In this paper, a new thermodynamically consistent model is presented for predicting the elastoplastic-damage behavior of ductile materials using the ordinary state-based peridynamic theory. The innovative idea of this paper lies in the definition of a damage variable for each material point to simulate deterioration. By coupling the newly defined damage variable with the elastoplastic formulation,

This work presents an implicit stabilized non-ordinary state-based peridynamic method (ImNSPD) to simulate the finite deformation and crack propagation in nearly incompressible hyperelastic materials. Firstly, a mixed displacement-pressure (u-p) formulation of the ImNSPD is derived to mitigate the volumetric locking issues expected in a purely displacement formulation near the incompressibility limit

Quantum computing, as an emerging technology, has experienced rapid development and attracted widespread attention across various disciplines over the past four decades. In the field of damage identification, as the demand for damage detection efficiency in real-world engineering continues to rise, the application of this fast computing technology also deserves attention. As a combination of genetic

We propose a novel FFT2 parallel multiscale computational method to predict the nonlinear behavior and failure of composite materials. Unlike traditional multiscale methods, the proposed approach reformulates the mechanical boundary value problem into Lippmann-Schwinger type integral equations at both the micro- and macro-scale, thereby leveraging the numerical efficiency of the fast Fourier transform

Solitons find widespread applications across diverse disciplines. Accurate identification of the internal parameters within soliton systems allows us for precise comprehension and effective regulation of these systems. The introduction of deep learning has revolutionized the way to address the issue of parameter identification in soliton systems. However, the lack of suitable weight initialization

CO2-induced dynamic covalent polymer networks (DCPNs) have received significant attention due to their capability of sequestering CO2 to remodel material properties. Despite the promising success of carbon sequestration in the polymer, the mechanistic understanding of the CO2-induced polymer network is still at the very beginning. A theoretical framework to understand the CO2-induced formation of bulk

This study presents a novel peridynamics (PD) fatigue model for the fatigue crack growth analysis under mixed-mode loading conditions. The foundational aspect of this work involves the application of Peridynamic Differential Operator (PDDO) theory, based on which the analytical relationships between the non-local bond deformations and local strain/stress tensors are first established with the consideration

Bayesian model updating based on variational inference (VI-BMU) methods have attracted widespread attention due to their excellent computational tractability. Traditional VI-BMU methods often employ the mean-field assumption, which simplifies computation by treating model parameters as independent. Recent advances in variational inference have introduced more flexible variational distributions, enabling

This study investigates the damage evolution characteristics throughout the complete deformation process of rocks. The analysis reveals five distinct stages in the stress–strain curves of rocks: elastic recovery, damage retention, damage initiation, damage acceleration, and damage slowdown. To simulate the stress–strain relationship of rocks, a damage model based on logistic equation is proposed. The

The analogy between frictional cracks, propagating along interfaces in frictional contact, and ordinary cracks in bulk materials is important in various fields. We consider a stress-controlled frictional crack propagating at a velocity cr along an interface separating two strips, each of height H, the frictional counterpart of the classical problem of a displacement-controlled crack in a strip, which

Finite element and isogeometric methods with non-boundary-conforming meshes, also known as immersed, embedding or trimming approaches, offer a fast and simple model generation process and thus became an attractive alternative to conventional boundary-fitted methods. One challenge inherent to these methods is the accurate modeling of discontinuities, such as small, narrow trimming features and cracks

Under some initial and boundary conditions, the rapid reaction-thermal diffusion process taking place during frontal polymerization (FP) destabilizes the planar mode of front propagation, leading to spatially varying, complex hierarchical patterns in thermoset polymeric materials. Although modern reaction–diffusion models can predict the patterns resulting from unstable FP, the inverse design of patterns

In peridynamics, a large amount of research related to material failure has applied the dynamic relaxation (DR) method under static or quasi-static loading conditions. However, as a pseudo-dynamic method that converts static problems into dynamic problems by introducing fictitious inertia and damping terms, the intermediate attenuation process of the DR method is not realistic. Whether it is truly

We consider optimal experimental design (OED) problems in selecting the most informative observation sensors to estimate model parameters in a Bayesian framework. Such problems are computationally prohibitive when the parameter-to-observable (PtO) map is expensive to evaluate, the parameters are high-dimensional, and the optimization for sensor selection is combinatorial and high-dimensional. To address

We demonstrated here the effect of welding heat input on the microstructure characteristics and fatigue behavior of the multi-pass welded joint of a FH690 grade ultra-heavy steel plate. The welded joint with a heat input of ∼15 kJ/cm exhibited higher ultimate fatigue stress (407 MPa at endurance limit of 107 cycles) than that of ∼50 kJ/cm. Moreover, the welded joint with a heat input of ∼15 kJ/cm fractured

Despite the critical importance of mechanical reliability in our modern economy, the prediction of fatigue failures remains a challenging endeavor. Traditional fatigue testing methods are not only slow and costly but also plagued by high variability, making it difficult to calibrate predictive models for real-world utilization. Towards addressing this challenge, we present a uniaxial mechanical fatigue

This article presents an error analysis of the recently introduced Frenet immersed finite element (IFE) method. The Frenet IFE space employed in this method is constructed to be locally conforming to the function space of the associated weak form for the interface problem. This article further establishes a critical trace inequality for the Frenet IFE functions. These features enable us to prove that

Understanding the fatigue behaviour of natural rubber is crucial for designing rubber components such as chassis and motor mounts. These components experience multiaxial loading during operation, which affects both mechanical behaviour and lifetime, for instance, due to self-heating or strain-induced crystallisation. In this study, a new methodology is introduced to analyse the fatigue behaviour of

Hemodynamic analysis is essential for assessing cardiovascular health. Computational fluid dynamics (CFD) methods, while precise, are computationally expensive and lack transfer learning capabilities, requiring recalculation for varying boundaries. Machine-learning methods, despite powerful data-fitting abilities, heavily rely on labeled datasets, limiting their use in clinical settings where data

The intricate relationship between the microstructure of materials and their mechanical properties remains a significant challenge in the field of materials science. This study introduces a novel deep learning framework aimed at predicting mechanical properties from both global and local perspectives. Taking the dual-phase Ti-6Al-4V alloy as an example, we first predict stress–strain curves and yield

An isogeometric analysis is proposed for solving acoustic problems in fluids with significant thermal and viscous dissipation. The approach is based on the Kirchhoff decomposition, which simplifies the governing linearized conservation laws for mass, momentum, and energy by dividing the physical problem into three superimposed modal wave fields; acoustic, thermal, and viscous fields. The wave fields

Data-driven evaluation of full-field variables over time poses considerable challenges and little explored. Therefore, we propose a novel dynamic parallel spatiotemporal order reduced Gaussian Process scheme (Dyna-PSTORGP) to accurately predict the full-field, time-sequenced multi-physics responses of hypervelocity collisions in real-time using limited data. In which, we first propose parallel and

Great attention has been attached to Al-Li alloys due to their excellent performance for aerospace structural components, which endure low-temperature environments and cyclic loads, posing intense demands on the fatigue resistance of materials. In this work, the fatigue crack propagation (FCP) behaviors at low temperatures (−80 °C) of as-rolled 2195 Al-Li alloy have been investigated and compared with

This article proposes a novel phase-field length scale insensitive model for fatigue failure in brittle materials. In the proposed model, we incorporate a necessary fatigue-related parameter to define the fatigue threshold energy as a function of the fracture strength and make the mechanical response of a material insensitive to the phase-field length scale. In the proposed model, we derive the governing

Inspired by the hierarchical distribution pattern of natural bamboo, this study presents a multi-layer assembly strategy for the design of mechanical metamaterials with extreme properties. Firstly, the material spatial layout is constructed by employing a bio-inspired arrangement with two types of cells distributed in a staggered manner. Based on this arrangement, a new theoretical model for evaluating

A systematic numerical study using discrete dislocation dynamics has been conducted to investigate the formation of geometrically necessary dislocation boundaries (GNBs), a fundamental component of dislocation patterning and work-hardening. The simulations presented in this paper focus on GNBs forming along the (010) plane, which are observed in the 121111 copper orientation on the β-fibre of the FCC

Multi-axis additive manufacturing significantly surpasses traditional 3-axis systems by utilizing multiple axes of motions that constructs complex three-dimensional structures with reduced need of supports. However, process planning for the curved layer slicing determines the interactions between the part and supports, and consequently, self-support topology optimization requires a numerically tractable

In this work we present a simultaneous shape and topology optimization framework that generates large-scale 3D designs on unstructured grids. We consider a “parameter-free” shape optimization approach, wherein the nodal coordinates in the finite element mesh serve as design variables. To regularize the design changes we use a PDE-based filter, similar to the filtering techniques used in topology optimization

Highly filled thermosets are widely used to encapsulate chips in the semiconductor packaging industry. A complete set of viscoelastic properties are required for package designs with optimum mechanical reliability. A novel test method, based on inert gas pressure, is proposed and implemented to measure the temperature-dependent viscoelastic hydrostatic creep compliance (or compressibility) of filled

This work develops a global-local adaptive meshing method for the phase-field model of brittle fracture, offering flexible adjustment of mesh density to produce seamless and high-quality adaptive meshes. The method first establishes a direct mapping from phase-field values and displacement errors to a normalized nodal density field, which is used to control the computational accuracy. On this basis

For complex products such as high-speed presses, it is imperative to optimize the dynamic characteristics of their moving components to avoid resonance, thereby ensuring safe and stable operation. Dynamic characteristic optimization of mechanical structures considering multi-source uncertainties remains a challenging task due to the violent confliction among multiple objectives and multiple constraints

Solving reliability-based topology optimization (RBTO) problems requires highly computational demand in finite element and sensitivity analyses, particularly for obtaining high-resolution results. To overcome this issue, a new data-driven RBTO framework is introduced by using the problem-independent machine learning method, which aims to significantly decrease the computational time incurred by finite

An algorithm for a family of self-starting high-order implicit time integration schemes with controllable numerical dissipation is proposed for both linear and nonlinear transient problems. This work builds on the previous works of the authors on elastodynamics by presenting a new algorithm that eliminates the need for factorization of the mass matrix providing benefit for the solution of nonlinear

The directors are randomly distributed in polydomain liquid crystal elastomers (LCEs), which can be rearranged upon external loading. This can further lead to a polydomain-monodomain transition, accompanied by a change from an opaque state to a fully transparent state. Currently, the mechanical response and the related phase transition in polydomain LCEs are typically characterized in uniaxial loading

In this work, we present and analyze a Stabilization-free Virtual Element high order scheme for 2D second order elliptic equation. This method is characterized by the definition of new polynomial projections that allow the definition of structure-preserving schemes. We provide a necessary and sufficient condition on the polynomial projection space that ensure the well-posedness of the scheme and we

Predicting railhead damage due to multiple wheel passes in railway operations can be computationally demanding, especially when accounting for the rail’s inelastic material response. In this paper, we use a steady-state assumption within a convective coordinate system and employ Reduced-Order Modeling (ROM) through the Proper Generalized Decomposition (PGD) method to increase the computational efficiency

Thermo-mechanical fatigue (TMF) is a complex damage mechanism considered to be one of the key issues limiting the service lives of hot section components in a gas turbine engine. Turbine blades and nozzle guide vanes are particularly susceptible to this form of material degradation, which results from the simultaneous cycling of mechanical and thermal loads. In this research, a series of TMF tests

Multiaxial fatigue under complex asymmetric loading paths has gained significant attention because it better represents the actual loading conditions of engineering components. However, research on this topic remains limited. In this study, a definition of the multiaxial fatigue stress ratio is proposed by identifying the peak and valley points of complex loading paths. Subsequently, the Walker mean

The paper introduces an innovative coupling technique, termed the Inter-System Iteration Technique (ISIT) in the whole time domain, which is effectively implemented by the coupling of the Finite Element Method (FEM) and Time Domain Boundary Element Method (TD-BEM) for dynamic analysis of intricate engineering problems. This approach divides the entire system into distinct FEM and TD-BEM parts, computed

Computational mechanics is essential for understanding and predicting complex material behaviors, particularly in areas such as material fracture mechanics and structural engineering. However, the high computational costs associated with traditional methods, especially for large-scale simulations, present significant challenges. Peridynamics (PD) offers a compelling alternative to classical continuum

Digital image correlation (DIC) is a prominent technique for full-field, non-contact deformation characterization. Despite its sub-pixel sensitivity for displacement measurement, conventional DIC often suffers from inadequate signal-to-noise ratios (SNRs) when measuring small deformations in stiff and/or brittle materials. This work presents phase-augmented DIC (PA-DIC), a novel method that integrates

A mathematical formulation incorporating the relationship between the damage tensor, healing tensor, and fabric tensors is presented. This formulation provides for a direct link between the subjects of Damage and Healing Mechanics using Fabric Tensors. A new damage-healing tensor is introduced that is based on the fabric of the material. This new tensor is pivotal in characterizing the micro-structure

Nematic elastomers exhibit transversely isotropic semisoft elasticity due to the coupling of the liquid crystal mesogen and polymer network. Existing constitutive models are unable to simultaneously capture both the elastic anisotropy at small deformations and the semisoft stress plateau under large orthogonal loadings. Based on the decompositions of the strain energy and the deformation gradient,

A finite-element method dependent adjoint-based procedure to determine the temperature field of structures based on measured displacements/strains and a set of standard loads is developed and tested. Given a series of force and deformation measurements, the temperature field is obtained by minimizing the adequately weighted differences between the measured and computed values. Three numerical examples

We propose a novel isogeometric collocation method (IGA-C) for trimmed domains, using weighted extended B-splines (WEB-splines). Our approach employs the implicit representations of the trimming boundaries to construct the weighted basis, which allows for the subsequent calculations based on a parametrization over a single tensor-product patch, despite the nontrivial shape of the domain. The stabilization

Advanced simulations of the mechanical behavior of soft tissues frequently rely on structure-based constitutive models, including smeared descriptions of collagen fibers. Among them, the so-called Discrete Fiber Dispersion (DFD) modeling approach is based on a discrete integration of the fiber-strain energy over all the fiber directions. In this paper, we review the theoretical framework of the DFD

We present a new framework for the simultaneous optimization of both the topology as well as the relative density grading of cellular structures and materials, also known as lattices. Due to manufacturing constraints, the optimization problem falls into the class of mixed-integer nonlinear programming problems. Since no algorithm is capable of solving these problems in polynomial time, we obtain a

Reduced order modelling is popular and widely used in engineering as it has the potential to gain several orders of magnitude CPU speedup for simulations with different parameters such as different initial or boundary conditions. This work presents a new parametric non-linear non-intrusive reduced-order model (P-NLNIROM) for the fluid problems, which extends the capabilities for non-linear NIROM Fuet

This paper proposes and studies two extensions of applying hp-variational physics-informed neural networks, more precisely the FastVPINNs framework, to convection-dominated convection–diffusion–reaction problems. First, a term in the spirit of a SUPG stabilization is included in the loss functional and a network architecture is proposed that predicts spatially varying stabilization parameters. Having

This study presents the effect of immersion in Simulated Body Fluid (SBF) on the fatigue behavior of Polylactic Acid (PLA) and PLA-wood composites. For the degraded fatigue tests, the testing specimens were 28 days submersed in 10X SBF, weighed, and then fatigue experiments were done. The immersed samples gained weight due to water absorption. Additionally, mineral deposits grew on their external shells

Liquid crystal elastomers (LCEs), as a unique class of smart soft materials combining the properties of liquid crystals and hyperelasticity, are capable of rapid, anisotropic, and reversible deformations in response to mechanical, thermal or optical stimuli. Here, we report a hitherto unknown stretching-induced twisting behavior of LCE bilayer strips. Under uniaxial stretching, we reveal that due to

Many fluid flows of engineering interest involve high-density ratios, the formation of shock waves, and the presence of multiple chemical species. In these situations, obtaining accurate results depends on the computational fluid dynamics (CFD) algorithm’s ability to ensure stable and robust time and space discretization of the governing equations, effectively minimizing numerical diffusion.

In force reconstruction, multi-source incomplete information makes it difficult for traditional methods to model and solve the problem accurately, especially with noise or measurement errors. Inspired by multi-objective optimization, this paper proposes a novel set theory-based regularization approach (STR) to enhance adaptability to uncertainties and improve reconstruction accuracy and robustness

The evolve-filter (EF) model is a filter-based numerical stabilization for under-resolved convection-dominated flows. EF is a simple, modular, and effective strategy for both full-order models (FOMs) and reduced-order models (ROMs). It is well-known, however, that when the filter radius is too large, EF can be overdiffusive and yield inaccurate results. To alleviate this, EF is usually supplemented

This study investigated the fracture mechanisms of dovetail joints under very high cycle fretting fatigue (VHCFF) loading and predicted the short crack propagation behavior through experiment and simulation. Dovetail specimens designed and manufactured using Inconel 718 superalloy are tested at room temperature (RT) and high temperature (650 °C). The scanning electron microscopy (SEM), electron backscatter

Nanoprecipitates typically strengthen alloys by blocking dislocation movement, but herein, they can be sheared off continually during fatigue. Cyclic slip irreversibility accumulates continually, with the local shear strain reaching ετ = 57.6 %. We reveal that dislocations slipping on the basal plane experience different critical resolved shear stress (CRSS) as they pass through the β′-nanoprecipitates

Creep-fatigue experiments were conducted on IN740H, a γʹ-lean Ni-based superalloy, at 750 °C with a strain ratio of −1, a strain amplitude of either 0.3 or 0.5 %, and a dwell period at the maximum strain of 0, 120 and 600s. Results indicate that the number of cycles to failure decreased with the dwell period, although overall rupture time increased. Grain boundary fracture was more prevalent at higher

Accurately predicting the fatigue life of welded components remains a challenging task. This work compares different geometric approaches, such as scanned or idealised weld geometries, using energy-based and strain-based fatigue damage parameters. Gradient effects have also been successfully considered and investigated. In addition to the analytical calculation using the damage parameters, the fatigue

Fatigue of metallic materials produced by Laser Powder Bed Fusion has been extensively studied for both standard testing specimens and application relevant components. However, fatigue properties of specimens and components suffer from large scatter, mainly due to the presence of volumetric anomalies, residual stresses and surface roughness. Therefore, the transferability from specimens to components