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In this paper the workflow for obtaining the optimal shape of thin-walled tubes in crashworthiness analysis is presented. The Macro Element Method approach is applied to model large deformations and to calculate crushing parameters of thin-walled sections. The objective of the work is to determine the optimal dimensions of a tube cross-section so as to achieve the maximal energy absorption of the structure. Two optimization algorithms have been developed and coupled with the Visual Crash Studio software that simulates the response of a thin-walled beam during the impact. The first approach applies a modified version of the random search Monte Carlo method. The second is based on Evolutionary Algorithm. Square and hexagonal tubes exposed to axial load are investigated in numerical examples. The best results from both approaches are compared and discussed. The obtained solution is very close to optimal results based on the FEM models and validated by experimental tests. This study illustrates the potential of the optimization in early design stages of the vehicle development process and prepares perspectives for the optimization of complex energy absorbing systems. [ABSTRACT FROM AUTHOR]

Currently, one challenge of deployable composite thin-walled lenticular tube (CTLT) is to identify its large deformation behaviors in flattening and wrapping process. In this paper, experiments and numerical simulation of flattening and wrapping of composite thin-walled lenticular tube were carried out. Firstly, elastic modulus of CFRP laminate with four-ply (45°/−45°/45°/−45°) was obtained from the uniaxial tensile test and theoretical solutions, results of which achieve a good agreement. Subsequently, the flattening experiments of composite thin-walled lenticular tube segments were performed, their corresponding tip displacements and strains on the surface were also measured in flattening process. Lastly, wrapping experiments of three CTLTs at the length of 700 mm were conducted, in the meantime, strains, deformations and wrapping moments were also measured. By using ABAQUS package, three-dimensional models were employed to numerically simulate the process of flattening and wrapping, effects of geometrical nonlinearity and contact interaction are also taken into account in the process. The results show that the numerical simulation method is available to predict mechanical characteristics of CTLT in its process of flattening and wrapping. [ABSTRACT FROM AUTHOR]

Shot peening is an essential process for forming large thin-walled components in aerospace industries. However, it is challenging to determine directly the mapping relationship between shot peening parameters and deformation response because of the complex elastic–plastic deformation of shot-peened components. In this paper, a computational model of bending deformation of peened plate samples is established by examining the shot peening behavior from the aspect of energy equivalence, in which the deformation energy of the shot-peened plate is determined by the total kinetic energy input due to the shot impacts and a correction factor that takes into account the influences of oblique impact, shot interaction and shot overlap on the peen forming process in practice. It is proven that the square of curvature radius is proportional to the cube of the thickness but inversely proportional to the indentation coverage and the average kinetic energy input of a single shot. For the effect of a single shot impact in peen forming, the average kinetic energy input of a single shot is a power function with the indentation diameter. • Deformation of peened plate is explained from the aspect of energy equivalence. • The square of curvature radius is proportional to the cube of the thickness. • The square of curvature radius is inversely proportional to the coverage. • The square of curvature radius is inversely proportional to the kinetic energy. • Kinetic energy input is a power function with the indentation diameter. [ABSTRACT FROM AUTHOR]

The aim of this paper is to develop two novel in-plane auxetic structures with remarkable stiffness and negative Poisson's ratio (NPR) appropriate for compression and tensile load-bearing structures. The combination of re-entrant and arrow-head (RAH) unit-cells as well as star and arrow-head (SAH) unit-cells are hybridized and configured as new auxetic structures. The conceptual design is based on the stretch-dominated-mechanism (SDM) deformation of the proposed structures. To investigate the mechanical behavior of the designed structures under compressive and tensile loading, the samples are manufactured by 3D fused deposition modeling printing method and subjected to mechanical testing. The results show that the designed structures present tunable NPRs and approximately equal stiffnesses for both compressive and tensile loadings. In addition, an analytical analysis is carried out to determine the elastic constants of the structures, and a finite element (FE) simulation is conducted to verify the results with experimental and theoretical models. Good agreements are found for the elastic constants calculated from the experimental, theoretical, and FE methods. Meanwhile, the effects of the geometry parameters on the mechanical properties of the designed structures are also investigated, and the stiffness, stiffness to relative density ratio, and NPR are compared with those of existing studies. The comparison results suggest that our developed structures can be considered as strong candidates for the next generation of SDM auxetic structures with high stiffness capability and noticeable NPR values. [Display omitted] • Novel auxetic structures are designed based on the stretch-dominated-mechanism. • The designed structures demonstrate the close stiffness under compressive and tensile loadings. • The designed structures have enhanced stiffness and negative Poisson's ratio values, simultaneously. [ABSTRACT FROM AUTHOR]

Traditional auxetic metamaterials are characterized by negative Poisson's ratio but weak stiffness. In this paper, a new auxetic metamaterial, re-entrant star-shape anti-chiral auxetic metamaterial (Re-S-AC), is proposed and the in-plane mechanical properties of the Re-S-AC are investigated by experimental test and numerical analysis. The crushing test of the Re-S-AC fabricated by the selective laser melting (SLM) method is performed to investigate the deformation mechanism and validate the accuracy of the numerical model. Compared with the anti-tetrachiral and re-entrant star-shape, the Re-S-AC simultaneously exhibits concave and rotational deformation under the in-plane compression, and mean compression stress is highest at the same thickness and same mass. In addition, parametric analysis is conducted to comprehensively reveal the influence of geometric characteristics on the mechanical properties of the Re-S-AC. The results found that the node center distance, node diameter and wall thickness have significant effect on the mechanical properties and deformation mode of the Re-S-AC. Compared with other parameters, wall thickness has the greater effect on the mechanical properties. When wall thickness is from 0.4 mm to 0.8 mm, the Young's modulus, yield strength, and mean compression stress increase by 447.27%, 530.62%, and 370.87%, respectively. This study provides a reference method for improving the mechanical properties of the auxetic metamaterial. • A new auxetic metamaterial (Re-S-AC) is proposed by coupling concave-rotation deformation. • The deformation mechanism of the Re-S-AC is explored by quasi-static crushing experiment. • The Re-S-AC has better mean compression stress than the anti-tetrachiral and re-entrant starshape metamaterial. • Parametric analysis is conducted to reveal the influence of geometric parameters on the mechanical properties. [ABSTRACT FROM AUTHOR]

Confining with an outer sleeve is an effective means of enhancing the load-bearing and deformation capacity of compression struts. The outer sleeve and compression strut, i.e., inner core, constitute a sleeved core-loaded member, where the latter ideally bears all the axial compression under the lateral restraint of the former. Additionally, an extension segment of the inner core is typically required as the allowance for contraction. However, the unrestrained extension segment is prone to excess flexural deformation, dramatically decreasing the overall load carrying capacity of the sleeved member. In this paper, first, an analytical investigation of the behaviour of the sleeved member with pinned ends is presented. Second, a numerical study was conducted to determine the limit state of the localized flexural failure and to propose the corresponding design criterion combining the analytical model. Last, the design criterion was further validated by compressive tests, indicating that the proposed method accurately predicted the localized​ flexural failure of both seamless-sleeved members and members with assembled outer sleeves. • A theoretical model on the localized flexural failure of sleeved members is built up. • The corresponding design criterion is proposed combining numerical cases. • The unrestrained length ratio of the core and the gap width exhibit notable effects. • The theory is validated by tests on both seamless- and assembled-sleeved members. [ABSTRACT FROM AUTHOR]

Generalised Beam Theory assumes the displacement field of a thin-walled member as a linear combination of deformation modes. The main family of deformation modes is constructed based on two simplifying assumptions: null membrane shear strain and null membrane transverse extension. If these modes are not sufficient for an accurate representation of the structural behaviour, two other families of modes are derived (from the main family) for which the two simplifying assumptions are eliminated. In this paper, for the special case of thin-walled cylinders, all three families of deformation modes are replaced by a new unified family, for which the membrane shear strain and transverse extension are not neglected. The derivation of the proposed modes is based on the stress equilibrium equations, and it involves the trigonometric series representation of the longitudinal modal amplitudes. The advantages of the proposed modes are highlighted throughout several linear buckling analyses with various loading and boundary conditions. • New GBT deformation modes are derived using the stress equilibrium equations. • Longitudinal modal amplitude functions are represented by trigonometric series. • Stiffness matrices are derived for linear buckling analysis. • Formulation is validated using shell finite element models. • Proposed formulation is compared with classical GBT. [ABSTRACT FROM AUTHOR]

When materials are in tension or in compression, their mechanical properties are essentially different, however, in existing studies it is generally ignored because of the complexity of the analysis. In this paper, a theoretical study of the problem of axisymmetric large deformation of thin shallow shells with different moduli in tension and compression (bimodular thin shallow shells) under uniformly vertical loading is presented. Based on the Föppl–von Kármán equations of flexible thin plates, the governing equation of the axisymmetric large deformation of bimodular thin shallow shells are established by introducing an appropriate curvature modification term from thin shallow shells and a bending stiffness term from bimodular plates. By selecting the central deflection as a perturbation parameter, the perturbation solution of the axisymmetric large deformation problem is derived using the perturbation method. The applications of variation method as well as the implementation of numerical simulation verify, from the theoretical and numerical perspectives, the correctness of the perturbation solution obtained. This study shows that the introduction of different moduli in tension and compression not only affects the relationship of loads vs. central deflection, but also affects the critical values of the rise-thickness ratio of bimodular thin shallow shells when the snapping phenomenon occurs. In particular, the bimodular effect may accelerate or slow down the occurrence of the snapping phenomenon of thin shallow spherical shells, according to the relative magnitude of tensile and compressive moduli. The work presented here will be helpful to analyze the mechanical response of heavily loaded thin shallow shells with obvious bimodular effect. • A set of governing equation for bimodular thin shallow shells is first established. • The perturbation method is first used to solve the governing equations. • The variation method and numerical simulation validate the perturbation solution. • The bimodular effect will influence the relationship of loads vs. central deflection. • The bimodular effect will accelerate or slow down the snapping phenomenon. [ABSTRACT FROM AUTHOR]

In this paper, the dynamic stiffness matrix of a completely free rectangular multi-layer plate element based on Reddy's higher-order shear deformation theory is derived. The reduction of the proposed model to the first-order shear deformation theory-based formulation is presented. Three coupled Euler-Lagrange equations of motion have been transformed into two uncoupled equations introducing a boundary layer function. The proposed model enables free transverse vibration analysis of rectangular multi-layer plates with (transversely) isotropic layers having arbitrary combinations of boundary conditions. The influence of transverse shear deformation is discussed along with the applicability of two shear deformable dynamic stiffness elements. Moreover, the influence of the boundary conditions on the free vibration characteristics of sandwich panels has been discussed. The natural frequencies obtained using different dynamic stiffness multi-layer plate elements have been validated against the solutions from the commercial software Abaqus and the previously verified numerical solutions using layered finite elements. The limitations of the model regarding the differences between material properties of the face and core layers within a sandwich plate are highlighted. The influence of face-to-core thickness ratio on natural frequencies is illustrated, while a variety of new results is provided as a benchmark for future investigations. [ABSTRACT FROM AUTHOR]

This paper introduces an experimental and analytical investigation of the large ductile transverse deformations of monolithic and multi-layered metallic square targets made of either aluminum alloy or mild steel or a combination of these materials struck normally by rigid spherical projectile. The experiments have been carried out by a single stage gas gun impact test apparatus and 25.1 g hard steel projectile with different velocities ranging from 42 to 158 m/s. By assuming an exponential transverse deformation shape function, a new analytical model is derived based on energy method and upper bound solution. A modification to the applied kinetic energy is created by assuming a localized distribution for initial impact velocity which provides quantitatively and qualitatively better analytical results and have acceptable consistency with experimental ones. The analytical results show that 15 out of 62 data are located on solid line, where the experimental and analytical values of final displacement are equaled. Also, 98% of data are set in the reliable range. [ABSTRACT FROM AUTHOR]

This paper presents a first-order Generalised Beam Theory (GBT) formulation for naturally curved thin-walled members with deformable cross-section, whose undeformed axis is a circular arc with no pre-twist. First, the strain-displacement relations for naturally curved thin-walled members are derived and it is shown how the classic GBT assumptions concerning the strains can be incorporated, namely: (i) Kirchhoff's thin-plate assumption, (ii) Vlasov's null membrane shear strain assumption and (iii) the null membrane transverse extension assumption. The equilibrium equations are obtained in terms of GBT modal matrices and stress resultants. It is demonstrated that, for the so-called “rigid-body” deformation modes (extension, bending and torsion), the GBT equations coincide with those of the Winkler (in-plane case) and Vlasov (out-of-plane case) theories. A standard displacement-based GBT finite element is used to solve a set of representative illustrative examples involving complex local-global deformation. It is shown that the proposed GBT formulation leads to extremely accurate results with a reduced number of DOF and that the GBT modal solution provides an in-depth insight into the structural behaviour of naturally curved members. [ABSTRACT FROM AUTHOR]

This paper presents a bending and free vibration analysis of functionally graded plates (FGPs) resting on elastic foundation by using an original first shear deformation theory (FSDT). This theory contains only four unknowns, which is even less than the classical FSDT. The elastic foundation follows the Pasternak (two-parameter) mathematical model. The governing equations for the bending and free vibration analysis are obtained through the principle of virtual work and Hamilton's principle, respectively. The original displacement field allows obtaining interesting governing equations. These equations are solved via Navier-type, closed form solutions. The accuracy of the current solution is verified by comparing it with 3D and other closed form solutions available in the literature. [ABSTRACT FROM AUTHOR]

The dynamic response of X70 grade steel pipeline under localized blast loading is studied by experimental and numerical investigations. The steel pipelines with large diameter and high grade are concerned in the paper. The influences of the explosive mass, contact area and wall thickness on the deformation/failure mechanisms of the X70 pipelines were investigated. The post-failure motion of the fragment was also observed during the experiment. Four different failure modes were observed during the experiment namely Mode I, Mode II, Mode IIIa and Mode IIIb. The features of each mode are analyzed concretely. Results revealed that the deflection and damage level of pipeline increased with the increase of explosive mass and contact area. The wall thickness plays an important role on the damage and post-failure motion. Numerical simulations based on the experimental results were conducted. The damage process, midpoint deflection, pressure distribution, energy changes and the post-failure fragment velocities were analyzed. The results of numerical simulations show good correlation with the experiments [ABSTRACT FROM AUTHOR]

A new type of braced frame structure with a double-cylinder arc energy dissipator is proposed in this paper. The energy dissipator is composed of an inner cylinder, an outer cylinder, and a stiffener fabricated and connected to a steel beam and column by welding, and the double cylinder arc energy dissipator is connected to a steel beam and steel column by welding. The seismic performance of the braced frame structure with a double-cylinder arc energy dissipator was analyzed by Abaqus. The results indicated that seismic energy could be dissipated through the deformation of the outer cylinder, inner cylinder, and rib plate. However, the double-cylinder arc energy dissipator could avoid the out-of-plane buckling deformation of the brace. Further, it exhibited properties similar to those of concentrically and eccentrically braced frames. The deformation of the braced frame with a double-cylinder arc energy dissipator mainly occurred on the dissipator and energy-dissipating beam (between the dissipator and column). During the loading process, the stiffener, outer and inner cylinders, and beam gradually yield. The height, thickness, and spacing of the stiffener of the double-cylinder arc energy dissipator were observed to significantly influence the seismic performance of the proposed braced frame. In contrast, the effect of the thicknesses of the inner and outer cylinder arcs on performance was negligible. • Seismic performance of braced frame structure with double cylinder arc energy dissipation was studied. • The initial stiffness, linear stiffness, and bearing capacity of the structures under monotonic load were studied. • Energy dissipation capacity, degradation property, failure, and deformation modes under low-cyclic loading were studied. [ABSTRACT FROM AUTHOR]

In this paper, an anti-buckling fixture was proposed to assess the deformation characteristics of DP500 and DP980 dual-phase steels, and AZ31B magnesium composite under tension–compression cyclic loading. The advantage of the device lies in the possibility of monitoring friction between the specimen and supporting blocks during the test. In consequence, it allows to avoid an error during stress determination. The full cyclic loading capacity for each material can be executed at the displacement amplitude within the range ± 2.5 mm which corresponds to the maximum strain amplitude of ± 0.2 for the specimen with the gauge length of 21.5 mm. It is concluded, that the technique proposed is promising since the thin sheet material can be tested under tension–compression in a wide range of deformation without the buckling effect. Furthermore, useful data for modelling cyclic deformation behaviour for shell structures can be obtained. [Display omitted] • Proposed fixture enables to avoid buckling during thin metal sheet compression. • The friction force is continuously registered during the test. • Complex characteristics could be successfully and precisely determined. • Useful data for modelling cyclic deformation can be obtained. [ABSTRACT FROM AUTHOR]

Due to lack of effective backup when drilling aircraft thin-walled CFRP structure, serious dynamic structural deformation including vertical and in-plane deformation usually occur, which extremely changes the cutting behavior and materials removed mechanism, causing severe entrance and exit damages. Therefore, this paper proposed a dynamic deformation measurement experiment in vertical and horizontal direction at various processing parameters to analyze their effects on cutting mechanism and damages distribution. Results show the vertical and in-plane deformation occurrence are highly dependent on the actual positions of tool-CFRP system. Namely elastic deformation, local deformation and drawback reflection appear many a time in different stages, causing obvious sudden change of thrust force and different initiation and propagation characteristics of damages. With the feed rate increasing and workpiece thickness decreasing, the maximum displacements of every stages all increase and some thinner workpiece displacement exceed several times the plate thickness. The larger in-plane deformation will nonuniformly distribute along borehole exit due to the different cutting mechanism and strength of different fiber cutting angles. The larger elastic deformation and drawback action in vertical direction will change the out-ply material remove mechanism into mainly puncture rather than only cutting. Under the joint action of deformation in two directions, the loose surface damages composed of delamination and uncut fiber will gather heavily at exit. • The vertical and in-plane deformation were characterized in divided stages by DIC. • The influence of drilling parameters on deformation and drawback was investigated. • The cutting behavior at various FCA under large drawback action was revealed. • The damage formation and propagation mechanism of drilling process was analyzed. • The in-plane damages in entrance and exit regions after deformation were evaluated. [ABSTRACT FROM AUTHOR]

Expanded metal tubes are economic and have great capacity for plastic deformation, what makes them suitable as energy absorbers in impact situations. This paper aims at investigating the impact response of expanded metal tubes subjected to axial crushing. A parametric analysis was performed using a central composite design (CCD) for design of experiments (DOE) techniques and a finite element modeling. Then, the influence of the expanded metal geometry, impact velocity, and material yield stress are investigated in depth. Results show that an increase in the size of the expanded metal cells leads to an enhancement in both, the mean and the peak load. Finally the main outcome of this investigation is to provide information regarding the use of expanded metal tubes in the design of impact attenuation devices. [ABSTRACT FROM AUTHOR]

Thin-walled structures are widely used as energy absorbing devices for their proven advantages on lightweight and crashworthiness. However, conventional thin-walled structures often exhibit unstable collapse modes and excessive initial peak crushing force (IPCF) followed by undesirable fluctuation in force-displacement curves under impact loading. This paper introduces a novel tubal configuration, namely sinusoidal corrugation tube (SCT), to control the collapse mode, and minimize the IPCF and fluctuations. Through validating the finite element (FE) models established, the effects of wavelength, amplitude, thickness and diameter of SCTs on collapse mode and energy absorption were investigated. The results showed that SCTs can make the deformation mode more controllable and predictable, which can be transformed from a mixed mode to a ring mode by simply changing the wavelength and amplitude. Compared with the traditional straight circular tube, the IPCF is reduced appreciably. Furthermore, SCTs have lower fluctuation in the force–displacement curves than traditional straight circular tubes. Finally, a multiobjective optimization is conducted to obtain the optimized SCT configuration for maximizing specific energy absorption (SEA), minimizing IPCF under the constraint of fluctuation criterion. The optimal SCTs are of even more superior crashworthiness and great potential as an energy absorber. [ABSTRACT FROM AUTHOR]

Defect tolerance is usually understood as the ability of a material to withstand an external load in the presence of a geometrical flaw. The case of a defect represented by a notch (i.e. a geometric discontinuity with finite curvature radius) can be described by the so-called stress (strain) concentration factor at the notch root and by the stress (strain) gradient in the vicinity of the notch root which is a preferential site for crack nucleation and propagation. Under static loads and within the elastic regime, notch effect in traditional structural materials is simply governed by the initial notch geometry. On the other hand, in highly deformable materials, such as soft matters (biological tissues, colloids, polymers, gels, foams, etc.), notch effect must be evaluated by considering large strain values arising around the notch, responsible for its blunting. In addition, when notches are contained in non-confined plate-like components, a sort of augmented notch blunting might occur as a consequence of local flexural instability of the material plate in the compressed zones. In the present paper, an experimental and theoretical study is discussed for a silicon sheet with different levels of notch severity. It is shown as the safety against notch concentration effect (that can reduce up to about 40–70%) can be greater than that in low deformable materials, and so notch blunting and plate's localized instability are beneficial contributions, leading to an increase of the element’s tensile strength. [ABSTRACT FROM AUTHOR]

The nonlinear dynamic responses of symmetric laminated composite beams subjected to combined in-plane and lateral loadings are studied in this paper. The composite laminates are modelled using the full layerwise theory (FLWT) based on the advanced first order shear deformation theory (AFSDT). The nonlinear governing differential equations of the laminated composite beams are derived using Hamilton's principle. The partial discretization based on Galerkin method is used to obtain the nonlinear ordinary differential equations (ODEs); in addition, the obtained nonlinear ODEs are solved numerically using step-by-step Newmark-Beta algorithm. In this study, the effects of two different cross-ply lay-up sequences and in-plane loading on the dynamic responses of composite beams are investigated. Moreover, the normal and interlaminar shear stress distributions are obtained. The results of present study are compared with the results of Partial Layerwise theory (PLWT) and validated with the exist results in this field of subject. Furthermore, the obtained results are compared with those obtained from finite element method (FEM) of analysis, which are in good agreement. Beside these, the number of used degrees of freedom in the present method is remarkably less than the FEM, leading to a significant computational cost reduction. Moreover, because of using FLWT, the present method is capable of predicting through the thickness normal stress and strain distributions. [ABSTRACT FROM AUTHOR]

This paper presents experimental and numerical investigations of a new type of combined energy absorber which working on the principle of expanding and splitting of the circular steel tube. In the first phase of deformation the tube is expanded by the cylinder part of the die. Second phase of deformation characterizes splitting of the expanded part of the tube into strips along the initial sawcuts by the cone part of the die. The strips bend outwards with certain radius to the end of the second phase. Quasi static compression test shows that this type of energy absorber is completely feasible and the combined absorber has 95.34% higher maximal force in compare with absorber which uses only expansion process of deformation. Using this system of deformation, the total energy absorption is obtained by the three mechanisms: elastic–plastic bending of the tube, splitting of the tube wall and friction between the tube and the die. The effect of friction coefficient is studied by simulation, it is found that the effect on friction energy is significant but negligible on splitting energy and plastic energy. [ABSTRACT FROM AUTHOR]

This paper considers the modeling of perforation of thin steel plates by cylindrical steel penetrators – fragment simulators. A comprehensive experimental investigation was performed and relevant data about the experiment setup and measuring equipment are reported. A numerical model developed in FEM based software Abaqus is described in detail. The Johnson–Cook thermo-viscoplastic constitutive law, as well as the Johnson–Cook damage model is used in the model. It has been shown that simulations correctly reproduce the main mechanisms of penetration process – indentation, bulging and plugging. Computational results are compared with experimental data in terms of the ballistic curves – diagrams that define the dependence of penetrator residual velocity on its impact velocity. The comparison of numerically obtained and measured values of deformed penetrator's diameter, plug thickness and maximum plate deflection has been also performed. Very good overall agreement is obtained between results of simulation and experimental measurements. After the validation of the numerical model, some empirical relations between perforation process parameters are derived. [ABSTRACT FROM AUTHOR]

Anti-sag bar is frequently adopted to enhance the lateral stiffness of cold-formed steel purlins. In existing studies, the anti-sag bar is normally treated as the rigid lateral restraint of cold-formed steel purlins, while according to the previous study of the authors', the local deformation of purlin web near the location connecting the anti-sag bar may significantly reduce the efficiency of anti-sag bar for providing the lateral restraint to cold-formed steel purlins. The lateral buckling of C-section purlins with one anti-sag bar at their middle span section is investigated in this paper, where the effective stiffness of the anti-sag bar taking into account the local deformation of purlin web is adopted. Two representative total potentials for the lateral buckling of C-section purlins are discussed with the differences between highlighted. Based on the proposed total potential, a hand-calculation solution for the lateral buckling load of C-section purlins is developed. The total potential and the solution for buckling load proposed in this study are verified by comparing their results with those from the finite element (FE) analysis using the shell element modeling of ANSYS or the FE program developed. The influences of the key parameters on the lateral buckling load of the C-section purlins are discussed in the parametric study. [ABSTRACT FROM AUTHOR]

This paper presents a one-dimensional finite element analysis of tapered thin-walled box beams under out-of-plane loads and twisting moments by developing new C 0 -continuous tapered higher-order beam elements. While higher-order sectional deformations such as distortion were considered earlier, there was no theoretical or finite element analysis on the tapering effect of variable cross-sectioned box beams. Case studies considering tapered box beams with various height-to-width ratios and a system of joint structure with a tapered box beam show that the results by the developed method are comparable with the shell finite element results unlike the stepped Timoshenko beam element results. [ABSTRACT FROM AUTHOR]

This paper presents an investigation of the behavior of CFDST members under low velocity lateral impact using ABAQUS, where nonlinear material behavior and strain rates of steel and concrete are included. The finite element analysis (FEA) models of CFDST members are described and verified using existing experimental results. Strain and stress states of concrete and steel tube in CFDST members are analyzed over the full loading range, followed by a parametric study investigating the influence of impact height, hollow ratio, nominal steel ratio, diameter-to-thickness ratio of inner steel tube and strength of materials on the impact force and global residual lateral deformation. Furthermore, the dynamic increase factor (DIF) of CFDST members under lateral impact is proposed, and the influence of the confinement factor on the dynamic increase factor (DIF) is analyzed. The results show that when the confinement factor is larger than 1.03, the dynamic increase factor needs to be considered to accurately estimate the dynamic resistance capacity of CFDST members subjected to lateral impact. [ABSTRACT FROM AUTHOR]

Under axial loading, the thin-walled structures will experience severe plastic collapse at the corners. The presented paper focuses on the axial dynamic performances of the thin wall tubes with star-shaped cross sections (S-tube). Firstly, the impact tests of the Aluminum S-tube samples are performed to confirm the accuracy of numerical simulation. Then, a mode classification chart is given based on simulations with tubes of various dimensions. It is found that the slenderness of tube plays an important role in the deformation mode. Besides, the relationship between the deformation mode and energy absorbing performance are discussed through FE method. The specific energy absorption (SEA) of S-tube is slightly better than the polygon tube (P-tube) due to the fact that the deformation mode of S-tube with longer fold length hinders the potential capability of multi-corner tube. Finally, a new design combining the characteristics of S-tube and traditional polygon tube (P-tube) is proposed. The numerical result shows that SEA of the new design is 40% higher than that of P-tube. [ABSTRACT FROM AUTHOR]

The present paper deals with a dynamic interactive response of FG beam-columns subjected to in-plane pulse loading when the shear lag phenomenon and distortional deformations are taken into account. The structures are assumed to be simply supported at the ends. In order to obtain the equations of motion of individual plates, the classical laminate plate theory (CLPT) has been modified in such a way that it additionally accounts for all components of inertial forces. Thin-walled trapezoidal FGM beam-columns are considered. A dynamic interaction of the global mode with the lowest primary local buckling mode and the secondary local mode has been analysed. Attention has been drawn to some unexpected aspects related to the fact that a two- and three-modal approach has been assumed in the analysis of dynamic interactive buckling. [ABSTRACT FROM AUTHOR]

The paper provides comparisons of sensitivity of buckling pressures to initial shape imperfections, for the case of externally pressurised steel domes. A priori defined deviations from perfect shape include: Legendre polynomials, increased-radius patch, and localised inward dimple. The latter is created by a concentrated force acting radially. In this case the effects of spring back and/or annealing of the dented patch and the surrounding area on the load carrying capacity are assessed. Some of the elastic solutions related to the lower-bound approach are compared with the available experimental data. [ABSTRACT FROM AUTHOR]

Typical methods of analysis and modelling of measured geometric imperfections make use of the Fourier transform to represent the imperfections as summations of sinusoids. The reconstruction of the imperfection usually consists of only a few harmonics, chosen with half-wavelengths equal to the half-wavelengths of the critical elastic buckling modes. This modelling of geometric imperfections is well suited for slender prismatic structures which buckle elastically and for which the buckling modes are harmonic in the longitudinal direction. However, when buckling occurs inelastically, buckling deformations are frequently confined to a relatively small part of the structure and associated with the formation of a spatial plastic mechanism. For this case, the accurate reconstruction of localised imperfections using sinusoids requires the summation of a wide range of frequencies. Further, the Fourier transform cannot explicitly give information on the positioning of localised components. This paper explores the application of the wavelet transform to the analysis and modelling of localised geometric imperfections. Seeing the similarity between various wavelets and the longitudinal variation of typical inelastic buckles, wavelet transforms are expected to be more suitable for modelling the geometric imperfections of non-slender thin-walled structures than the Fourier transform. The theory of the wavelet transform is briefly covered including methods by which practical issues that arise in evaluating the transform, and reconstructing the analysed imperfection, may be resolved. Three imperfection schemes are developed and compared to numerical models incorporating detailed longitudinal and transverse geometric imperfection measurements. These schemes represent the pertinent imperfection components via Fourier series, via wavelet frames, and via a few empirically selected wavelets. The scheme utilising wavelet frames produces excellent results, as does that utilising Fourier series, although it requires a great number of component wavelets due to their finite length. As such, it is worth noting that, in addition to those covered herein, many more methods of reconstruction utilising wavelets are possible. [ABSTRACT FROM AUTHOR]

The exact differential equations for the axisymmetric bending of elliptic toroidal shells are difficult to solve. In this paper, and by considering a semi-elliptic toroid, we present an approximate bending solution that is valid in regions adjacent to the horizontal equatorial plane. The formulation accurately simulates edge effects which may arise from loading and geometric discontinuities located in the equatorial plane of elliptic toroids. In particular, the developed closed-form results provide a very effective means for evaluating the state of stress in the relatively narrow zones experiencing mid-side local effects in complete elliptic toroidal vessels subjected to hydrostatic loading, and for calculating the deformed shape of the shell midsurface. [ABSTRACT FROM AUTHOR]

Elastic instabilities (such as buckling) have been recognized as a promising phenomenon to design smart materials and mechanical systems. Thin-walled cylindrical shells under axial compression can attain multiple bifurcation points in their postbuckling regime due to the natural transverse deformation restraint provided by their geometry; but harnessing such behavior for smart purposes is lacking extensive study due to its notoriously high imperfection sensitivity. In this paper, the concept of seeded geometric imperfection (SGI) design is proposed to modify and control the elastic postbuckling behavior of cylindrical shells. Eigenvalue-based mode shapes were used as basic geometric forms to generate a seeded imperfection. Prototyped SGI cylindrical shells were fabricated through 3D printing and tested under loading–unloading cycles. Numerical and experimental results suggest that the SGI cylindrical shells are less sensitive to initial imperfections and load variation than uniform ones. Cylindrical shells with seeded geometry can be potentially used in the design of smart devices and mechanical systems such as energy harvesters and self-powered sensors. [ABSTRACT FROM AUTHOR]

The toroidal shell with stiffened ribs is a new-style structure in ocean engineering especially in underwater engineering. This paper attempts to provide a simple theoretical method to obtain the stress solution of toroidal shell with ribs for its strength assessment. Firstly according to the structural property of toroidal shell with ribs and theory of curve-beam, a simple model for toroidal shell with ribs has been developed; then coupled with theory of thin-shell and elastic beam, its stress and deformation have been solved and can be expressed into analytic formulas; lastly by finite element method (FEM) and model experiment method, this simple theoretical solution has been verified to be reasonable and quite accurate. Thus this simple theoretical solution could be applied for analysis and design of pressure equipment in such toroidal structure type. [ABSTRACT FROM AUTHOR]

Multi-cell tubes have been drawn increasing attention for their excellent energy-absorbing ability. However, the effect of cell number and oblique loads on crashing behaviors has seldom been studied to date. In this paper, a group of multi-cell tubes with different cell numbers were comprehensively investigated under both axial and oblique loads. The finite element models were first established and then validated by experimental tests. The simulation results showed that the increase in cell number can be beneficial to the energy absorption ( EA ) but detrimental due to increase in peak force ( F max ) under axial load. When the oblique loads were taken into account, the tubes could undergo global bending, which is an inefficient deformation mode. By applying complex proportional assessment (COPRAS) method, the 7×7 tube was selected as the best based on multi-criteria under multiple loading angles. Then the Kriging modeling technique and multiobjective particle optimization (MOPSO) algorithm were integrated to address the optimization problems, where EA and F max were taken as objectives and tube sizes as design variables. The results demonstrated that different loading angles have different requirements on cell allocation and optimizations of multiple load cases (MLC) can yield better solutions in a weighted average fashion, whereas the optimization for separate single load cases (SLC) could result in inferior performance under other load cases. [ABSTRACT FROM AUTHOR]

In this paper the impact of a hollow elastic ellipsoidal thin shell with an elastic flat half space is analyzed. Due to the nonlinearity and complexity of the impact equation, classical numerical solutions cannot be employed. A closed-form solution for this problem is accomplished, using Hertzian theory [6] and the Vella ’ s analysis [17] in conjunction with the Newtonian method and a linearization scheme. The closed-form solution facilitates a parametric study of this problem. In next step, the closed-form analytical solution is validated by other research studies and explicit finite element method. Good agreement between the closed-form solution and other numerical results is observed. Based on the closed-form solution the maximum total deformation of the shell, the maximum transmitted force and the time duration of the contact were determined. The variations of the total deflection and the transmitted force as a function of the shell thickness and the different geometry of the shell were also determined. Finally it is concluded that the closed form equations are trustworthy and appropriate to investigate the impact of elastic ellipsoidal shells. [ABSTRACT FROM AUTHOR]

Few researches have focused on elastoplastic mechanical performances of functionally graded plates and shells. In this paper, elastoplastic and plastic buckling behaviors of externally pressured cylindrical shells made from functionally graded materials are investigated by using Donnell shell theory. Either J 2 flow theory or J 2 deformation theory helps to found the constitutive relation of functionally graded materials. The material properties vary smoothly through the thickness, and a multi-linear hardening elastoplasticity is used in the analysis. The buckling governing equations are solved by Galerkin method, and the expression of the elastoplastic critical external pressure is given analytically. Numerical results from the present theory are derived by an iterative arithmetic developed in MATHEMATICA code. The theoretical critical loads of the present J 2 deformation theory are well verified by experimental and numerical results in literature. The elastic, elastoplastic, and plastic buckling regions of functionally graded cylindrical shells can be effectively distinguished by the present method, and various effects of the dimensional parameters, the power law exponent, and the elastoplastic material parameters are investigated. [ABSTRACT FROM AUTHOR]

When analysing the structural behaviour of a thin-walled member by means of Generalised Beam Theory (GBT) – a one-dimensional folded-plate theory expressing the member deformed configuration as a linear combination of cross-section deformation modes with amplitudes varying along its length – the performance of the so-called “cross-section analysis” is the key step. Indeed, it consists of determining the deformation modes and evaluating the corresponding modal mechanical properties. However, the available procedures to perform this task are strongly dependent on the cross-section geometry type, a feature precluding its general, efficient and systematic numerical implementation. In order to overcome this difficulty, this paper presents the development and illustrates the application of a novel procedure to perform “GBT cross-section analyses” that (i) is able to handle arbitrary (flat-walled) cross-section shapes, (ii) can be numerically implemented in a systematic and straightforward fashion, and (iii) provides a rational set of deformation modes, which are hierarchically organised into several families, each with well-defined structural/mechanical characteristics. Both the analytical derivations and the underlying mechanical reasoning are explained in detail, and the selected illustrative examples cover the various types of relevant cross-section geometries. [ABSTRACT FROM AUTHOR]

The paper presents a theoretical, numerical and experimental investigation into the dynamic behavior of internally nested tube systems subjected to lateral impact loading. A theoretical model based on rigid, perfectly plastic material idealization is proposed, in which the effects of strain-hardening and strain-rate are considered. The analytical solutions to the crushing behavior of nested tube systems are obtained. Numerical simulations based on finite element method using the explicit code LS-DYNA and experiments are performed and the response of force and displacement versus time impacted by a drop hammer are compared with the theoretical predictions, resulting in good agreement. [ABSTRACT FROM AUTHOR]

This paper presents the experimental and theoretical studies on square tubed reinforced-concrete (TRC) short columns under eccentric compression. The main parameters of the test specimens included eccentricity and width-to-thickness ratio of the steel tube. The axial load versus lateral deformation curves, stresses in the steel tubes and the observed failure modes were discussed. The test results indicated that the eccentrically loaded specimens exhibited good ductile behavior with a bending failure mode. A new approach to determine the effective lateral confining pressure for TRC columns with square section was proposed. A numerical analysis model was developed to simulate the mechanical behaviors of square TRC short columns. Valuable attempts were made to describe the variation rules between the parameters in stress block method for tubed concrete and the magnitude of confinement. Furthermore, the axial force versus moment capacity interaction diagrams of square TRC columns were calculated. [ABSTRACT FROM AUTHOR]

In order to prevent vehicle access to a protected area, vehicle barriers can be installed around the perimeter of the area. Bollards are commonly used as vehicle barriers. This is due to the fact that they can be readily blended with other architectural features and present fewer disturbances to a building’s functionality when compared to other barrier systems. Hollow steel tubes are used in a variety of barrier system applications where they are required to absorb deformation energy. Varying methods, such as finite element analysis or experimental observation, can be used to determine the collapse behaviour and energy absorption of these steel structures under lateral impact load. These methods have high accuracy but demand a significant amount of time and computational resources. Apart from experimental and numerical analyses, Yield Line Mechanism (YLM) is an approach that can provide the collapse response of sections. This is when a section fails and the YLM of failure forms at its localised plastic hinge point. The YLM analysis approach is commonly used to investigate the performance of thin-wall structures that have local failure mechanisms. This paper investigates the collapse behaviour and energy absorption capability of hollow steel tubes under large deformation due to lateral impact load. The YLM technique is applied using the energy method, and is based upon measured spatial plastic collapse mechanisms from experiments. Analytical solutions for the collapse curve and in-plane rotation capacity are developed, and are used to model the large deformation behaviour and energy absorption. The analytical results are shown to compare well with the experimental values. The YLM model is then used to verify the finite element model (FEM), and then the failure behaviour and energy absorption of hollow steel tubes under lateral impact load is investigated in more detail. [ABSTRACT FROM AUTHOR]

Over the last several decades, various approaches to strengthening steel structures through the use of Carbon fibre reinforced polymer (CFRP) composites have been investigated; however, most of the studies have been focused on the steel tubes. This paper presents the feasibility analysis on the application of CFRP composite strips to strengthen the CFST column member under axial loading. CFRP strips having a width of 50 mm were used to confine the columns. The experimental parameters were the spacing between the CFRP strips (20 and 30 mm) and number of CFRP layers (one, two and three layers). All columns were tested under axial compression until failure. The experimental results revealed that bonding of CFRP composites effectively delayed the local buckling of the columns and also reduced the axial deformation by providing a confinement/restraining effect against the elastic deformation at both spacings. The confinement effect provided by CFRP composites was increased with the increase in the number of layers; however, the enhancement in buckling stress was not proportional. The load carrying capacity of the column increased with the application of CFRP strips, by up to 30% compared to the of un-strengthened column. From the test results it is suggested that the application of CFRP strips at a spacing of 20 mm or 30 mm is suitable for strengthening of a CFST circular column member; however, the application of strips at intervals of 30 mm recommended as an economical approach to strengthening compared to the 20 mm spacing. Finally, an analytical equation was proposed to predict the load carrying capacity of the CFRP strengthened CFST column, and the average difference between the calculated and experimental value was only ±5%. [ABSTRACT FROM AUTHOR]

Thin-walled open section beams are carefully analysed by Vlasov׳s theory of the sectorial areas. It allows to take into account their peculiar warping deformation which appears in the presence of torsional actions. This behaviour determines a further stress state along the axis of the element which is rarely considered in structural analyses. The aim of the present paper is the evaluation of the warping deformation of thin-walled open section beams subjected to torsion. Firstly, the analytical theory proposed by Vlasov is verified through an experimental test on a steel specimen defined by a U profile. Specific analyses are performed with the aim of a sophisticated optical device in order to assess the transverse distortion of the section. Then, the results obtained experimentally and confirmed by a Finite Element (FE) programme permit to validate a computer programme based on the analytical theory and devised to study the structural behaviour of high-rise buildings stiffened by thin-walled open section shear walls. In order to evaluate the effectiveness of the programme, an example which highlights the benefits provided by the present method compared to FE programme is carried out. [ABSTRACT FROM AUTHOR]

Curved tubes are widely used on autobody to suffer the transverse bending loads. This paper studies the energy absorption performance of curved tubes under transverse bending load. Firstly, three-point-bending and fully clamped bending experiments are conducted for three kinds of curved tubes with different radii. It is found that the curvature has a significant impact on the energy absorption effect under the fully clamped condition. However, the influence is limited and it will be easily ignored in the three-point-bending condition. Under fully clamped condition, tubes with large radii have three-plastic-hinges, and curved tubes with small radius have five-plastic-hinges. Due to the participation of axial force, the energy absorption of the curved tubes under fully clamped condition is 2.8–4.1 times that of the three-point-bending condition. Subsequently, FE models of curved tubes with different radii are established to analyze the effect of curvature on the deformation mechanism and energy absorption. It is found that whether the shortening of the plastic hinges can meet the requirements of geometric compatibility determines the deformation modes of curved tubes. The influence of loading (loading direction) and geometric (cross-section and thickness) factors are also discussed. Finally, a theoretical model of curved tubes with three-plastic-hinges mode is proposed to predict the energy absorption performance. • Three-point-bending experiments and fully clamped bending experiments are conducted on curved tubes. • FE models of curved tubes are established and verified by experimental results. • How the curvature influences the energy absorption mechanism of tubes under transverse loading is presented. • The effects of loading direction, cross-section and thickness on curved tubes are discussed. • Theoretical analysis is conducted on curved tubes with three-plastic-hinges mode under fully clamped condition. [ABSTRACT FROM AUTHOR]

This paper presents a new deformation assisted joining process for connecting tubes to stronger tubesheets, which involves reduction of the free tube end by local indentation of the tubesheet and subsequent flaring against the tubesheet surface to create a mechanical interlocking. The methodology draws from the fundamentals of the new proposed process to the identification of the major variables and their influence on the overall deformation mechanics. The work combines experimentation and numerical simulation with finite elements and is carried out in unit cells consisting of a polymer tube and a metallic sheet with a drilled hole that are representative of the tube-to-tubesheet connections of heat exchangers. It is shown that the new deformation assisted joining process can produce tube-to-tubesheet connections in which the tubes are softer than the tubesheets, paving the way for manufacturers of heat exchangers to combine polymer tubes with metallic tubesheets (and shells) in applications where the media running inside the tubes is incompatible with the use of metallic tubes in long service life. In addition to the originality resulting from the new polymer-metal tube-to-tubesheet connections, the new proposed deformation assisted joining process is also the first ever in its category to make use of tube reduction, instead of tube expansion, to produce these types of joints. • Innovative deformation assisted joining process for connecting tubes to stronger tubesheets. • First time ever application of tube reduction to produce tube-to-tubesheet joints. • Fostering new heat exchanger designs that make use of polymer tubes and metallic tube sheets and shells. • Numerical and experimental investigation on unit cells to demonstrate the process applicability. • Destructive pull-out tests to evaluate the force to detach the tubes from the tubesheets. [ABSTRACT FROM AUTHOR]

In this paper, the plastic behavior of a fully clamped sandwich beam with fiber metal laminate (FML) face-sheets and metal foam core under transverse loading is analytically and numerically studied. Based on the modified rigid plastic model, the analytical solution for large deflection of FML sandwich beams under transverse loading is given, in which the local denting deformation is considered. Finite element results are conducted, and analytical solutions capture numerical results reasonably. The influences of material and geometrical parameters on the plastic behavior of FML sandwich beams are considered. The results show that the present analytical model can be used to predict the plastic behavior of fully clamped FML sandwich beams considering the local denting deformation. • Plastic behavior of sandwich beams with fiber metal laminate (FML) face-sheets is studied. • A simplified formula for plastic behavior of FML sandwich beams is obtained considering local denting. • Analytical solutions capture numerical results reasonably. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a comprehensive experimental and numerical investigation on the cyclic response of cold-formed steel columns with hollow rectangular sections. The present study examined the columns׳ post-buckling strength and rigidity degradation, deformation and failure modes, ductility, and energy dissipation capacity. The cold-formed steel members exhibited stable hysteretic performance up to the point of local buckling with considerable degradation in strength and ductility. The energy dissipation mechanisms from the in-plane plastic behavior and out-of-plane elastic buckling deformation were identified. The influence of the height-to-width ratio and axial-compression ratio on energy-dissipation and failure mode was also investigated. [Copyright &y& Elsevier]

Abstract: This paper reports on an experimental study on the flexural behavior of fiber reinforced polymer (FRP)-high-strength concrete (HSC)-steel composite beams. Seven double-skin tubular beam (DSTBs) and a concrete-filled FRP tube (CFFT) with an internal steel I-beam were tested as simply supported beams in four-point bending. The main parameters of the experimental study included the cross-sectional shapes of inner steel reinforcement and external FRP tube, concrete strength, presence (or absence) of concrete filling inside the steel tube, and effects of the use of mechanical connectors on the inner steel tube. The results indicate that DSTBs are capable of developing very high inelastic flexural deformations. However, the results also indicate that slip between the concrete and the steel tube of the DSTB can be relatively large, unless the bond between concrete and steel tube is enhanced through the use of mechanical connectors. The results of the beam tests illustrate that the flexural behavior of DSTBs is influenced significantly by the diameter and thickness of the inner steel tube. Concrete-filling the inner steel tube and increasing the concrete strength increase the flexural capacity of DSTBs without affecting their overall ductility. Furthermore, the shape of the inner steel tube influences both the flexural capacity of DSTBs and the occurrence of slippage between the concrete and the inner steel tube. It is shown that the bond slip between the concrete and inner steel tube can be prevented through the use of mechanical connectors. These results are presented together with a discussion on the influence of the main parameters on the flexural behavior of DSTBs. [Copyright &y& Elsevier]

Abstract: This paper presents a finite element analysis (FEA) of circular concrete filled steel tubular (CFST) members under local bearing forces applied either perpendicularly to the member or at an angle of 45°. The established FEA modeling was verified by the experimental results that have been published in an international journal. The FEA modeling was then used to perform analysis on the typical failure modes and full-range load-deformation relations of CFST subjected to local bearing forces. Finally, simplified formulae for calculating the strength of CFST under local bearing forces was presented. Practical guidance was also given to avoid premature local buckling of brace member and premature fracture of chord member. [Copyright &y& Elsevier]

Abstract: In this paper we revisit an elastic constitutive equation proposed in two previous works and extend it in order to include all higher-order terms on the deformations. Our purpose is to assess the influence of these terms on the elastic buckling of thin-walled rods. The resulting material model was incorporated into a geometrically exact rod formulation and implemented into a nonlinear finite element code. By means of simple numerical examples we show that the higher order terms may play a significant role on the values of the buckling loads and on the post-buckling behavior of thin-walled beams and columns. [Copyright &y& Elsevier]

Abstract: This paper investigated the bending strength of girth-welded stainless steel circular hollow sections by numerical method. At first, finite element simulation of girth welding process was carried out to obtain the weld-induced residual stresses and deformations employing sequentially coupled three-dimensional thermo-mechanical finite element formulation. Then, nonlinear finite element analysis in which the moment versus end-rotation response, the ultimate moment resistance and the failure mode of the girth-welded circular hollow sections under pure bending were explored incorporating the residual stresses and depressions along with the initial global geometric imperfections was performed. Feasibility of adopting the current codified provisions (Eurocode 3) for stainless steel circular hollow sections in bending as the cross-section slenderness limit for girth-welded stainless steel circular hollow section flexural members was also examined. Results showed that the flexural behavior of girth-welded stainless steel circular hollow sections always involves local buckling near the girth weld on the compression side, which significantly affects the moment versus end-rotation behavior. Moreover, the results demonstrated that the Class 3 slenderness limit of 280 from Eurocode 3 for stainless steel circular hollow sections in flexure may be applied to girth-welded stainless steel circular hollow sections subjected to bending. [Copyright &y& Elsevier]

Abstract: This paper presents the main steps and procedures involved in the development of a Generalised Beam Theory (GBT) formulation to perform dynamic analyses of thin-walled members subjected to initial perturbations or acting loads. It combines (i) the GBT modal discretisation of the cross-section deformation with (ii) the commonly adopted vibration mode superposition approach – this combination leads to an original “doubly modal” representation of the displacement field, which (i) provides deep insight into the mechanics involved in the dynamic response under consideration and, moreover, (ii) makes it possible to obtain accurate results with surprisingly low degree of freedom numbers. The application and potential of the formulation is illustrated by presenting and discussing numerical results concerning the dynamic responses of cold-formed steel lipped channel beam in several situations, namely (i) the damped oscillations following the release from a deformed configuration, (ii) the action of uniformly distributed loads with periodic (sinusoidal and square-wave) and impulsive (rectangular) time variations, and (iii) the effect of a point load moving along the span with constant speed. For validation purposes, the GBT-based results are compared with values yielded by Ansys shell finite element analyses – the total number of degrees of freedom involved in the GBT analyses was significantly lower. [Copyright &y& Elsevier]