The paradox of abnormal frequencies exists for free vibration of nonlocal cantilever beams. This work is concerned with solving this paradox within the framework of nonlocal strain gradient theory. The inconsistences of the reported boundary conditions are updated by using the weighted residual method. Then, the closed-form solutions for free vibration of cantilever beams is obtained in terms of the

In this paper, Shi's high-order shear deformation theory (HSDT) is introduced to compute the free vibration of the cracked functionally graded material (FGM) plates according to the power law resting on Pasternak elastic foundations. The rectangular plate has a linearly variable thickness and has a crack in the center. The phase field theory and finite element method are used to study the vibration

This paper presents the derivation of nondimensional buckling equations of sandwich cylindrical shells made of composite facesheets with a shear deformable core. The procedure yields an analytical solution in terms of a series of nondimensional parameters for the axial buckling load investigating the influence of the core transverse shear. The developed equations and the nondimensional parameters are

Self-supporting design is an important issue that needs to be considered in the combination of topology optimization (TO) and additive manufacturing (AM). In this paper, the self-supporting and printable Messerschmitt–Bölkow–Blohm (MBB) beams of Ti6Al4V alloy are designed by combining Solid Isotropic Microstructure with Penalization method (SIMP) with Langelaar's AM filter and manufactured by selective

This study discusses the ultimate strength and collapse behavior of ring-stiffened cylindrical shells under external pressure with local shell buckling or torsional buckling of stiffeners. In past studies, the effect of initial deflection shape on the ultimate strength has not been completely elucidated. Additionally, a clarification of the collapse behavior and theoretical formulation based on it

A joining process for aluminum alloy/stainless steel pipes, named electrohydraulic expansion joining was presented. The process experiment, simulation analysis and mechanical tests were conducted. The results revealed that the deformation degree increased with the increase of the discharge voltage and the groove width, which further improved the joint performance. The ultimate pull-out load was 18

The blast response of clamped sandwich panels with layered-gradient aluminium foam cores was studied experimentally and numerically. The effective blast impulse acting on specimens in ballistic pendulum tests was first calibrated, and the influences of blast impulse and core-layer arrangement on the deformation modes and shock resistance were revealed. Then, the corresponding numerical simulations

The buckling behaviour and resistances of press-braked stainless steel channel section beam-columns under combined compression and minor-axis bending have been studied in the present paper through laboratory testing and numerical modelling. The testing programme adopted two press-braked stainless steel channel sections and included initial global and local geometric imperfection measurements and ten

Thin curved shells are widely used in engineering. A shallow spherical shell is an effective representation of a curved shell affected by local impact loading. Therefore, the dynamic response of spherical shells under impact loading should be investigated to provide a design reference for curved shells applicable to engineering fields. In this study, the dynamic response and perforation of an aluminum

A penetrator with enhanced lateral effects (PELE), which is a particular thin-walled structure, is characterized by a low-density filling material surrounded by a high-density jacket material. When the PELE projectile penetrates a concrete target, the target is destroyed by its thin-walled jacket to a large opening. An analytical model describing deformation mode of the jacket during the penetration

A nonlinear shell augmented finite element method (NS-AFEM) is proposed in this paper to account for the multiple fractures and their interactive evolutions in thin laminated composites with large deformations. This NS-AFEM employed a nonlinear elemental condensation algorithm based on Newton-Raphson method, which explicitly treated the strong discontinuity of a cracked element without the need of

Over the past few decades, underground utility tunnels have become increasingly popular in many countries, especially in North America and China. Utility tunnels host multiple services’ infrastructures inside an accessible underground space that allows regular inspection, maintenance, and easy replacement. Previous studies on the safety of underground utility tunnels were mainly focused on the seismic

Structural skins of aerospace vehicles are typically made of large, internally reinforced curved panels. The presence of stiffening components subdivides the panel into several bays that interact structurally. In this context, the present study investigates the effects of adjacent bays interaction in curved panels under supersonic flutter. The analyses reveal severe jumps in the post-flutter LCO amplitudes

Recent experimental studies have shown that the current EN1993-1-5 patch loading resistance model underestimates the ultimate strength of steel plate girders in certain cases, especially for longitudinally stiffened steel plate girders and longer patch load lengths. In addition to this resistance model, the design standard allows the use of finite element analysis for the ultimate limit state. The

In current structural steel design specifications, the local buckling of cross-sections is typically treated on an element-by-element basis, with the boundary conditions along the adjoined longitudinal edges of the individual plates assumed to be simply-supported. In reality, cross-sections buckle locally as a whole and the individual plate elements interact. As a result, the boundary conditions along

The aim of this paper is to predict web-post buckling shear strength of cellular beams made from normal strength steel using the Artificial Neural Networks (ANN). 304 developed finite-element numerical models were used to train, validate and test 16 different ANN models. To verify the accuracy of the ANN model, the ANN predictions were compared with experimental and analytical results. Results show

Cold-formed steel C- and Z-section beams are widely used in light gauge steel building systems as flexural members. In their applications as flexural members, mono-symmetric C-sections and point-symmetric Z-sections are often subjected to transverse loads eccentric to the shear centre, leading to combined bending and torsion actions. However, research and design methods for cold-formed steel beams

Functionally graded materials are considered to be a special composite material. By continuously changing the composition and structure of the material, the interface and delamination problems of the material can be eliminated, which causes the material properties to change slowly with the change of the composition and structure of the material. In this paper, a lattice spring model, which can accurately

This paper seeks to gain an in-depth understanding of the seismic behavior of oval hollow section (OHS) beam-columns through experimental and numerical investigations. Quasi-static tests on nine OHS beam-column specimens with varying tube thicknesses, axial load ratios and bending directions are conducted, where the failure mode, yield/ultimate strength, ductility, and energy dissipation-related quantities

An investigation of interfacial fracture modelling of carbon fibre reinforced plastic (CFRP) laminates at the atmosphere similar to the cruise condition of an aircraft has been carried out in this article. The Mode I & Mode II fracture tests are carried out using specimen of aerospace grade composite (AS4/914) at−550C. Compliance based methods for estimation of crack growth have been adopted for monitoring

Studies show that lining cracks are one of the most common anomalies that occur in the operational tunnels. Therefore, investigating the performance of the cracked linings is of significant importance during the tunnel maintenance. In the present study, model tests and numerical simulations are performed to investigate the influence of the longitudinal cracks at the invert on the mechanical behavior

Stability performance of cylindrical shells and providing a potential method to enhance the buckling stability of these structures are major concerns for designers. Carbon Fiber Reinforced Polymer (CFRP) composites are promising materials for application in the design and retrofit of such thin-walled structures. On this basis, this paper presents a comprehensive numerical study on the buckling behavior

This paper aims at the bifurcations and chaotic motions of a harmonically driven rectangular plate subjected to a uniform incompressible subsonic airflow. The plate equation of motion is derived by considering the von Karman’s large deflection and Kelvin’s type damping of material. A Galerkin-type solution is applied for the plate stress function and the aerodynamic force. The governing partial differential

The star-shaped reentrant honeycomb produces lateral shrinkage but also rotation under compression. With the consideration of such interesting deformation characteristics, the dynamic deformation evolution of the sandwich beam with star-shaped reentrant honeycomb core (SSRHC) was carried out for the first time. In this experiment, the aluminum foam projectile was used to produce local impulsive loading

This paper presents the results of a study aiming at shape optimising singly-symmetric cold-formed steel purlins. The “self-shape” optimisation algorithm previously developed, proven to be robust and to converge to known solutions is used for this purpose. Eight optimisation cases are considered, consisting of 1.5 mm and 1.9 mm thick purlins, spanning either 3000 mm or 8000 mm and drawn with either

This paper investigates the elastic lateral-torsional instability of shear deformable fixed arches having a monosymmetric cross-section when subjected to a localized uniform radial load. Hitherto, this topic has not been addressed in the open literature. The complex in-plane internal actions in a fixed arch with a monosymmetric section are produced by a localized uniform radial load and are affected

In this paper, the forced resonance vibration analysis of curved micro-size beams made of graphene nanoplatelets (GNPs) reinforced polymer composites is presented. The approximating of the effective material properties is on the basis of Halpin–Tsai model and a modified rule of mixture. The Timoshenko beam theory is applied to describe the displacement field for the microbeam. To incorporate small-size

In this research, the dynamic behavior of a thin rectangular plate subjected to a mass moving with variable velocity is studied. In previous studies, the main focus was on the vibration analysis of the structure, while there are many cases in which mass-structure interaction and how the motion of the mass is affected by the structure is of great importance. Three coupled nonlinear equations governing

Design rules for web crippling of stainless steel tubular sections at elevated temperatures are currently unavailable. In this study, non-linear finite element models (FEMs) were developed for the web crippling of cold-formed lean duplex stainless steel (CFLDSS) square and rectangular hollow sections under the concentrated end bearing loads, namely the loading conditions of End-One-Flange (EOF), End-Two-Flange

The elastic-plastic deformation of materials provides limited displacement for metal gaskets, so as to ensure the sealing performance of flanges. In order to study the sealing performance of a novel metal gasket with a convex structure of a semi-cylindrical shell between two flanges, the compression-springback behavior of semi-cylindrical shell is investigated. By introducing the rebound and anti-coupled

This paper presents the structural behavior of doubly-symmetric built-up cold-formed steel (CFS) columns that fail in local-global (flexural-torsional) interactive buckling modes. The built-up column investigated in this study is formed (back-to-back) by connecting two identical unlipped channel sections with the use of self-drilling screws. A total of 45 column tests were carried out, with various

In the current work, an accurate modified couple stress-based cylindrical micro-panel model is developed in the framework of sinusoidal shear deformation theory. The classical strain tensors and curvature tensor components in a modified couple stress-based model are given with consideration of the geometric curve of cylindrical panels. In conjunction with a general Lagrange procedure, the proposed

The detailed investigation on the nonlinear vibration analysis of functionally graded graphene platelets-reinforced composites (FG GPL-RC) conical panels on the elastic medium is presented. The nonlinear governing equations of nanocomposite panels are derived following the first-order shear deformation shell theory (FSDST) and the von Kármán nonlinear kinematic relations using Hamilton's principle

Shape morphing is an attractive functionality for fibre reinforced composites. Shape morphing composites can adopt various shapes and undergo different shape morphologies in response to a set of external stimuli. One of the approaches to attain shape morphing materials is through fabrication of multi-layered and asymmetric composites where morphing stems from structural anisotropy. In this work, asymmetric

Light-gauge steel framed (LSF) wall systems of low- and mid-rise buildings are made of cold-formed steel studs and tracks and lined with sheathing material such as gypsum plasterboard. The stiffness provided by sheathing can be idealised into three main components, namely, in-plane, out-of-plane and rotational stiffness. Idealised in-plane stiffness has been used commonly in the numerical and analytical

This paper numerically investigated the effects of manufacturing defects and braiding angle on the impact compressive properties of three-dimensional (3D) carbon fiber/epoxy resin circular braided composite tubes. Based on the realistic geometrical architecture of 3D tubular braided preform, the full-size microstructural finite element analysis (FEA) models of the braided composite tubes with different

Suspension effect poses a big threat to the integrity and safety of corroded pipelines. In this work, a finite element (FE) based multi-physics field coupling model was developed to determine the mechano-electrochemical (M-E) interaction at an external corrosion defect on a suspended X100 steel pipe and predict its failure pressure. Theoretical calculations were used for model validation. Parameter

When composite laminated panels under compression are allowed to continuously loaded into the moderately deep postbuckling regime, further weight savings can be achieved. For this purpose, this work presents an optimization scheme for the design of postbuckling behavior of composite laminates. An efficient tool, termed the Koiter perturbation-based approximation FE method, is developed to obtain the

The load carrying capacity of unstiffened thin-walled shell structures is highly sensitive to geometric imperfections. These imperfections are usually unknown during the preliminary design phase. The manufacturing process of these structures has a major influence on the geometric imperfections as well as on the manufacturing costs. The goal of this paper is to show the potential of a previously developed

The Vibration Correlation Technique (VCT), a nondestructive in-situ method to assess buckling loads is applied today to all basic thin walled structures, like columns (beams), plates, panels and shells yielding very good predictions for the experimental buckling load. The present review of the VCT highlights its analytical and experimental state-of-the-art by presenting the relevant derivations for

Losses caused by the recent fire incidents are demanding proper fire safety regulations and fire protection measures around the globe while construction cost and call for environmental protection are increasing. The expansion of cold-formed steel (CFS) construction to mid-rise buildings in recent times has therefore identified the need for the accurate prediction of the load bearing capacities of CFS

Natural frequencies of a conical–spherical functionally graded material (FGM) shell are obtained in this study. It is assumed that the conical and spherical shell components have identical thickness. The system of joined shell is made from FGMs, where properties of the shell are graded through the thickness direction. The first order shear deformation theory of shells is used to investigate the effects

The lateral-torsional buckling behavior of functionally graded (FG) non-local beams with a tapered I-section is here investigated using an innovative methodology. The material properties are supposed to vary continuously along the longitudinal direction according to a homogenization procedure, based on a power-law function, whereas the nanobeam is modeled within the framework of a Vlasov thin-walled

A finite element axisymmetric model has been developed to study the energy absorption capacity of thin Aluminum plates (0.2–20 mm thickness) in terms of the ballistic limit. The Johnson-Cook material model was used to describe the mechanical behavior of the 2024-T3 Aluminum. Numerical results were validated by comparison with experimental tests carried on similar plates using a gas gun with two high-speed

Exact analytical solutions for the free vibrations of Thin-Walled shallow shells are presented in this work. The shells considered have rectangular planform and two principal constant curvatures. Past treatment of this problem included only one possible case of boundary conditions, and was limited to symmetric modes only. The new solutions address six different cases of in-plane and out-of-plane boundary

The energy finite element method (EFEM) provides researchers with an efficient tool to analyze high-frequency vibrating solid structures with less calculation and clear distribution of the energy density. However, the corresponding applications in structure optimization mainly focus on modifying the size and material properties, and it leaves a scientific gap that the topology flexibility is not addressed

A new-type of fabricated coupled composite column (CCC) system composed of closely spaced double small-section concrete filled steel tubes (CFST) connected by steel connector beams using blind bolts was proposed. An experimental investigation and finite element analysis were carried out by testing CCC specimens and CFST column counterparts for various eccentricity ratios and connector beam configurations

The baseplate upright connections of the steel storage racks are often attached to the concrete floor by anchor bolts possibly at an eccentric location. Currently available rack design specifications do not provide any guidelines to take account of the influence of eccentric anchor bolt location and do not consider the associated baseplate behavior in the design of such storage rack base connections

Fire loading on structures generally involves considerable degrees of uncertainties due to surrounding environmental conditions. Therefore, a reliable structural analysis depends on a proper evaluation of fire disturbing parameters such as wind and smoke concentrations. Wind intensity and direction could affect the heat flux distribution on the structures. Also, smoke (soot) concentration would decrease

This paper aims to investigate the dynamic plastic behavior of single and nested circular rings traditionally used as energy absorbers. The response characteristics of these structures are experimentally and numerically determined when they are subjected to high rate lateral impacts. It should be emphasized that a gas gun is employed in order to conduct experimental tests in which a load cell is utilized

In the present study, thin-walled tubes filled with aluminum foam and CFRP skeleton (FCFTs) are developed and manufactured based on a multiple material system. The structural crashworthiness of the proposed design is investigated under quasi-static lateral loading. Further, the aluminum tube, the foam-filled tube and the tubes filled with CFRP skeleton are also designed and tested to perform a comparative

In the present work, similar thickness laser welded blanks (LWBs) and dissimilar thickness laser welded tailored blanks (LWTBs) of extra deep drawing (EDD) steels were fabricated and these were stretch formed by a 50 mm diameter hemispherical punch under lubricated condition. All these stretch-formed domes were manufactured keeping a consistent combined geometry of hemispherical and conical sections

An accurate structural analysis is a fundamental requirement for modern design. Nevertheless, this is often difficult for systems comprised of thin-walled members, mostly because of their complicated cross-section shapes with non-coincidence of shear center and centroid, and complex buckling modes. Recent research, using efficient line-finite-element formulations, has made important progress in simulating

Currently, in several engineering fields there is an increasing demand for lightweight structural components with high-strength and capable to dissipate energy, due to impact or seismic events, in a controlled manner. In this regard, expanded metal meshes have been successfully implemented in various applications, therefore this paper presents a review of manufacturing, applications, and structural

Cast steel joints (CSJ) are widely used in complex tubular structures to connect different parts of structures. This paper presents a simplified approach for efficient fatigue life estimation of full-scale welded cast steel structures. The proposed approach is applied to analyze a set of fatigue data of a full-scale CSJ thin-walled tubular truss structure. The results indicate that the fatigue lives

In this study, thirty specimens were tested using a drop hammer impact test machine, comprising six reinforced concrete columns and twenty-four specimens of the composite columns. The composite columns include steel tubular-encased reinforced concrete (R-ST) columns, steel-reinforced concrete-filled steel tubular (S-ST) columns, hollow concrete-filled double steel tubular (H-DS) columns, and solid