Parameter Identification Methods for Generalized Maxwell Models: Engineering Approach for Small-Strain Viscoelasticity

2010 ◽  
Vol 659 ◽  
pp. 379-384 ◽  
Author(s):  
Gábor Bódai ◽  
Tibor Goda
Keyword(s):  
Parameter Identification ◽  
Maxwell Model ◽  
Small Strain ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Compression Tests ◽  
Identification Methods ◽  
Generalized Maxwell Model ◽  
Limited Frequency

The present paper surveys briefly the parameter identification methods widely used in case of generalized Maxwell-model. Beside those basing on dynamical-mechanical thermal analysis (DMTA) and stress relaxation measurement authors have presented a technique using simple tensile tests. The latter can be effectively used by combining it with the genetic algorithm of Matlab for parameter identification in a limited frequency/time domain. The proposed method can be generalized easily for example for shear and compression tests too. After comparing it with other existing methods author make a proposal for the strain rate of the uniaxial tensile test.

Systematic Experimental Investigation of Dielectric Electroactive Polymers Using a Custom-Built Uniaxial Tensile Test Rig

2015 ◽  
Author(s):  
Micah Hodgins ◽  
Alexander York ◽  
Stefan Seelecke
Keyword(s):  
Pure Shear ◽  
Tensile Force ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Specimen Preparation ◽  
Testing Device ◽  
Test Results ◽  
Test Rig ◽  
Geometry Test

This work presents the design, fabrication and testing of a comprehensive DEAP test station. The tester is designed to perform tensile tests of planar DEAPs while measuring quantities such as tensile force, stretch, film thickness and voltage/current. The work details the specimen preparation and how the specimen is placed in the clamps. While the assembly process is performed by hand features were built-in to the design of the specimen frame and clamps to enable reliable placement and specimen geometry. Test results of the pure-shear specimen demonstrated good performance of the testing device. Although the electrode surface was rough the thickness stretch was evident during the stretching/actuation of the DEAP actuator.

Experimental Determination of Layer-Specific Hyperelastic Parameters of Human Descending Thoracic Aortas

2019 ◽  
Author(s):  
Isabella Bozzo ◽  
Marco Amabili ◽  
Prabakaran Balasubramanian ◽  
Ivan Breslavsky ◽  
Giovanni Ferrari
Keyword(s):  
Storage Modulus ◽  
Thoracic Aorta ◽  
Loss Tangent ◽  
Viscoelastic Model ◽  
Viscoelastic Behavior ◽  
Axial Direction ◽  
Maxwell Model ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Descending Thoracic Aorta

Abstract Heart disease is the second leading cause of death in Canada resulting in $20.9 billion annual healthcare expenditures [1,2]. Understanding the mechanics of the human descending thoracic aorta is fundamental for comprehending the development of pathologies and improving surgical prostheses. This study presents hyperelastic and viscoelastic material characterizations of the human descending thoracic aorta from twelve different donors, with a mean age of 49.4 years. The specimens were dissected into the three constituent layers: intima, media and adventitia. Evaluating the layer-specific opening angles led to the computation of the circumferential residual stresses. Uniaxial tensile tests of each layer, in both the circumferential and axial direction, were used to model the hyperelastic behavior according to the Gasser-Ogden-Holzapfel model (GOH). The storage modulus and loss tangent for the layers were obtained from uniaxial harmonic excitations at varied frequencies, to model the viscoelastic behavior with the generalized Maxwell model. The results showed a positive correlation between age and stiffness for all layers, both axially and circumferentially. Similar loss tangent values were found across the three layers. A large increase in the storage modulus from static to dynamic experiments further corroborates the importance of a viscoelastic model of the aorta, rather than solely hyperelastic.

Evaluating the Mechanical Behavior of ARB Processed Aluminum Composites Using Shear Punch Testing

2020 ◽  
Vol 986 ◽  
pp. 86-92
Author(s):  
Dhyai Hassan Jawad ◽  
Ali Hosseinzadeh ◽  
Mustafa Misirli ◽  
Guney Guven Yapici
Keyword(s):  
Tensile Tests ◽  
Mechanical Analysis ◽  
Test Method ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Punch Test ◽  
Processed Material ◽  
Shear Punch Test ◽  
Shear Punch ◽  
Shear Punch Testing

Multi-layered metal composites have received considerable attention due to their improved mechanical and physical properties. In this study, Al6061/Al2024 composite was processed by accumulative roll bonding (ARB) as a severe plastic deformation technique. Mechanical properties of processed material were evaluated using the uniaxial tensile test and shear punch test method (SPT). The correlation between the results of the tension experiments and shear strengths was calculated. Experimental results demonstrated that the shear strength enhanced with increased number of ARB passes. However, the elongation under shear manifested a reduction when the number of ARB passes increased. Inspection of the results of tensile tests and SPT revealed that they follow a similar trend for both strength and ductility. Therefore, it can be asserted that the shear punch test represents a useful and complementary tool in the mechanical analysis of the ARB sample.

scholarly journals Assessment of the Suitability of Elastomeric Bearings Modeling Using the Hyperelasticity and the Finite Element Method

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7665
Author(s):  
Marcin Daniel Gajewski ◽  
Mikołaj Miecznikowski
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Constitutive Relations ◽  
Experimental Tests ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Compression Tests ◽  
The Finite Element Method ◽  
Elastomeric Bearings ◽  
Element Method

The paper presents modeling of bridge elastomeric bearings using large deformation theory and hyperelastic constitutive relations. In this work, the simplest neo-Hookean model was compared with the Yeoh model. The parameters of the models were determined from the elastomer uniaxial tensile test and then verified with the results from experimental bearing compression tests. For verification, bearing compression tests were modeled and executed using the finite element method (FEM) in ABAQUS software. Additionally, the parameters of the constitutive models were determined using the inverse analysis method, for which the simulation results were as close as possible to those recorded during the experimental tests. The overall assessment of the suitability of elastomer bearings modeling with neo-Hookean and Yeoh hyperelasticity models is presented in detail.

Mechanical Behavior Characterization of Magnesium Alloy Sheets at Warm Temperature

2015 ◽  
Vol 32 (4) ◽  
pp. 391-399
Author(s):  
J. Huang ◽  
Y. Yuan ◽  
H. Liu ◽  
J. Cao
Keyword(s):  
Elevated Temperature ◽  
Magnesium Alloy ◽  
Mechanical Behavior ◽  
Yield Criterion ◽  
Tensile Tests ◽  
Alloy Sheet ◽  
Uniaxial Tensile ◽  
Compression Tests ◽  
Warm Temperature ◽  
Yield Anisotropy

AbstractMagnesium (Mg) alloy sheet has received increasing attention in automotive, transportation, and aerospace industries. It is widely recognized that magnesium sheet has a poor formability at room temperature. While at elevated temperature, its formability can be dramatically improved. To better understand the warm forming properties of magnesium alloy sheet, an accurate description of the mechanical behavior at elevated temperature is required.In this paper, both uniaxial tensile tests and uniaxial compression tests were carried out at warm temperature for Mg AZ31B alloy sheets. The tensile tests were conducted under various strain rates and material orientations, while the compression tests only considered different material orientations. Based on the orthotropic yield criterion for hexagonal close packed (HCP) metals proposed by Cazacu et al., 2006, a viscoplasticity model has been developed to describe the initial yield anisotropy and asymmetry hardening behavior in tensile and compression of Mg sheet. This model was incorporated into ABAQUS through a user-defined material subroutine. The numerical results show a good agreement with experimental data in a large range of deformation.

scholarly journals Material parameter identification of unidirectional fiber-reinforced composites

2021 ◽  
Vol 91 (2) ◽  
pp. 687-712
Author(s):  
Stefan Hartmann ◽  
Rose Rogin Gilbert ◽  
Ali Kheiri Marghzar ◽  
Chris Leistner ◽  
Pranav Kumar Dileep
Keyword(s):  
Parameter Identification ◽  
Material Parameter ◽  
Transverse Isotropy ◽  
Composite Plates ◽  
Image Correlation ◽  
Uniaxial Tensile ◽  
Compression Tests ◽  
Material Parameter Identification ◽  
Common Procedure ◽  
Material Parameters

AbstractIn this article, several aspects of material parameter identification are addressed. We compare several methods to identify material parameters of a constitutive model for small strain, linear elastic transverse isotropy based on experimental data of specimens made from composite plates. These approaches range from identifying the five material parameters from purely analytical considerations to the fully numerical identification on the basis of finite elements and various data provided by digital image correlation (DIC). The underlying experimental tests range from purely uniaxial tensile tests with varying fiber orientation to shear and compression tests. A specific measuring instrument has been developed for the latter tests to obtain unique material parameters—motivated by the concept of local identifiability. Besides, we compare the numerical differentiation, which is the common procedure in parameter identification, with the fully analytical derivation of sensitivities within the DIC/FEM approach.

scholarly journals Determination of the Material Parameters in the Holzapfel-Gasser-Ogden Constitutive Model for Simulation of Age-Dependent Material Nonlinear Behavior for Aortic Wall Tissue under Uniaxial Tension

2019 ◽  
Vol 9 (14) ◽  
pp. 2851 ◽  
Author(s):  
Up Huh ◽  
Chung-Won Lee ◽  
Ji-Hun You ◽  
Chan-Hee Song ◽  
Chi-Seung Lee ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Nonlinear Behavior ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Computational Simulations ◽  
Healthy Human ◽  
Element Analysis ◽  
Material Parameters ◽  
Hgo Model

In this study, computational simulations and experiments were performed to investigate the mechanical behavior of the aorta wall because of the increasing occurrences of aorta-related diseases. The study focused on the deformation and strength of porcine and healthy human abdominal aortic tissues under uniaxial tensile loading. The experiments for the mechanical behavior of the arterial tissue were conducted using a uniaxial tensile test apparatus to validate the simulation results. In addition, the strength and stretching of the tissues in the abdominal aorta of a healthy human as a function of age were investigated based on the uniaxial tensile tests. Moreover, computational simulations using the ABAQUS finite element analysis program were conducted on the experimental scenarios based on age, and the Holzapfel–Gasser–Ogden (HGO) model was applied during the simulation. The material parameters and formulae to be used in the HGO model were proposed to identify the failure stress and stretch correlation with age.

scholarly journals RESEARCHES REGARDING THE INFLUENCE OF MALT EXTRACT ADDITION ON THE BREAD QUALITY

1970 ◽  
Vol 62 ◽  
Author(s):  
Mariana Atena Poiana ◽  
Diana Dogaru ◽  
C. Mateescu ◽  
Daniela Mucete ◽  
Luminita Parvulescu
Keyword(s):  
Alcoholic Fermentation ◽  
Young Modulus ◽  
Maxwell Model ◽  
Malt Extract ◽  
Compression Tests ◽  
Relaxation Data ◽  
Force Relaxation ◽  
Generalized Maxwell Model ◽  
Strain Relationship ◽  
Relaxation Curves

The purpose of this study is the pointing out of the physic-chemical modifications of the bakery products in case those during the technological process have been added malt extracts in different percentages The addition of the malt extract in different percents (1%, 2% and 3%) has been tested. In this sense, the aspect of the crust and porosity is observed, the diameter and the height of bread has been established. Also, it was determined from compression tests the young modulus for bread. A sigmoid compressive stress-strain relationship is characteristic of bread. The influence of viscoelastic characteristics of bread was studied with relaxation tests. The relaxation data could be fitted by equations that derived from generalized Maxwell model and by normalization and linearization of the experimental force relaxation curves. The alcoholic fermentation was more intense for all samples with malt extract. This was showed by decreasing the content of reducing sugars during leaven. Also, can be observed that volume of all samples was bigger than the whiteness sample, the porosity was more visible and more uniform, the elasticity was better, and the crust was more colored because of the Maillard compounds formed during baking.

Effects of Microstructure on Material Behaviors of Solder Alloys

2005 ◽  
Vol 297-300 ◽  
pp. 825-830 ◽  
Author(s):  
Tae Kyung Hwang ◽  
Soon Bok Lee
Keyword(s):  
Electronic Devices ◽  
Ternary Eutectic ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Cu Alloys ◽  
Material Behaviors ◽  
Elongation To Failure ◽  
Process Behavior ◽  
Free Solder

The leading candidates for replacing lead-contained solders are near ternary eutectic Sn/Ag/Cu alloys. The electronic industry has begun to study both the process behavior and the reliability assessment of these alloys in detail to figure out their applicability to electronic devices and products. In recent publications, the solidification behavior and the fatigue life of the accelerated thermal cycle test have been reported in terms of microstructure variations such as the formation of large Ag3Sn plates and their effects. In this study, coupon type bulk specimens have been made for uniaxial tensile test by casting. To consider the effects of microstructure, casting cooling rates were controlled to 0.02-2.0 oC/sec. Eutectic Sn/Pb and near eutectic lead-free solder materials – Sn/Ag/Cu and Sn/Cu alloys – were used in mechanical testing. Also, nanoindentation tests were performed to measure Young’s modulus of materials having different microstructures. Tensile tests were performed at 3 different strain rates and then acquired 0.2% offset proof stress, ultimate tensile strength and elongation to failure.

Comparison of two uncoupled ductile damage initiation models applied to DP900 steel sheet under various loading paths

2020 ◽  
Vol 30 (1) ◽  
pp. 25-45
Author(s):  
Zhiyu Tuo ◽  
Zhenming Yue ◽  
Xincun Zhuang ◽  
Xinrui Min ◽  
Houssem Badreddine ◽  
...  
Keyword(s):  
Hot Spot ◽  
Material Model ◽  
Tensile Tests ◽  
Research Field ◽  
Forming Limit ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Forming Process ◽  
Damage Initiation ◽  
Loading Paths

Accurate prediction of the fracture occurrence of high strength materials is always the hot spot in the research field of metal-forming process. Appropriate material model is the key issue which can accurately describe the mechanical forming behavior under different forming conditions. However, advanced fully coupled damage/behavior models are heavy to use by engineers and have a high cost in term of calculation consuming time. In this paper, a simple uncoupled damage approach, designed to be easy to use for engineers and accurate as well, is investigated. Two uncoupled damage models, which consider the effect of the Lode angle and the hydrostatic pressure, combing three typical hardening rules, are selected and applied to the damage prediction of DP900 dual-phase steel. The hardening properties and forming limit strains under different loading paths of DP900 are investigated and studied throughout a variety of mechanical experiments, including the uniaxial tensile test, the pre-notched tensile tests with three notched radii, and the butterfly tests. Finally, the prediction accuracy of the used models for DP900 is compared and discussed.

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