A Visco-hyperelastic Model for the Thermo-mechanical Behavior of Polymer Fibers

2010 ◽  
Vol 20 (7) ◽  
pp. 1002-1020 ◽  
Author(s):  
G.P. Potirniche ◽  
A. Pascu ◽  
N. Shoemaker ◽  
P.T. Wang ◽  
M.F. Horstemeyer ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Penetration Resistance ◽  
Polymer Chains ◽  
Polymer Fibers ◽  
Deformation Characteristics ◽  
Uniaxial Deformation ◽  
The Finite Element Method ◽  
Dynamic Event ◽  
Hyperelastic Model ◽  
Strain Rate Hardening

A visco-hyperelastic model for the thermo-mechanical behavior of polymer yarns is presented. The model assumes that the stress in a yarn during uniaxial deformation results from the superposition of strain rate hardening effects and the softening caused by filament damage. The filament damage accounts for the fracture of polymer chains and the failure of inter-chain bonds. The constitutive model was implemented in the finite element method as a 1D rope element, and was applied to the study of nylon 6.6 and Kevlar ® 29 behavior. Numerical simulations of fabrics subjected to ballistic impact were performed, and the model is shown to predict the fabric penetration resistance and the deformation characteristics during the dynamic event.

scholarly journals The effect of the outlet angle β2 on the thermomechanical behavior of a centrifugal compressor blade

2020 ◽  
Vol 29 (1) ◽  
pp. 1-8
Author(s):  
Ahmed Allali ◽  
Sadia Belbachir ◽  
Ahmed Alami ◽  
Belhadj Boucham ◽  
Abdelkader Lousdad
Keyword(s):  
Mechanical Behavior ◽  
Centrifugal Compressor ◽  
Three Dimensional ◽  
Complex Form ◽  
Compressor Blade ◽  
Stress Fields ◽  
The Finite Element Method ◽  
Mechanical Fatigue ◽  
Outlet Angle ◽  
The Impact

AbstractThe objective of this work lies in the three-dimensional study of the thermo mechanical behavior of a blade of a centrifugal compressor. Numerical modeling is performed on the computational code "ABAQUS" based on the finite element method. The aim is to study the impact of the change of types of blades, which are defined as a function of wheel output angle β2, on the stress fields and displacements coupled with the variation of the temperature.This coupling defines in a realistic way the thermo mechanical behavior of the blade where one can note the important concentrations of stresses and displacements in the different zones of its complex form as well as the effects at the edges. It will then be possible to prevent damage and cracks in the blades of the centrifugal compressor leading to its failure which can be caused by the thermal or mechanical fatigue of the material with which the wheel is manufactured.

DESIGN AND ANALYSIS OF NEW STENT PATTERNS FOR ENHANCED PERFORMANCE

2020 ◽  
Vol 20 (06) ◽  
pp. 2050039
Author(s):  
NISANTHKUMAR PANNEERSELVAM ◽  
SREEKUMAR MUTHUSWAMY
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Blood Flow ◽  
Coronary Artery ◽  
Mechanical Behavior ◽  
Internal Diameter ◽  
Cell Design ◽  
The Finite Element Method ◽  
Stent Expansion ◽  
Stenting Procedure

Deploying a stent to restore blood flow in the coronary artery is very complicated, as its internal diameter is smaller than 3[Formula: see text]mm. It has already been proven that mechanical stresses induced on stent and artery during deployment make the placement of stent very difficult, besides the development of complications due to artery damage. Various stent designs have already been developed, especially in the metallic category. Still, there are possibilities for developing new stent designs and patterns to overcome the complexities of the existing models. Also, the technology of metallic stents can be carried forward towards the development of bioresorbable polymeric stents. In this work, three new stent cell designs (curvature, diamond, and oval) have been proposed to obtain better performance and life. The finite element method is utilized to explore the mechanical behavior of stent expansion and determine the biomechanical stresses imposed on the stent and artery during the stenting procedure. The results obtained have been compared with the available literature and found that the curvature cell design develops lower stresses and, hence, be suitable for better performance and life.

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.

scholarly journals Modeling of the Mechanical Behavior of 3D Bioplotted Scaffolds Considering the Penetration in Interlocked Strands

2018 ◽  
Vol 8 (9) ◽  
pp. 1422 ◽  
Author(s):  
Saman Naghieh ◽  
M. Sarker ◽  
Mohammad Karamooz-Ravari ◽  
Adam McInnes ◽  
Xiongbiao Chen
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Mechanical Behavior ◽  
Model Development ◽  
Three Dimensional ◽  
The Finite Element Method ◽  
Hydrogel Scaffolds ◽  
Important Index ◽  
Geometrical Features ◽  
Scaffold Structure

Three-dimensional (3D) bioplotting has been widely used to print hydrogel scaffolds for tissue engineering applications. One issue involved in 3D bioplotting is to achieve the scaffold structure with the desired mechanical properties. To overcome this issue, various numerical methods have been developed to predict the mechanical properties of scaffolds, but limited by the imperfect representation of one key feature of scaffolds fabricated by 3D bioplotting, i.e., the penetration or fusion of strands in one layer into the previous layer. This paper presents our study on the development of a novel numerical model to predict the elastic modulus (one important index of mechanical properties) of 3D bioplotted scaffolds considering the aforementioned strand penetration. For this, the finite element method was used for the model development, while medium-viscosity alginate was selected for scaffold fabrication by the 3D bioplotting technique. The elastic modulus of the bioplotted scaffolds was characterized using mechanical testing and results were compared with those predicted from the developed model, demonstrating a strong congruity between them. Once validated, the developed model was also used to investigate the effect of other geometrical features on the mechanical behavior of bioplotted scaffolds. Our results show that the penetration, pore size, and number of printed layers have significant effects on the elastic modulus of bioplotted scaffolds; and also suggest that the developed model can be used as a powerful tool to modulate the mechanical behavior of bioplotted scaffolds.

PERSONALIZED FSI-MODELING OF THE AORTIC BULB AND ARCH TO PREDICT ITS MECHANICAL BEHAVIOR AND ASSESS THE LOADS DURING THE CARDIAC CYCLE

2021 ◽  
Vol 11 (2) ◽  
pp. 13-16
Author(s):  
Artur Ovsepyan ◽  
Alexander Smirnov ◽  
Sergey Dydykin ◽  
Yuriy Vasil'ev ◽  
Evgeniy Trunin ◽  
...  
Keyword(s):  
Blood Flow ◽  
Mechanical Behavior ◽  
Dynamic Model ◽  
Cardiac Cycle ◽  
Fluid Structure Interaction ◽  
Complex Dynamic ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Dynamic Event

The interaction of the blood flow with the aorta is a complex dynamic event described in biomechanics as the Fluid-structure interaction. In this study we’ve developed a method for creation of a personalized 3D dynamic model of the aortic bulb and arch for the prediction of its mechanical behavior using FSI-analysis. We found that the accuracy of predicting geometric aortic deformities based on FSI modeling is on average 92%.

scholarly journals Mechanical Behavior of Cemented Sand Reinforced with Different Polymer Fibers

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Xiangfeng Lv ◽  
Xiaohui Yang ◽  
Hongyuan Zhou ◽  
Shuo Zhang
Keyword(s):  
Compressive Strength ◽  
Mechanical Behavior ◽  
Brittle Failure ◽  
Unconfined Compressive Strength ◽  
Polypropylene Fiber ◽  
Ductile Failure ◽  
Polymer Fibers ◽  
Chemical Compositions ◽  
Peak Strain ◽  
Cemented Sand

In this study, the specimens of cemented sand were prepared by reinforcing it separately with different contents (0.5%, 1.0%, 1.5%, and 2.0%) of three different polymer fibers (polyamide, polyester, and polypropylene) prepared as filaments of different lengths (6, 9, and 12 mm). Then, these specimens were tested, and the improvement effects of the three fibers on the engineering-mechanical behavior of the cemented sand were analyzed and compared. The different microstructures and chemical compositions of the fiber-reinforced cemented sand specimens were investigated using electron microscopy and X-ray diffraction. Compression tests were performed to obtain the stress-strain curves of the specimens. Comparative analysis was performed on the variation patterns of the mechanical parameters (such as unconfined compressive strength and peak strain) of the specimens. Quantitative analysis was performed on the effect of fiber content and fiber filament length on the failure mode of the specimens. It was shown that the inclusion of fibers led to a change from brittle failure to ductile failure. The macro- and microexperimental results revealed that polypropylene fiber had the best improvement effect on the mechanical behavior of the cemented sand, followed by polyester fiber and polyamide fiber. In particular, the cemented sand specimen reinforced with 1.5% polypropylene fiber prepared as 9 mm length filaments had a brittleness index of 0.0578, exhibited ductile failure (in contrast to the brittle failure of the nonreinforced cemented sand), and yielded the highest unconfined compressive strength and shear strength among the specimens.

A Comparative Study of Mechanical Properties of Fresh and Elastic-Network Only Proximal Artery Tissues

2007 ◽  
Author(s):  
Philip Kao ◽  
H. Jerry Qi ◽  
Steve Lammers ◽  
Robin Shandas
Keyword(s):  
Mechanical Properties ◽  
Least Squares Method ◽  
Pulmonary Arteries ◽  
Quantitative Comparison ◽  
Uniaxial Deformation ◽  
Elastic Network ◽  
Descending Aorta ◽  
Material Parameters ◽  
Hyperelastic Model ◽  
Left And Right

The contribution of the elastic network to the mechanical behavior of arterial tissues is not well quantified. This paper focuses on the quantification of the behavior of fresh and elastic-network-only (digested) calf arterial tissues in uniaxial deformation using the anisotropic hyperelastic model proposed by Bischoff et al. ([1]). This model characterizes an orthotropic, hyperelastic response, which is well-suited for the modeling of arterial tissues ([2],[3]). For this paper, we attempt to match the material constants associated with the Bischoff-Arruda anisotropic hyperelastic model to our experimental data from arterial tissues including the ascending aortic arch, descending aorta, main, left, and right pulmonary arteries, using a least-squares method. The material parameters obtained from the data fit provide a quantitative comparison of mechanical properties of fresh artery tissues and elastin networks.

Computational Approach of the Cortical Bone Mechanical Behavior Based on an Elastic Viscoplastic Damageable Constitutive Model

2020 ◽  
Vol 12 (07) ◽  
pp. 2050081
Author(s):  
Tesnim Kraiem ◽  
Abdelwahed Barkaoui ◽  
Tarek Merzouki ◽  
Moez Chafra
Keyword(s):  
Mechanical Behavior ◽  
Bone Quality ◽  
Damage Evolution ◽  
Sensitivity Study ◽  
Computational Approach ◽  
Material Behavior ◽  
The Finite Element Method ◽  
Non Invasive ◽  
Applied Loading ◽  
Good Agreement

Bone mechanical behavior varies according to the mechanical loading to which it is subjected, and its response effectiveness mainly depends on its quality. Thus, measuring the indicators controlling the bone quality is required to assess its strength. Indeed, the Finite Element Method (FEM) provides a non-invasive tool to interpret bone quality. Therefore, this work coupled the FEM with a micromechanical law, aiming to provide an exhaustive description of the human bone mechanical behavior. Anisotropy, viscoplasticity and damage were introduced in the material behavior law and the damage evolution was plotted based on the applied loading. Then a sensitivity study was conducted to evaluate the effects of viscoplasticity and damage parameters on bone behavior. The obtained numerical results were in a good agreement with the previously reported experimental data and allowed to distinguish key parameters from non-significant ones. This new computational model provided a better understanding of the main parameters affecting bone behavior.

Investigation of API 8 Round Casing Connection Performance—Part I: Introduction and Method of Analysis

1984 ◽  
Vol 106 (1) ◽  
pp. 130-136 ◽  
Author(s):  
W. T. Asbill ◽  
P. D. Pattillo ◽  
W. M. Rogers
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Internal Pressure ◽  
Mechanical Behavior ◽  
Experimental Analysis ◽  
Strain Gages ◽  
The Finite Element Method ◽  
Strength Of Materials ◽  
Methods Of Analysis ◽  
Element Method

The purpose of this investigation was to gain a better understanding into the mechanical behavior of the API 8 Round casing connection, when subjected to service loads of assembly interference, tension and internal pressure. The connection must provide both structural and sealing functions and these functions were evaluated by several methods. Part I discusses the methods of analysis, which include hand calculations using strength of materials, finite element method via unthreaded and threaded models, and experimental analysis using strain gages. Comparisons of all three methods are made for stresses and show that the finite element method accurately models connection behavior.

Mechanical Behavior and Constitutive Equation of Concrete under High-Temperature Dynamical Conditions

2011 ◽  
Vol 228-229 ◽  
pp. 303-308
Author(s):  
Bin Jia ◽  
Zheng Liang Li ◽  
Jun Lin Tao ◽  
Chun Tao Zhang
Keyword(s):  
High Temperature ◽  
Constitutive Equation ◽  
Strain Rate ◽  
Mechanical Behavior ◽  
Test Data ◽  
Dynamical Behavior ◽  
Hardening Effect ◽  
Failure Evolution ◽  
Different Temperatures ◽  
Strain Rate Hardening

SPHB tests of concrete under different temperatures and various loading conditions are completed, and high-temperature dynamical behavior of concrete is obtained. Dynamical mechanical behavior of concrete with high temperature is affected by not only the strain rate effect, but also the high temperature weakening effect, and the strain rate hardening effect is coupled with high temperature weakening effect, but the latter has greater influence. Concrete failure evolution is described on basis of the damage factor, the intercoupling strain rate hardening effect and temperature weakening effect are simply set as mutually independent factors, each parameter is respectively fitted with test data, finally, concrete constitutive equation under high-temperature dynamical conditions is established, and comparative analysis with test data are conducted, indicating good coincidence with test results.

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