A Nonlinear Transformation Field Procedure for Periodic Masonry Based on an Equivalent Cosserat Medium

2010 ◽  
Vol 89-91 ◽  
pp. 6-11
Author(s):  
E. Sacco ◽  
Daniela Addessi ◽  
Achille Paolone
Keyword(s):  
Constitutive Law ◽  
Constitutive Relationship ◽  
Field Analysis ◽  
Homogenization Procedure ◽  
Linear Elastic ◽  
Cosserat Medium ◽  
Masonry Material ◽  
Transformation Field Analysis ◽  
Cauchy Model

The paper deals with the problem of the determination of the in-plane behavior of periodic masonry material. The masonry is considered as a composite material obtained as a regular distribution of blocks connected by horizontal and vertical mortar joints. The macromechanical equivalent Cosserat medium is derived by a rational homogenization procedure based on the Transformation Field Analysis. The micromechanical analysis is developed considering a Cauchy model for the masonry components. In particular, linear elastic constitutive relationship is considered for the blocks, while nonlinear constitutive law is adopted for the mortar joints, accounting for the damage and friction phenomena occurring during the loading history. Numerical applications are performed in order to assess the performances of the proposed procedure in reproducing the mechanical behavior of the masonry material.

scholarly journals Elastic and inelastic local strain fields in composites with coated fibers or particles: theory and validation

2019 ◽  
Vol 24 (9) ◽  
pp. 2858-2894 ◽  
Author(s):  
George Chatzigeorgiou ◽  
Fodil Meraghni
Keyword(s):  
Coating Layer ◽  
Mean Field ◽  
Local Strain ◽  
Constitutive Law ◽  
Field Analysis ◽  
Spherical Particles ◽  
Composite Cylinder ◽  
Composite Sphere ◽  
Transformation Field Analysis ◽  
Cylinder Method

This paper deals with mean field multiscale approaches for coated fiber- or particle-reinforced composites under nonlinear strain. The current work attempts to extend Dvorak’s well-known transformation field analysis for mean field approaches, in which the composite’s constitutive law is split into an elastic and an inelastic part. The classical Eshelby’s inhomogeneity problem considering eigenstrains is revisited in order to address the presence of a coating layer. For this scope, three different methodologies are employed, one for general ellipsoidal inhomogeneities, a modified composite cylinder method for long cylindrical fibers and a modified composite sphere method for spherical particles. After identifying proper interaction tensors for the inhomogeneity and its coating layer, the composite’s overall response is evaluated by extending classical mean field techniques, such as the Mori–Tanaka and the self-consistent methods. Numerical examples illustrate the differences in macroscopic and microscopic predictions between the general approach and the modified composite cylinder and sphere Assemblages.

scholarly journals Determination of Transverse Shear Stiffness of Sandwich Panels with a Corrugated Core by Numerical Homogenization

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1976
Author(s):  
Tomasz Garbowski ◽  
Tomasz Gajewski
Keyword(s):  
Transverse Shear ◽  
Shear Stiffness ◽  
The Finite Element Method ◽  
Homogenization Procedure ◽  
Plate Structures ◽  
Corrugated Board ◽  
Energy Equivalence ◽  
The Stability ◽  
Global Stiffness Matrix

Knowing the material properties of individual layers of the corrugated plate structures and the geometry of its cross-section, the effective material parameters of the equivalent plate can be calculated. This can be problematic, especially if the transverse shear stiffness is also necessary for the correct description of the equivalent plate performance. In this work, the method proposed by Biancolini is extended to include the possibility of determining, apart from the tensile and flexural stiffnesses, also the transverse shear stiffness of the homogenized corrugated board. The method is based on the strain energy equivalence between the full numerical 3D model of the corrugated board and its Reissner-Mindlin flat plate representation. Shell finite elements were used in this study to accurately reflect the geometry of the corrugated board. In the method presented here, the finite element method is only used to compose the initial global stiffness matrix, which is then condensed and directly used in the homogenization procedure. The stability of the proposed method was tested for different variants of the selected representative volume elements. The obtained results are consistent with other technique already presented in the literature.

scholarly journals Determination of macro-scale soil properties from pore-scale structures: model derivation

2018 ◽  
Vol 474 (2209) ◽  
pp. 20170141 ◽  
Author(s):  
K. R. Daly ◽  
T. Roose
Keyword(s):  
Pore Space ◽  
Solid Particles ◽  
Underlying Structure ◽  
Pore Scale ◽  
Homogenization Procedure ◽  
Macro Scale ◽  
Model Derivation ◽  
Scale Structures ◽  
Homogenization Scheme

In this paper, we use homogenization to derive a set of macro-scale poro-elastic equations for soils composed of rigid solid particles, air-filled pore space and a poro-elastic mixed phase. We consider the derivation in the limit of large deformation and show that by solving representative problems on the micro-scale we can parametrize the macro-scale equations. To validate the homogenization procedure, we compare the predictions of the homogenized equations with those of the full equations for a range of different geometries and material properties. We show that the results differ by ≲ 2 % for all cases considered. The success of the homogenization scheme means that it can be used to determine the macro-scale poro-elastic properties of soils from the underlying structure. Hence, it will prove a valuable tool in both characterization and optimization.

Field analysis Cr(VI) in water samples by a smartphone-based ultralong absorption path reflection colorimetric device

2021 ◽  
Author(s):  
Xiaolan Chen ◽  
Cheng Ma ◽  
Qi Kang ◽  
Yu-Qin Chen ◽  
Dazhong Shen
Keyword(s):  
Hexavalent Chromium ◽  
Water Samples ◽  
Environmental Samples ◽  
Field Analysis ◽  
Absorption Path

Hexavalent chromium is highly toxic and regarded as one of the main pollutants in environmental samples. Sophisticated laboratory instruments are commercially available for in-field determination of chromium. It is highly...

scholarly journals Some indicators of water quality of the Tamis river

2011 ◽  
Vol 17 (1) ◽  
pp. 107-115 ◽  
Author(s):  
Nada Babovic ◽  
Dejan Markovic ◽  
Vojkan Dimitrijevic ◽  
Dragan Markovic
Keyword(s):  
Water Quality ◽  
Ph Value ◽  
Ammonium Nitrogen ◽  
Field Analysis ◽  
Total Hardness ◽  
Chemical Parameters ◽  
Physico Chemical

This paper shows the results obtained in field analysis performed at the Tamis River, starting from the settlement Jasa Tomic - border between Serbia and Romania to Pancevo - confluence of Tamis into the Danube. The Tamis is a 359 km long river rising in the southern Carpathian Mountains. It flows through the Banat region and flows into the Danube near Pancevo. During the years the water quality of the river has severely deteriorated and badly affected the environment and the river ecosystem. In situ measurements enabled determination of physico-chemical parameters of water quality of the Tamis River on every 400 m of the watercourse, such as: water temperature, pH value, electrical conductivity, contents of dissolved oxygen and oxygen saturation. The main reason of higher pollution of Tamis is seen in connection to DTD hydro system. Sampling was performed at 7 points with regard to color, turbidity, total hardness, alkalinity, concentration of ammonium nitrogen, nitrite nitrogen, nitrate nitrogen, iron, chlorides and sulphates in samples. The aim of the present work was to evaluate water quality in the Tamis River taking into account significant pollution, which originates from settlements, industry and agriculture, and to suggest appropriate preventive measures to further pollution decreasing of the river's water.

On the Nonlinear Viscoelastic Behaviour of the PVC-Coated Fabric

2010 ◽  
Vol 160-162 ◽  
pp. 1476-1481 ◽  
Author(s):  
Wu Lian Zhang ◽  
Xin Ding ◽  
Xu Dong Yang
Keyword(s):  
Viscoelastic Model ◽  
Constitutive Relationship ◽  
Viscoelastic Behaviour ◽  
Viscoelastic Response ◽  
Nonlinear Parameters ◽  
Creep And Recovery ◽  
Nonlinear Viscoelastic ◽  
Coated Fabric ◽  
Nonlinear Viscoelastic Model

The nonlinear viscoelastic response of a PVC-Coated Fabric has been studied. For the needs of the present study, creep and recovery tests in tension of both the warp and the weft directions at the different stress levels were executed while measurements were made of the creep and recovery strain response of the system. For the description of the viscoelastic behaviour of the material, Schapery’s nonlinear viscoelastic model was used. For the description of the nonlinear viscoelastic response and the determination of the nonlinear parameters, a method by using a combination of analytical formulations and numerical procedures based on a modified version of Schapery’s constitutive relationship where an instantaneous plastic and a transient plastic terms were added, has been developed. The method has been successfully applied to the current tests.

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