A Multiscale Homogenization Approach for Architectured Knitted Textiles

2019 ◽  
Vol 86 (11) ◽  
Author(s):  
D. Liu ◽  
S. Koric ◽  
A. Kontsos
Keyword(s):  
Mechanical Behavior ◽  
Equivalent Stress ◽  
Kinetic Properties ◽  
Computationally Efficient ◽  
User Subroutine ◽  
Material Stiffness ◽  
Homogenization Approach ◽  
Homogenization Scheme ◽  
Architectured Material ◽  
Multiscale Homogenization

Abstract As a type of architectured material, knitted textiles exhibit global mechanical behavior which is affected by their microstructure defined at the scale at which yarns are arranged topologically given the type of textile manufactured. To relate local geometrical, interfacial, material, kinematic and kinetic properties to global mechanical behavior, a first-order, two-scale homogenization scheme was developed and applied in this investigation. In this approach, the equivalent stress at the far field and the consistent material stiffness are explicitly derived from the microstructure. In addition, the macrofield is linked to the microstructural properties by a user subroutine which can compute stresses and stiffness in a looped finite element (FE) code. This multiscale homogenization scheme is computationally efficient and capable of predicting the mechanical behavior at the macroscopic level while accounting directly for the deformation-induced evolution of the underlying microstructure.

Biomechanical Behavior of All-Ceramic Crowns with Variable Thicknesses of Zirconia Frameworks

2016 ◽  
Vol 835 ◽  
pp. 97-102
Author(s):  
Liliana Porojan ◽  
Florin Topală ◽  
Sorin Porojan
Keyword(s):  
Mechanical Behavior ◽  
Equivalent Stress ◽  
The Finite Element Method ◽  
Static Loads ◽  
Biomechanical Behavior ◽  
All Ceramic ◽  
Ceramic Crowns ◽  
Von Mises Equivalent Stress ◽  
Von Mises ◽  
Posterior Restorations

Zirconia is an extremely successful material for prosthetic restorations, offering attractive mechanical and optical properties. It offers several advantages for posterior restorations because it can withstand physiological posterior forces. The aim of the study was to achieve the influence of zirconia framework thickness on the mechanical behavior of all-ceramic crowns using numerical simulation. For the study a premolar was chosen in order to simulate the mechanical behavior in the components of all-ceramic crowns and teeth structures regarding to the zirconia framework thickness. Maximal Von Mises equivalent stress values were recorded in teeth and restorations. Due to the registered maximal stress values it can be concluded that it is indicated to achieve frameworks of at least 0.5 mm thickness in the premolar area. Regarding stress distribution concentration were observed in the veneer around the contact areas with the antagonists, in the framework under the functional cusp and in the oral part overall and in dentin around and under the marginal line, also oral. The biomechanical behavior of all ceramic crowns under static loads can be investigated by the finite element method.

A Multiscale Model of Composite Failure Under Impact

2006 ◽  
Author(s):  
Caglar Oskay ◽  
Jacob Fish
Keyword(s):  
Mesoscale Model ◽  
Computational Cost ◽  
Expansion Method ◽  
Multiple Scale ◽  
Multiscale Model ◽  
Field Analysis ◽  
Computationally Efficient ◽  
Composite Failure ◽  
Homogenization Approach ◽  
Transformation Field Analysis

We present a new computationally efficient mesoscale model aimed at predicting the dominant characteristics of failure at the microstructural level. This method combines the multiple scale asymptotic expansion method with the generalized transformation field analysis (GTFA) to reduce the computational cost of the direct homogenization approach. A computational validation methodology was devised for the validation of the proposed mesoscale model against experimental data. The proposed validation methodology permits incorporation of various types of experiments to the validation process by employing an experiment simulator repository.

scholarly journals A 3D trabecular bone homogenization technique

2020 ◽  
Vol 22 (3) ◽  
Author(s):  
Marco C. Marques ◽  
Jorge Belinha ◽  
António F. Oliveira ◽  
Maria Cristinha M. Cespedes ◽  
Renato M. Natal Jorge
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behavior ◽  
Trabecular Bone ◽  
Multiple Scales ◽  
Bone Adaptation ◽  
Computationally Efficient ◽  
Micro Scale ◽  
Special Cases ◽  
Homogeneous Models ◽  
Time Required

Purpose: Bone is a hierarchical material that can be characterized from the microscale to macroscale. Multiscale models make it possible to study bone remodeling, inducing bone adaptation by using information of bone multiple scales. This work proposes a computationally efficient homogenization methodology useful for multiscale analysis. This technique is capable to define the homogenized microscale mechanical properties of the trabecular bone highly heterogeneous medium. Methods: In this work, a morphology - based fabric tensor and a set of anisotropic phenomenological laws for bone tissue was used, in order to define the bone micro-scale mechanical properties. To validate the developed methodology, several examples were performed in order to analyze its numerical behavior. Thus, trabecular bone and fabricated benchmarks patches (representing special cases of trabecular bone morphologies) were analyzed under compression. Results: The results show that the developed technique is robust and capable to provide a consistent material homogenization, indicating that the homogeneous models were capable to accurately reproduce the micro-scale patch mechanical behavior. Conclusions: The developed method has shown to be robust, computationally less demanding and enabling the authors to obtain close results when comparing the heterogeneous models with equivalent homogenized models. Therefore, it is capable to accurately predict the micro-scale patch mechanical behavior in a fraction of the time required by classic homogenization techniques.

Finite Element Analysis of Tapped Thread Joints: Setup of a Computationally Efficient Modeling Approach

2019 ◽  
Author(s):  
Massimiliano De Agostinis ◽  
Dario Croccolo ◽  
Stefano Fini ◽  
Giorgio Olmi ◽  
Francesco Robusto ◽  
...  
Keyword(s):  
Equivalent Stress ◽  
Three Dimensional ◽  
Computational Effort ◽  
Simplified Model ◽  
Computationally Efficient ◽  
Dimensional Approach ◽  
Element Analysis ◽  
Threaded Connections ◽  
Threaded Joints ◽  
Actual Geometry

Abstract This contribution deals with the efficient numerical modeling of tapped thread joints. Commercial FE packages provide different strategies to tackle the problem of modeling threaded joints, which is a recurrent one for the design engineer. Different modeling techniques are characterised by how the screw is modeled: either three-dimensional elements (thetra, hexa or wedge) or mono-dimensional elements (beam) can be used. In the case of three-dimensional approaches, the thread helix is seldom modeled: the actual geometry is often replaced by a plain cylinder and a suitable choice of contact settings between the screw and the “threaded” hole. In the case of road vehicles, due to the high number of threaded connections to be modeled, it is paramount to reach a trade-off between modeling accuracy and computational effort. This paper aims at comparing two modeling approaches, namely a three dimensional approach (baseline) and a mono-dimensional one (simplified model). Based on several criteria, such as equivalent stress on the screw shank, pressure distribution at the interface of the plates and in the underhead region, optimal contact settings for the simplified model are suggested. These settings allow replicating the results provided by the three-dimensional approach for given load case. The comparison is carried out on single lap, single screw joints, by the ANSYS R17 software. The methodology can be easily extended to other softwares or joint configurations.

scholarly journals Elastic Constants Prediction of 3D Fiber-Reinforced Composites Using Multiscale Homogenization

Processes ◽  
2020 ◽  
Vol 8 (6) ◽  
pp. 722 ◽  
Author(s):  
S. Z. H. Shah ◽  
Puteri S. M. Megat Yusoff ◽  
Saravanan Karuppanan ◽  
Zubair Sajid
Keyword(s):  
Experimental Data ◽  
Numerical Methods ◽  
Elastic Constants ◽  
Good Accuracy ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Multi Scale ◽  
Homogenization Approach ◽  
Multiscale Homogenization

This paper presents a multi-scale-homogenization based on a two-step methodology (micro-meso and meso-macro homogenization) to predict the elastic constants of 3D fiber-reinforced composites (FRC). At each level, the elastic constants were predicted through both analytical and numerical methods to ascertain the accuracy of predicted elastic constants. The predicted elastic constants were compared with experimental data. Both methods predicted the in-plane elastic constants “ E x ” and “ E y ” with good accuracy; however, the analytical method under predicts the shear modulus “ G x y ”. The elastic constants predicted through a multiscale homogenization approach can be used to predict the behavior of 3D-FRC under different loading conditions at the macro-level.

scholarly journals Elastin haploinsufficiency in mice has divergent effects on arterial remodeling with aging depending on sex

2020 ◽  
Vol 319 (6) ◽  
pp. H1398-H1408
Author(s):  
Jie Z. Hawes ◽  
Austin J. Cocciolone ◽  
Amy H. Cui ◽  
Diana B. Griffin ◽  
Marius Catalin Staiculescu ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Arterial Wall ◽  
Circumferential Stress ◽  
Arterial Remodeling ◽  
Mechanical Parameters ◽  
Structural Stiffness ◽  
Set Point ◽  
Material Stiffness ◽  
Future Work ◽  
Comprehensive Study

A comprehensive study on arterial mechanical behavior as a function of elastin content, aging, and sex in mice. Elastin haploin-sufficient arteries start at a different homeostatic set point for mechanical parameters such as circumferential stress, stretch, and material stiffness. Structural stiffness of the arterial wall greatly increases with aging, as expected, but there are interactions between sex and aging for most of the mechanical parameters that are important to consider in future work.

ORTHOTROPIC DAMAGE MODEL USING TSAI-WU FAILURE CRITERIA

2021 ◽  
Author(s):  
M. R. T. ARRUDA ◽  
L. ALMEIDA-FERNANDES, ◽  
L. CASTRO ◽  
J. R. CORREIA
Keyword(s):  
Failure Modes ◽  
Numerical Models ◽  
Equivalent Stress ◽  
Damage Model ◽  
Failure Criteria ◽  
Simple Method ◽  
Finite Element Software ◽  
User Subroutine ◽  
Novel Approach ◽  
The Moment

This paper presents a novel approach concerning the development of an orthotropic damage model, based on the original plane Tsai-Wu failure criteria. In its original formulation, the Tsai-Wu is a mode independent criterion only capable of acknowledging the existence of damage in a certain point of the material. It is not capable of identifying if the damage is located in the fiber, matrix or intralaminar zone. This work plans to fill this gap in knowledge by providing a simple method, based on equivalent stress and strains, that identifies the failure modes when the Tsai-Wu failure criteria is near the on-set of damage. Using this novel method, it is possible to implement classical damage evolutions constitutive laws based on the MTL formulation. At the moment the proposed damage formulation is based on plane stress space and Mode I fracture, but it is expected in the future to evolve in to a full 3D damage model. The damage model is implemented in the commercial finite element software ABAQUS using user-subroutine UMAT, and all numerical models are compared with the experimental results.

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