scholarly journals Mindlin second-gradient elastic properties from dilute two-phase Cauchy-elastic composites Part II: Higher-order constitutive properties and application cases

2013 ◽  
Vol 50 (24) ◽  
pp. 4020-4029 ◽  
Author(s):  
M. Bacca ◽  
D. Bigoni ◽  
F. Dal Corso ◽  
D. Veber
Keyword(s):  
Elastic Properties ◽  
Higher Order ◽  
Two Phase ◽  
Second Gradient ◽  
Constitutive Properties ◽  
Elastic Composites

Novel Formulations for Higher-Order Bounds on Effective Transverse Elastic Moduli of Three-Phase Cylindrical Fiber Reinforced Composites

2012 ◽  
Author(s):  
Yu-Fu Ko ◽  
J. W. Ju
Keyword(s):  
Elastic Properties ◽  
Elastic Moduli ◽  
Homogenization Method ◽  
Higher Order ◽  
Two Phase ◽  
Special Event ◽  
Three Phase ◽  
Cylindrical Fiber ◽  
Theoretical Predictions ◽  
Order Bounds

A higher-order multiscale structure for three-phase composites containing randomly located yet unidirectionally aligned circular fibers is proposed to predict effective transverse elastic moduli based on the probabilistic spatial distribution of circular fibers, the pairwise fiber interactions, and the ensemble-area multi-level homogenization method. Specifically, the two inhomogeneity phases feature distinct elastic properties and sizes. In the special event, two-phase composites with same elastic properties and sizes of fibers are studied. Two non-equivalent micromechanical formulations are considered to derive effective transverse elastic moduli of two-phase composites leading to new higher-order bounds. Furthermore, the effective transverse elastic moduli for an incompressible matrix containing randomly located and identical circular rigid fibers and voids are derived. It is demonstrated that significant improvements in the singular problems and accuracy are achieved by the proposed methodology. Numerical examples and comparisons among our theoretical predictions, available experimental data, and other analytical predictions are rendered to illustrate the potential of the present method.

Micromechanical analysis of effective mechanical properties of graphene/ZrO2-hybrid poly (methyl methacrylate) nanocomposites

2021 ◽  
pp. 251659842110388
Author(s):  
Ankit Rathi ◽  
S. I. Kundalwal
Keyword(s):  
Methyl Methacrylate ◽  
Elastic Properties ◽  
Mechanical Performance ◽  
Volume Fraction ◽  
Element Model ◽  
Two Phase ◽  
Effective Elastic Properties ◽  
Poly Methyl Methacrylate ◽  
Three Phase ◽  
Effective Mechanical Properties

In this study, the tensile properties of two-phase and three-phase graphene/ZrO2-hybrid poly (methyl methacrylate) (PMMA) nanocomposites are investigated by developing finite element model using ANSYS. Primarily, the effective elastic properties of two- and three-phase graphene/ZrO2-hybrid PMMA nanocomposites (GRPCs) are estimated by developing mechanics of material (MOM) model. Results indicated that the effective elastic properties of GRPCs increase with an increase in the volume fraction of graphene. Also, the stiffness of GRPCs is increased by 78.12% with increasing in the volume fraction of graphene from 0.1 to 0.5 Vf. The incorporation of an additional ZrO2 interphase significantly improved the mechanical performance of resulting GRPCs.

FROUDE’S LAW OF SIMILITUDE – CONTEMPORARY AND FUTURE SEAKEEPING TESTING

2021 ◽  
Vol 153 (A2) ◽  
Author(s):  
R P Dallinga ◽  
R H M Huijsmans
Keyword(s):  
Model Test ◽  
Scale Effects ◽  
Higher Order ◽  
Air Pressure ◽  
Test Results ◽  
Viscous Effects ◽  
Two Phase ◽  
Scale Models ◽  
Non Linear

Historically “scale effects” in the interpretation of tests with scale models in waves using Froude’s Law of Similitude are mostly associated with viscous effects. Nowadays, with a much more complete modelling of reality and a focus on higher order non-linear phenomena, scaling of model test results implies a wider range of assumptions than the validity of Froude’s Law. Our contribution to the conference is a visionary review of contemporary and future problems in the interpretation of these tests. In this context we will discuss the developments in test techniques, including the development of a new Two-Phase Laboratory facilitating seakeeping and sloshing tests at reduced air pressure.

scholarly journals Second gradient substitution model for high contrast bi-phase structure

2020 ◽  
Vol 14 (2) ◽  
pp. 116-126
Author(s):  
Trinh Duy Khanh
Keyword(s):  
Phase Structure ◽  
Homogeneous Model ◽  
Homogeneous Boundary Condition ◽  
Higher Order ◽  
Material Behavior ◽  
Equivalent Model ◽  
Potential Candidate ◽  
Substitution Model ◽  
Second Gradient ◽  
Soft Inclusion

Lightweight structures with soft inclusion material, such as hollow core slabs, foam sandwich wall, pervious pavement ... are widely used in construction engineering for sustainable goals. Voids and soft inclusion can be modeled as a very soft material, while the main material is modeled with its original rigidity, which is so much higher than inclusion's one. In consequence, highly contrast bi-phase structure attracts the interests of scientists and engineers. One important demand is how to build a homogeneous equivalent model to replace the multi-phase structure which requires much resources and time to perform structure analysis. Various homogenization schemes have succeeded in establishing a homogeneous substitution model for composite materials which fulfill the scale separation condition (characteristic length of heterogeneity is very small in comparison to structure dimensions). Herein, elastic stiffness matrix of a homogeneous model which replaces a bi-phase material is computed by a higher-order homogenization scheme. A non-homogeneous boundary condition (a polynomial inspired from Taylor series expansion) is used in computation. Homogeneous substitution model constructed from this computation process, can give engineers a fast and effective tool to predict the behavior of bi-phase structure. Instead of a classical Cauchy continuum, second gradient model is selected as a potential candidate for substituting the composite material behavior because of the separation scale (volume ratio of inclusion to matrix phase reaches unit). Keywords: generalized continuum; second-gradient medium; higher-order homogenization; non-homogeneous boundary conditions; representative volume element.

Effective Elastic Properties of 3D Composites with Short Curvilinear Fibers: Numerical Simulation and Experimental Validation

2016 ◽  
Vol 258 ◽  
pp. 452-455 ◽  
Author(s):  
Victor V. Mykhas'kiv ◽  
Bohdan M. Stasyuk
Keyword(s):  
Elastic Properties ◽  
Effective Strain ◽  
Matrix Material ◽  
Theoretical Aspect ◽  
Concrete Specimen ◽  
Field Approximation ◽  
Two Phase ◽  
Fiber Fractions ◽  
Cylindrical Steel ◽  
Curvilinear Fibers

Theoretical and experimental estimation of elastic properties of two-phase composites containing matrix material and arc-shaped cylindrical fibers is given. Theoretical aspect consists in hybrid micro-macro formulation of problem with consideration of two associated subproblems –nume­rical simulation of fiber influence on the representative volume element and effective strain-stress field approximation by the averaging procedures. Boundary element method is applied for the solution of micro-level subproblem as well as Mori-Tanaka model is adopted for the overall description of composite properties at the macro-level. Then interfacial displacements are involved into solution scheme only. The effective elastic moduli of arc-fiber-reinforced composites are analyzed for the different materials combinations and fiber fractions. For the validation of numerical results, the prismatic concrete specimen filled by the curvilinear shaped cylindrical steel fibers under compression is investigated experimentally. Comparison of theoretical and experimental data is made.

Higher-Order Multipolar Effects on Elastic Properties of PrNi5

2004 ◽  
Vol 73 (6) ◽  
pp. 1514-1518 ◽  
Author(s):  
Tomoo Udagawa ◽  
Susumu Hashio ◽  
Kengo Morita ◽  
Osamu Suzuki ◽  
Akira Tamaki ◽  
...  
Keyword(s):  
Elastic Properties ◽  
Higher Order

scholarly journals Elasticity of Phases in Fe-Al-Ti Superalloys: Impact of Atomic Order and Anti-Phase Boundaries

Crystals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 299 ◽  
Author(s):  
Martin Friák ◽  
Vilma Buršíková ◽  
Naděžda Pizúrová ◽  
Jana Pavlů ◽  
Yvonna Jirásková ◽  
...  
Keyword(s):  
Solid Solution ◽  
Chemical Composition ◽  
Elastic Properties ◽  
Formation Energy ◽  
Chemical Species ◽  
Two Phase ◽  
Nano Structure ◽  
The Matrix ◽  
Free Material ◽  
Excess Fe

We combine theoretical and experimental tools to study elastic properties of Fe-Al-Ti superalloys. Focusing on samples with chemical composition Fe71Al22Ti7, we use transmission electron microscopy (TEM) to detect their two-phase superalloy nano-structure (consisting of cuboids embedded into a matrix). The chemical composition of both phases, Fe66.2Al23.3Ti10.5 for cuboids and Fe81Al19 (with about 1% or less of Ti) for the matrix, was determined from an Energy-Dispersive X-ray Spectroscopy (EDS) analysis. The phase of cuboids is found to be a rather strongly off-stoichiometric (Fe-rich and Ti-poor) variant of Heusler Fe2TiAl intermetallic compound with the L21 structure. The phase of the matrix is a solid solution of Al atoms in a ferromagnetic body-centered cubic (bcc) Fe. Quantum-mechanical calculations were employed to obtain an insight into elastic properties of the two phases. Three distributions of chemical species were simulated for the phase of cuboids (A2, B2 and L21) in order to determine a sublattice preference of the excess Fe atoms. The lowest formation energy was obtained when the excess Fe atoms form a solid solution with the Ti atoms at the Ti-sublattice within the Heusler L21 phase (L21 variant). Similarly, three configurations of Al atoms in the phase of the matrix with different level of order (A2, B2 and D03) were simulated. The computed formation energy is the lowest when all the 1st and 2nd nearest-neighbor Al-Al pairs are eliminated (the D03 variant). Next, the elastic tensors of all phases were calculated. The maximum Young’s modulus is found to increase with increasing chemical order. Further we simulated an anti-phase boundary (APB) in the L21 phase of cuboids and observed an elastic softening (as another effect of the APB, we also predict a significant increase of the total magnetic moment by 140% when compared with the APB-free material). Finally, to validate these predicted trends, a nano-scale dynamical mechanical analysis (nanoDMA) was used to probe elasticity of phases. Consistent with the prediction, the cuboids were found stiffer.

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