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Frequency range optimization for linear viscoelastic characterization of Burger's model

INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES 2025年 285卷

作者： Wang, Chen Anupam, Kumar Kasbergen, Cor Erkens, Sandra Delft Univ Technol Fac Civil Engn & Geosci Sect Pavement Engn Stevinweg 1 NL-2628 CN Delft Netherlands

The linear viscoelastic behavior of materials is represented using mechanical models of choice, which are further utilized in different numerical investigations, such as finite element simulations and discrete element simulations. Burger's model is one of the widely adopted mechanical models and remains highly favored in contemporary research due to its multiple advantages. Specifically, it excels in representing long-term creep and stress relaxation behavior in a relatively simplified manner. Accurate identification of the long-term behavior for the viscoelastic material, particularly asphalt concrete, is crucial, as it serves as a key indicator of asphalt pavement performance over its service life. However, past research studies show that the parameters of Burger's model should be back-calculated from experimental data only within a limited range of frequency, otherwise, the parameters fail to represent the true material behavior. To the best of the authors' knowledge, there is no approach for researchers to obtain the critical frequency range in which the experiments should be performed. Therefore, this study proposes a novel framework to find the critical frequency range to obtain appropriate model parameters of Burger's model, to better characterize the viscoelastic behavior of the materials. To examine the framework, asphalt concrete mixtures are used as examples in this study. Necessary laboratory tests including complex modulus tests and stress relaxation tests, are performed on two distinctive types of asphalt concrete mixtures. The generalized Maxwell model with different number of Maxwell chains are used to evaluate the performance of Burger's model. Furthermore, since commercially available finite element packages generally do not have a direct built-in Burger's model, the article shows a way of implementing Burger's model in finite element simulation. The simulations corresponding to the laboratory tests are carried out in both frequency domain and time

关键词： viscoelastic characterization Constitutive modeling Computational method Burger's model Optimal frequency range Stress relaxation

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viscoelastic characterization and self-heating behavior of laminated fiber composite driveshafts

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MATERIALS & DESIGN 2015年第PartA期66卷 346-355页

作者： Henry, Todd C. Bakis, Charles E. Smith, Edward C. Penn State Univ Dept Aerosp Engn University Pk PA 16802 USA Penn State Univ Dept Engn Sci & Mech University Pk PA 16802 USA

The high cyclic strain capacity of fiber reinforced polymeric composites presents an opportunity to design driveshafts that can transmit high power under imperfect alignment conditions without the use of flexible couplers. In weight sensitive applications such as rotorcraft, the design of highly optimized driveshafts requires a general modeling capability that can predict a number of shaft performance characteristics-one of which is self-heating due to dynamic loading conditions. The current investigation developed three new flexible matrix composite materials of intermediate matrix modulus that, together with previously developed composites, cover the full range of material properties that are of potential interest in driveshaft design. An analytical model for the self-heating of spinning, misaligned, laminated composite shafts was refined to suit the full range of materials. Inputs to the model include ply-level dynamic material properties of the composite, cyclic strain amplitude and frequency, and various heat transfer constants related to conduction, radiation, and convection. Predictions of the surface temperature of spinning shafts correspond well with experimental measurements for bending strains of up to 2000 le, which encompasses the range of strains expected in rotorcraft driveshaft applications. (C) 2014 Elsevier Ltd. All rights reserved.

关键词： Composite driveshaft Dynamic mechanical analysis viscoelastic characterization Self-heating

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viscoelastic characterization of Microwave Drying Nature Rubber

Viscoelastic Characterization of Microwave Drying Nature Rub...

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International Conference on Advanced Engineering Materials and Technology (AEMT2011)

作者： Zhang, Fuquan Wang, Yongzhou Chen, Mei Huang, Maofang Hainan Univ Hainan 570228 Haikou Peoples R China Minist Agr Agr Prod Proc Res Inst Key Lab Nat Rubber Proc Zhanjiang 524001 Peoples R China

ISBN: (纸本)9783037851937

Nature rubber (NR) is neither completely viscous nor elastic in nature, but viscoelastic in their properties. In the experiment, we used two types of equipments named rubber process analyzer (RPA) 2000 and mooney viscometer to characterize the viscoelastic properties of NR dried by microwave and hot-air, respectively. In present research, RPA tests on uncured NR dried by different methods were carried out using frequency and strain sweeps, and Mooney viscometer was detected using the big rotor at 100 degrees C. The results showed that microwave drying has not influenced the viscoelastic properties of NR greatly, without changing the profiles of its rheological behavior. Compared with hot-air drying, the properties of NR dried by microwave improved significantly. As a new application, microwave drying technology offered an alternative way to the drying of NR.

关键词： nature rubber microwave drying viscoelastic characterization mooney viscometer RPA 2000

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Thermal, structural, and viscoelastic characterization of cis-poly(phenylene vinylene) related to its photo-isomerization

POLYMER JOURNAL

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POLYMER JOURNAL 2006年第2期38卷 184-189页

作者： Katayama, H Ozawa, F Matsumiya, Y Watanabe, H Kyoto Univ Inst Chem Res Kyoto 6110011 Japan

A cis-poly(phenylene vinylene) (cis-PPV) recently synthesized by Katayama, Ozawa, and coworkers undergoes photo-isomerization into trans configuration. This isomerization occurred rather quickly within 45 min in solvent-cast films at room temperature. The cis-PPV chains exhibiting this quick isomerization were expected to be highly mobile in the bulk state, and this expectation was examined from thermal, structural, and viscoelastic tests for a cis-PPV sample with M-n = 4300 and M-w/M-n = 2.16. It turned out that the as-polymerized cis-PPV was partially crystalline and fully melted at T-m congruent to 109 degrees C. The samples quenched from a molten state to lower temperatures (<= 70 degrees C < T-m) as well as cast from a solution were amorphous for few hours, enabling the viscoelastic test in the fully amorphous state. The WLF-type time-temperature superposition was valid for these quenched and/or cast sample, confirming the amorphous character of the cis-PPV chains therein. The terminal viscoelastic relaxation time of these chains, equivalent to a time required for thermal changes in a large-scale conformation, was congruent to 10 s at room temperature. This result suggested that the conformational changes of the amorphous chains (the major component in the cast films) were sufficiently fast to allow the efficient cis-to-trans photo-isomerization.

关键词： poly(phenylene vinylene) semicrystalline viscoelastic characterization

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Linear Hygrothermal viscoelastic characterization of Nafion NRE 211 Proton Exchange Membrane

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FUEL CELLS 2012年第5期12卷 787-799页

作者： Patankar, K. A. Dillard, D. A. Case, S. W. Ellis, M. W. Lai, Y. -H. Gittleman, C. S. Virginia Polytech Inst & State Univ Engn Sci & Mech Dept Blacksburg VA 24061 USA Virginia Polytech Inst & State Univ Dept Mech Engn Blacksburg VA 24061 USA Gen Motors Corp Fuel Cell Res Lab Honeoye Falls NY 14472 USA

The tensile relaxation modulus of a commercially available proton exchange membrane, Nafion (R) NRE 211, was obtained over a range of humidity levels and temperatures using a commercial dynamic mechanical analyzer (DMA). Hygral stress relaxation master curves were first constructed, followed by a hygrothermal master curve using the time temperature moisture superposition principle. The hygrothermal master curve was fitted using a 10-term Prony series and validated using longer term stress relaxation tests. To validate the results from the stress relaxation experiments, short and long-term creep compliance was converted into stress relaxation modulus using a well-known viscoelastic conversion formula, and compared with the relaxation modulus obtained under identical conditions. Good agreement was found between the two datasets. It was evident that relaxation data at 2% RH at the test temperatures was not superposable with the master curves obtained at higher relative humidity (10%?

关键词： Doubly Shifted Master Curve Dry-Humid Transition Hygrothermal Stresses Mechanical Durability Nafion NRE 211 Physical Aging Proton Exchange Membranes Time Temperature Moisture Superposition Principle viscoelastic characterization

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On the viscoelastic characterization of thin tissues via surface-wave sensing

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INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES 2011年第14-15期48卷 2209-2217页

作者： Bialas, Marcin Guzina, Bojan B. Univ Minnesota Dept Civil Engn Minneapolis MN 55455 USA Inst Fundamental Technol Res PL-02106 Warsaw Poland

This paper establishes a theoretical and computational framework for the development of a novel piezoelectric sensor array for the monitoring of surficial tissue motion that can be used as a basis for the reconstruction of layered viscoelastic skin properties. This is accomplished by the scale reduction of the so-called Multi-channel Analysis of Surface Waves (MASW), a methodology that is successfully used in engineering geophysics for the seismic-wave reconstruction of vertical geological profiles. The utility of the new sensor, containing an array of hair-like PVDF sensors that are sensitive to surficial tissue motion, is enhanced through a systematic solid-fiber interaction analysis that furnishes integral information, cumulative over the length of each fiber, about the attenuation and dispersion of surface waves. On employing such a predictive model as a lynchpin of the full waveform back-analysis used to interpret electric charges generated by the fibers, the methodology allows for an effective reconstruction and viscoelastic characterization of cutaneous and subcutaneous tissue sublayers on a millimeter scale. The performance of the proposed sensor array and data interpretation framework is illustrated through numerical simulations, which point to the feasibility of cost-effective, in vivo mechanical characterization of skin sublayers. (C) 2011 Elsevier Ltd. All rights reserved.

关键词： viscoelastic characterization Mechanical skin properties Multi-channel Analysis of Surface Waves Piezoelectric sensor

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A Novel Nondestructive Procedure for Tire Tread viscoelastic characterization

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TIRE SCIENCE AND TECHNOLOGY 2022年第1期50卷 61-77页

作者： Genovese, Andrea Pastore, Sebastian Rosario Univ Naples Federico II Dept Ind Engn Via Claudio 21 I-80125 Naples Italy

Vehicle dynamics is largely influenced by the phenomena occurring in the tire-road interface, and a great portion of these phenomena is mainly conditioned by the viscoelastic properties of the tire tread compound. It is not surprising that the possibility of obtaining the viscoelastic response of a compound by means of a nondestructive procedure is a growing research topic that affects application fields ranging from monitoring of the material performance during its entire life cycle to the quantitative analysis of product quality and repeatability of production processes. In this article, a novel nondestructive procedure for the viscoelastic characterization of tire tread compound is proposed. A portable instrument, based on instrumented indentation. was designed and prototyped with the aim to allow a real-time assessment of moduli directly on site. The testing procedure adopted to perform the test on three different compounds was described. A signal-processing procedure was developed for the identification of compound stiffness and damping parameters from which viscoelastic moduli were estimated. The results were also compared with the Dynamic Mechanical Analysis characterization showing the same relative ranking between the compounds with a different trend in temperature due to the amount of the tests' indentation depth.

关键词： properties of tire materials nondestructive test viscoelastic characterization viscoelastic properties polymer testing indentation

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Hygrothermal characterization of the viscoelastic properties of Gore-Select® 57 proton exchange membrane

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MECHANICS OF TIME-DEPENDENT MATERIALS 2008年第3期12卷 221-236页

作者： Patankar, Kshitish A. Dillard, David A. Case, Scott W. Ellis, Michael W. Lai, Yeh-Hung Budinski, Michael K. Gittleman, Craig S. Virginia Polytech Inst & State Univ Dept Engn Sci & Mech Blacksburg VA 24061 USA Virginia Polytech Inst & State Univ Dept Mech Engn Blacksburg VA 24061 USA Gen Motors Corp Fuel Cell Res Labs Honeoye Falls NY 14472 USA

When a proton exchange membrane (PEM) based fuel cell is placed in service, hygrothermal stresses develop within the membrane and vary widely with internal operating environment. These hygrothermal stresses associated with hygral contraction and expansion at the operating conditions are believed to be critical in membrane mechanical integrity and durability. Understanding and accurately modeling the viscoelastic constitutive properties of a PEM is important for making hygrothermal stress predictions in the cyclic temperature and humidity environment of operating fuel cells. The tensile stress relaxation moduli of a commercially available PEM, Gore-Select (R) 57, were obtained over a range of humidities and temperatures. These tests were performed using TA Instruments 2980 and Q800 dynamic mechanical analyzers (DMA), which are capable of applying specified tensile loading conditions on small membrane samples at a given temperature. A special humidity chamber was built in the form of a cup that encloses tension clamps of the DMA. The chamber was inserted in the heating furnace of the DMA and connected to a gas humidification unit by means of plastic tubing through a slot in the chamber. Stress relaxation data over a temperature range of 40-90 degrees C and relative humidity range of 30-90% were obtained. Thermal and hygral master curves were constructed using thermal and hygral shift factors and were used to form a hygrothermal master curve using the time temperature moisture superposition principle. The master curve was also constructed independently using just one shift factor. The hygrothermal master curve was fitted with a 10-term Prony series for use in finite element software. The hygrothermal master curve was then validated using longer term tests. The relaxation modulus from longer term data matches well with the hygrothermal master curve. The long term test showed a plateau at longer times, suggesting an equilibrium modulus.

关键词： proton exchange membranes polymer electrolyte membranes fuel cell viscoelastic characterization mechanical durability hygrothermal stresses dynamic mechanical analyzer Gore-Select (R) 57 stress relaxation time temperature moisture superposition principle doubly shifted master curve

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Moisture content, temperature, and grain orientation in timber and their effects on the viscoelastic properties and the characteristics of ultrasonic-guided waves

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MATERIALS AND STRUCTURES 2025年第4期58卷 1-23页

作者： Yassine, Reem Mustapha, Samir Malinowski, Pawel H. Amer Univ Beirut Dept Mech Engn Lab Smart Struct & Struct Integr SSSI Beirut Lebanon Polish Acad Sci Inst Fluid Flow Machinery PL-80231 Gdansk Poland

Timber is an essential natural material used in engineering applications, and its performance should be enhanced to ensure safe and long-term usage. This work studies the effect of moisture content (MC), temperature, and grain orientation on timber's viscoelastic properties. Accordingly, a non-destructive testing method is developed using a non-contact laser Doppler vibrometer (LDV) on timber structures. A dynamic mechanical analyzer (DMA) is employed to measure timber's viscoelastic properties with 0% to similar to 22% MCs and over - 20 degrees C to 100 degrees C for longitudinal, tangential, and radial specimens. Additionally, the dominant ultrasonic-guided wave (GW) is explored while studying the propagating modes in 10% to 27% moist timbers. The phase velocities are computed and compared to the analytical curves generated from the mechanical properties extracted from the DMA data. The results showed that the storage modulus, loss modulus, and tan delta decrease with increasing temperature and MC. Longitudinally, the storage modulus reduced by 27.5% at 0% MC and by 57.7% at 18% MC within the studied temperature range. The reduction is larger transversely than longitudinally, and the lowest storage modulus is observed radially. The relaxation peaks shifted to lower temperatures as MC increased. LDV results proved A(0) mode is dominant, and its phase velocities matched analytical results. The change in phase velocity is proportional to MC and temperature, due to the MC effect on timber's mechanical properties. The presented results showed high promise in terms of characterizing the viscoelastic behavior and the high sensitivity of A(0) mode along various directions of grain growth and MC.

关键词： viscoelastic characterization Ultrasonic guided waves Timber structures Grain orientation Moisture content

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characterization of viscoelastic bending stiffness of uncured carbon-epoxy prepreg slit tape

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COMPOSITE STRUCTURES 2021年 275卷 114295-114295页

作者： Rajan, Sreehari Sutton, Michael A. Wehbe, Roudy Gurdal, Zafer Kidane, Addis Emri, Igor Univ South Carolina Dept Mech Engn Columbia SC 29208 USA Univ Ljubljana Ljubljana Slovenia

In support of computational modeling of tow placement at elevated temperature, the creep response of IM7/8552 uncured prepreg slit tape material during 3-point bend loading at different temperatures is measured using an RSA III dynamic mechanical analyzer. Short term creep experiments were conducted for a duration of 1000 s at ten different temperatures ranging from -5 degrees C (below Tg of 0 degrees C) to 40 degrees C, with the latter being the nominal processing temperature for the tow. Results show that the tow material obeys the time-temperature superposition principle (TTSP) in the temperature range selected for the creep experiments. Using the TTSP, creep compliance master curve spanning more than eight logarithmic decades is obtained for the nominal processing temperature of 40 degrees C. The time-temperature shift factor is observed to follow closely the William-Landel-Ferry (WLF) model, with the WLF parameters obtained by least square fitting of the experimentally determined shift factors utilizing closed form shifting algorithm (CFS). The WLF model for the material is used to extend the master curve to a range of temperatures above glass transition temperature (Tg) of the material. The creep compliance data is further employed to obtain the retardation spectra of the material using an algorithm based on the work of a co-author and applied recently to a different material system by the authors. Details for extraction of the retardation spectra from the creep compliance results are provided. Results from these studies demonstrate that the creep compliance reconstructed from the retardation spectra accurately represent the experimental results while providing baseline data to quantify the importance of viscoelastic behavior in wrinkle formation during advanced manufacturing of aerospace components.

关键词： Uncured prepreg carbon epoxy slit tape viscoelastic characterization Bending stiffness Retardation spectra Automated fiber placement

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