The paper presents a gradient enhanced model dealing with nonlocal phenomena driven by the ductile damage in semicrystalline polymers that exhibit rate-dependent and rate-independent mechanisms. The study aims at capturing the material localization at high damage levels. To this end, a viscoelastic-viscoplastic constitutive model is formulated considering a gradient enhanced thermodynamic potential

The sulfate attack (SA) of cementitious materials widely exists, which severely reduces the mechanical properties and durability of cementitious materials. However, few numerical SA damage models of cementitious materials have been comprehensively developed. The understanding and simulation of the chemo-mechanical behavior of cementitious materials are beneficial to better modeling, predictions and

A series of triaxial compression tests were conducted on deep-buried marble to reveal its deformation and failure characteristics along with the formation mechanism under high in-situ stress. The effects of confining pressure on the strength, deformation of marble samples were firstly analyzed. Then, the internal failure characteristics and energy evolution of the samples were comprehensively investigated

With the localizing gradient enhancement, a damage model for quasi-brittle materials is able to achieve regularized softening responses, with localized damage profiles corresponding to the development of macroscopic cracks, to resolve the numerical spurious effects induced by the conventional gradient enhancement. The typical implementation strategy for a gradient enhanced model is to solve the system

An appropriate constitutive model to characterize the mechanical behavior of fiber reinforced concrete (FRC) plays a critical role in accurate prediction of structural performance. In this study, an elastoplastic damage constitutive model is developed for hybrid steel-polypropylene fiber reinforced concrete (HFRC), which can predict the versatile mechanical responses of HFRC as a result of various

The existence of excavation damaged zone (EDZ) generally influences the stability and safety of the underground openings. To investigate the influence of EDZ on the stability of underground excavation under dynamic stress disturbances, underground excavations with EDZs are represented by holed rock specimens with damage zones. The fracture evolution and dynamic mechanical properties of damaged holed

Freeze-thaw action of rocks has caused many engineering geological disasters in cold regions. Estimation of the freeze-thaw damage degree and strengths loss of rocks are crucial for the prevention of freeze-thaw disasters. The main aim of this research is to investigate the influence of water saturation on the deterioration of rocks under freeze-thaw and find the best evaluation index. P-wave velocity

In this paper, a modified intermediately homogenized peridynamic (IH-PD) model for analyzing impact failure of wet concrete has been presented under the configuration of ordinary state-based peridynamic theory. The meso-structural properties of concrete are linked to the macroscopic mechanical behavior in the IH-PD model, where the heterogeneity of concrete is taken into account, and the calculation

Damage evolution in concrete after high temperature is a complicated procedure, in which the pre-peak strain hardening behaviour, the post-peak strain softening behaviour and the impact of high temperature play key roles. Uniaxial and biaxial compression damage models of concrete considering high temperature degradation effect are proposed based on damage theory and experimental phenomena. They consider

Concrete structures in extremely cryogenic environments may be subject to dynamic loadings as a result of occasional accidents or terrorist attacks during the service life. Considering the cryogenic temperature effect and strain rate effect of each phase for concrete, a meso-scale numerical model of the concrete subjected to cryogenic temperature and dynamic loadings was presented in this study, which

Ageing conditions and braided structures will affect dynamic damage and failure mechanisms of 3D braided composites. Here we report the influence of thermo-oxidative ageing on impact compression behaviors of 3D braided composite with and without axial yarns, i.e., four directional (3D4d) and five directional (3D5d) braided composites. We found a significant difference in mechanical properties between

Forming limit curves (FLCs), which are constructed using the limit strains at localised necking, are the most widely used tools for the evaluation of the formability of sheet metals. Fracture forming limit curves (FFLCs) are more recently developed, complementary tools for formability evaluation which are instead constructed using the limit strains at fracture. Since the formability depends strongly

We present a novel microcrack-damage theory for brittle solids under compression. Instead of using internal variables like zeroth, second or fourth rank damage tensors, the state of material damage is represented by an internal function that encapsulates the information of direction, density and size of microcracks. Just like other internal variables, the evolution of this state function must obey

For plain concrete materials, the degradation of concrete by seawater is mainly reflected in the corrosion of sulfate ions. In this study, the variation in the flexural strength of concrete specimens with different water-cement ratios under different sulfate concentrations for 470 days is explored, and the effect of sulfate environment on the decay of flexural strength of concrete with corrosion time

In orthodontic treatments, mechanical characterization of orthodontic bracket bonded to the tooth is essential to determine the bond strength and mechanical behavior of the bracket-adhesive-tooth system. In this study, the linear-nonlinear mechanical behavior and damage characterization of Filtek Z350 XT (3M ESPE) nanocomposite as a dental adhesive material to bond orthodontic brackets to tooth enamel

Multiaxial high-cycle fatigue failure criterion and life prediction is important for structural components under complex low stress. A new multiaxial high-cycle fatigue damage parameter based on the plane of maximum shear stress is proposed, which includes the maximum shear stress amplitude, normal stress amplitude and maximum equivalent normal stress. The maximum equivalent normal stress is defined

The focus of this study is to investigate the mechanical properties, of ±35° and ±55° filament wound (FW) composite tubes under axial compression loading using the acoustic emission technique. For this purpose, material failure, crashworthiness characteristics, and the effect of each mechanism on the energy absorption capacity were studied using numerical and experimental approaches. Also, to identify

In this work, a constitutive model of an intrinsically self-healing composite matrix material is presented. The developed model comprises a micro-damage initiation and evolution model, and a healing evolution model, which are combined with the von Mises linear isotropic hardening plasticity. It is implemented into the Abaqus/Standard user material subroutine UMAT and validated using experimental results

Rock mass is often encountered with complicated stress disturbance caused by human-induced engineering loads and the environmental loads. Cyclic or fatigue loading path with fixed loading frequency are widely performed. To date, however, damage and fracture evolution of the pre-flawed rock under variable-frequency multi-level constant amplitude (VFMLCA) cyclic loads was not well understood. In the

This paper presents a systemic calibration methodology to efficiently simulate progressive damage evolution in four different pultruded glass fiber reinforced polymer (GFRP) composites using the strain-based COMposite DAMage Model (CODAM2) in the commercial finite element software LS-DYNA. In particular, Compact Tension (CT), scaled-up CT, and wide CT tests are simulated to find the best set of input

In this contribution, a modification and application of the Lemaitre damage evolution law is proposed for the problem of fatigue life estimate under low number of cycles. For this, the denominator of damage, considered constant for Lemaitre, was replaced by a function dependent on the stress triaxiality. The new function has a nonlinear and thermodynamically consistent behavior. In addition, the evolution

The stability of rock mass after fire is a concern of many engineering projects. In this paper, the effects of open fire and different cooling methods on granites were investigated. The static Brazilian test, dynamic Brazilian test, and P-wave velocity test were carried out to evaluate the mechanical properties and damage evolution behavior. A high-speed camera is employed to monitor the failure process

When subjected to fires, cementitious composites can be seriously damaged. However, the mechanical behavior of nanoscale calcium silicate hydrate (C–S–H) grains, which are the main binder of cementitious composites, exposed to elevated temperatures under shear deformations remain poorly investigated. In this paper, considering different calcium/silicate (C/S) molar ratios (i.e., C/S = 1.10, 1.33, and

Digital-image correlation (DIC) is a deformation-measurement technique used to determine rock and soil mechanics. We review DIC tests of rock and soil, with data categorized according to specimen shape, test type, and DIC method. A new three-dimensional-DIC system integrates a transparent triaxial-compression servo-control test system for rocks. The confining pressure cell is transparent and three

In this study, a non-local approach is developed for the fatigue life prediction of notched specimens, considering stress/strain gradient and elastic-plastic fatigue damage. The damage coupled constitutive models are presented to model the mechanical behavior of material. The critical plane method and triaxiality factor are employed to determine the location of the couple point. The gradient values

Corrosion fatigue damage can lead to degradation of engineering structures and components. As a major stage of the total corrosion fatigue life, the crack initiation of pitting corrosion and fatigue is studied. A continuum damage mechanics model for predicting the crack initiation life of pitting corrosion fatigue is presented based on a pure fatigue damage model and a fracture-mechanics-based pit-to-crack

A modified fatigue damage model is proposed considering the loading sequence effect under variable amplitude loading conditions. The transition sequence is obtained from the counting sequence by an equivalent rainflow counting method and is used to provide the loading sequence information for fatigue damage accumulation prediction. Rainflow counting matrix and sequence transition matrix are formulated

Transforming intact coal seams into broken coals that are convenient to transport is one of the technical problems of fluidized coal mining. In this paper, cyclic freeze-thaw by liquid nitrogen (CFT-LN2) was adopted to improve the fragmentation degree of coal seams. The coal pore structure evolutions and coal breakage properties were explored using the acoustic emission (AE) parameter method (the kernel

The repeated action of high temperature and water cooling will have a strong deteriorating effect on the mechanical properties of the rock, which will eventually lead to the damage and cracking of the rock. In order to study the influence of heating and water-cooling cycles on rocks, the P-wave velocity and mechanical properties of red sandstone after heating and water-cooling cycles were tested. Meanwhile

2198-T8 aluminum-lithium alloy is an advanced aeronautical engineering material. The multiaxial fatigue tests of notched specimens are conducted with the variables of notch diameter, notch number, and equivalent stress amplitude, respectively. The strain field and fatigue life are characterized and calculated by digital image correlation (DIC) technique. The results show that: the fatigue life decreases

Although cylindrical and prismatic specimens are often used in laboratory tests, the differences between their deformation and failure characteristics remain unclear. Cylindrical and prismatic specimens of two rocks (marble and granite) were analyzed under various conventional triaxial conditions. The failed prismatic specimens exhibit multiple fractures intersecting in the cross section. With increasing

The formability limits of bulk metal forming in principal strain space and in the effective strain vs. stress-triaxiality space are characterized by an uncertainty region in which cracks may be triggered by tension (mode I of fracture mechanics) or by out-of-plane shear (mode III). The problem in obtaining experimental data in this region has been known for a long time and the main objective of this

Power plants production’s growth capacity has led to increased concerns about efficiency and reliability of steam turbines. Its components are prone to cracking and failure caused by creep and fatigue. The present work used Ansys® and nCode GlyphWorks® package to predict tensions and deformations. The methodology used allows calculate the level of structural damage caused to each work cycle. Analysis

Predicting fatigue life of magnetorheological elastomers (MREs) containing, different volumes of carbonyl iron particles (CIPs) with various external magnetic fields has been investigated. Unlike many studies on fatigue behavior of MREs, representing experimental models, a novel three-dimensional constitutive magneto-hyper-viscoelastic semi-coupling model based on strain energy density function (3DSED)

This paper reports the influence of woven (0°/90°) and (±45°) lamina position interchanging about the midplane in an eight-layered quasi-isotropic glass fibre reinforced polymer (GFRP) composite under low velocity impact (LVI). In order to fabricate GFRP composite, two lamina orientations as (0°/90°) (referred as ‘a’) and (±45°) (referred as ‘c’) arranged in different stacking sequences. Three number

This paper presents an experimental and numerical analysis of damage evolution in AA2011 aluminum alloy wires drawn under different scenarios. To this end, load-unload tensile tests were firstly carried out in order to characterize the degradation of the mechanical response in every cycle where the experimental results show a bilinear damage relationship in terms of the effective plastic strain. Therefore

In the past few decades, extensive research on concrete modeling to predict behavior, crack propagation, microcrack coalescence by utilizing different approaches (fracture mechanics, continuum damage mechanics) were investigated theoretically and numerically. The presented paper aims to review the theoretical work of continuum concrete damage and plasticity modeling in part I of the work. The detailed

In this part II, companion article, we present the numerical review of continuum damage mechanics and plasticity in the context of finite element. The numerical advancements in local, nonlocal, and rate-dependent models are presented. The numerical algorithms, type of elements utilized in numerical analysis, the commercial software’s or in-house codes used for the analysis, iterative schemes, explicit

Andra, the French national radioactive waste management agency, is in charge of studying the disposal of high-level and long-lived intermediate-level waste (HLW and ILW-LL) in a deep geological repository. According to the reference concept, it is planned to encapsulate high-level waste in non-alloy P285NH steel overpacks before inserting them into horizontal steel cased micro-tunnels. This work is

The short beam shear performance of GLARE 3A-3/2 laminates with adhesive layers was investigated by combining the short beam test and the digital image correlation technique. The failure behavior was further analyzed based on finite element simulation and micro failure morphology. The results show an 8% and 58% difference in the short beam strength and bending displacement at failure of laminates along

In this paper, a multi-disciplinary analysis method is proposed for evaluating the fatigue life of railway vehicle car body structure under random dynamic loads. Firstly, the hybrid fatigue analysis method was used with Multi-Body System simulation and finite element method for evaluating the carbody structure dynamic stress histories. The dynamics stress is calculated from the longitudinal load using

With the rapid development of microelectronics and nanoelectronics, Moore law has significantly slowed down and More than Moore based system in packaging (SiP) is expected to be more and more important, at least for next one to two decades. Mechanical behaviors of interconnect materials such as solders are critical for yield in processes and reliability in testing and operation. Based on the framework

To study the influence of osmotic pressure on the uniaxial compression mechanical properties of limestone, uniaxial compression tests were carried out on limestone specimens under different osmotic water pressure. The test results show that with the increase of osmotic pressure, the closure strain, yield strain and peak strain of limestone gradually increase, while the closure stress, yield stress

From the analysis of massive fatigue test data, we find a mismatch between the fatigue life predictions done by stress-life method (SN) and those by strain-life method (εN) around the yield stress of ductile metals. Since the SN and εN methods are widely used in engineering applications, this work aims to explain such mismatch and thereby to address the fatigue life prediction at material’s yield stress

Current numerical methods cannot simulate well three-dimensional (3D) fracture process of solids. In order to study 3D fracture process of brittle-like materials and improve crack growth path prediction accuracy, a method is developed based on continuum damage mechanics and finite element method. In the developed method, damage is computed by homogenizing stress or strain in the preset characteristic

With the lattice element method, it is required to introduce a length via, for example, a non-local approach in order to satisfy the objectivity of the mechanical response. In spite of this, the mesoscale structuring of inclusions within a matrix conveys the natural origin of the internal length for a fixed mesh. In other words, internal length is not explicitly provided to the model, but rather governed

In this study, the relationship between the computed tomography (CT) number and the density of frozen soil was established on a macro and mesoscopic scale, aimed at overcoming the shortcomings of the mesoscopic damage behavior predicted by previous macroscopic research on frozen soil. In addition, considering the influence of stress level and temperature, a mesoscopic structural damage variable was

In previous study the failure initiation and development in hybrid fiber laminates was successfully monitored and determined. In current investigation a novel damage monitoring approach is proposed for hybrid laminates by combining different optical strain measurement techniques namely digital image correlation (DIC), fiber Bragg grating sensors (FBG) and infrared thermography (IRT) with smoothing

To predict fatigue life more accurately, we consider the relationship between static toughness and fatigue toughness in fatigue failure process, the numerical model of total dissipated plastic strain energy (TDPSE) and fatigue life is established. And considering the effect of surface roughness and surface processing coefficient on fatigue life, the life prediction method of TDPSE is modified. In addition

A comprehensive finite element analysis at the mesoscopic level has been conducted into the complex topic of size effect coupling dynamic strain-rates. Taking the lightweight aggregate concrete (LWAC) dumbbell-shaped samples as the object of numerical investigation, the influence of strain-rate (with the range of 10−5/s ∼ 100/s) on direct-tensile failure of LWAC (including different lightweight aggregate

An extensive experimental campaign was run to investigate the influence of the loading direction, stress state (triaxiality ratio ranging from −0.5 to 1), and strain rate (from 10−3 to 1.5x103s−1) on the ductile fracture of Ti-6Al-4V titanium alloy. Microscopic and macroscopic observations provided some insight into the shear-driven or micro-voiding-controlled damage mechanisms prevailing at low and

In this study, an effective numerical framework for fracture simulations is proposed using the edge-based smoothed finite element method (ES-FEM) and isotropic damage model. The duality between the Delaunay triangulation and Voronoi tessellation is utilized for the mesh construction and the compatible use of the finite element solution with the Voronoi-cell lattice geometry. The mesh irregularity is

This paper presents a comprehensive analysis of the mesh-dependency issue for both plain concrete and reinforced concrete (RC) members under uniaxial loading. The detailed mechanisms for each case are firstly derived, and the analytical and numerical strain energies for concrete in different cases are compared to explain the phenomena of mesh-dependency. It is found that the mesh-dependency will be

Accurate prediction of stiffness degradation in the damaged plies (laminae) is a fundamental requirement for developing damage models for composite materials. In this study, a mesoscale analysis is proposed to predict all the effective thermo-elastic constants of damaged plies containing ply cracks and delaminations based on a numerical homogenization method. To do so, the in-plane and out-of-plane

A new progressive damage model for the three-dimensional (3 D) woven carbon/carbon (C/C) composites is developed at fiber-matrix level using the micromechanics method. A woven architecture based Representative Volume Element (RVE) model composed of yarns, matrix and yarn/matrix interface is constructed, in which the manufacturing void defects are accounted for. The fiber-matrix concentric cylinder

Rocksalt and mudstone are usually under common stress in salt storage caverns, resulting in different mechanical properties from pure rocksalt and mudstone. To accurately obtain the creep mechanical characteristics of rocksalt-mudstone combined body, we have made three different combinations. The long-term creep experiment of bedded rocks can more closely reflect the long-term mechanical behavior of

Failure mechanism of complex profile component is always different from that of conventional plate counterpart due to the coupling effect of material and structure. In this work, the low-velocity impact (LVI) and compression after impact (CAI) behaviors of Ω-shape hybrid carbon/Kevlar 3 D orthogonal woven (3DOW) composite made for vehicle B-pillar were comprehensively studied by mechanical tests and

Effective numerical analysis is significant for the optimal design and reliability evaluation of MEMS, but the complexity of multi-physical field couplings and irreversible damage accumulation in long-term performance make the analysis difficult. In the present paper, the continuum damage mechanics method is used to develop a creep damage model and conduct long-term performance analysis for MEMS thermal

A novel synergistic multi-scale modeling framework with a coupling of micro- and meso-scale is proposed to predict damage behaviors of 2D-triaxially braided composite (2DTBC). Based on the Bridge model, the internal stress and micro damage of constituent materials are respectively coupled with the stress and damage of tow. The initial effective elastic properties of tow (IEEP) used as the predefined

A comprehensive strain-rate-dependent (SRD) finite element modeling procedure, based on continuum damage mechanics has been developed to predict the behavior of ultra-high molecular weight polyethylene (UHMWPE) fiber composite laminates under impact loading. A user-defined material subroutine implemented into ABAQUS/Explicit is used to define SRD constitutive damage model of UHMWPE composite. The effect