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A new nonlinear hyper-viscoelastic constitutive model was developed to describe the mechanical behavior of filled rubbers. It consists of a conventional strain energy density function like Arruda-Boyce weighted by a four-parameter decay relationship, designed as a function of time and the deviatoric part of the first invariant of the left Cauchy-Green deformation tensor. It was implemented in Abaqus code as a user subroutine. A SBR/BR rubber compound filled with carbon black was selected as the test material. The material parameters were determined by calibrating the data from the uniaxial stress–strain tensile, volumetric, and stress relaxation tests using an optimization loop designed in Isight program. To validate the proposed model, a series of simulations were performed on two rubber strips and a rubber cylinder under extensive and compressive loads, respectively. Comparison with their corresponding experimental data confirmed the accuracy, and validity of the proposed model and approach. 相似文献
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Shirin Shokoohi Ghasem Naderi Mehdi Kharazmkia Mir Hamidreza Ghoreishy 《乙烯基与添加剂工艺杂志》2017,23(1):21-27
Micromechanics of elastomer nanocomposite samples based on polybutadiene (BR), ethylene‐propylene diene terpolymer (EPDM) hyperelastic matrixes prepared via melt compounding was investigated using uniaxial tensile analysis. Constitutive hyperelastic models, including Polynomial, Yeoh, Ogden, Arruda‐Boyce, and Van der Waals were used to determine material parameters in incompressible isotropic elastic strain‐energy functions on the basis of a nonlinear least squares optimization method by fitting the data obtained from uniaxial classic experiments. Effect of nanoclay (0, 3, 5, 7, and 10 phr) content on the simulation accuracy was investigated. Simulation results compared with the experimental data suggested that the Ogden model as the most consistent model investigated here. J. VINYL ADDIT. TECHNOL., 23:21–27, 2017. © 2015 Society of Plastics Engineers 相似文献
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Mir Hamid Reza Ghoreishy Mojtaba Bagheri-Jaghargh Ghasem Naderi Sedigheh Soltani 《应用聚合物科学杂志》2012,125(5):3648-3657
This work is devoted to the simulation of the flow of a high viscosity NR/SBR rubber compound through the die of a single screw extruder with axisymmetric geometry. An in-house developed computer code based on the use of continuous penalty finite element method was employed. Three constitutive equations including two generalized Newtonian models namely; power-law and Carreau and an explicit viscoelastic model named CEF (Criminale-Ericksen-Fillbey) were used to reflect the rheological behavior of the material. Using the parameters of the rheological models determined by a slit die rheometry technique, the flow of the compound was simulated through the die and results were compared with experimentally measured mass flow rates. It is shown that for high viscosity rubber compounds the use of generalized Newtonian models which do not take the normal stress in simple shear flow into consideration gives rise to significant errors in prediction of mass flow rates. On the other hand, comparing the simulations results using the CEF equation with experimental data revealed that this model is the best compromise between generalized Newtonian and full viscoelastic models which need high computational costs and effort. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
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Mohammad Reza Nakhaei Amir Mostafapour Charles Dubois Ghasem Naderi Mir Hamid Reza Ghoreishy 《Polymer Composites》2019,40(8):3306-3314
In this paper, PP/EPDM nanocomposites with 5 wt% nanoclay are fabricated by friction stir processing (FSP) and compared to the results obtained via a conventional twin screw extruder (TSE). Also, the effects of process parameters of these process on morphology and mechanical properties of this nanocomposites are investigated using Taguchi analysis. The prepared PP/EPDM/clay nanocomposites by two methods were characterized using X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and mechanical property tests. Comparison of the results of these methods indicated that PP/EPDM/clay nanocomposite fabricated by FSP had a better dispersion of nanoclay and mechanical properties. The results show that by addition of 5 wt% nanoclay to the base material, the tensile strength and tensile modulus of FSP sample are 12% and 8% higher than the TSE sample. The TGA results shows that, the temperature at 50% weight loss for PP/EPDM blend is 382°C. While this temperature for TSE and FSP samples are 395°C and 406°C, respectively. Under optimal conditions of rotational speed of 1,200 rpm, traverse speed of 50 mm/min, shoulder temperature of 100°C and number passes of 3, simultaneous maximization of tensile strength (19.35 MPa), tensile modulus (643 MPa), impact strength (63 J/m) and elongation at break (101%) can be obtained. POLYM. COMPOS., 40:3306–3314, 2019. © 2018 Society of Plastics Engineers 相似文献
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Elnaz Esmizadeh Abdollah Irani Ghasem Naderi Mir Hamid Reza Ghoreishy Charles Dobious 《应用聚合物科学杂志》2018,135(12)
Thermoplastic elastomer (TPE) nanocomposites based on polyamide‐6 (PA6)/poly(epichlorohydrin‐co‐ethylene oxide) (ECO)/multiwall carbon nanotube (MWCNTs) were prepared by melt compounding process. Different weight ratios of ECO (20, 40, and 60 wt %) and two kinds of functionalized and non‐functionalized MWCNTs were employed to fabricate the nanocomposites. The morphological, rheological, and mechanical properties of MWCNTs‐filled PA6/ECO blends were studied. The scanning electron microscopy of PA6/ECO blends showed that the elastomer particles, ECO, are well‐dispersed within the PA6 matrix. The significant improvement in the dispersibility of the carboxylated carbon nanotubes (COOH‐MWCNTs) compared to that of non‐functionalized MWCNTs (non‐MWCNTs) was confirmed by transmission electron microscopy images. The tensile modulus of samples improved with the addition of both types of MWCNTs. However, the effect of COOH‐MWCNTs was much more pronounced in improving mechanical properties of PA6/ECO TPE nanocomposites. Crystallization results demonstrated that the MWCNTs act as a nucleation agent of the crystallization process resulted in increased crystallization temperature (Tc) in nanocomposites. Rheological characterization in the linear viscoelastic region showed that complex viscosity and a non‐terminal storage modulus significantly increased with incorporation of both types of MWCNTs particularly at low frequency region. The increase of rheological properties was more pronounced in the presence of carboxylic (COOH) functional groups, in the other words by addition of COOH‐MWCNTs. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45977. 相似文献
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Saman Ghaderzadeh Elnaz Esmizadeh Ali Vahidifar Ghasem Naderi Mir Hamid Reza Ghoreishy Tizazu H. Mekonnen 《乙烯基与添加剂工艺杂志》2021,27(4):855-867
A facile approach of using halloysite nanotubes (HNTs) was proposed to address the durability performance demands of natural rubber (NR)/ethylene propylene diene monomer rubber (EPDM) blends and to protect them from the deleterious effects of the service environment including ozone, chemicals, abrasion, and cyclic loading. The introduction of HNTs substantially improved the stability of NR/EPDM when exposed to ozone (over fourfold enhancement with the addition of 5 phr HNTs). Moreover, the HNT-filled NR/EPDM vulcanizates offered approximately 66% reduction in the solvent-mediated swelling in comparison to the unfilled sample. Fatigue life studies showed that the HNT-reinforced NR/EPDM composite could withstand 30% more cycles to failure than the un-reinforced NR/EPDM blend. The effect of various HNT loading on the morphological, mechanical, physical, and rheological properties of nanocomposite vulcanizates based on NR/EPDM was also investigated. The morphological investigations revealed that the introduction of HNT into the NR/EPDM rubber matrix caused a rough morphology in fracture surface and a well-dispersed structure was obtained with the addition of up to 5 phr of HNTs. These findings were further supported by rheological, mechanical, and thermodynamical results. 相似文献
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