found that the buckling capacity of jacket members in splash zone reduces significantly with ageing. This reduction is around 29 and 14% for the selected brace and leg member respectively, during the design life. Finally, it is concluded that corrosion reduces the buckling capacity significantly and the proposed formula can be easily applied by practicing engineers to give an accurate and slightly conservative estimate the remaining buckling capacity.

The main finding is the new formula which accurately and conservatively estimate the buckling capacity of corroded tubular members. The proposed formula considers the secondary effect of both initial geometrical imperfections and shifting of centroid because of corrosion.

The proposed new formula is unique and original in that it considers both secondary effects from geometrical imperfections, reduction of cross-section from corrosion wastage and shifting of centroid because of corrosion. Finally, it is concluded that corrosion reduces the buckling capacity significantly and the proposed formula can be easily applied by practicing engineers to conservatively estimate the remaining buckling capacity and verify if further, more advanced estimations are needed.

Fused deposition of ceramics (FDC) is a solid freeform fabrication technique based on extrusion of highly loaded polymer systems. The process utilizes particle loaded thermoplastic binder feedstock in the form of a filament. The filament acts as both the piston driving the extrusion and also the feedstock being deposited. Filaments can fail during FDC via buckling, when the extrusion pressure needed is higher than the critical buckling load that the filament can support. Compressive elastic modulus determines the load carrying ability of the filament and the viscosity determines the resistance to extrusion (or extrusion pressure). A methodology for characterizing the compressive mechanical properties of FDC filament feedstocks has been developed. It was found that feedstock materials with a ratio (E/η_a) greater than a critical value (3×10⁵ to 5×10⁵ s^‐1) do not buckle during FDC while those with a ratio less than this range buckle.

The initiation and growth of wrinkles are influenced by many factors such as stress ratios, the mechanical properties of the sheet material, the geometry of the workpiece, contact condition, etc. It is difficult to analyze wrinkling initiation and growth while considering all the factors because the effects of the factors are very complex and studies of wrinkling behavior may show a wide scattering of data even for small deviations in factors. The finite element analyses of wrinkling initiation and growth in sheet metal forming process provide detailed information about the wrinkling behavior of sheet metal. The direct analysis of wrinkling initiation and growth, however, brings about a little difficulty in complex industrial problems because it requires large memory size and long computation time. From the industrial viewpoint of tooling design, therefore, readily available information on the possibility and location of wrinkling is sometimes more preferable to detailed and time‐consuming analysis results. In the present study, in order to give such readily available information on wrinkling initiation, the wrinkling factor, which shows the locations and relative possibility of wrinkling initiation, is proposed as a convenient tool of relative wrinkling estimation based on the energy criterion. The reliability of the wrinkling factor is verified through the buckling analyses of sheet strips. The location and relative possibility of wrinkling initiation are predicted by calculating the wrinkling factor in various sheet metal forming processes such as cylindrical cup deep drawing, spherical cup deep drawing, and elliptical cup deep drawing. Finally, the wrinkling factor proposed in the present study is also implemented in the prediction of wrinkling in the door inner stamping process. For verification of the calculated wrinkling factor, detailed zone analyses with fine meshes are carried out for the regions where wrinkling is predicted.

Application of the engineering design optimization methods and tools to the design of automotive body‐in‐white (BIW) structural components made of polymer metal hybrid (PMH) materials is considered. Specifically, the use of topology optimization in identifying the optimal initial designs and the use of size and shape optimization techniques in defining the final designs is discussed. The optimization analyses employed were required to account for the fact that the BIW structural PMH component in question may be subjected to different in‐service loads be designed for stiffness, strength or buckling resistance and that it must be manufacturable using conventional injection over‐molding. The paper demonstrates the use of various engineering tools, i.e. a CAD program to create the solid model of the PMH component, a meshing program to ensure mesh matching across the polymer/metal interfaces, a linear‐static analysis based topology optimization tool to generate an initial design, a nonlinear statics‐based size and shape optimization program to obtained the final design and a mold‐filling simulation tool to validate manufacturability of the PMH component.

The purpose of this paper is to provide a summarization and review of the present author's main investigations on failure modes of reticular metal foams under different loadings in engineering applications.

With the octahedral structure model proposed by the present authors themselves, the fundamentally mechanical relations have been systematically studied for reticular metal foams with open cells in their previous works. On this basis, such model theory is continually used to investigate the failure mode of this kind of porous materials under compression, bending, torsion and shearing, which are common loading forms in engineering applications.

The pore-strut of metal foams under different compressive loadings will fail in the tensile breaking mode when it is brittle. While it is ductile, it will tend to the shearing failure mode when the shearing strength is half or nearly half of the tensile strength for the corresponding dense material and to the tensile breaking mode when the shearing strength is higher than half of the tensile strength to a certain value. The failure modes of such porous materials under bending, torsional and shearing loads are also similarly related to their material species.

This paper presents a distinctive method to conveniently analyze and estimate the failure mode of metal foams under different loadings in engineering applications.

Rigid multibody modelling is used to study the crash‐related global behaviour of transport vehicles. These models are made up rigid bodies, joints and springs. Distinct kinematic models have been developed in order to analytically determine the resistance to collapse of thin‐walled structures of simple geometry subjected to compression or bending loading. The modeller must position these different elements but has no information on their numbers and their locations. For this reason, a modelling aiding tool, based on the elastic buckling analysis, has been developed. This method is used to resolve a problem of an “S” frame undergoing a collision against a rigid block to estimate its validity.

THE efficient design and construction of the latest types of Swedish military aircraft, with wings with high critical Mach numbers, has necessitated a thorough investigation into the structural behaviour of swept and delta wings of both the thin and thick types. It is the main purpose of this paper to present some important test results and pertinent details of some of the small scale models which have been built to supplement the theoretical estimation of the stress distribution and deflexion patterns. In some cases these models have also been constructed to provide information on certain unusual structural configurations, which would have otherwise taken many months to obtain by using approximate theoretical methods. The stress distributions for each model are illustrated in such a way that comparison between the different types of structures may readily be made.

Since the use of advanced finite element analysis (FEA) in the design of steel structures has been increasing its popularity in order to avoid unsafe or highly conservative designs, a solid know-how in computer-aided design (CAD) and engineering (CAE) codes is necessary. Therefore the purpose of this paper is to provide an extensive review of useful guidelines concerning modelling, simulation and result validation for the accurate performance of those analyses.

Such guidelines are obtained from international steel design codes like Eurocode 3 and DNV, publications from experienced CAE engineers and renowned FE software companies like Ansys and Altair. Topics like mesh independence, the effect of the load sequence on the load bearing capacity and steel fracture criteria are underlined.

Since the use of advanced FEA in the design of steel structures is becoming more and more traditional due to the increase of its competitiveness when compared to the use of (very) conservative design rules, a solid know-how in CAD and CAE codes is necessary.

This work will be quite useful for structural steel stress engineers, contributing for a safer use of FEA in research and design.

This work will be quite useful for structural steel stress engineers, contributing for a safer use of FEA in research and design.