Explore the vast range of titles available.

This chapter contains sections titled: Theories of Membranes, Plates and Shells Displacement Fields of Structural Membrane Elements Displacement Fields of Structural Plate Elements Displacement Fields of Structural Shell Elements Certain Numerical Considerations Examples of Numerical Calculations References

A nonlinear two-dimensional (2D) continuum with a latent internal structure is introduced as a coarse model of a plane network of beams which, in turn, is assumed as a model of a pantographic structure made up by two families of equispaced beams, superimposed and connected by pivots. The deformation measures of the beams of the network and that of the 2D body are introduced and the former are expressed in terms of the latter by making some kinematical assumptions. The expressions for the strain and kinetic energy densities of the network are then introduced and given in terms of the kinematic quantities of the 2D continuum. To account for the modelling abilities of the 2D continuum in the linear range, the eigenmode and eigenfrequencies of a given specimen are determined. The buckling and post-buckling behaviour of the same specimen, subjected to two different loading conditions are analysed as tests in the nonlinear range. The problems have been solved numerically by means of the COMSOL Multiphysics finite element software.

This article reports on a numerical and experimental investigation to understand and improve computer methods in application of the Goldak model for predicting thermal distribution in submerged arc welding (SAW) of APIX65 pipeline steel. Accurate prediction of the thermal cycle and residual stresses will enable control of the fusion zone geometry, microstructure, and mechanical properties of the SAW joint. In this study, a new Goldak heat source distribution model for SAW is presented first. Both 2D and 3D finite element models are developed using the solution of heat transfer equations in ABAQUS Standard implicit. The obtained results proved that the 2D axi-symmetric model can be effectively employed to simulate the thermal cycles and the welding residual stresses for the test steel. As compared to the 3D analysis, the 2D model significantly reduced the time and cost of the FE computation. The numerical accuracy of the predicted fusion zone geometry is compared to the experimentally obtained values for bead-on-plate welds. The predictions given by the present model were found to be in good agreement with experimental measurements.

This paper presents a novel C0 higher-order layerwise finite element model for static and free vibration analysis of functionally graded materials (FGM) sandwich plates. The proposed layerwise model, which is developed for multilayer composite plates, supposes higher-order displacement field for the core and first-order displacement field for the face sheets maintaining a continuity of displacement at layer. Unlike the conventional layerwise models, the present one has an important feature that the number of variables is fixed and does not increase when increasing the number of layers. Thus, based on the suggested model, a computationally efficient C0 eight-node quadrilateral element is developed. Indeed, the new element is free of shear locking phenomenon without requiring any shear correction factors. Three common types of FGM plates, namely, (i) isotropic FGM plates; (ii) sandwich plates with FGM face sheets and homogeneous core and (iii) sandwich plates with homogeneous face sheets and FGM core, are considered in the present work. Material properties are assumed graded in the thickness direction according to a simple power law distribution in terms of the volume power laws of the constituents. The equations of motion of the FGM sandwich plate are obtained via the classical Hamilton’s principle. Numerical results of present model are compared with 2D, quasi-3D, and 3D analytical solutions and other predicted by advanced finite element models reported in the literature. The results indicate that the developed finite element model is promising in terms of accuracy and fast rate of convergence for both thin and thick FGM sandwich plates. Finally, it can be concluded that the proposed model is accurate and efficient in predicting the bending and free vibration responses of FGM sandwich plates.

The efficient modeling of 3D-printed parts, especially long fiber-reinforced composite parts, is a significant concern. This paper discusses finite-element modeling using the embedded element technique to simulate the mechanical behavior of specimens reinforced with long glass fibers. The study considered the concentric deposition mode of the fibers, the walls, and the solid filling pattern of the printed parts as parameters. In addition, classical numerical modeling of the composites using 2D Shell elements and an analytical prediction of the Young’s modulus using the rule of mixtures were implemented. The results showed that both the classical 2D Shell modeling and the law of mixtures predict the Young’s modulus with acceptable prediction error. However, these approaches have limitations in predicting the overall behavior of the specimens. The use of the embedded element technique allowed for the prediction of both the Young’s modulus and the global behavior of the specimens with acceptable prediction error.

Dynamic loads are common mechanical phenomena affecting many structural systems and components. When exposed to these loads, structures experience vibrations that can cause progressive damage over repeated cycles. To minimize this effect, dampers are often used to reduce the risk of structural failure. Among various types, metallic dampers are widely applied due to their excellent energy absorption and dissipation capabilities. One notable example is the Steel Ring Damper (SRD), which operates through the deformation of a steel ring under cyclic loading. When subjected to dynamic excitation, the SRD effectively dissipates energy and reduces vibration amplitude. In this study, nine SRD models were analyzed using the Finite Element Method (FEM) under static and dynamic conditions. Static analysis produced hysteresis curves from tensile and compressive loading cycles, enabling evaluation of stiffness, energy dissipation, and damping performance. Dynamic analysis was performed on a 2D frame structure equipped with the SRD, using computational simulations to obtain time– response graphs under dynamic loading. Results showed that SRD Model 9 had the highest energy dissipation of 20.99 kN·m. In the frame analysis, Model 9 reduced displacement to 4.33 mm for Type 1 and 4.77 mm for Type 2 bracing members, demonstrating superior vibration mitigation compared to frames without SRDs.

The interaction between convection and solute transport during solidification has significant influence on the dendritic evolution. By employing the phase-field lattice-Boltzmann approach together with the parallel and adaptive-mesh-refinement algorithm, the dendritic evolution under convection is simulated in both 2D and 3D cases. The flow-induced redistribution of the solute alters both tip velocity and the development of dendritic arms. The effect of both convection and undercooling is quantified and compared using the length ratio of the dendritic arms. The effect of convection behavior (i.e., natural and forced) and domain dimension (i.e., 2D and 3D) on dendritic growth is discussed. Results show that the convection effect is mainly dominated by the convection mode, and the melt flow in 2D can produce biased results comparing with those in 3D.

Fibre-reinforced polymer composites in general, and especially glass fibre-reinforced polymer (GFRP), have increasingly been used in recent decades in construction. The advantages of GFRP as an alternative construction material are its high strength-to-weight ratio, corrosive resistance, high durability, and ease of installation. The main purpose of this study is to evaluate the response of GFRP under dynamic conditions (more specifically, under seismic loads) and to compare the performance of this composite material with that of two traditional building materials: reinforced concrete and structural steel. To this aim, a finite element analysis is carried out on a two-dimensional frame modelled with steel, reinforced concrete (RC), or GFRP pultruded materials and subjected to a seismic input. The dynamic response of the structure is evaluated for the three building materials in terms of displacements, inter-storey drift, base shear, and stress. The results show a good performance of the GFRP frame, with stress distribution and displacements halfway between those of RC and steel. Most importantly, the GFRP frame outperforms the other materials in terms of reduced weight and, thus, base shear (−40% compared to steel and −88.5% compared to RC).

Large-scale simulations and forensic analyses of the seismic behaviour of real case studies are often based on simplified analytical approaches to estimate the reduction in fundamental frequency and the amount of radiation damping induced by dynamic soil-foundation-structure (SFS) interaction. The accuracy of existing closed-form solutions may be limited because they were derived through single degree-of-freedom structural models with shallow rigid foundations placed on a homogeneous, linear elastic half-space. This paper investigates the effectiveness of those formulations in capturing the dynamic out-of-plane response of single load-bearing walls within unreinforced masonry buildings having either a shallow foundation or an underground storey embedded in layered soil. To that aim, analytical predictions based on the replacement oscillator approach are compared to results of two-dimensional dynamic analyses of coupled SFS elastic models under varying geotechnical and structural properties such as the soil stratigraphy, foundation depth and number of building storeys. Regression models and a relative soil-structure stiffness parameter are proposed to quickly predict the frequency reduction induced by SFS interaction, accounting for the presence of an embedded foundation, an underground storey and a layered soil. The effects of SFS interaction are also evaluated in terms of equivalent damping ratio, showing the limitations of simplified approaches. Since the geometric layouts considered in this study are rather recurrent in the Italian and European built heritage, the proposed procedure can be extended to similar structural configurations.

In order to study the performance of a special threaded joint of a tubing under severe well conditions, a two-dimensional finite element model of this joint was established in the finite element software, and the mechanical properties and sealing performance of the special threaded joint under different working conditions were analyzed and studied. The results of the study indicate: under different make-up torques, the Mises stress value on the thread has a small difference, and there is a significant difference at the shoulder. When subjected to complex loads, the Mises stress on the load-bearing surface of the thread head and tail ends is high, the overall maximum Mises stress exceeds the yield limit of the material, but the stress level in most areas is low, there is no plastic penetration part and structural damage on the thread teeth. The sealing index of the threaded joint is greater than the critical sealing performance index. This shows that this threaded joint can meet the requirements of use.