The response of a structure subjected to the impact of a dry sand slug has been studied using a fully coupled approach, in which a novel algorithm based on the smoothed particle hydrodynamics (SPH) method is proposed for soil-solid interaction (SSI). The proposed algorithm is a hybrid continuum/discrete approach that can determine two regimes of contact behavior. When the granular assembly has a high

The use of origami cores in sandwich structures is attracting increasing attention in many engineering applications due to origami cores’ good compromise between weight and strength and their ability to dissipate energy. Modeling is one of the best tools for estimating design parameters for high performance. The primary outcome of this investigation is a general platform for modeling polymeric origami

In this paper, a mixed tetrahedral element based on the Lagrange multiplier is newly developed for the modified couple stress theory. The limitations of the Lagrange multiplier method are that the total number of degrees of freedom is increased and that there are zeros in the diagonal term of the stiffness matrix. We developed a method to overcome the limitations by condensing out the Lagrange multipliers

The aim of this work is to take full advantage of Spectral Element (SE) and Finite Element (FE) codes by setting up a SEM/FEM co-simulation strategy for soil structure interaction problems, involving a SE code to generate and propagate elastic waves in the soil, while a FE code enables the detailed representation of the studied structure. The spatial coupling is managed by the standard coupling mortar

Directed energy deposition processes can reduce material waste and manufacturing time of large metal parts through near net-shape production at high deposition rates. However, the localised high heat input gives rise to undesired heat accumulation, residual stresses and distortions. In this work, a fast thermal model is developed to aid in predicting and preventing these drawbacks by providing insight

In this study, the parameter free Jaya algorithm (PFJA) is developed for sizing and layout optimization of truss structures subject to natural frequency constraints. The distinctive feature of PFJA is that it uses neither algorithm-specific parameters nor common parameters in the search process. Besides using an elitist strategy where new structural analyses are performed only if strictly necessary

In this paper we focus on the L-stable β1/β2-Bathe time integration method to obtain new insights for transient and wave propagation solutions. The method is a specific case of the ρ∞- Bathe scheme but deserves special attention because it can be used directly as a first-order and second-order scheme effective in certain analyses. We show how the parameters β1 and β2 can be used to introduce appropriate

An optimization algorithm is proposed to assist in the design of extradosed concrete bridges under static and seismic loading. This procedure is composed of structural analysis, sensitivity analysis and optimization modules. The finite element method is used for the three-dimensional analysis considering static loading (dead load and road traffic live load), geometrical nonlinearities, time-dependent

Results from subset simulation often have significant variability that can be attributed to sample fluctuation and correlation among the conditional samples. In extreme cases, such as when conditional distributions are highly anisotropic or degenerate, sample correlation can cause conditional sampling to break down, resulting in failed subset simulations. To address the extreme cases where subset simulation

A number of physical systems can be described by ordinary differential equations. When physics is well understood, the time dependent responses are easily obtained numerically. The particular numerical method used for integration depends on the application. Unfortunately, when physics is not fully understood, the discrepancies between predictions and observed responses can be large and unacceptable

The current study uses knowledge from digital architecture, computer science, engineering informatics, and structural engineering to formulate an algorithmic framework for integrated Computer-Aided Design (CAD) and Computer-Aided Engineering (CAE) of Integrally-Attached Timber Plate (IATP) structures. The algorithm is designed to take the CAD 3D geometry of an IATP structure as input and automates

A proportional viscous damping model based on a bell-shaped basis function parameterized by the frequency and damping ratio at its peak has recently been proposed. The basis function in the frequency domain has a fixed frequency bandwidth and could not match a damping ratio curve that changes precipitously over a short frequency interval. This study proposes new parameters to control the bandwidth

The traditional structural optimal design methods aiming to generate a global optimum may fall into the unfeasible domain due to the presence of uncertainty. This issue can be addressed by generating a group of satisfactory design or sub-design regions rather than a single optimal one. A data mining method has been recently developed based on the decision tree technique and applied to the engineering

The paper proposes an efficient methodology that allows to design smart deformable aeronautical configurations that are able to achieve pre-defined target shapes by adjusting the temperature of Shape Memory Alloy (SMA) actuators. SMA-based actuation finds extensive application in morphing concepts which are adopted in aeronautics to enhance the aerodynamic performance by continuously varying the geometry

Topology optimization of trusses is one of the most inviting topics in the structural optimization field. In search for the computational efficiency, researchers have implemented many algorithms for this problem. With the advent of metaheuristic algorithms, structural optimization problems have become simpler to model; however, solution of these problems remains computationally expensive. The design

Mixed-effects regression models are widely applicable for predicting degradation growths in structural components. The Bayesian inference method is used to estimate the regression parameters when the degradation data are confounded by measurement and parameter uncertainties. The Gibbs sampler (GS), commonly used for this purpose, works when the regression errors are assumed as normally distributed

Currently, most works on layout optimization problem of continuum structure embedded with movable holes are all carried out to maximize the stiffness of the overall system. In this work, the embedding problem is solved for minimum stress design for the first time. To this end, we propose an effective hybrid methodology under SIMP-based computational framework. The material density characterizing the

Two novel finite element schemes were earlier proposed to reduce the meshing effort needed for practical finite element analysis and their promising performance was demonstrated in the AMORE (AMORE stands for Automatic Meshing with Overlapping and Regular Elements) framework. In the first scheme “overlapping finite elements” are established that combine advantages of meshless and traditional finite

In this paper, the free vibration characteristics of Sigmoid Functionally Graded Material (S-FGM) Levy-type plates are investigated by developing the Dynamic Stiffness Method (DSM) through the application of the Wittrick-Williams algorithm, as solution technique. Kirchoff-Love Plate Theory (KLPT) and Hamilton principle are utilised to derive the governing equation of motion and associated natural boundary

Nowadays, it is still difficult to analyze no-tension/compression materials by using commercial software packages, although the option of no-tension/compression constitutive law has been provided. The paper presents a variational principle for bi-modulus elasticity that can be used to model no-tension/compression materials and structures. Equivalence between the derived complementarity finite element

Computational efficiency of metaheuristic optimization algorithms depends on appropriate balance between exploration and exploitation. An important concern in metaheuristic optimization is that there is no guarantee that new trial designs will always improve the current best record. In this regard, there not exist any metaheuristic algorithm inherently superior over all other methods. This study compares

This article concerns numerical simulations of glass plates loaded by a force impulse caused by a low velocity impact. Three types of numerical models of different complexity – the spring-mass system, the modal decomposition based model, and the conventional finite element method – all exploiting the Hertz contact law are compared and their advantages and limitations are discussed. Their performance

This paper presents a novel family of multiple springs models capable of reproducing the nonlinear response typical of mechanical systems and materials having a biaxial kinematic rate-independent hysteretic behavior. In such a formulation, the generalized force vector, representing the output variable, is computed by summing the contribution of n springs, respectively made up of a nonlinear elastic

Concrete is undoubtedly the most important and widely used construction material of the last centuries. Nevertheless, mathematical models that can accurately capture the particular material behaviour under all loading conditions of significance are scarce at best. Although concepts and suitable models have existed for quite a while, their practical significance is low due to the limited attention to

A computational approach to simulating the deformation response of additively manufactured aluminum alloys is presented. A three-dimensional microstructure with the grain geometry typical for aluminum alloys produced by selective laser melting is generated by the method of step-by-step packing. The grain behavior is described in terms of crystal plasticity with explicit consideration of the slip systems

This paper proposes monolithic and partitioned methods to calculate the static deformation of a membrane structure due to a given volume of ponding water. The partitioned methods involve coupling of a structural solver for membranes and a volume-conserving solver, modeling static incompressible fluid. Two methods of this type are proposed, either using coupling iterations with convergence accelerator

This paper presents a novel approach to evaluate the role of non-classical effects, e.g., shear deformability, over a shell finite element model. Such an approach can identify the areas of a structural model in which the use of first-order shear deformation theories may lead to significant inaccuracies. Furthermore, it can indicate optimal distributions of structural theories over the finite element

In this research, a new topology optimization scheme considering the evaporation cooling effect that cools air through the evaporation of liquid is presented. To efficiently cool down hot surfaces or products, it is a viable approach to use the evaporating cooling effect when water absorbs a large amount of heat on evaporating. To numerically consider the evaporating cooling effect, the three nonlinear

The Fourier analysis is conventional technique for approximating the frequency content of earthquake ground motions. These approaches assume that earthquake excitation is a stationary process. Time frequency analysis techniques such as wavelet transform consider an earthquake to be a non-stationary process that shows a variation in frequency content over time, but these techniques are not easy to apply

We consider the Lamé system posed in a domain with the reentrant corner of 2π as a mathematical model for the crack problem. We construct a version of the weighted finite-element method (FEM) on the base of a novel definition of the Rν-generalized solution. This allows us to suppress the influence of the singularity caused by the presence of the reentrant corner on the accuracy of computation of the

In this paper, an efficient time domain formulation is proposed for computing time history dynamic responses of 2D structures, i.e. various types of trusses and frames. Unlike the methods using frequency domain, the proposed method employs the time weighted residual approach to solve the governing differential equations of the axial and flexural wave propagation problems, directly in time. Upon choosing

In high-speed vehicles, rudders often endure both aerodynamic pressure and thermal loads. The innovative design of rudders is of great importance for the performance of the whole vehicle. In this work, thermo-elastic topology optimization is adopted to design a typical all-movable rudder structure. The compliance of the rudder skin is considered to be a new objective and the moment of inertia of the

Mixed mode-I/II/III fatigue crack growth experiments and their simulations are performed using a system permitting all possible combinations of three-dimensional mixed mode loading conditions. The so-called Compact Tension-Shearing and Tearing (CTST) specimens used in the experiments are made of 7075-T651 aluminum alloy. Different mixed mode loading conditions are considered and the applicability of

This article introduces a novel equilibrium-based form-finding approach for air-supported structures that relies on vector-based 3D graphic statics and the Combinatorial Equilibrium Modelling (CEM). The proposed approach is particularly suitable for the conceptual phase of the design process, as it allows generating a wide range of design options of discrete air-supported structures without membrane

In this paper a novel application of the (high-order) H(div)-conforming Hybrid Discontinuous Galerkin finite element method for monolithic fluid-structure interaction (FSI) is presented. The Arbitrary Lagrangian Eulerian (ALE) description is derived for H(div)-conforming finite elements including the Piola transformation, yielding exact divergence free fluid velocity solutions. The arising method is

Digital twin technology has a huge potential for widespread applications in different industrial sectors such as infrastructure, aerospace, and automotive. However, practical adoptions of this technology have been slower, mainly due to a lack of application-specific details. Here we focus on a digital twin framework for linear single-degree-of-freedom structural dynamic systems evolving in two different

The objective of this study is to propose a relatively simple and efficient method for reliability based topology optimization for structures made of elasto-plastic material. The process of determining the optimal topology of elasto-perfectly plastic structures is associated with the removal of material from the structure. Such a process leads to weakening of structural strength and stiffness causing

Large-scale liquid storage tanks are used worldwide for storing water, chemicals and fuels, such as liquefied natural gas (LNG) and oil. Any major damage due to man-made or natural hazards, such as earthquakes, to these critical infrastructures would cause serious socio-economical losses and devastating environmental consequences. Moreover, they should remain functional even after a severe earthquake

In this paper, a new solution approach of using Free Element Method (FrEM) is proposed to solve thermal-mechanical problems consisting of composite materials and cracks. In this approach, the computational domain of the problem is discretized into multi-zones and in each zone a set of local nodes are generated. At the local nodes of each zone, the high order free elements are used to collocate the

Due to the inherent uncertainties in various systems, deterministic approaches may not be able to satisfactorily characterize their response. In such cases, stochastic approaches that can systematically consider uncertainties have to be employed. In the past, many stochastic finite element analysis (SFEA) methods have been developed for uncertainty quantification (UQ), among which the perturbation

The present manuscript presents a framework for automating the formulation and resolution of limit analysis problems in a very general manner. This framework relies on FEniCS domain-specific language and the representation of material strength criteria and their corresponding support function in the conic programming setting. Various choices of finite element discretization, including discontinuous

Several finite element models have been analysed to numerically investigate the effects on the compressive strength and on the elastic modulus of a concrete with partial replacement of natural aggregates with different amounts and types of rubber particles from waste tyres. Percentages of substitution from 0% to 83% have been considered with rubber particles size ranging from 3 mm to 30 mm. Analytical

The conventional Cellular Automata (CA) approach has the disadvantage of being particularly suited for design optimization of uniform truss ground structures with identical cells. Moreover, the conventional CA algorithms, which are intrinsically local, have to be modified in order to be able to tackle problems involving displacement constraints. This paper presents a new non-uniform Cellular Automata

As the development of new grades of Ceramic Matrix Composites (CMC) for civil aviation grows, different manufacturing processes have been perfected and several of them can be used successively in order to obtain different types of micro-structures and a variable material quality. Consequently a versatile model should be developed in order to compare these materials and create a tool to help engineers

The sensitivity analysis of hysteretic systems under nonstationary random excitations is of great concern to the stochastic optimal design and control of structures. The equivalent linear equation of motion is first constructed for the hysteretic system by the equivalent linearization method (ELM), and the sensitivity equation of the equivalent linear system is then derived by the direct differentiation

This paper proposes a non-stationary signal decomposition approach to remove the harmonic responses in the operational modal analysis for time-varying structures. Two time–frequency representations, the non-parametric windowed Fourier transform and the power spectral density estimated by the parametric functional series time-dependent autoregressive moving average model, are combined to decompose the

Surrogate model-based sensitivity analysis, especially framed by neural network ensemble (NNE), is an attractive but unresolved issue in structural reliability assessment. In this paper, differing from existing studies, an overview and assessment of typical methods for surrogate model-based parameter sensitivity analysis, namely the input perturbation method, the local analysis of variance, the connection

Spectral element method (SEM) is a robust and efficient mathematical technique for dynamic analysis of structures in frequency domain. Unlike finite element method (FEM), in SEM, the dynamic stiffness matrix forms a nonlinear eigenvalue problem (NLEP) to compute the natural frequencies and vibration modes of the structure which cannot be solved using linear numerical eigen-solvers. In this paper, two

The theory of archgrids of minimal weight has been formulated in the late 1970s and recently reconsidered by means of duality theory in the calculus of variations. In the current study, we follow this approach by putting forward an efficient computational scheme. Trial functions for both primal and dual problems are decomposed in two function bases: trigonometric (Fourier) and polynomial (Legendre)

The optimization of truss structures is a complex computing problem with many local minima, while metaheuristics are naturally suited to deal with multimodal problems without the need of gradient information. The Coyote Optimization Algorithm (COA) is a population-based nature-inspired metaheuristic of the swarm intelligence field for global optimization that considers the social relations of the coyote

A novel efficient stochastic incremental dynamics methodology considering first-excursion probability for nonlinear structural systems subject to stochastic seismic excitations in alignment with contemporary aseismic codes provisions is developed. To this aim, an approximate nonlinear stochastic dynamics technique for conducting first-passage probability density function (PDF) based stochastic incremental

The paper presents a locking-free four-node element for laminated composite and sandwich plates based on Refined Zigzag Theory (RZT). Initially, two RZT-based plate elements are derived using four-node and eight-node configurations, achieved by way of standard C0 isoparametric shape functions. In addition, with a view on improving the modelling of extremely thin plates, an anisoparametric four-node

Wire-and-Arc Additive Manufacturing (WAAM) has been recently adopted to create innovative structural forms and architectural shapes. As shown by few experimental investigations, the layer-by-layer deposition induces a remarkable anisotropy in the elastic response of the WAAM-produced alloys. A suitable topology optimization technique is implemented to account for this peculiar behavior of the material

In this paper, we introduce an extension of the piecewise rigid displacement (PRD) method for addressing the stability of a generic two-dimensional masonry structure subjected to large displacements. So far, the PRD method has been applied to simulate cracks in the reference configuration considering small displacements. Here, we investigate both cracks and internal forces in the presence of large

The interfacial transition zone (ITZ) between cement paste and aggregates in concrete plays an important role in the macro-mechanical properties of concrete. It generally exhibits as a weak link, restricting the material resistance of concrete. The present work aims at proposing a numerical bridge from mesostructure features to macro-mechanical properties based on the extended finite element method

Structural indicators of asphalt mixtures, including aggregate gradation, spatial distribution, orientation, shape, angularity, texture, aggregate content, asphalt content and air void content, determine mixture heterogeneity and therefore significantly affect the micromechanical response of mixtures. An approach to the virtual design of mixture microstructure using structural indicators is proposed

Research on the control of wave propagation has received continuous attention due to its potentially rewarding applications in the past decades, and numerous methods have been developed for controlling wave propagation in certain materials or structures. Despite previous work has made many innovations in controlling wave propagation, they are limited to the research from a band gap perspective. Herein

Parts of the irreversible response of materials can be described by a plasticity approach. For modelling quasi-brittle materials such as concrete, the microplane approach is a powerful method. In order to predict the load–displacement as well as the stress–strain relation, numerous constitutive models developed for small strains have been used successfully. Nevertheless, for example, at high hydrostatic

In this paper, a new and robust formulation to solve three-dimensional thermomechanical contact problems under non-linear interface thermal contact (ITC) conditions is presented. This methodology allows us to consider non-linear thermal contact conductance, including the presence of thermal interface materials (TIM), and convective conditions at the interstitial contact region. The Boundary Element

A step by step method is presented for reducing the need for a large number of response history analyses (RHAs) in developing surrogates to predict the structural responses. These surrogates, which map ground motions features and characteristics of the structural systems into structural responses, are used in deriving fragility curves; and mostly are developed using machine learning algorithms. A machine