Universal aspects of composite viscoelastic behavior

Sullivan, J. L.; Wen, Yuan; Gibson, Ronald F.

doi:10.1002/pc.750160103

Cited by 14 publications

(4 citation statements)

References 11 publications

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“…One of the criteria for the applicability of TTS is that the temperature dependence of a T must have a reasonable form consistent with experience [23]. Generally, a T is a function of temperature alone if there is no physical aging [24,25]. So, it is important to examine the form of a T as a function of temperature.…”

Section: Time-temperature Superpositionmentioning

confidence: 99%

Viscoelastic Behaviors of Ultrahigh Molecular Weight Polyethylene Under Three-Point Bending and Indentation Loading

Deng

Uhrich

2009

J Biomater Appl

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Dynamic mechanical properties under three-point bending and deformation behavior under indentation loading of an ultrahigh molecular weight polyethylene (UHMWPE) were investigated in this study. Dependence of its viscoelastic properties on temperature, frequency, load level, specimen geometry and heating rates were examined. The results showed that temperature and frequency had significant effects on the response of UHMWPE to the dynamic load. With the increase in temperature, the storage modulus (E') was decreased and the loss angle (tan delta) was increased, indicating an increase in the trend in viscoelastic response of the polymer at high temperature. On the other hand, when frequency was increased, higher E' and lower tan delta were observed, suggesting that the material behaved more elastically. While the two heating rates of 5 degrees C/min and 10 degrees C/min had little effect on E' and tan delta, the load level significantly influenced the dynamic mechanical properties of the polymer. UHMWPE showed quite different responses at 0.5 and 20 Hz than at 1-10 Hz, which is worth further investigation. The results from indentation experiment showed that temperature, specimen geometry and load level had significant effects on the response of UHMWPE to the indentation load. With the increase in temperature, the penetration depth was increased, indicating an increase in the deformation trend in the polymer at high temperature. High load led to high penetration. The time-temperature superposition (TTS) method could be used to predict the long-term penetration behaviors of the polymer. From TTS analysis, the activation energy associated with penetration deformation was obtained. Further analysis showed that it might be possible to increase the resistance of UHMEPE to indentation deformation by increasing the thickness and/or decreasing the diameter of the polymer samples.

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Section: Time-temperature Superpositionmentioning

confidence: 99%

Viscoelastic Behaviors of Ultrahigh Molecular Weight Polyethylene Under Three-Point Bending and Indentation Loading

Deng

Uhrich

2009

J Biomater Appl

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“…The principle of time-temperature superposition is applicable to fiberreinforced plastics, though only for short-term creep [13]. The viscoelastic nature of polymers causes their deformation to depend on time as well as temperature.…”

Section: Dma Creep Testmentioning

confidence: 99%

Finite Element Analysis of Composite Worm Gears

Maheedhara

Pourboghrat

2007

Journal of Thermoplastic Composite Materials

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Worm gears are commonly used in windshield wipers and power windows of automobiles. The goal of this work is to study several material problems, such as production bottlenecks and excessive scrap, resulting from the production of steel worm shafts. A possible solution is explored in this work by characterizing material properties of a promising candidate (glass reinforced acetal copolymer) that can replace steel in worm gears. Finite element analysis of the worm thread under static loading and constant temperature is performed in order to calculate the size of the new composite part. The results obtained in this work support the possibility of manufacturing composite worm shafts that could operate at elevated temperatures without sacrificing part performance, while reducing part weight leading to improved fuel economy, noise reduction, and manufacturing problems associated with the steel part. The finite element analysis shows that compared to a steel gear, the axial pitch of a composite worm gear must be increased by 250% in order for it to operate without failure for 10 years at a constant temperature of 23%C. This increase in the axial pitch would ramp up to 400%, if the composite worm gear is expected to operate for 10 years at a constant temperature of 100 C.

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“…21 Generally, a T is a function of temperature alone if there is no physical aging. 22,23 Thus, it is important to examine the form of a T as a function of temperature for the material systems used in this study. First, the classical WLF equation 21 was used to describe the relationship between a T and temperature.…”

Section: Shift Factormentioning

confidence: 99%

Study of creep behavior of ultra-high-molecular-weight polyethylene systems

Deng

Latour

Ogale

et al. 1998

J. Biomed. Mater. Res.

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The short- and long-term creep behaviors of ultra-high-molecular-weight polyethylene (UHMWPE) systems (compression-molded UHMWPE sheets and self-reinforced UHMWPE composites) have been investigated. The short-term (30-120 min) creep experiment was conducted at a load of 1 MPa and a temperature range of 37-62 degrees C. Based on short-term creep data, the long-term creep behavior of UHMWPE systems at 1 MPa and 37 degrees C was predicted using time-temperature superposition and analytical formulas. Compared to actual long-term creep experiments of up to 110 days, the predicted creep values were found to well describe the creep properties of the materials. The creep behaviors of the UHMWPE systems were then evaluated for a creep time of longer than 10 years, and it was found that most creep deformation occurs in the early periods. The shift factors associated with time-temperature superposition were found to increase with increasing temperature, as per the Arrhenius equation. The effects of temperature, materials, and load on the shift factors could be explained by the classical free volume theory.

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Universal aspects of composite viscoelastic behavior

Cited by 14 publications

References 11 publications

Viscoelastic Behaviors of Ultrahigh Molecular Weight Polyethylene Under Three-Point Bending and Indentation Loading

Viscoelastic Behaviors of Ultrahigh Molecular Weight Polyethylene Under Three-Point Bending and Indentation Loading

Finite Element Analysis of Composite Worm Gears

Study of creep behavior of ultra-high-molecular-weight polyethylene systems

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