A hyper-elastic thermal aging constitutive model for rubber-like materials

2019 ◽  
Vol 52 (8) ◽  
pp. 677-700
Author(s):  
Ahmed G Korba ◽  
Abhishek Kumar ◽  
Mark Barkey
Keyword(s):  
Natural Rubber ◽  
Thermal Aging ◽  
Biaxial Loading ◽  
Strain Curve ◽  
Aging Effect ◽  
Elastic Materials ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Hyper Elastic ◽  
Uniaxial And Biaxial Loading

Different phenomenological, empirical, and micromechanical constitutive models have been proposed to describe the behavior of incompressible isotropic hyper-elastic materials. Among these models, very few have accounted for the thermal aging effect on the model constants and parameters. This article introduces a new empirical constitutive hyper-elastic model for thermally aged hyper-elastic materials. The model named “the weight function based (WFB) model” considers the effect of aging temperature and time on its parameters. The WFB model formulation can facilitate fatigue analysis and lifetime prediction of rubber-like materials under aging conditions. The WFB model in this article defines all rubber-like material properties, such as fracture stretch, strength, and stiffness, by predicting the full stress–strain curve at any aging time and temperature. The WFB model was tested on natural rubber for uniaxial and biaxial loading conditions. More than 100 specimens were aged and tested uniaxially under various temperatures and aging times to extract the stress–strain behavior. The temperatures used in the test ranged from 76.7°C to 115.5°C, and the aging time ranged from 0 to 600 hours (hrs). A classical bulge test experiment was generated to extract the biaxial natural rubber material behavior. An ABAQUS finite element analysis model was created to simulate and verify the generated biaxial stress–strain curve. The proposed model represents the aging effect on the tested natural rubber under uniaxial and biaxial loading conditions with an acceptable error margin of less than 10% compared to experimental data.

A Model for Hyper-Elastic Material Behavior Under Thermal Aging With an Application to Natural Rubber

2018 ◽  
Author(s):  
Ahmed G. Korba ◽  
Abhishek Kumar ◽  
Mark E. Barkey
Keyword(s):  
Natural Rubber ◽  
Aging Time ◽  
Elastic Material ◽  
Thermal Aging ◽  
Least Square ◽  
Material Behavior ◽  
Model Parameters ◽  
Stress Strain ◽  
Strain Behavior ◽  
Hyper Elastic

Numerous hyper-elastic theoretical material models have been proposed over the past 60 years to capture the stress-strain behavior of large deformation incompressible isotropic materials. Among them, however, only few models have considered the thermal aging effect on model parameters. Having a simple, closed-form equation that includes the effect of aging temperature and time in describing the stress-strain behavior could facilitate fatigue analysis and life time prediction of rubber-like materials. In this vein, this paper defines a new and simple Weight Function Based (WFB) model that describes hyper-elastic materials’ behavior as a function of aging time and temperature variations. More than 130 natural rubber specimens were thermally aged in an oven and tested under uni-axial loading to observe their stress-strain behavior at various temperatures and aging times. The temperature ranged from 76.7 °C to 115.5 °C, and the aging time from zero to 600 hours. The proposed WFB model is based on the Yeoh model and basic continuum mechanics assumptions, and it was applied to the tested natural rubber materials. Moreover, it was verified against Treloar’s historic tensile test data for uni-axial tension of vulcanized natural rubber material, and also compared to the Ogden and the Yeoh models. A non-linear least square optimization tool in Matlab was used to determine all hyper-elastic material model parameters and all other fitting purposes. The proposed model has better accuracy in fitting Treloar’s data compared to the Ogden and the Yeoh models using the same fitting tool under the same initial numerical conditions.

New Model for Hyper-Elastic Materials Behavior With an Application on Natural Rubber

2017 ◽  
Author(s):  
Ahmed G. Korba ◽  
Mark E. Barkey
Keyword(s):  
Natural Rubber ◽  
Test Data ◽  
Pure Shear ◽  
Testing Machine ◽  
Shear Loading ◽  
Least Square ◽  
Elastic Materials ◽  
Stress Strain ◽  
Strain Behavior ◽  
Hyper Elastic

This paper is concerned with defining a new Weight Function Based model (WFB), which describes the hyper-elastic materials stress-strain behavior. Numerous hyper-elastic theoretical material models have been proposed over the past 60 years capturing the stress-strain behavior of large deformation incompressible isotropic materials. The newly proposed method has been verified against the historic Treloar’s test data for uni-axial, bi-axial and pure shear loadings of Treloar’s vulcanized rubber material, showing a promising level of confidence compared to the Ogden and the Yeoh methods. A non-linear least square optimization Matlab tool was used to determine the WFB, Yeoh and Ogden models material parameters. A comparison between the results of the three models was performed showing that the newly proposed model is more accurate for uni-axial tension as it has an error value which is less than the Ogden and Yeoh models by 1.0 to 39%. Also, the parameters calculation by more than 95%, for the bi-axial and pure shear loading cases compared to the Ogden model. Natural rubber test specimens have been tensioned using a tensile testing machine and the WFB model was applied to fit the test data results showing a very good curve fitting with an average error of 0.44%.WFB model has reduced processing time for the model.

Energy of Resilience and Abrasion Resistance. A Comparison of Reclaimed and Crude Natural Rubber

1949 ◽  
Vol 22 (4) ◽  
pp. 1060-1062
Author(s):  
F. N. Upham
Keyword(s):  
Natural Rubber ◽  
Abrasion Resistance ◽  
Test Specimen ◽  
Strain Curve ◽  
Routine Procedure ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Work Done

Abstract When laboratory-machine tests on rubber were first introduced as a routine procedure, the only tests made were the elongation and tensile at break. Later, the tests were extended to the measurement of the amount of work done in stretching and breaking the test-specimen, and the computation was based on the area under the stress-strain curve.

Application of Strain Gages to the Study of (Tire) Cord at High Elongation Rates

1959 ◽  
Vol 32 (3) ◽  
pp. 907-914 ◽  
Author(s):  
N. N. Pavlov ◽  
E. Ya Yaminskaya ◽  
B. M. Krymov
Keyword(s):  
Strain Curve ◽  
Strain Gages ◽  
Substantial Influence ◽  
Tire Cord ◽  
Elastic Materials ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Simplified Method ◽  
High Elongation

Abstract 1. A new simplified method of recording the stress-strain curve of elastic materials using strain gages was developed and tested. 2. It was found that there is a substantial influence of rate of deformation on the character of the stress-strain curves of the samples tested. 3. It was established that the work of breaking the tested samples decreases with increasing speed of stretching.

Improving the Adhesion between Pineapple Leaf Fiber and Natural Rubber by Using Urea Formaldehyde Resin

2019 ◽  
Vol 824 ◽  
pp. 107-113
Author(s):  
Chanaporn Tongphang ◽  
Samar Hajjar ◽  
Karine Mougin ◽  
Taweechai Amornsakchai
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Urea Formaldehyde ◽  
Stress Transfer ◽  
Strain Curve ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Pineapple Leaf Fiber ◽  
Uf Resin ◽  
Leaf Fiber

Green composites, especially that are reinforced with natural fibers, have received a great deal of attention due to the problems of global warming and resources depletion. Pineapple leaf fiber (PALF) is an interesting choice because of its high mechanical properties and it is obtained from agricultural waste. In this work PALF is combined with natural rubber (NR) to produce green rubber composite with enhanced mechanical properties. Since the two materials are so different in their stiffness and polarity, poor interfacial adhesion and thus low stress transfer, between NR and PALF may be expected. Attempts were made to use urea formaldehyde (UF) resin to improve the adhesion between PALF and NR. PALF was coated with different amounts of UF resin in solution. The fiber was characterized with FTIR, XPS and SEM. Uniaxially aligned PALF reinforced rubber composites with a fixed amount of 10 parts per hundred of rubber (phr) PALF were prepared. The adhesion between PALF and NR was evaluated from the tensile stress-strain curve and fracture surface of the composite. It was found that UF resin had negligible effect in improving the stress transfer but rather reduced it as shown in the stress-strain curve. Thicker coating of UF resin led to lower reinforcement effect and, hence, lower modulus. Stress at break, on the other hand, increased with increasing the coating thickness.

scholarly journals Black rubber and the non-linear elastic response of scale invariant solids

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Matteo Baggioli ◽  
Víctor Cáncer Castillo ◽  
Oriol Pujolàs
Keyword(s):  
Strain Curve ◽  
Effective Field ◽  
Elastic Response ◽  
Elastic Behaviour ◽  
Scale Invariant ◽  
Stress Strain ◽  
Nonlinear Stress ◽  
Hyper Elastic ◽  
Simple Class ◽  
Nonlinear Elastic

Abstract We discuss the nonlinear elastic response in scale invariant solids. Following previous work, we split the analysis into two basic options: according to whether scale invariance (SI) is a manifest or a spontaneously broken symmetry. In the latter case, one can employ effective field theory methods, whereas in the former we use holographic methods. We focus on a simple class of holographic models that exhibit elastic behaviour, and obtain their nonlinear stress-strain curves as well as an estimate of the elasticity bounds — the maximum possible deformation in the elastic (reversible) regime. The bounds differ substantially in the manifest or spontaneously broken SI cases, even when the same stress- strain curve is assumed in both cases. Additionally, the hyper-elastic subset of models (that allow for large deformations) is found to have stress-strain curves akin to natural rubber. The holographic instances in this category, which we dub black rubber, display richer stress- strain curves — with two different power-law regimes at different magnitudes of the strain.

A modified version of MATLAB application window for predicting the weld bead profile and stress–strain plot of AA5052 CMT weldment using ER4043

SIMULATION ◽  
2021 ◽  
pp. 003754972110315
Author(s):  
B Girinath ◽  
N Siva Shanmugam
Keyword(s):  
Strain Curve ◽  
Weld Bead ◽  
Welding Parameters ◽  
Bead Geometry ◽  
Hybrid Technique ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Weld Bead Geometry ◽  
Inference System ◽  
Engineering Stress

The present study deals with the extended version of our previous research work. In this article, for predicting the entire weld bead geometry and engineering stress–strain curve of the cold metal transfer (CMT) weldment, a MATLAB based application window (second version) is developed with certain modifications. In the first version, for predicting the entire weld bead geometry, apart from weld bead characteristics, x and y coordinates (24 from each) of the extracted points are considered. Finally, in the first version, 53 output values (five for weld bead characteristics and 48 for x and y coordinates) are predicted using both multiple regression analysis (MRA) and adaptive neuro fuzzy inference system (ANFIS) technique to get an idea related to the complete weld bead geometry without performing the actual welding process. The obtained weld bead shapes using both the techniques are compared with the experimentally obtained bead shapes. Based on the results obtained from the first version and the knowledge acquired from literature, the complete shape of weld bead obtained using ANFIS is in good agreement with the experimentally obtained weld bead shape. This motivated us to adopt a hybrid technique known as ANFIS (combined artificial neural network and fuzzy features) alone in this paper for predicting the weld bead shape and engineering stress–strain curve of the welded joint. In the present study, an attempt is made to evaluate the accuracy of the prediction when the number of trials is reduced to half and increasing the number of data points from the macrograph to twice. Complete weld bead geometry and the engineering stress–strain curves were predicted against the input welding parameters (welding current and welding speed), fed by the user in the MATLAB application window. Finally, the entire weld bead geometries were predicted by both the first and the second version are compared and validated with the experimentally obtained weld bead shapes. The similar procedure was followed for predicting the engineering stress–strain curve to compare with experimental outcomes.

Stress-strain curve of paper revisited

2012 ◽  
Vol 27 (2) ◽  
pp. 318-328 ◽  
Author(s):  
Svetlana Borodulina ◽  
Artem Kulachenko ◽  
Mikael Nygårds ◽  
Sylvain Galland
Keyword(s):  
Three Dimensional ◽  
Strain Curve ◽  
Failure Behavior ◽  
Three Dimensional Model ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Fiber Network ◽  
Bonding Parameters ◽  
Particle Level ◽  
The Impact

Abstract We have investigated a relation between micromechanical processes and the stress-strain curve of a dry fiber network during tensile loading. By using a detailed particle-level simulation tool we investigate, among other things, the impact of “non-traditional” bonding parameters, such as compliance of bonding regions, work of separation and the actual number of effective bonds. This is probably the first three-dimensional model which is capable of simulating the fracture process of paper accounting for nonlinearities at the fiber level and bond failures. The failure behavior of the network considered in the study could be changed significantly by relatively small changes in bond strength, as compared to the scatter in bonding data found in the literature. We have identified that compliance of the bonding regions has a significant impact on network strength. By comparing networks with weak and strong bonds, we concluded that large local strains are the precursors of bond failures and not the other way around.

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