Abstract not available

Multiscale models are known to be successful in uncovering and representing structure in data at different resolutions. We propose here a feature driven Reproducing Kernel Hilbert Space (RKHS) for which the associated kernel has a weighted multiscale structure. For generating approximations in this space, we provide a practical forward–backward algorithm that is shown to greedily construct a set of

Surface integrity is critical for gear contact fatigue performance. The relation between gear surface integrity and contact fatigue remains unclear, which is a challenge for gear anti-fatigue design. This study investigates the relation between surface integrity and contact fatigue of 18CrNiMo7-6 carburized gears through fatigue experiments and data-driven modeling. A series of gear contact fatigue

The fatigue behavior of low-carbon steel made by wire and arc additive manufacturing (WAAM) is studied. The role of the microstructures underpins the difference in fatigue performance between WAAM and hot-rolled materials is investigated using scanning electron microscopy (SEM), optical metallography, and in-situ acoustic emission. Results show the WAAM low-carbon steel has a lower fatigue crack growth

When a crack interacts with material heterogeneities, its front distorts and adopts complex tortuous configurations that are reminiscent of the energy barriers encountered during crack propagation. As such, the study of crack front deformations is key to rationalize the effective failure properties of micro-structured solids and interfaces. Yet, the impact of a localized dissipation in a finite region

Void nucleation on grain boundary (GB) has been regarded as an important mechanism of damage initiation in ductile polycrystalline materials under dynamic loading. The high tensile stress induced by this loading mode enables interface incompatibility (i.e. the incompatibility of mechanical properties across the GB) to significantly affect intergranular spall damage initiation. In the present work,

Crystalline materials can be strengthened by introducing dissimilar phases that impede dislocation glide. At the same time, the changes in microstructure and chemistry usually make the materials less ductile. One way to circumvent the strength-ductility dilemma is to take advantage of heterogeneous nanophases which simultaneously serve as dislocation barriers and sources. Owing to their superior mechanical

This study deals with the computation of parameterized reduced order models for hydroelastic vibrations of interior fluid–structure systems with a free surface. The main parameter is the weight of the liquid acting on the structure, which allows static and dynamic simulations for different liquid heights in a tank. Both the structure and the liquid domains are mapped in reference configurations, which

We first establish a variable density and viscosity, volume-conserved, hydrodynamically coupled phase-field variable elastic bending energy model for lipid vesicles, and then construct an efficient time-discrete scheme for solving it. The numerical scheme combines the penalty method for solving the Navier–Stokes equation, the explicit-IEQ (invariant energy quadratization) method for the nonlinear potentials

Fluid–structure interaction (FSI) incorporates effects of fluid flows on deformable solids and vice versa. Complex biomedical problems in clinical applications continue to challenge numerical algorithms, as incorporating the underlying mathematical methods can impair the solvers’ performance drastically. In this regard, we extend a semi-implicit, pressure Poisson-based FSI scheme for non-Newtonian

Multiscale simulations are demanding in terms of computational resources. In the context of continuum micromechanics, the multiscale problem arises from the need of inferring macroscopic material parameters from the microscale. If the underlying microstructure is explicitly given by means of μCT-scans, convolutional neural networks can be used to learn the microstructure–property mapping, which is

In this study, analytical formulations for energy dissipation rate and critical energy dissipation have been derived for concrete under cyclic loading conditions. Initially, the formulation for micro-crack growth rate has been derived adopting nano-mechanistic approach, which subsequently has been extended to express the critical energy dissipation. In order to eliminate the scale effect encountered

In the present paper, the capability of two multiaxial fatigue criteria in both estimating the fatigue life and predicting the crack initiation path of metallic components under random loading is investigated. As a matter of fact, it is very difficult to find in the literature the predicted crack initiation path data when the loading has a random nature. To such an aim, an experimental campaign performed

Anisotropy in the mechanical response of materials with microstructure is common and yet is difficult to assess and model. To construct accurate response models given only stress–strain data, we employ classical representation theory, novel neural network layers, and L1 regularization. The proposed tensor-basis neural network can discover both the type and orientation of the anisotropy and provide

Creep fracture mechanics has been extensively studied in the past half a century, but the gap between the creep crack-tip asymptotic field and crack growth prediction has not been effectively bridged so far, hindering the development of high temperature damage tolerance design. Here a predicting model is developed for three-dimensional crack growth in power-law creeping solids with the C(t)PC-Tz asymptotic

This paper investigates issues that have arisen in experimental and theoretical studies of the stability of a dielectric elastomeric layer bonded to a stiff substrate and subject to a voltage difference across the top and bottom conducting surfaces of the layer. The role of equi-biaxial pre-stretch of the layer prior to bonding to the substrate is a central factor in the investigation. The focus is

Fully 3-D models can be prohibitively expensive when dealing with industrial-scale problems while plate and shell models are not able to capture localized 3-D effects around cracks, welds, and other structural features. This paper presents an iterative multiscale Generalized Finite Element Method (GFEM) able to automatically couple 3-D solid and shell models and capture interactions among structural

In this paper, we address the effective and robust identification of material behavior parameters from full-field measurements obtained by means of the advanced Digital Image Correlation (DIC) experimental technique. The objective is to optimize the identification procedure by defining an appropriate and flexible numerical methodology that automatically incorporates the limited knowledge on both the

Predicting the dynamic behaviors of particles in suspension subject to hydrodynamic interaction (HI) and external drive can be critical for many applications. By harvesting advanced deep learning techniques, the present work introduces a new framework, hydrodynamic interaction graph neural network (HIGNN), for inferring and predicting the particles’ dynamics in Stokes suspensions. It overcomes the

For metallic materials, high-cycle fatigue life is sensitive to underlying microstructure features including secondary phases, textures, grains morphology, etc. The traditional, data-based safe-life approaches for modeling fatigue don’t explicitly consider the microstructure and can’t guide study in microstructure modification for improved fatigue property. Crystal plasticity-based simulation provides

Modeling an unsteady flow is an important problem in pressurized pipeline systems. Depending on the dimensions and properties of the fluid and pipeline material, the generation of hydraulic transient issues and their spatiotemporal variation patterns can be different. To address the water hammer problem without scale issues in pipeline systems, this study developed a dimensionless impedance method

Short fatigue crack growth across grain boundaries of differing tilt and twist combinations has been investigated in three dimensions using coupled crystal plasticity and extended finite element methods. Crack path selection and growth rate are mechanistically determined by considering crystallographic planes containing the highest shear strain and the achievement of a critical stored energy density

We discuss crack nucleation observations from a series of experiments that have proven to be particularly challenging for model validation. In particular, we focus attention on crack nucleation from a series of V-notched specimens of an AISI 4340 steel alloy subjected to four-point bending. Details of the specimen geometry, loading, and experimentally-measured forces are provided for V-notches with

This paper presents a model-free data-driven strategy for linear and non-linear finite element computations of open-cell foam. Employing sets of material data, the data-driven problem is formulated as the minimization of a distance function subjected to the physical constraints from the kinematics and the balance laws of the mechanical problem. The material data sets of the foam are deduced here from

The fatigue crack growth (FCG) rates and crack-tip plastic zone size data for wire + arc additive manufacturing (WAAM)-processed 5087 alloys before and after in situ hot-rolling treatment were investigated and compared. After hot-rolling, the WAAM-processed alloys possessed higher strength. During the FCG tests, the crack-tip field was monitored using a digital image correlation (DIC) technique. The

In the present study, the residual fatigue life (RFL) of natural rubber (NR) components under variable amplitude loads is predicted. To this end, a support vector machine (SVM) model is established to estimate the fatigue life of NR specimens under a constant amplitude load. Here, the strain amplitude and strain mean of NR specimens are used as input variables while the rubber fatigue life is considered

The change of residual stress is complex in the fatigue cycle. The method of evaluating the fatigue state through physical models couldn’t express the possibility of residual stress evolution. The data-driven model doesn’t conform to the physical evolution law in detail and the most model need large-scale data. In this paper, a probabilistic model based on physical model and Gaussian Process Flow is

Martensite/ferrite (M/F) interface damage largely controls failure of dual-phase (DP) steels. In order to predict the failure and assess the ductility of DP steels, accurate models for the M/F interfacial zones are needed. Several M/F interface models have been proposed in the literature, which however do not incorporate the underlying microphysics. It has been recently suggested that (lath) martensite

This study proposes a novel topology optimization approach for design of continuous steering fiber path for composite structures using a level set method. The radial basis function (RBF) is employed to construct the level set function (LSF). Fiber orientations are parameterized by LSF and fiber paths can be determined instinctively for the inherent advantages of the level set approach. Besides, the

The external and internal airflow and air renewal inside urban buses have taken especial relevance since the COVID-2 pandemic. Computational fluid dynamics (CFD) simulations, which focus on the estimation of indoor airflow are not conclusive about the impact of using Heat, Ventilation and Air Conditioning (HVAC) systems on diseases’ transmission risk while travelling with open windows has shown to

The extended finite element method (XFEM) has been successfully implemented in solving crack propagation problems by enriching the polynomial basis functions of standard finite elements with specialized non-smooth functions. The resulting approximation space can be used to solve problems with moving discontinuities, such as cracks, without the need of remeshing in the vicinity of the crack. The enrichment

This study presents a numerical modelling framework based on complex variable meshless methods, which can accurately and efficiently track arbitrary crack paths in two-dimensional linear elastic solids. The key novelty of this work is that the proposed meshless modelling scheme enables a direct element-free approximation for the solutions of linear elastic fracture mechanics problems. The complex variable

This paper introduces a novel strength-based structural optimization technique capable of concurrent design of shape and fiber path in continuous fiber-reinforced composites. To this end, a higher order function, i.e., the level-set function, is employed to update both shape and fiber placement. The shape evolution relies on a shape sensitivity analysis based on the Tsai–Wu failure criterion. The fiber

Polynomial chaos expansion has received considerable attention in uncertainty quantification since its great modeling capability for complex systems. However, considering the different variable distribution types and the ‘curse of dimensionality’ of the expansion coefficients, the polynomial chaos expansion has some limitations in the practical engineering application. In this paper, an optimal sparse

To efficiently predict the crack propagation in thin-walled structures, a global–local approach for phase field modeling using large-deformation solid shell finite elements considering the enhanced assumed strain (EAS) and the assumed natural strain (ANS) methods for the alleviation of locking effects is developed in this work. Aiming at tackling the poor convergence performance of standard Newton

This study presents an isogeometric layerwise element, L-IGA based on the principle of virtual displacement theory to model the bending behavior of laminated smart composite plates integrated with piezoelectric layers. Instead of using Lagrangian or Hermitian type polynomials encountered in standard finite element technology, L-IGA utilizes high-order Non-Uniform Rational B-Splines (NURBS) functions

A two-step optimization method is proposed for the efficient multiscale design of heterogeneous materials whose nonlinear macroscopic response is driven by volumetric and interfacial damage taking place at the microstructural level. The Eigendeformation-based reduced-order Homogenization Method (EHM) is used in a reduced-order design phase, allowing for a preliminary design that combines multiple initial

Parametric multiscale tumor models have been used nowadays as tools to understand and predict the behavior of tumor onset, development, and decrease under treatments. In order to obtain a useful model, its parameters have to be accurately estimated, often requiring numerous model evaluations. This can be computationally prohibitive for complex problems. In this work, we propose an approximate Bayesian

This paper extends the high-order entropy stable (ES) adaptive moving mesh finite difference schemes developed in Duan and Tang (2022) to the two- and three-dimensional (multi-component) compressible Euler equations with the stiffened equation of state (EOS). The two-point entropy conservative (EC) flux is first constructed in the curvilinear coordinates, which is nontrivial in the case of the stiffened

Topology optimization using the variable substitution among three fields can achieve a design with desired solid and/or void features. This paper proposes a three-field floating projection topology optimization (FPTO) method using the linear material interpolation. The implicit floating projection constraint is used as an engine for generating a 0/1 solution at the design field. The substitution filtering

We establish a dynamic homogenization framework catering for the linear elastic wave motion in periodic origami structures. The latter are modeled via “bar-and-hinge” paradigm where: (i) the folding of the structure and the bending of individual panels are modeled via elastic hinges, and (ii) the in-plane deformation of each panel is modeled with elastic bars. Using the so-formulated discrete model

This work presents an extension of the highly efficient de-homogenization method for obtaining high-resolution, near-optimal 2D topologies optimized for minimum compliance subjected to multiple load cases. We perform a homogenization-based topology optimization based on stiffness optimal Rank-N microstructure parameterizations to obtain stiffness optimal multi-scale designs on relatively coarse grids

Gas exchange is an essential function of the respiratory system that couples fundamentally with perfusion in respiratory alveoli. Current mathematical formulations and computational models of these two phenomena rely on one-dimensional approximations that neglect the intricate volumetric microstructure of alveolar structures. In this work, we introduce a coupled three-dimensional computational model

The complete elimination of flaws in complex parts raises the overall costs, especially under stringent safety or service targets, while advanced knowledge might grade the risk of running defected parts with savings. Introducing the novel concept of defect tolerance, this work proposes to exploit experiment-based full-field measurements from optical techniques, in conjunction with fatigue spectral

Concrete structures in the atmosphere are continuously subjected to thermal cycle (TC) induced by varying environmental temperature. However, the influencing mechanism of thermal cycling fatigue on the mechanical properties and microstructure of cement-based materials has not been thoroughly documented. To address this issue, the relationship between the macro-properties and microstructure of cement

Due to being composed of different materials, Aluminum-CFRP hybrid (riveted/bonded) joints (HJs) exhibit different fatigue failure modes under different loading and environmental conditions. This paper investigates the influence of hygrothermal environment on the fatigue fracture mechanism of HJs through experimental and simulation researches. Experiments demonstrate the multi-stage character of HJs’

Recent experimental and computational studies at different scales reveal an apparent flow-induced anisotropy of the inelastic deformation behaviour in metallic glasses (MGs). However, the anisotropic damage behaviour accompanied by the formation of shear bands is not adequately described in the previous constitutive modelling work. In this study, we develop a thermodynamically-consistent, anisotropic

This paper presents experimental studies on the mechanical properties and low-cycle fatigue behaviour of corroded austenitic stainless steel (3 0 4) and ferritic stainless steel (4 3 0). Tensile and low-cycle fatigue tests are conducted on 28 specimens. The corrosion process of the specimens is finished by using salt spray and dry/wet cycle tests. In the tensile tests, the key parameters of the constitutive

The possibility to obtain optimized components with a reduced weight is the main driver of space and aeronautic industries in seriously considering the metal additive manufacturing (AM) technology for production. Despite the incontrovertible advantages offered by this manufacturing technique, the material produced is usually affected by the presence of internal defects, a poor surface quality, and

T article addresses the results of the study of the examination of fatigue fracture in mixed and I+II and I+III modes in heat treated steel 42CrMo4. Three types of thermal treatments were performed, each caused various mechanical properties of the material. Tests were performed on two sample types: compact tension specimen (CTS) and rectangular cross-sectional samples for mixed mode and I+III. Mixed

The present paper discusses the formulation of weight functions for inclined edge cracks in finite width plates, typical of Rolling Contact Fatigue defects, to obtain the Stress Intensity Factor and the T-stress. Because the weight functions do not depend on the load and boundary conditions, their use is convenient to study cracks subjected to complex stress fields, e.g. fretting fatigue and rolling

The compressive fatigue performance of cementitious composites largely depends on the generation and connection of fatigue nano/micro-cracks in the composites. These types of cracks are beyond the scope that traditional fibers can restrain, but can be effectively eliminated and inhibited by incorporating nano-materials, especially those with fiber shape, such as carbon nanotube (CNT). Unfortunately

A procedure for the treatment of tricuspid regurgitation through membrane insertion has been developed recently. However, membrane optimization is required to balance treatment effectiveness with valve damage. This optimization must be performed based on hemodynamic analyses, using the computational fluid dynamics method. The objectives of this study were to analyze hemodynamic features and provide

We investigated differences in haemodynamic forces between carotid arteries that underwent primary closure (PC) or patch angioplasty (PA) using computational fluid dynamics (CFD). A total of 30 subjects were enrolled in this study, consisting of 10 subjects who underwent PC, 10 who underwent PA and 10 healthy subjects. Three-dimensional models of carotid arteries were reconstructed using patient-specific