This paper proposes a modified Lemke algorithm to determine the non-holonomic response of rigid plastic skeletal structures subjected to extreme dynamic loading. The basic formulation for the dynamic rigid-plastic response has a mathematical form of linear complementarity problem (LCP), and, equivalently, a pair of dual quadratic programs (QP). Previous attempts using the Wolfe type LCP solver exhibited

The present research contributes in the structural topology optimization with the manufacturing limitation called the overhang constraint and the optimization of the anisotropic material properties. For the optimization with self-supporting structure, the overhang-free shadow filter method is developed. To consider the anisotropic material property, the raster angles of each layer (the printing direction

Optimum design of post-tensioned flat slabs with its columns is complicated by the presence of many nonlinear constraints and the non-homogeneous nature of the material used. This study presents three design optimization algorithms where the design provisions are implemented in accordance with ACI 318-11. Design variables are divided into two groups. The first group of variables refers to post-tension

Stiffness matrices of beams embedded in an elastic medium and subjected to axial forces are considered. Both the bending and the axial deformations have been incorporated. Two approaches for deriving the element stiffness matrix analytically have been proposed. The first approach is based on the direct force–displacement relationship, whereas the second approach exploits shape functions within the

In this paper, a novel design strategy to minimize the dynamic compliance of a vibrating infill structure with a solid outer coating and a periodic uniform infill lattice is presented. The vibration of the linearly elastic infill structure is excited by time-harmonic external mechanical loading. The design optimization of the infill lattice is performed simultaneously with the topology optimization

In many applications, such as textiles, fibreglass, paper and several kinds of biological fibrous tissues, the main load-bearing constituents at the micro-scale are arranged as a fibre network. In these materials, rupture is usually driven by micro-mechanical failure mechanisms, and strain localisation due to progressive damage evolution in the fibres is the main cause of macro-scale instability. We

We introduce a finite-element-model-updating-based open-source framework to identify mechanical parameters of heterogeneous hyperelastic materials from in silico generated full-field data which can be downloaded here https://github.com/aflahelouneg/inverse_identification_soft_tissue. The numerical process consists in simulating an extensometer performing in vivo uniaxial tensile experiment on a soft

A new substitution approach is proposed for decoupled two-scale analysis of a materially nonlinear composite plate with in-plane periodic meso-structures within the framework of computational homogenization. The macroscopic nonlinear mechanical behavior of the plate is characterized by numerical plate tests on an in-plane unit structure (IPUS), which enables us to obtain the relationship between macroscopic

This paper presents a novel localized collocation Trefftz method (LCTM) for heat conduction analysis in two kinds of heterogeneous materials (functionally graded materials and multi-medium materials) under temperature loading. In contrast to the conventional collocation Trefftz method (CTM), the proposed LCTM divides the whole domain into many stencil support domains consisting of several discretization

This paper presents a general formulation and solution method for the problem of two-scale concurrent topology optimization of cellular structure and its anisotropic materials. This formulation seeks simultaneous determination of the macro and micro structural topologies and the orientations of microstructures, such as a unit cell with anisotropic and inhomogeneous material properties. In the present

The work presents the parametric study of a steel–concrete composite beam with composite dowel connectors. The designed beam is located in a highly loaded warehouse ceiling with a useful load of 20 kN/m2. In the first part of the work, the best solution of the composite dowel beam was selected from among 7 variants. The parameterization of the composite beam was made on the basis of the following parameters

Within a structural health monitoring (SHM) framework, we propose a simulation-based classification strategy to move towards online damage localization. The procedure combines parametric Model Order Reduction (MOR) techniques and Fully Convolutional Networks (FCNs) to analyze raw vibration measurements recorded on the monitored structure. First, a dataset of possible structural responses under varying

This article presents a datadriven multiscale optimization method for solving 3D problems under given boundary conditions. The topology is represented by an extended level-set function that allows the nucleation of new holes throughout the process making it less sensitive to the initial guess. The two scales involved are the structural (macro) scale and the material (micro) scale. For the macro scale

The spectral elements of the Lobatto family provide desirable characteristics of convergence and accuracy using a diagonal mass matrix in dynamic analysis. These characteristics might be expected to render the spectral element method with the use of an explicit time integration scheme effective for the transient analysis of wave propagations. In this paper we study the use of the central difference

A meso-scale numerical model is established to simulate concrete cracking induced by the three-dimensional (3D) corrosion expansion of helical strands in the present study. A 3D corrosion expansion model is proposed to consider the longitudinal helix shape and transverse flower-like shape of the strand. The concrete in the model is considered as a three-phase composite material consisting of a mortar

An empirical study of masonry wall repair is presented in the current work. The textile reinforced mortar used for repair comprises a stainless-steel grid embedded in a cement matrix. This composite was applied locally and along the cracks, on a previously damaged unreinforced masonry wall. The repaired wall was then subjected to a pushover load until its maximal strength was reached. Results of the

Nanoscale features present in structural and functional materials affect their macroscopic properties and hence have been extensively studied. As experimental investigations of different nanoscale events can be tedious, computational techniques evolved as a cost-cutting method to replace or complement difficult to perform experiments. Classical molecular dynamics (MD) simulation is an effective tool

This study proposes an efficient approximation method for the Moore–Penrose pseudo-inverse when, for a matrix, the eigenvectors associated to the eigenvalues zero (referred to herein as zeros eigenvectors) are known in advance. The method reduces the computational cost by several orders of magnitude. The approximation is performed by the addition of a small-amplitude diagonal matrix to regularise the

In this study we investigate a stabilized space-time formulation for linear and non-linear elastodynamics. We use Isogeometric Analysis (IGA) in order to benefit from its numerical qualities. We focus on two points: the formulation of stabilized weak-forms in a linear and non-linear context and the interest of using continuous Galerkin schemes in space and time with higher order and higher continuity

A novel practical three-dimensional (3D) wheel-rail interaction (WRI) element is developed to simulate the interaction between a fast-moving wheel node and nodes of the rail. Different from most previous methods of wheel-rail contact in multibody dynamics, the wheel-rail relationship in this paper is simulated by the WRI element. The WRI element is implemented into a general finite element software

Prediction of effective elastic and strength parameters of both regular and irregular masonry walls from homogenization is presented. To that end, the widely accepted first order homogenization method is adopted to provide the homogenized elastic stiffnesses or compliances as well as macroscopic parameters of the selected nonlinear constitutive models. These include the tensile and compressive strength

This article presents a multi-physics methodology for the numerical simulation of physical systems that involve the non-linear interaction of multi-phase reactive fluids and elastoplastic solids, inducing high strain-rates and high deformations. Each state of matter is governed by a single system of non-linear, inhomogeneous partial differential equations, which are solved simultaneously on the same

In the context of historical seismology, studying the behaviour of historic masonry buildings is of great importance, as they are witnesses of past events. While interesting methods can be found in the literature to assess the seismic vulnerability of masonry structures subject to strong earthquakes, the topic of moderate seismicity, as encountered in many European countries, is still to be investigated

The paper presents an extension of the subspace iteration method for application in systems with viscoelastic damping elements, which are described by both classical and fractional models. The presented method enables determination of only a certain number of eigenvalues and associated eigenvectors. This is very useful, especially when the considered problem has many degrees of freedom, in which case

The dynamic analysis of railway vehicles requires an accurate representation of the vehicle, the track geometry and structure, and their interaction. Generally, flexible tracks models with curved geometries represent the rails with straight beam elements, which results in a piecewise linear representation of the rails. As a result, the wheel-rail contact mechanics are not properly captured, and the

The objective of this paper is to identify the optimal load selection at the intermediate time point of the ρ∞-Bathe time integration method. We study the truncation errors of the scheme in homogeneous and forced responses for various parameters. The optimal load at the sub-step is determined by minimizing the global truncation errors of forced responses. A numerical impulse analysis shows that the

Significant progress has been made for assessing the influence of porosity on the performance metrics for cast components through various modeling techniques. However, a computationally efficient framework to account for porosity with various shapes and sizes is still lacking. The main contribution of this work is to address this limitation. Specifically, a novel porosity sensitivity method is proposed

In this paper, the Fiber Reinforced Cementitious Matrix (FRCM) material is considered as a composite material obtained embedding a fiber grid into the mortar matrix. The mechanical response of the FRCM is, hence, derived through an homogenization procedure for periodic composite materials, considering the nonlinear behavior of the constituents. In particular, the mortar is modeled introducing a nonlocal

The key to the design of advanced micro electro–mechanical devices is an accurate evaluation of the circuit-integrated piezoelectric oscillator that accounts for its complicated configuration. Here, the direct numerical modeling of this oscillator leads to a general formulation as a structure–piezoelectric–circuit interaction. Hence, this study developed a strongly coupled partitioned iterative method

In this paper, we present an efficient and accurate numerical approach for static bending and free vibration analyses of microstructure-dependent Bernoulli-Euler beams. The current approach includes strain gradient, couple stress (rotation gradient) and velocity gradient effects simultaneously through a reformulated strain gradient elasticity, which applies only one material parameter for each gradient

This paper reports 3D nonlinear finite element (FE) models of reinforced concrete (RC) beams externally strengthened with mechanically fastened (MF) and externally bonded (EB) aluminum alloy (AA) plates. The measured and observed parameters of each specimen were obtained from an experiment conducted by the authors of this study. Each FE model adopted accurate material constitutive laws and appropriate

This paper presents the newly developed Mechanics of structure genome (MSG) technique as an alternative for homogenizing masonry without reinforcement or reinforced by the FRP repointing technique. In the numerical examples analyzed, the results obtained with MSG were compared to those presented by Barbieri and Cecchi (2007), as well as with the finite element method (FEM). For unreinforced masonry

This paper presents a two-step probabilistic framework for stochastic dynamic analysis of the coupled vehicle-bridge system (VBS) involving both uncertain parameters and random track irregularity. Firstly, an explicit time-domain method is extended to evaluate the conditional response statistics of the VBS subjected to random irregularity at specific parameter points, and an efficient spectral representation-based

This paper presents a new approach for nonlinear multi-component seismic response prediction of structures using hybrid deep learning techniques. Modern recurrent neural networks map the relationship between acceleration time-series of the base/ground of a building and the superstructure, as a form of nonlinear time-history analysis method. Seismic responses were measured in three components which

A sequential permutation search (SPS) optimization algorithm is proposed for the stacking sequence design of doubly-curved laminated composite shallow shells. The SPS algorithm takes advantages of the inherent physical–mechanical features of composite laminates that the outer layers contribute more than the inner layers to bending rigidity and the convexity of lamination parameters. In SPS, the linear

Multi-objective structural optimization problems (MOSOPs) with two objectives are widely discussed in the literature. Most MOSOPs that refer to trusses are formulated to minimize the weight and the maximum nodal displacement. This paper formulates MOSOPs with several objective functions combined with various formulations. The objective functions are the weight, the natural frequencies of vibration

In this paper, a two-step automated procedure based on adaptive limit and pushover analyses is developed for the seismic assessment of masonry structures. Inspired by an akin procedure previously developed by the authors for the out-of-plane behaviour, the procedure herein presented is extended to in-plane and combined in- and out-of-plane loading conditions, accounting also for the effect of masonry

Design optimization considering uncertainties arising from different sources has been one of the hotspots in the area of structural optimization. This paper presents a robust topology optimization method for structures with bounded loads and spatially correlated material uncertainties. We first develop a new model for random structural loads with bounded nature, in which the uncertain load components

Finite element (FE) based structural health monitoring (SHM) algorithms seek to update structural damage indices through solving an optimisation problem in which the difference between the response of the real structure and a corresponding FE model to some excitation force is minimised. These techniques, therefore, exploit advanced optimisation algorithms to alleviate errors stemming from the lack

In many applications, such as those which drive new material discovery, constitutive models are sought that have three characteristics: (1) the ability to be derived in automatic fashion with (2) high accuracy and (3) an interpretable nature. Traditionally developed models are usually interpretable but sacrifice development time and accuracy. Purely data-driven approaches are usually fast and accurate

This paper introduces Granular algorithm enhancing Material Point Method (MPM) that allows for simulation of granular flows in the quasi-static state, the moderate flow state and the disconnected flow state. The paper first shows the shortcomings of MPM algorithms in modelling the different states of granular flows. Next, it proposes Granular MPM, an enhancement that explicitly introduces the different

We present a Finite Element model, which is devoted to describing the failure mechanics of quasi-brittle materials (e.g. concrete), such as the stiffness recovery effect at the transition from tension to compression, and the cyclic behavior with a low number of cycles. The material is studied at the meso-scale, and thus considered as a heterogeneous medium. The model is formulated within the framework

Boundary conditions are critical to the partial differential equations (PDEs) as they constrain the PDEs ensuring a unique and well defined solution. Based on combinatorial and surgery theory of manifolds, we develop multi-element boundary conditions as the generalization of the traditional boundary conditions in classical mechanics: Dirichlet boundary conditions, Neumann boundary conditions and Robin

This paper presents a Dynamic Partitioning Method (DPM) to solve the vehicle-bridge interaction (VBI) problem via a set of exclusively second-order ordinary differential equations (ODEs). The partitioning of the coupled VBI problem follows a localized Lagrange multipliers approach that introduces auxiliary contact bodies between the vehicle’s wheels and the sustaining bridge. The introduction of contact

This paper presents a study of two-pin arches of constant cross-section that are moment-less under statistically prevalent (permanent) load. The arches are defined by analytical form-finding previously reported in Lewis (2016) [1]. The work provides guidance regarding the solution process, and expressions for reactions and axial forces. New analytical results include the derivation of the arch length

A finite element based framework that formulates an adaptive multiresolution multiscale technique is presented, with the goal of both accurately and efficiently simulating large masonry structures. In order to find a compromise between accuracy and computational efficiency a scale embedding multiscale model where both macro- and microscale elements come into play is proposed, combining the advantages

In this paper, a new design sensitivity analysis (DSA) method for transient responses of non-viscously damped systems is developed. The damping force of the non-viscously damped systems depends on the past history of motion and is represented by convolution integrals over suitable kernel functions. The equations of motion are first transformed into a state-space formulation and the time-history analysis

A field-enriched finite element method is proposed in this paper to simulate the failure process of rocks. According to the different types of defects, the proposed method can select the appropriate failure criteria for voids and cracks. Field variables are used to characterize the crack location and to realize the influence of cracks on the physical field of the numerical model. The main features

This paper presents a novel coupled formulation for fluid-structure interaction (FSI) problems involving free-surface fluid flows, fracture phenomena, solid mutual contact and large displacements. The numerical formulation combines three different Lagrangian computational methods. The Particle Finite Element Method (PFEM) is used to solve the free-surface fluid flow, a Finite Element Method (FEM) with

The scope of this paper is to present a novel design methodology that relies on the tabu search (TS) algorithm and aims to optimize the shear wall layout of high-rise buildings. By discretizing the distributable area of a shear wall into wall elements, different possible shear wall layouts can be described by binary code where ‘0’ and ‘1’ indicate the absence or presence of a wall element respectively

This paper presents a new density-based topology optimization algorithm for the design of constructible rigid interlocking assemblies with multiple components. The multiple components or structural parts are introduced by having multiple sets of design variables: one for each component. These are filtered separately and combined to create a density field for each structural part. In addition, the framework

In this paper, we propose a non-orthodox Multipoint Flux Approximation scheme with a “Diamond” stencil (MPFA-D) for the solution of the 3-D steady state diffusion equation. Following the work of GAO and WU (2011), in our method, the auxiliary vertex unknowns are eliminated by a novel explicit interpolation that is flux conservative and is constructed under the Linearity-Preserving Criterion (LPC).

Past research has shown that, from a long-term damage perspective, a multi-hazard approach should often be considered for the design of tall buildings. This also stands for the design of supplemental dissipation devices such as multiple tuned mass dampers (MTMDs). Although MTMDs present several advantages over conventional TMDs, their design is a rather complex process. Thus, an efficient optimization

This study presents a new random search method for solving discrete robust design optimization (RDO) problem of planar linear-elastic steel frames. The optimization problem is formulated with an explicit objective function of discrete design variables, unknown-but-bounded uncertainty in material properties and external loads, and black-box constraint functions of the structural responses. Radial basis

This contribution presents a meta-modeling framework that employs artificial intelligence to design a neural network that replicates the path-dependent constitutive responses of composite materials sampled by a numerical testing procedure of Representative Volume Elements (RVE). A Deep Reinforcement Learning (DRL) combinatorics game is invented to automatically search for the optimal set of hyper-parameters

The paper reports the development of an implicit numerical scheme for plane stress cyclic elasto-plasticity, capable of integrating a wide range of hardening rules, and simulating multi-axial ratcheting in metal structural components. Constitutive relations account for von Mises yielding in combination with mixed hardening. Emphasis is given to the kinematic hardening part, which is described with

In a conventional railway system, timber sleepers have been widely used for ballasted railway tracks to carry passengers and transport goods. However, due to the limited availability of reliable and high-quality timbers, and restrictions on deforestation, the “interspersed” approach is adopted to replace ageing timbers with concrete sleepers. The replacement of ageing timber sleepers is frequently

In this paper, a recently-developed phase-field damage model is incorporated into the topology optimization framework to take into account crack initiation and propagation in a path-dependent fashion. The proposed topological design can enhance fracture resistance of structures made of brittle materials such as advanced ceramics. For the first time, a path-dependent shape derivative is developed in

The purpose of this paper is to present a simplified nonlinear equations-model that is intended to design shape memory alloy (SMA) dampers in three-dimensional structures of unsymmetrical-plan and in yielding shear-frames. The equations-model is based on a schematic idealization of the SMA damper's hysteretic behavior and the structure's transient tangent stiffness matrix, which corresponds to yielding