An Alternative Protocol for Determining Viscoelastic Material Properties Based on Tensile Tests Without the Use of Poisson’s Ratios

2007 ◽  
Author(s):  
Abraham Shtark ◽  
Hagay Grosbein ◽  
Guy Sameach ◽  
Harry H. Hilton
Keyword(s):  
Constitutive Relations ◽  
Testing Machine ◽  
Tensile Tests ◽  
Experimental Results ◽  
Tensile Creep ◽  
Time Interval ◽  
Tensile Testing Machine ◽  
Experimental Protocols ◽  
Poisson's Ratios ◽  
Poisson’S Ratios

Analytical and experimental protocols are formulated and outlined in detail wherein unidirectional tensile creep or relaxation experiments are performed on viscoelastic specimen. A combination of a photogrametric system and a tensile testing machine provides stress data in the loaded direction and strains in both longitudinal and transverse directions. The data is integrated through the use of the integral constitutive relations, and produce values for the creep compliance parameters. Subsequently, the viscoelastic Young’s, shear and bulk moduli are determined without the use of viscoelastic Poisson’s ratios. Experimental results indicate strong time, stress and stress history dependencies of viscoelastic PRs. Current experimental results are compared with traditional methods based on assumed time independent Poisson ratios. Maximum errors in strain values from 160% to 205% for the constant PR approach are demonstrated when its results are compared to results for the experimental time interval.

Viscoelastic Temperature Dependent Characterization Protocols Without the Use of Poisson’s Ratios

2009 ◽  
Author(s):  
Abraham Shtark ◽  
Hagay Grossbein ◽  
Harry H. Hilton
Keyword(s):  
Constitutive Relations ◽  
Testing Machine ◽  
Tensile Creep ◽  
Tensile Testing Machine ◽  
Single Temperature ◽  
Experimental Protocols ◽  
Relaxation Experiments ◽  
Relaxation Curves ◽  
Poisson's Ratios ◽  
Poisson’S Ratios

The previously formulated analytical and experimental protocols for a single temperature conditions in [1] are extended to multi temperatures in order to develop shift factors and master relaxation curves. The system consist of unidirectional tensile creep or relaxation experiments performed on viscoelastic specimen. A combination of a photogrametric device and a tensile testing machine provides stress data in the loaded direction and strains in both longitudinal and transverse directions. The data is integrated through the use of the integral constitutive relations, and produce values for the creep compliance parameters. Subsequently, the viscoelastic Young’s, shear and bulk moduli are determined without the use of viscoelastic Poisson’s ratios (PR). Experimental results indicate strong time, temperature, stress and stress history dependencies of viscoelastic PRs.

scholarly journals Research on multidimensional loading device of material mechanical test

2018 ◽  
Vol 207 ◽  
pp. 03012
Author(s):  
Guohua Zhao ◽  
Dan Wang ◽  
Liangbao Liu ◽  
Rui Fanand ◽  
Rukun Mi
Keyword(s):  
Tensile Testing ◽  
Inverse Kinematics ◽  
Parallel Mechanism ◽  
Mechanical Test ◽  
Testing Machine ◽  
Tensile Tests ◽  
Determination Method ◽  
Average Yield ◽  
Tensile Testing Machine ◽  
Loading Device

A multidimensional loading device for the material mechanical test based on Stewart Platform was proposed and manufactured in this paper. A determination method of mechanism parameters toward specific engineering requirements was analysed via inverse kinematics and contact interference boundary condition of mechanism components. A set of optimized mechanism parameters was achieved and then the pose space was obtained. Meanwhile, five repeated quasi-static standard tensile tests were performed on the multidimensional loading device and the standard tensile testing machine, respectively. The average yield strength and ultimate strength of the specimen achieved from the different testers were both merely 1.13%. Results indicated that material mechanical multidimensional loading could be conducted by the parallel mechanism.

Fabrication and Characterization of Micro-Patterned Magnetorheological Elastomeric Structures

2013 ◽  
Author(s):  
Ammar S. Yashaa ◽  
Souran Manoochehri
Keyword(s):  
Size Range ◽  
Testing Machine ◽  
Magnetorheological Fluid ◽  
Tensile Tests ◽  
Tensile Testing Machine ◽  
Latitudinal Patterns ◽  
Fabrication And Characterization ◽  
Low Magnetic Field ◽  
Magnetic Field Condition

This paper presents fabrication and characterization of micro-patterned magnetorheological elastomeric structures composed of magnetorheological fluid (MRF) sandwiched with magnetorheological elastomeric (MRE) materials. The MRE structures are made of polydimethylsiloxane (PMDS) with and without an additive of carbonyl iron (CI) particles with a size range of 6–9 um and the MRF is composed of silicon fluid mixed with the CI particles of the same size range. Three different SU-8 master molds of plain, longitudinal, and latitudinal patterns are constructed. Also, four MR elastomeric structures of different CI particle arrangements of isotropic MRE, anisotropic top-to-bottom-aligned MRE, anisotropic side-to-side-aligned MRE, and pure PDMS for each SU-8 master mold are fabricated. MRE structures are then characterized by using a tensile testing machine under a normal condition (off-state) and a low magnetic field condition (on-state). The tensile tests were performed to experimentally investigate their tunable properties. Later, the data gathered are compared for different conditions.

DIRECTION-DEPENDENT AND MULTIAXIAL STRESS-SOFTENING BEHAVIOR OF CARBON BLACK–FILLED RUBBER

2014 ◽  
Vol 87 (1) ◽  
pp. 139-151 ◽  
Author(s):  
Hasan Kahraman ◽  
Edmund Haberstroh
Keyword(s):  
Mechanical Behavior ◽  
Anisotropic Material ◽  
Tensile Testing ◽  
Testing Machine ◽  
Material Behavior ◽  
Experimental Results ◽  
Mullins Effect ◽  
Induced Anisotropy ◽  
Tensile Testing Machine ◽  
Biaxial Tensile Testing

ABSTRACT The mechanical behavior of filled rubbers depends on the maximum stretch previously reached and consequently on the induced stress softening. This softening effect is referred to as the Mullins effect. Current investigations point out that the Mullins effect exhibits a significant directional dependence, which calls for an anisotropic material model. But for the formulation and validation of anisotropic material models, there is still a lack of suitable experimental data. For this the purpose, experiments based on chloroprene rubber (CR) are reported. To trace the anisotropic Mullins effect, the standard test method for characterization of the isotropic mechanical behavior must be extended. The appropriate type of specimen enables us to perform multiple load steps with alternating load directions. After repeated stretching in the same direction, a subsequent first uniaxial loading in any other direction is characterized by a stiffer stress–strain behavior compared with the stabilized curve of the previous primary load. Hence, the experimental results confirm the deformation-induced anisotropy. To identify the multiaxial material behavior after the prestretching in one direction, a biaxial tensile-testing machine is developed. A specific property of the biaxial tensile-testing machine is the independent control of both the loading axes. Thus, the rubber material can be subjected to arbitrary loading histories. Therefore, a cross-shaped specimen with four arms is used. Multiple slits parallel to the sides on each arm ensures the homogenous uniaxial load condition in the primary load. In the secondary load step, the loading axis, which was previously inactive, is moved in a uniform manner as the master axis or in any arbitrary defined ratio. The experimental results confirm the deformation-induced anisotropy of the Mullins effect. In summary, the material behavior significantly results from the deformation mode and the loading direction applied in the loading history.

Mechanical Behavior of a Pt-Cr Jewelry Alloy Hardened by Nano-Sized Ordered Particles

2004 ◽  
Vol 842 ◽  
Author(s):  
Kamili M. Jackson ◽  
Miyelani P. Nzula ◽  
Silethelwe Nxumalo ◽  
Candace I. Lang
Keyword(s):  
Binary Systems ◽  
Cold Working ◽  
Testing Machine ◽  
Tensile Tests ◽  
Heat Treatments ◽  
Small Scale ◽  
Tensile Testing Machine ◽  
Materials Engineering ◽  
Hardness Tests ◽  
The Cost

ABSTRACTThe materials engineering of platinum jewelry is interesting because only 5wt% can be used for alloying in order to maintain hallmarking. However, pure platinum is very soft and must be alloyed in order to be used effectively as jewelry. In several binary systems an increase in hardness has been found after cold working and annealing at low temperatures. The hardening in these alloys has shown to be a result of nano-sized ordered particles. In particular, the existence of the ordered particles has previously been confirmed for a Pt-Cr alloy by TEM. Extensive work has been done on the Pt-Cr alloy to understand the crystal structure and mechanisms of the ordered phase. Hardness tests were performed to measure mechanical properties after various heat treatments. In addition, tensile tests were conducted using a small-scale tensile testing machine. An 8mm long specimen is used, which significantly reduces the cost of the specimens while providing necessary properties. Tensile tests on the Pt-Cr alloys at various post deformation heat treatments show an increase in tensile strength with no effect on ductility. They confirm results of the hardness tests while providing additional properties data. In addition, the results show a fairly good relationship between strength and hardness.

Full-strain range characteristics of the Poisson’s ratio for coated biaxial warp-knitted fabrics under bias tensile loading

2018 ◽  
Vol 89 (10) ◽  
pp. 1997-2009 ◽  
Author(s):  
Jianwen Chen ◽  
Han Zhou ◽  
Wujun Chen ◽  
Mingyang Wang ◽  
Bing Zhao ◽  
...  
Keyword(s):  
Poisson’S Ratio ◽  
Interaction Mechanism ◽  
Strain Range ◽  
Tensile Tests ◽  
Image Correlation ◽  
Poisson's Ratio ◽  
Correlation Technique ◽  
Poisson Effect ◽  
Poisson's Ratios ◽  
Poisson’S Ratios

It is undeniable that full-strain range characteristics of Poisson’s ratios on the behaviors of a fabric composite are crucial. However, there have been relatively few papers devoted to this subject. In this study, tensile tests of seven bias angles with a 15° increment are conducted on a typical coated biaxial warp-knitted fabric (BWKF) to estimate the Poisson’s ratios in full-strain range. By utilizing the digital image correlation technique, experimental results are processed, and detailed responses of strain contours and Poisson’s ratios are determined for specific strain states. Then, two typical types, that is recession and peak types, of the Poisson’s ratio strain curves are proposed and their characteristics evolving with the strain, bias angle and stress state are discussed. Results show that characteristics of Poisson’s ratios and strain contours vary noticeably with the yarn orientations, strain and stress levels. As the strain increases, the Poisson’s ratio of peak type first ascends markedly, and then descends moderately after arriving at a peak, generating three distinct stages: the ascending, peak and post-peak stages; in contrast, the recession type only experiences a downward trend, resulting in two characteristic stages: the recession and stable stages. In addition, there is an M-shaped relationship between the Poisson’s ratio and bias angle, with a local valley at 45°, which is not consistent with results in previous works. This investigation could provide new insights into the orientation dependence, Poisson effect and warp–weft interaction mechanism of BWKFs.

scholarly journals Effect of Nanometric Metallic Hydroxides on the Flame Retardant Properties of HDPE Composites

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
F. I. Beltrán-Ramírez ◽  
L. F. Ramos-deValle ◽  
E. Ramírez-Vargas ◽  
S. Sánchez-Valdes ◽  
A. B. Espinoza-Martínez ◽  
...  
Keyword(s):  
Flame Retardant ◽  
Tensile Properties ◽  
Cone Calorimeter ◽  
Flame Retardants ◽  
Testing Machine ◽  
Tensile Tests ◽  
Tensile Testing Machine ◽  
Cone Calorimeter Test ◽  
Ul 94 ◽  
Flame Retardant Properties

The effect of nanometric magnesium and aluminum hydroxides on the flame retardancy of high density polyethylene was studied. Additionally, the effect of maleic anhydride grafted polyethylene (PEgMA) and methyl acrylate grafted polyethylene (EMA) compatibilizers, on the tensile properties, was also studied. Morphological characterization of nanocomposites was carried out by means of scanning transmission electron microscopy (STEM). Flame retardant properties of nanocomposites were evaluated by the UL-94 horizontal and vertical tests as well as by cone calorimeter tests. Thermal degradation behavior was analyzed with a thermogravimetric analyzer (TGA). Tensile tests were carried out according to ASTM D 638-03 in an Instron 4301 tensile testing machine. From STEM images, a good dispersion of flame retardants (MH and ATH) in the polymer matrix was observed, which was reflected in the flame retardant properties. Results showed that the combination of nanometric MH and ATH produced excellent flame retardant properties, achieving a classification of V0 in the UL-94-V test and producing the lowest peak of heat release rate (PHRR) and the lowest total heat released (THR) in the cone calorimeter test. Finally, the addition of compatibilizer, especially PEgMA, resulted in much better tensile properties as compared to the noncompatibilized composition, maintaining the flame retardant properties.

scholarly journals Stress-Strain Behavior – Deformation Degree Relationship Investigation of Alloy CrNi60WTi

2021 ◽  
Vol 65 (1) ◽  
pp. 105-107
Author(s):  
Yaroslav Kosmatskiy ◽  
Nikolai Fokin ◽  
Kseniya Yakovleva ◽  
Vladislav Nikolenko ◽  
Boris Barichko ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cold Deformation ◽  
Testing Machine ◽  
Tensile Tests ◽  
Outer Diameter ◽  
Test Results ◽  
Deformation Degree ◽  
Tensile Testing Machine ◽  
Strain Behavior ◽  
Static Tensile

The article presents the results of a research of the dependence of the mechanical properties of the CrNi60WTi alloy on the degree of cold deformation. As part of the study, five samples were taken from a pipe with an outer diameter of 89.0 mm and a wall thickness of 11.0 mm. The samples were cold-deformed to varying degrees and static tensile tests were performed on an SSI MTSInsight tensile testing machine. Based on the test results, the dependences of the mechanical properties on the degree of cold deformation were calculated.

Cellular Materials With Extremely High Negative and Positive Poisson’s Ratios: A Mechanism Based Material Design

2013 ◽  
Author(s):  
Kwangwon Kim ◽  
Jaehyung Ju ◽  
Doo-Man Kim
Keyword(s):  
Porous Materials ◽  
Analytical Model ◽  
Compliant Mechanisms ◽  
Constitutive Relations ◽  
Functional Materials ◽  
Material Design ◽  
The Other ◽  
Yield Strain ◽  
Poisson's Ratios ◽  
Poisson’S Ratios

In an effort to tailor functional materials with customized anisotropic properties — stiffness and yield strain, we propose porous materials consisting of flexible mesostructures designed from the deformation of a re-entrant auxetic honeycomb and compliant mechanisms. Using an analogy between compliant mechanisms and a cellular material’s deformation, we can tailor in-plane properties of mesostructures; low stiffness and high strain in one direction and high stiffness and low strain in the other direction. Two mesostructures based on hexagonal honeycombs with positive and negative cell angles are generated. An analytical model is developed to obtain effective moduli and yield strains of the porous materials by combining the kinematics of a rigid link mechanism and deformation of flexure hinges. A numerical technique is implemented to the analytical model for nonlinear constitutive relations of the mesostructures and their strain dependent Poisson’s ratios. A Finite Element Analysis (FEA) is used to validate the analytical and numerical model. The moduli and yield strain of a porous aluminum alloy are about 6.3GPa and 0.26% in one direction and about 2.8MPa and 12% in the other direction. The mesostructures have extremely high positive and negative Poisson’s ratios, νxy* (∼ ±40) due to the large rotation of the link member in the transverse direction caused by the input displacement in the longitudinal direction. The mesostructures also show higher moduli for compressive loading due to the contact of slit edges at the center region. This paper demonstrates that compliant mesostructures can be used for a next generation material design in terms of tailoring mechanical properties; moduli, strength, strain, and Poisson’s ratios. The proposed mesostructures can also be easily manufactured using a conventional cutting method.

Thermo-Oxidation Analysis of Structural Adhesives: An Experimental Study

2020 ◽  
Author(s):  
Sharif Alazhary ◽  
Hamid Mohammadi ◽  
Roozbeh Dargazany
Keyword(s):  
Experimental Study ◽  
Testing Machine ◽  
Tensile Tests ◽  
Material Behavior ◽  
Constitutive Behavior ◽  
Tensile Testing Machine ◽  
Model Free ◽  
Structural Applications ◽  
Aging Conditions ◽  
Effects Of Aging

Abstract Cross-linked polymers play an important role in structural applications as adhesives. In this article, we performed an experimental study to understand the effects of high temperature i.e. thermo-oxidative aging on the mechanical behavior of polymers. Subsequently, the constitutive behavior, i.e. stress-strain relation of these adhesives before and after the accelerated aging tests were studied on samples aged at different temperature and different time durations at zero humidity. The aging conditions and periods selected for the tests have been specifically designed to simulate the effects of aging under the working conditions that the materials will be subjected to in their standard applications. The focus of this study is on the investigation of the effects of aging on the polymeric adhesives used in automotive applications. Consequently, four different polymeric adhesives (one silicone-based, two polyurethane-based, and one acrylic type), which are being used extensively in these applications, have been chosen. The quasi-static tensile loading was used on these four adhesives and the changes in the constitutive behavior were measured. The failure tensile tests as well as the cyclic tensile tests were performed in our lab using a Test-Resources tensile testing machine. The temperatures that were used in this work are 60, 80 and 95°C for varying aging periods of 24hrs, 240hrs, and 720hrs. Then, all the data was collected and consequently analyzed, and the resulting behavior was compared to that of the unaged material, showing varying results depending on the material, temperature, and aging period. Different behaviors have been observed after aging. The polymers’ behavior was expanding from no effect to significant damage caused by aging conditions. This work provides the core understanding required for modeling the material behavior during aging and lays down the groundwork for further data-infused model-free approaches.

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