Search results for "Boundary element method."

showing 10 items of 158 documents

Modelling intergranular and transgranular micro-cracking in polycrystalline materials

2018

Abstract In this work, a grain boundary formulation for intergranular and transgranular micro-cracking in three-dimensional polycrystalline aggregates is presented. The formulation is based on the displacement and stress boundary integral equations of solid mechanics and it has the advantage of expressing the polycrystalline problem in terms of grain boundary variables only. The individual grains within the polycrystalline morphology are modelled as generally anisotropic linear elastic domains with random spatial orientation. Transgranular micro-cracking is assumed to occur along specific cleavage planes, whose orientation in space within the grains depend upon the crystallographic lattice.…

Materials scienceIntergranular crackingComputational MechanicsPolycrystalline materialsGeneral Physics and Astronomy02 engineering and technologyMathematical SciencesTransgranular crackingEngineeringPolycrystalline material0203 mechanical engineeringMicro-mechanicsBoundary element methodComposite materialAnisotropyBoundary element methodMechanical EngineeringCohesive zone modellingApplied MathematicsLinear elasticityMetallurgyMicromechanicsMicro-mechanicIntergranular corrosion021001 nanoscience & nanotechnologyComputer Science Applications020303 mechanical engineering & transportsMechanics of MaterialsSolid mechanicsGrain boundaryCrystallite0210 nano-technology
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Boundary Element Method for Composite Laminates

2017

The boundary element method (BEM) is a numerical technique to solve engineering/physical problems formulated in terms of boundary integral equations. Composite laminates are assemblages of stacked different materials layers, generally consisting of variously oriented fibrous composite materials

Materials scienceLaminate solution by BEMComposite laminatesComposite materialSettore ING-IND/04 - Costruzioni E Strutture AerospazialiBoundary element methodBoundary integral equations and solution for composite laminate
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Magneto-Electro-Elastic Bimorph Analysis by the Boundary Element Method

2008

The influence of the magnetic configuration on the behavior of magneto-electro-elastic bimorph beams is analyzed by using a boundary element approach. The problem is formulated by using the generalized displacements and generalized tractions. The boundary integral equation formulation is obtained by extending the reciprocity theorem to magneto-electro-elastic problems; it is numerically implemented by using the boundary element method multidomain technique to address problems involving nonhomogeneous configurations. Results under different magnetic configurations are compared highlighting the characteristic features of magnetopiezoelectric behavior particularly focusing on the link between …

Materials scienceMechanical EngineeringGeneral MathematicsMathematical analysisBimorphGeometrySingular boundary methodBoundary knot methodElectromagnetic inductionMechanics of MaterialsAnalytic element methodMethod of fundamental solutionsGeneral Materials ScienceSettore ING-IND/04 - Costruzioni E Strutture AerospazialiBoundary element methodMagnetomagneto-electro-elastic bimorph beams boundary element approach magnetopiezoelectric interlaminar stressesCivil and Structural Engineering
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A Grain-Scale Model of Inter-Granular Stress Corrosion Cracking in Polycrystals

2017

In this contribution, we propose a cohesive grain-boundary model for hydrogen-assisted inter-granular stress corrosion cracking at the grain-scale in 3D polycrystalline aggregates. The inter-granular strength is degraded by the presence of hydrogen and this is accounted for by employing traction-separation laws directly depending on hydrogen concentration, whose diffusion is represented at this stage through simplified phenomenological relationships. The main feature of the model is that all the relevant mechanical fields are represented in terms of grain-boundary variables only, which couples particularly well with the employment of traction-separation laws.

Materials scienceMechanical EngineeringMetallurgyMicromechanicsStress corrosion cracking02 engineering and technology01 natural sciencesStrength of materials010101 applied mathematics020303 mechanical engineering & transportsPolycrystalline material0203 mechanical engineeringMechanics of MaterialsBoundary element methodMechanics of MaterialGeneral Materials ScienceMaterials Science (all)0101 mathematicsStress corrosion crackingComposite materialCohesive zone modelingMicromechanicScale modelBoundary element methodEnvironmental stress fractureKey Engineering Materials
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A microstructural model for homogenisation and cracking of piezoelectric polycrystals

2019

Abstract An original three-dimensional generalised micro-electro-mechanical model for computational homogenisation and analysis of degradation and micro-cracking of piezoelectric polycrystalline materials is proposed in this study. The model is developed starting from a generalised electro-mechanical boundary integral representation of the micro-structural problem for the individual bulk grains and a generalised cohesive formulation is employed for studying intergranular micro-damage initiation and evolution into intergranular micro-cracks. To capture the electro-mechanical coupling at the evolving damaging intergranular interfaces, standard mechanical cohesive laws are enriched with suitab…

Materials scienceMechanical EngineeringNumerical analysisComputational MechanicsGeneral Physics and AstronomyBoundary (topology)010103 numerical & computational mathematicsMechanicsMicro-mechanicDegrees of freedom (mechanics)Intergranular corrosionPiezoelectric material01 natural sciencesComputer Science ApplicationsMicro-cracking010101 applied mathematicsPolycrystalline materialMechanics of MaterialsBoundary element methodGrain boundaryCrystalliteBoundary value problem0101 mathematicsComputational homogenisationReduction (mathematics)
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Grain-boundary modelling of hydrogen assisted intergranular stress corrosion cracking

2018

Abstract A novel hybrid strategy for modelling intergranular hydrogen embrittlement in polycrystalline microstructures is proposed. The technique is based on a grain-boundary integral representation of the polycrystalline micro-mechanics, numerically solved by the boundary element method, coupled with an explicit finite element model of the intergranular hydrogen diffusion. The intergranular interaction between contiguous grains in the aggregate is modelled through extrinsic cohesive-frictional traction-separation laws, whose parameters depend on the concentration of intergranular hydrogen, which diffuses over the interface according to the Fick’s second law, inducing the weakening of the i…

Materials scienceMetallurgyMicromechanicsMicro-mechanicStress corrosion cracking02 engineering and technologyMechanicsIntergranular corrosion021001 nanoscience & nanotechnologyFinite element method020303 mechanical engineering & transportsPolycrystalline material0203 mechanical engineeringDiffusion processMechanics of MaterialsBoundary element methodGeneral Materials ScienceGrain boundaryDiffusion (business)0210 nano-technologyHydrogen embrittlementInstrumentationBoundary element methodHydrogen embrittlementMechanics of Materials
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Numerical analysis of a piezoelectric structural health monitoring system for composite flange-skin delamination detection

2013

Abstract In this paper, a piezoelectric based Structural Health Monitoring (SHM) system is proposed to detect skin/stiffener debonding and delamination cracks proper of laminated composite structures. The SHM system is analyzed by means of a boundary element code implemented in the framework of piezoelectricity. The multidomain technique, coupled with an interface spring model, is used to model laminated composite structures as well as the bonding between the host delaminated structure and the piezoelectric sensor. Static sensitivity analyses are firstly performed on a drop-ply delaminated structure in order to identify a suitable configuration for the sensor. Then, the dynamic electromecha…

Materials sciencePiezoelectric sensorbusiness.industryDelaminationComposite numberFracture mechanicsStructural engineeringFlangePiezoelectricityCeramics and CompositesStructural health monitoringComposite materialComposite flange-skin Piezoelectric sensor Structural health monitoring DelaminationSettore ING-IND/04 - Costruzioni E Strutture AerospazialibusinessBoundary element methodCivil and Structural EngineeringComposite Structures
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Dual boundary element model of 3D piezoelectric smart structures

2017

In this paper, the application of the dual boundary element method (DBEM) in the field of structural health monitoring (SHM) is explored. The model involves a 3D host structure, which is formulated by the DBEM in the Laplace domain, and 3D piezoelectric transducers, whose finite element model is derived from the electro-mechanical behaviour of piezoelectricity. The piezoelectric transducers and the host structure are coupled together via BEM variables. The practicability of this method in active sensing applications is demonstrated through comparisons with established FEM and parametric studies.

Materials scienceStructural health monitoringDual boundary element methodAcousticsMechanical Engineering02 engineering and technologyPiezoelectric transducer01 natural sciencesPiezoelectricityDual (category theory)010101 applied mathematics020303 mechanical engineering & transports0203 mechanical engineeringMechanics of MaterialsGeneral Materials ScienceMechanics of MaterialStructural health monitoringMaterials Science (all)0101 mathematicsBoundary element method
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A Multiscale Approach to Polycrystalline Materials Damage and Failure

2014

A two-scale three-dimensional approach for degradation and failure in polycrystalline materials is presented. The method involves the component level and the grain scale. The damage-induced softening at the macroscale is modelled employing an initial stress boundary element approach. The microscopic degradation is explicitly modelled associating Representative Volume Elements (RVEs) to relevant points of the macro continuum and employing a cohesive-frictional 3D grain-boundary formulation to simulate intergranular degradation and failure in the Voronoi morphology. Macro-strains are downscaled as RVEs' periodic boundary conditions, while overall macro-stresses are obtained upscaling the micr…

Materials sciencebusiness.industryMechanical EngineeringMicromechanicsStructural engineeringMechanicsMechanics of MaterialsMaterial DegradationPeriodic boundary conditionsGeneral Materials ScienceCrystalliteMacrobusinessVoronoi diagramBoundary element methodSofteningKey Engineering Materials
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Electroelastic Analysis of Piezoelectric Composite Laminates by Boundary Integral Equations

2004

A boundary integral representation for the electroelastic state in piezoelectric composite laminates subjected to axial extension, bending, torsion, shear/bending, and electric loadings is proposed. The governing equations are presented in terms of electromechanical generalized variables by the use of a suitable matrix notation. Thus, the three-dimensional electroelasticity solution for piezoelectric composite laminates is generated from a set of two partially coupled differential equations defined on the cross section of each individual ply within the laminate. These ply equations are linked through the interface conditions, which allow restoration of the model of the laminate as a whole. …

Materials sciencebusiness.industryNumerical analysisPiezoelectricityAerospace EngineeringTorsion (mechanics)Mechanical engineeringStructural engineeringFiber-reinforced compositeComposite laminatesPiezoelectricitylaminates boundary element methodMethod of characteristicsSettore ING-IND/04 - Costruzioni E Strutture AerospazialibusinessActuatorBoundary element methodAIAA Journal
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