A finite element unit-cell method for homogenised mechanical properties of heterogeneous plates

2014 ◽  
Vol 61 ◽  
pp. 23-32 ◽  
Author(s):  
A. Schmitz ◽  
P. Horst
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Unit Cell ◽  
Cell Method

scholarly journals WANG TILES LOCAL TILINGS CREATED BY MERGING EDGE-COMPATIBLE FINITE ELEMENT MESHES

2017 ◽  
Vol 13 ◽  
pp. 161
Author(s):  
Lukáš Zrůbek ◽  
Anna Kučerová ◽  
Martin Doškář
Keyword(s):  
Finite Element ◽  
Mechanical Response ◽  
Unit Cell ◽  
Cell Method ◽  
Mechanical Field ◽  
Wang Tiles ◽  
Small Set ◽  
Finite Element Meshes ◽  
Heterogeneous Microstructures ◽  
Periodic Unit Cell

In this contribution, we present the concept of Wang Tiles as a surrogate of the periodic unit cell method (PUC) for modelling of materials with heterogeneous microstructures and for synthesis of micro-mechanical fields. The concept is based on a set of specifically designed cells that compresses the stochastic microstructure into a small set of statistical volume elements – tiles. Tiles are placed side by side according to matching edges like in a game of domino. Opposite to the repeating pattern of PUC the Wang Tiles method with the stochastic tiling algorithm preserves the randomness for reconstructed microstructures. The same process is applied to obtain the micro-mechanical response of domains where the evaluation as one piece would be time consuming. Therefore the micro-mechanical quantities are evaluated only on tiles (with surrounding layers of tiles of each addressed tile included into the evaluation) and then synthesized to the micro-mechanical field of whole domain.

Mechanical Properties of Open-Cell Cellular Structures With Rhombic Dodecahedron Cells

2010 ◽  
Author(s):  
Sahab Babaee ◽  
Babak Haghpanah Jahromi ◽  
Amin Ajdari ◽  
Hamid Nayeb-Hashemi ◽  
Ashkan Vaziri
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Single Unit ◽  
Cellular Structure ◽  
Three Dimensional ◽  
Small Deformation ◽  
Unit Cell ◽  
Analytical Models ◽  
Open Cell ◽  
Principal Directions

We present a series of analytical models and finite element results (FE) for special 3-D open cellular foam to determine the effective material properties of a 3D rhombic dedecahedron open-cell cellular structure. The analytical approach is based on minimizing the total energy associated with small deformation of a single unit cell of the cellular structure. The finite element models were developed for both a single unit cell and three dimensional foam structure and used to obtain the mechanical properties in all three principal directions.

scholarly journals Multiscale simulation of fullerene reinforced composite structures: From molecular dynamics to finite element continuum mechanics

2018 ◽  
Vol 188 ◽  
pp. 01013
Author(s):  
Georgios I. Giannopoulos ◽  
Stylianos K. Georgantzinos ◽  
Androniki S. Tsiamaki ◽  
Nick K. Anifantis
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Finite Element ◽  
Finite Elements ◽  
Continuum Mechanics ◽  
Mechanical Behaviour ◽  
Composite Structures ◽  
Multiscale Simulation ◽  
Unit Cell ◽  
Solid Finite Elements

The aim of the present study is to propose a multiscale computational technique for the prediction of the elastic mechanical properties of nanoreinforced composites. The proposed method utilizes a molecular dynamics (MD) based numerical scheme to capture the mechanical behaviour of the nanocomposite at nanoscale and then a classical continuum mechanics (CM) analysis based on the finite element method (FEM) to characterise the microscopic performance of the nanofilled composite material. The material under investigation is polyamide 12 (PA 12) randomly reinforced with fullerenes C60. At the first stage of the analysis, in order to capture the atomistic interfacial effects between C60 and PA 12, a very small cubic unit cell containing a C60 molecule, centrally positioned and surrounded by PA 12 molecular chains, is simulated via MD. Inter- and intra-molecular atomic interactions are described by using the Condensed Phase Optimized Molecular Potential for Atomistic Simulation Studies (COMPASS). According to the elastic properties data arisen by the MD simulations, an equivalent finite element volume with the same size as the unit cell is developed. At the second stage, a CM micromechanical representative volume element (RVE) of the C60 reinforced PA 12 is developed via FEM. The matrix phase of the RVE is discretised by using solid finite elements which represent the PA 12 mechanical behaviour while each C60 location is meshed with equivalent solid finite elements. Several multiscale simulations are performed to study the effect of the nanofiller volume fraction on the mechanical properties of the C60 reinforced PA 12 composite. Comparisons with other corresponding experimental results are attempted, where possible, to test the performance of the proposed method.

Mechanical Properties of Carbon Nanotubes

2002 ◽  
Author(s):  
Xuekun Sun ◽  
Youqi Wang
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Finite Element ◽  
Cell Isolation ◽  
Unit Cell ◽  
Poisson's Ratio ◽  
Finite Element Approach ◽  
Nano Scale ◽  
Element Approach ◽  
Longitudinal Modulus

Nano-scale finite element approach was used to predict the mechanical properties of carbon nanotubes. The unit-cell isolation scheme was same as that from Eric Seather [1], and nothing was assumed to exist inside any nanotube. Arm-chair, zigzag and chiral type of nanotubes with different radii were discussed in detail. The longitudinal modulus of nanotubes Ez was found to decrease with increasing nanotube radius, but to be independent of nanotube helicity. The modulus was not over 0.5 TPa for any case. Meanwhile, Poisson’s ratio νzθ was also predicted.

scholarly journals Symmetric Nature of Stress Distribution in the Elastic-Plastic Range of Pinus L. Pine Wood Samples Determined Experimentally and Using the Finite Element Method (FEM)

Symmetry ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 39
Author(s):  
Łukasz Warguła ◽  
Dominik Wojtkowiak ◽  
Mateusz Kukla ◽  
Krzysztof Talaśka
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Stress Distribution ◽  
Moisture Content ◽  
Tool Geometry ◽  
Wood Fibers ◽  
Data Set ◽  
Plastic Deformations ◽  
Pine Wood ◽  
Elastic Plastic

This article presents the results of experimental research on the mechanical properties of pine wood (Pinus L. Sp. Pl. 1000. 1753). In the course of the research process, stress-strain curves were determined for cases of tensile, compression and shear of standardized shapes samples. The collected data set was used to determine several material constants such as: modulus of elasticity, shear modulus or yield point. The aim of the research was to determine the material properties necessary to develop the model used in the finite element analysis (FEM), which demonstrates the symmetrical nature of the stress distribution in the sample. This model will be used to analyze the process of grinding wood base materials in terms of the peak cutting force estimation and the tool geometry influence determination. The main purpose of the developed model will be to determine the maximum stress value necessary to estimate the destructive force for the tested wood sample. The tests were carried out for timber of around 8.74% and 19.9% moisture content (MC). Significant differences were found between the mechanical properties of wood depending on moisture content and the direction of the applied force depending on the arrangement of wood fibers. Unlike other studies in the literature, this one relates to all three stress states (tensile, compression and shear) in all significant directions (anatomical). To verify the usability of the determined mechanical parameters of wood, all three strength tests (tensile, compression and shear) were mapped in the FEM analysis. The accuracy of the model in determining the maximum destructive force of the material is equal to the average 8% (for tensile testing 14%, compression 2.5%, shear 6.5%), while the average coverage of the FEM characteristic with the results of the strength test in the field of elastic-plastic deformations with the adopted ±15% error overlap on average by about 77%. The analyses were performed in the ABAQUS/Standard 2020 program in the field of elastic-plastic deformations. Research with the use of numerical models after extension with a damage model will enable the design of energy-saving and durable grinding machines.

scholarly journals Thermo-Viscoelastic Response of 3D Braided Composites Based on a Novel FsMsFE Method

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 271
Author(s):  
Jun-Jun Zhai ◽  
Xiang-Xia Kong ◽  
Lu-Chen Wang
Keyword(s):  
Finite Element ◽  
Cell Model ◽  
Structural Parameters ◽  
Thermal Relaxation ◽  
Viscoelastic Behavior ◽  
Unit Cell ◽  
Time Dependent ◽  
3D Braided Composites ◽  
Equivalent Time ◽  
Representative Unit Cell

A homogenization-based five-step multi-scale finite element (FsMsFE) simulation framework is developed to describe the time-temperature-dependent viscoelastic behavior of 3D braided four-directional composites. The current analysis was performed via three-scale finite element models, the fiber/matrix (microscopic) representative unit cell (RUC) model, the yarn/matrix (mesoscopic) representative unit cell model, and the macroscopic solid model with homogeneous property. Coupling the time-temperature equivalence principle, multi-phase finite element approach, Laplace transformation and Prony series fitting technology, the character of the stress relaxation behaviors at three scales subject to variation in temperature is investigated, and the equivalent time-dependent thermal expansion coefficients (TTEC), the equivalent time-dependent thermal relaxation modulus (TTRM) under micro-scale and meso-scale were predicted. Furthermore, the impacts of temperature, structural parameters and relaxation time on the time-dependent thermo-viscoelastic properties of 3D braided four-directional composites were studied.

scholarly journals Characterization of Mechanical Heterogeneity in Dissimilar Metal Welded Joints

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4145
Author(s):  
He Xue ◽  
Zheng Wang ◽  
Shuai Wang ◽  
Jinxuan He ◽  
Hongliang Yang
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Welded Joints ◽  
Structural Integrity ◽  
Material Interfaces ◽  
Mechanical Heterogeneity ◽  
Finite Element Software ◽  
Dissimilar Metal ◽  
Stress Changes

Dissimilar metal welded joints (DMWJs) possess significant localized mechanical heterogeneity. Using finite element software ABAQUS with the User-defined Material (UMAT) subroutine, this study proposed a constitutive equation that may be used to express the heterogeneous mechanical properties of the heat-affected and fusion zones at the interfaces in DMWJs. By eliminating sudden stress changes at the material interfaces, the proposed approach provides a more realistic and accurate characterization of the mechanical heterogeneity in the local regions of DMWJs than existing methods. As such, the proposed approach enables the structural integrity of DMWJs to be analyzed in greater detail.

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