Creep characterization of gels and nonlinear viscoelastic material model

In this paper, we examine gel creep behavior and develop a material model for useful and simple numerical simulation of this behavior. This study has three stages and aims: (1) gel creep behavior is examined; (2) the material model is determined and the material constants are identified; and (3) the versatility of the material model and the constants are evaluated. The creep behavior is found to be independent of the initial stress level in the present experiment. Thus, the viscoelastic model proposed by Simo is selected, and its material constants are identified using the results of creep tests. Moreover, from the results of numerical calculations and experiments, it is found that the chosen material model has good reproducibility, predictive performance and high versatility.

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Rate Dependence and Short-Term Creep Behavior of a Thermoset Polymer at Elevated Temperature

Journal of Pressure Vessel Technology ◽

10.1115/1.3027475 ◽

2008 ◽

Vol 131 (1) ◽

Cited By ~ 12

Author(s):

C. M. Falcone ◽

M. B. Ruggles-Wrenn

Keyword(s):

Creep Behavior ◽

Viscoelastic Model ◽

Rate Sensitivity ◽

Monotonic Loading ◽

Stress Rate ◽

Creep Tests ◽

Strain Behavior ◽

Thermoset Polymer ◽

Term Creep ◽

Prior Stress

The inelastic deformation behavior of PMR-15 neat resin, a high-temperature thermoset polymer, was investigated at 288°C. The effect of loading rate on monotonic stress-strain behavior as well as the effect of prior stress rate on creep behavior were explored. Positive nonlinear rate sensitivity was observed in monotonic loading. Creep response was found to be significantly influenced by prior stress rate. The effect of loading history on creep was studied in stepwise creep tests, where specimens were subjected to a constant stress rate loading followed by unloading to zero stress with intermittent creep periods on both loading and unloading paths. The strain-time response was strongly influenced by prior deformation history. Negative creep was observed on the unloading path. In addition, the behavior of the material was characterized in terms of a nonlinear viscoelastic model by means of creep and recovery tests at 288°C. The model was employed to predict the response of the material under monotonic loading/unloading and multistep load histories.

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Nonlinear Viscoelastic–Plastic Creep Model Based on Coal Multistage Creep Tests and Experimental Validation

Energies ◽

10.3390/en12183468 ◽

2019 ◽

Vol 12 (18) ◽

pp. 3468 ◽

Cited By ~ 1

Author(s):

Junxiang Zhang ◽

Bo Li ◽

Conghui Zhang ◽

Peng Li

Keyword(s):

Creep Behavior ◽

Physical Property ◽

Creep Model ◽

Creep Process ◽

Creep Tests ◽

Model Based ◽

Nonlinear Viscoelastic ◽

Improved Model ◽

And Control ◽

Plastic Creep

The development of fractures, which determine the complexity of coal creep characteristics, is the main physical property of coal relative to other rocks. This study conducted a series of multistage creep tests to investigate the creep behavior of coal under different stress levels. A negative elastic modulus and a non-Newtonian component were introduced into the classical Nishihara model based on the theoretical analysis of the experimental results to propose a nonlinear viscoelastic–plastic creep model for describing the non-decay creep behavior of coal. The validity of the model was verified by experimental data. The results show that this improved model can preferably exhibit decelerating, steady state, and accelerating creep behavior during the non-decay creep process. The fitting accuracy of the improved model was significantly higher than that of the classical Nishihara model. Given that acceleration creep is a critical stage in predicting the instability and failure of coal, its successful description using this improved model is crucial for the prevention and control of coal dynamic disasters.

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Prediction of creep behavior of laminated woven fabric with adhesive interlining under low stress in the bias direction

Textile Research Journal ◽

10.1177/0040517516629144 ◽

2016 ◽

Vol 87 (3) ◽

pp. 285-295 ◽

Cited By ~ 2

Author(s):

Masayuki Takatera ◽

Ken Ishizawa ◽

KyoungOk Kim

Keyword(s):

Creep Strain ◽

Creep Behavior ◽

Viscoelastic Model ◽

Element Model ◽

Woven Fabric ◽

Creep Model ◽

Creep Tests ◽

Viscoelastic Models ◽

Experimental Creep ◽

The Face

The effect of adhesive interlining on the creep behavior of a woven fabric in the bias direction was investigated. Three-element viscoelastic models were used to approximate the creep behavior of a face fabric and adhesive interlining. The creep model of a laminated fabric comprised a six-element model in which two three-element models are connected in parallel with the three-element model. Creep tests were carried out using face fabrics, adhesive interlinings, and their laminated fabrics without and with bonding adhesive interlining by hanging samples in the 45° bias direction under their own weight for 7 days. Creep strains of face fabrics bonded with adhesive interlining were found to be weaker than those of the face fabrics. The creep behavior for the face and interlining fabrics could be approximated using the three-element viscoelastic model with appropriate parameters. The experimental creep behavior of a laminated fabric without bonding was similar to the theoretical behavior. However, the experimental creep of laminated fabrics with bonding interlining was less than the calculated creep, owing to the increase in stiffness due to the adhesive. By revising the six-element model with the strains just after hanging and for 2 days, it was possible to predict the creep strain over 7 days.

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Microstructural and mechanical characterization of the effect of the welding process on creep behavior of welded joint and base metal specimens of Inconel 600

MRS Advances ◽

10.1557/adv.2020.407 ◽

2020 ◽

Vol 5 (59-60) ◽

pp. 3003-3014

Author(s):

Lourdes Y. Herrera-Chávez ◽

Alberto Ruiz ◽

Víctor H. López-Morelos ◽

Carlos Rubio-González ◽

Martín R. Barajas-Álvarez ◽

...

Keyword(s):

Base Metal ◽

Creep Behavior ◽

Heat Affected Zone ◽

Structural Integrity ◽

Welded Joint ◽

Welding Process ◽

Creep Tests ◽

Inconel 600 ◽

Two Temperatures

AbstractIn this study, plates of Inconel 600 superalloy were gas metal arc welded to investigate the effects of the welding process on the creep behavior of the welded samples and compare it to the creep behavior of samples in the as-received condition. Creep tests were performed at two temperatures (600 and 650 °C) with different stress levels. During the welding process, three distinctive microstructural zones are generated, i.e. welded material, heat affected zone, and base metal that may affect the properties of the welded joint. Microstructural, elemental analysis of samples was conducted using Scanning Electron Microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDS). The experimental results show that creep rupture preferentially occurs in the heat-affected zone of the base metal at 4 mm from the fusion line and that the creep behavior of welded samples is different from that of the base metal. These results can be used in the design of structural components to assure their structural integrity.

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Computer simulation of tire rolling resistance using finite element method: Effect of linear and nonlinear viscoelastic models

Proceedings of the Institution of Mechanical Engineers Part D Journal of Automobile Engineering ◽

10.1177/0954407018804117 ◽

2018 ◽

Vol 233 (11) ◽

pp. 2746-2760 ◽

Cited By ~ 3

Author(s):

Mehdi Rafei ◽

Mir Hamid Reza Ghoreishy ◽

Ghasem Naderi

Keyword(s):

Research Work ◽

Viscoelastic Model ◽

Rolling Resistance ◽

Experimental Tests ◽

Material Model ◽

Resistance Force ◽

Model Parameters ◽

Inflation Pressure ◽

Viscoelastic Models ◽

Nonlinear Viscoelastic

This research work is devoted to the study of the effect of model parameters and material properties on tire rolling resistance. The main goal of this research is to investigate and clarify the effect of the adopted hyper-viscoelastic material model on tire rolling resistance simulation results. For this purpose, some new approaches were used and current shortcomings were introduced. Computer simulations were carried out using Abaqus standard command line. Linear and parallel rheological framework viscoelastic models were implemented and rolling resistance of a passenger car tire was determined. Different parametric simulations were carried out and the results were compared with rolling resistance data obtained from experimental tests. The results revealed that the calculated rolling resistance force depends on the implemented viscoelastic model. The linear viscoelastic model could not accurately predict the trend of rolling resistance with variation of tire inflation pressure and applied load. On the contrary, parallel rheological framework could cope with this trend. The parallel rheological framework model is more sensitive to inflation pressure. However, the sensitivity of both models to applied vertical load is nearly the same. Although cornering simulation is independent of the adopted viscoelastic model, the type of viscoelastic model could affect the footprint contact pressure contour.

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Influence of hydrostatic pressure and volumetric strain on the mechanical long term behavior of polymers

Journal of Polymer Engineering ◽

10.1515/polyeng-2012-0033 ◽

2012 ◽

Vol 32 (6-7) ◽

pp. 327-333 ◽

Cited By ~ 4

Author(s):

Tobias Naumann ◽

Markus Stommel

Keyword(s):

Hydrostatic Pressure ◽

Mechanical Behavior ◽

Free Volume ◽

Creep Behavior ◽

Volumetric Strain ◽

Material Model ◽

Tensile Creep ◽

Creep Tests ◽

Long Term Behavior

Abstract One of the most crucial issues in developing a material model to describe the long term behaviour of polymers is to represent adequately the load dependency of the considered material. In many publications, it is shown that the free volume affects the mechanical behavior of polymers. For a further investigation of the dependency of the creep behavior on free volume, different experiments are presented in this paper. In one experiment, the creep behavior under tension and shear are compared, to see how the different hydrostatic pressures in these tests influence mechanical behavior. Furthermore, tensile creep tests under different hydrostatic pressures are conducted experimentally. The experiments are conducted on a polycarbonate, a polypropylene and a polymethyl methacrylate. It is shown that the hydrostatic pressure has a significant influence on the creep behavior of all three materials. This effect is related to the change of free volume.

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Rheological characterization of tack and viscoelasticity of compositions of crepe coating used in the Yankee dryer

TAPPI Journal ◽

10.32964/tj18.11.641 ◽

2019 ◽

Vol 18 (11) ◽

pp. 641-649

Author(s):

JOSHUA OMAMBALA ◽

CARL MCINTYRE

Keyword(s):

Normal Force ◽

Weight Ratio ◽

Good Combination ◽

Rheological Characterization ◽

Nonlinear Viscoelastic ◽

Coating Composition ◽

Linear And Nonlinear ◽

Work Done ◽

Tissue Production

The vast majority of tissue production uses creping to achieve the required set of properties on the base sheet. The Yankee coating helps to develop the desired crepe that in turn determines properties such as bulk and softness. The adhesion of the sheet to the Yankee surface is a very important characteristic to consider in achieving the desired crepe. The coating mix usually consists of the adhesive, modifier, and release. A good combination of these components is essential to achieving the desired properties of the tissue or towel, which often are determined by trials on the machine that can be time consuming and lead to costly rejects. In this paper, five compositions of an industrial Yankee coating adhesive, modifier, and release were examined rheologically. The weight ratio of the adhesive was kept constant at 30% in all five compositions and the modifier and release ratios were varied. The normal force and work done by the different compositions have been shown at various temperatures simulating that of the Yankee surface, and the oscillatory test was carried out to explain the linear and nonlinear viscoelastic characteristic of the optimal coating composition.

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NUMERICAL CHARACTERIZATION OF ACRYLIC POLYMER UNDER QUASI-STATIC AND DYNAMIC LOADING BY IMPLEMENTING VISCOELASTIC MATERIAL MODEL

Composites Mechanics Computations Applications An International Journal ◽

10.1615/compmechcomputapplintj.v5.i3.20 ◽

2014 ◽

Vol 5 (3) ◽

pp. 195-205

Author(s):

Uzair Ahmed Dar

Keyword(s):

Dynamic Loading ◽

Viscoelastic Material ◽

Material Model ◽

Acrylic Polymer ◽

Numerical Characterization ◽

Static And Dynamic Loading

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Statistical analysis of creep behavior in thermoset and thermoplastic composites reinforced with carbon and glass fibers

The Journal of Strain Analysis for Engineering Design ◽

10.1177/0309324720976637 ◽

2020 ◽

pp. 030932472097663

Author(s):

Francisco Maciel Monticeli ◽

Ana Karoline dos Reis ◽

Roberta Motta Neves ◽

Luis Felipe de Paula Santos ◽

Edson Cocchieri Botelho ◽

...

Keyword(s):

Creep Behavior ◽

Glass Fibers ◽

Laminated Composite ◽

Analytical Models ◽

Thermoplastic Composites ◽

Temperature Dependent ◽

Creep Tests ◽

Thermoset Composites ◽

Strain Behavior ◽

Sensitivity Range

The thermoplastic and thermoset laminates reinforced with different fibers generate variations in the laminated composite mechanical behavior. This work aims to analyze thermoplastic and thermoset composites creep behavior with a reduced number of experiments, applying curve-fitting analytical models (Weibull and Findley) and statistical approach (ANOVA, F-test, and SRM) in order to describe creep behavior. Creep tests were carried out using a design of experiments to define parameter levels, aiming to reduce the number of the experiments, keeping reliability relevance. The temperature shows a stronger influence of creep deformation compared with the use of distinct materials. Thermoplastic matrices seem to be more sensitive to deformation, decreasing the reinforcement contribution. On the other hand, the creep resistance of the thermoset matrix conducts a significant contribution of strain behavior for the reinforcement used. The Findley model showed a temperature-dependent response. While, the Weibull-based model exhibits temperature and material-dependence, ensuring a greater sensitivity range of the parameters applied, an essential factor for a more realistic method description.

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