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How to accurately quantify the uncertainty of stochastic dynamical responses affected by uncertain loads and structural parameters is an important issue in structural safety and reliability analysis. In this paper, the conditional uncertainty propagation problem for the dynamical response of stochastic structures considering the measurement data with random error is studied in depth. A method for extracting

The design of high-resolution topology-optimised (TO) structures is important for many industrial and medical applications because of their better mechanical performance under different load conditions. Traditional density-based TO methods, like the Solid Isotropic Material with Penalisation (SIMP) method, can produce detailed designs but are very computationally expensive, especially for fine meshes

This study is dedicated to the multi-material topology optimization formulation (MMTO) for finite strain nonlocal elastoplasticity. The subloading surface model is newly incorporated into the primal problem to achieve the gradual change of the deformation process from pure elastic to material-specific plastic hardening. The stress–strain relationship of the model is a smooth continuous function, which

We present a quantitative comparison between two different Implicit–Explicit Runge–Kutta (IMEX-RK) approaches for the Euler equations of gas dynamics, specifically tailored for the low Mach limit. In this regime, a classical IMEX-RK approach involves an implicit coupling between the momentum and energy balance so as to avoid the acoustic CFL restriction, while the density can be treated in a fully

In recent years, the phase field method has been widely used in the simulation of fatigue crack propagation. However, fine mesh and cyclic simulation cycle by cycle significantly increase the computational cost of phase field simulation, which poses challenges in simulating the entire process of fatigue crack propagation. This paper proposes a cycle jump method considering the effect of plasticity

Physics-informed neural network (PINN) prevails as a differentiable computational network to unify forward and inverse analysis of partial differential equations (PDEs). However, PINN suffers limited ability in complex transient physics with nonsmooth heterogeneity, and the training cost can be unaffordable. To this end, we propose a novel framework named physics-encoded convolutional attention network

Metal additive manufacturing via laser-based powder bed fusion (PBF-LB/M) faces performance-critical challenges due to complex melt pool and vapor dynamics, often oversimplified by computational models that neglect crucial aspects, such as vapor jet formation. To address this limitation, we propose a consistent computational multi-physics mesoscale model to study melt pool dynamics, laser-induced evaporation

This study employs a cutting-edge process known as laser-assisted ultrasonic nanocrystal surface modification (LA-UNSM) to form a surface composite gradient deformation layer on A100 ultra-high strength steel to harmonize its corrosion and fatigue characteristics. The results revealed that the innovative method softened the sample surface via laser preheating, while the ultrasonic impact forged a composite

A new statistical technique is proposed to quantify the experimental uncertainty observed during ultrasonic fatigue testing of metals and its propagation into the stress-lifetime predictive curve. Hierarchical Bayesian method is employed during the calibration and operation steps of ultrasonic fatigue testing for the first time in this paper. This is particularly important due to the significant dispersion

Soft magnetorheological elastomers (s-MREs) are a kind of smart composites composed of a mechanically soft viscoelastic matrix filled with soft magnetic particles. This work provides a standard two-potential framework for the constitutive model of s-MREs incorporating viscous dissipative mechanism, which rigorously adheres to the physical constrains imposed by even magneto-mechanical coupling, material

Hamiltonian operator inference has been developed in Sharma et al. (2022) to learn structure-preserving reduced-order models (ROMs) for Hamiltonian systems. The method constructs a low-dimensional model using only data and knowledge of the functional form of the Hamiltonian. The resulting ROMs preserve the intrinsic structure of the system, ensuring that the mechanical and physical properties of the

The Dimension-Reduced Probability Density Evolution Equation (DR-PDEE) provides a promising tool for evaluating the evolution of probability density in high-dimensional stochastic dynamical systems. However, solving DR-PDEE relies heavily on accurately identifying unknown spatio-temporal-dependent intrinsic drift coefficients, which drive the evolution of probability density. Recognizing the potential

A novel plastic-damage model is presented for the study of materials exhibiting combined plastic strain accumulation and stiffness degradation. This constitutive law is based on a phenomenological pseudo-composite theory, the Rule of Mixture (RoM), in which each constitutive behaviour, damage and plasticity, act as a virtual material component of the whole physical entity. In this way, each nonlinearity

Continuous monitoring and real-time control of high-dimensional distributed systems are often crucial in applications to ensure a desired physical behavior, without degrading stability and system performances. Traditional feedback control design that relies on full-order models, such as high-dimensional state-space representations or partial differential equations, fails to meet these requirements

Hydromechanical models of Darcy–Brinkman–Stokes type consider mass- and momentum conservation of an incompressible fluid on a domain with varying permeability. They include the two important limits of free flow governed by the classical Navier–Stokes equations and porous Darcy flow. The conceptual simplicity makes the model attractive from a modeling perspective, but any numerical solution procedure

In this paper, an implicit cell-based material point method (MPM) with particle boundaries is proposed to effectively solve large deformation static problems. The volume integrals of the incremental weak form based on an updated Lagrangian approach are evaluated at integration points defined by equally sub-dividing grid cells, which eliminates the cell-crossing error and reduces the integration error

Flexoelectricity is an electromechanical coupling phenomenon in which electric polarization is generated in response to strain gradients. This effect is size-dependent and becomes increasingly significant at micro- and nanoscale dimensions. While heterogeneous flexoelectric materials demonstrate enhanced electromechanical properties, their effective application in nanotechnology requires robust homogenization

Accurately analyzing the probabilistic responses of high-dimensional nonlinear dynamical structures subjected to non-white and non-stationary stochastic excitations is a critical and challenging task. To address this issue, an efficient stochastic response analysis method is proposed by constructing an auxiliary diffusion process related to the non-white and non-stationary excitation process and incorporating

The fatigue life of components under cyclic loading is highly sensitive to surface conditions, as imperfections lead to stress concentrations and early fatigue crack initiation. This study investigates the fatigue performance of both rough and smooth specimens made from S355 low-alloy carbon steel using a cold metal transfer (CMT)-based wire arc additive manufacturing (WAAM) process. Three types of

The influence of a hybrid surface modification combining fine particle peening (FPP), which is defined as peening using particles less than 200?μm in diameter, and sulfurizing on the fatigue properties of low-alloy steels (AISI4120) were investigated. Three types of sulfurized samples were prepared by electrochemical polishing and FPP with iron(II) sulfide (FeS) particles or steel particles as a pre-treatment

Fatigue crack closure (FCC) and growth (FCG) behavior under variable amplitude loading (VAL) are ubiquitous in engineering structures. With the plasticity-induced cack closure concept, Budiansky and Hutchinson (1978) pioneered the analytical FCC model under plane stress state and constant amplitude loading (CAL) conditions with stress ratio R?≥?0. Here, we developed the analytical model into three-dimensional

This paper addresses the issue of the influence of geometry and size on the fatigue strength of steel butt weld joints. It aims to develop a series of continuously defined influencing factors, similar to the stress concentration factors in conventional un-welded notches. Such coefficients are mainly based on theoretical outcomes from Fracture Mechanics and Notch Mechanics and, where necessary, they

Blisks (bladed disks) are critical components in modern aero-engines that offer significant weight savings compared to conventional blade and disk rotor designs, resulting in improved fuel efficiency. However, due to their integrated design, blisks are susceptible to unique failure modes following foreign object damage (FOD) and crack initiation. Of particular interest is the trajectory of crack propagation

Hydrogels are particularly versatile materials that are widely found in both Nature and industry. One key reason for this versatility is their high water content, which lets them dramatically change their volume and many of their mechanical properties – often by orders of magnitude – as they swell and dry out. Currently, we lack techniques that can precisely characterize how these properties change

A pull-off force Fc is required to separate two objects in adhesive contact. For a rigid sphere on an elastic slab, the classic Johnson–Kendall–Roberts (JKR) theory predicts Fc=32πγRs, where γ represents the interface adhesion or toughness and Rs is the radius of the sphere. Here, we investigate an alternative, extreme scenario: the pull-off force required to detach a rigid, frictionless sphere from

Porous structures have gained widespread applications in aerospace, biomedical, and other fields due to their lightweight, high specific strength, and energy absorption properties. However, existing gradient design methods for Voronoi porous structures predominantly rely on iterative optimization and explicit modeling, which suffer from high computational costs, insufficient precision in local density

The goal of this work is to develop a machine-learning enabled digital-twin to rapidly ascertain optimal programming to achieve desired tactical multi-drone swarmlike behavior. There are two main components of this work. The first main component is a framework comprised of a multibody dynamics model for multiple interacting agents, augmented with a machine-learning paradigm that is based on the capability

Effect of multilevel lamellar microstructures (MLMs) on notch high cycle fatigue (NHCF) property and microcrack initiation behavior of TC21 alloy were systematically investigated. The MLMs was created via a triple heat treatment, including parallel-aligned α laths (αlath) within the α colony (αc) and aged α fine lamellae (αfine) in the β transformation matrix (βtrans). Results indicate that microstructural

This work proposes a novel Isogeometric Analysis (IGA) extension of the assumed natural strain (ANS) method to alleviate locking phenomena in solid beams, which are modeled as 3D elements accounting for displacement degrees of freedom solely and designed such that accurate analyses can be generally obtained using only one element to discretize the structure’s cross-section. ANS methods substitute covariant

3D swept volume, enabled by advancements in additive manufacturing, present new opportunities for lightweight and functional optimization. However, efficient design methodologies for conformal filling gradient lattice structures (CFGLSs) remain scarce. This paper proposes a modified level set function (MLSF) that matches lattice structures to the geometry of 3D swept volume. Furthermore, a multiscale

The Material Point Method (MPM) has been shown to be an effective approach for analysing large deformation processes across a range of physical problems. However, the method suffers from a number of spurious artefacts, such as a widely documented cell crossing instability, which can be mitigated by adopting basis functions with higher order continuity. The larger stencil of these basis functions exacerbate

The study of the fatigue stiffness degradation behavior of carbon fiber composites under combined high and low cycle fatigue (CCF) loading is essential for the design of aviation structures subjected to cyclic loads. In this paper, an experimental study of plain weave composites (PWCs) is performed under designed CCF loading spectra, indicating that the superimposed high-cycle fatigue load significantly

Cold Spray is a solid-state deposition technique where metal powder particles are accelerated to supersonic velocities by a pressurised gas jet, forming a solid-state bond with the substrate through rapid, localised plastic deformation. Recent advancements in cold spray have enabled its application as an additive manufacturing and repair technology. This study investigates the structural integrity

Large data source for rotating bending fatigue tests of carburized steels obtained from a common research project were analyzed, and the factors influencing their fatigue properties were investigated from the viewpoint of microstructural characteristics and reliability engineering. The fatigue test results indicated that carburizing increased the fatigue strength of AISI 4120 steel, although the residual

We develop a strain gradient elastodynamics model for heterogeneous materials based on the two-scale asymptotic homogenization theory. Utilizing only the first-order cell functions, the present model is more concise and more computationally efficient than previous works with high-order truncations. Furthermore, we rigorously prove that the coefficient tensors, including the homogenized elasticity tensor

The effect of multifunction cavitation (MFC) processing on the fatigue properties of carburized low-alloy steel rods was examined under rotating bending. MFC was conducted for electrochemically polished steel rods pre-treated with gas carburizing and tempering. In contrast to conventional surface modification techniques that use a cavitation jet, MFC can generate compressive residual stress and suppress

A homogenization framework for materials incorporating evolving cracks is proposed, with machine learning to discover the evolution laws of the internal variables describing the homogenized anisotropic damage. The damage model is constructed using data-driven harmonic analysis of damage (DDHAD). First, simulations on Representative Volume Elements (RVEs) with local crack initiation and propagation

The application of geometrically nonlinear topology optimization (GNTO) poses a substantial challenge due to the extensive memory requirements and prohibitive computational demands involved. To tackle this challenge, a discrete physics-informed neural network (dPINN) is suggested as a promising approach to alleviate computational demands and enhance the applicability to large-scale problems. In comparison

Unlike conventional wrought or cast martensitic steels, which are prone to embrittlement and hydrogen cracking, 3D-printed martensitic steels exhibit exceptional weldability due to their tailored microstructural homogeneity and reduced precipitate segregation. This study investigated resistance spot welds (RSWs) in additively manufactured martensitic steel under complex loading conditions, specifically

This work presents a shear elastoplasticity model for textile fabrics within the theoretical framework of anisotropic Kirchhoff–Love shells with bending of embedded fibers proposed by Duong et al. (2023). The plasticity model aims at capturing the rotational inter-ply frictional sliding between fiber families in textile composites undergoing large deformation. Such effects are usually dominant in dry

Time-variant uncertainties are omnipresent in engineering systems. These significantly impact the structural performance. The main challenge in this context is how to handle them in dynamic domain response topology optimization. To tackle this challenge, a new transient dynamic robust topology optimization (TDRTO) method is proposed to optimize the topology of continuous structures. This method comprehensively

A new micromechanics-inspired thermodynamic constitutive model is developed for fluid-saturated granular materials. The model development begins with the conceptual assumption that a granular material, when subjected to an external load, is supported by networks of microscopic force chains, including strong and weak force networks. The model also considers the heterogeneous nature of the fabrics in

Variable stiffness laminates offer the advantage of tailoring structural performance by adjusting in-plane stiffness through curved fiber paths. Additionally, material distribution at the structural level can further fine-tune performance by varying the topology. If both the structural topology and curved fiber paths are optimized together, super-efficient composite laminates can be achieved. In this

In this paper, a decoupled, linearized, unconditionally stable, and fully discrete numerical scheme is presented for simulating two-phase ferrofluid flows. This scheme is constructed by introducing two scalar auxiliary variables. It is based on the backward Euler scheme with variable time step and mixed finite element discretization. Nonlinear terms are treated explicitly to simplify the computational

This research paper investigates the lifetime span and the crack propagation mechanism for a steel cylinder/plane contact under severe variable plastic fretting fatigue conditions that are representative of high pressure dynamic flexible pipe risers. An FEA model was used to predict the total life of the contact by separating the crack nucleation and the crack propagation mechanisms. Good correlation

This study presents a novel approach for reconstructing localized heat sources associated with fatigue degradation in metallic materials using 1D and 2D Inverse Heat Conduction Problem (IHCP) techniques, integrated with a Finite Element Method (FEM) framework. Traditional fatigue analysis methods are often constrained in their ability to analyze complex geometries. To address these limitations, an

Laser powder bed fusion (LPBF) provides advanced manufacturing capabilities for nickel-based superalloy, and solution aging treatment enhances its mechanical properties. However, the fatigue properties of solution-aged LPBF nickel-based superalloy at elevated temperature are not fully well understood. Here, high-cycle and very-high-cycle fatigue tests are conducted at 650 °C with stress ratios of R?=??1

This study investigates the fatigue crack growth (FCG) behavior of laser powder bed fused (L-PBF) Ti-6Al-4V parts with an emphasis on the effects of notch orientation, stress ratio, R, and process-induced volumetric defects. Process parameters were altered during fabrication to induce different defect types and populations. FCG tests were conducted using compact tension specimens at stress ratios of

Fibre-reinforced polymer composites are generally seen as more fatigue resistant than metals. However, layup features such as discontinuous plies and/or manufacturing-induced defects such as wrinkles, can initiate fatigue damage and reduce the overall performance of composites. Through an extensive experimental programme and an advanced progressive damage model, this paper investigates the influence

In this article, strain-controlled Low-Cycle Fatigue (LCF) tests were performed on Inconel 718 nickel-based superalloy at temperatures of 300 °C, 650 °C, and 730 °C. The LCF tests were conducted at various mechanical strain amplitudes between 3.5×10?3 and 1×10?2, and three different mechanical strain rates: 1×10?4/s, 1×10?3/s, and 1×10?2/s. Cyclic straining resulted in cyclic softening under all investigated

We propose a method to accurately and efficiently identify the constitutive behavior of complex materials through full-field observations. We formulate the problem of inferring constitutive relations from experiments as an indirect inverse problem that is constrained by the balance laws. Specifically, we seek to find a constitutive relation that minimizes the difference between the experimental observation

Randomized neural networks (RaNNs), characterized by fixed hidden layers after random initialization, offer a computationally efficient alternative to fully parameterized neural networks trained using stochastic gradient descent-type algorithms. In this paper, we integrate RaNNs with overlapping Schwarz domain decomposition in two primary ways: firstly, to formulate the least-squares problem with localized

A comprehensive investigation was conducted to elucidate the correlation between nitrogen-atmosphere heat treatment parameters and hydrogen embrittlement (HE) resistance in 304 austenitic stainless steel weldments. The HE susceptibility was quantitatively evaluated through in-situ slow strain rate tensile (SSRT) and fatigue crack growth rate (FCGR) tests under hydrogen exposure. Heat treatment temperature

The fatigue life of magnetic pulse crimping (MPC) joints is crucial for the safe fatigue design of connection structures. Traditional fatigue life prediction methods primarily rely on loading condition analysis and fail to fully account for the impact of manufacturing variations (such as raw material dimensions, process parameters, and joint deformations), which presents challenges for accurate fatigue

A theoretical analysis of random vibration fatigue is possible in time- or frequency-domain. In time-domain, sampled signal realizations are used, whereas the power spectral density (PSD) method is based on second-order statistics in frequency-domain. PSDs have important advantages over the sampled time-domain signals: (i) PSDs use a statistical model, enabling sound modeling of extreme value statistics

This study presents a fourth-order reaction-diffusion isogeometric optimization method to effectively control curvature variations in minimum mean compliance optimization problems. Using isogeometric analysis with k-refinement technique, the level set function—parameterized using Non-Uniform Rational B-Splines (NURBS) to represent complex geometries while maintaining computational stability accurately—is

Water entry is a current but challenging topic with numerous applications in engineering. However, little work has been devoted to water entry problems involving contact and fracture dynamics of solid systems. This work presents a complete immersed finite-discrete element method (IFDEM) framework that contains multiphase fluid dynamics, elastodynamics and a fracture model for crack initiation and propagation

The finite element method (FEM) and its associated field have mainly been developed for adiabatic and closed systems. Nonetheless, open systems, which allow for the exchange of energy and mass with the surroundings, have gained increasing interest in applications where mass change occurs. For solving open systems two approaches can be undertaken. The first is the local approach, which incorporates