Molecular mobility of poly(methyl methacrylate) glass during uniaxial tensile creep deformation

The uniaxial tensile creep of a commercial grade Poly(methyl methacrylate) was measured for 4000 seconds under various temperatures and stress levels ranging from 14 oC to 26 oC and 6 MPa to 32 MPa. The resultant creep compliance curves depart from each other for stresses beyond a critical value which varies with temperature, indicating nonlinear viscoelastic behavior. The time-temperature-stress superposition principle (TTSSP) was used to construct a smooth master compliance curve with a much longer time-scale interval from the short-term tests at higher stresses and temperatures. It is shown that the master curve covers a period of over 290 days, which is nearly 3.9 decades longer than the test duration. Moreover, it is verified that the time-temperature shift factors are dependent on stresses at which the shifts are applied, and that the time-stress shift factors are dependent on reference temperatures.

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Microstructure evolution accompanying high temperature; uniaxial tensile creep of self-reinforced silicon nitride ceramics

Materials Science and Engineering A ◽

10.1016/s0921-5093(99)00497-9 ◽

1999 ◽

Vol 272 (2) ◽

pp. 380-388 ◽

Cited By ~ 6

Author(s):

Q Wei ◽

J Sankar ◽

A.D Kelkar ◽

J Narayan

Keyword(s):

High Temperature ◽

Silicon Nitride ◽

Microstructure Evolution ◽

Tensile Creep ◽

Uniaxial Tensile ◽

Nitride Ceramics ◽

Uniaxial Tensile Creep

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Tensile Creep Behavior of HPC at Early Ages under Different Curing Temperatures

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.250-253.434 ◽

2011 ◽

Vol 250-253 ◽

pp. 434-439 ◽

Cited By ~ 1

Author(s):

Yang Yang ◽

Peng Li ◽

Yan Ping Wu

Keyword(s):

Creep Rate ◽

Creep Behavior ◽

Strength Class ◽

Concrete Specimen ◽

Curing Temperature ◽

Tensile Creep ◽

Uniaxial Tensile ◽

Creep Coefficient ◽

The Difference ◽

Uniaxial Tensile Creep

This paper presents an experimental investigation on tensile basic creep behavior of HPC at early ages by using a uniaxial tensile creep testing apparatus. Concrete specimens of 100×100×400mm with compressive strength class 60MPa was used, sealed and loaded at different curing temperature. The effects of the curing temperature and the age at loading on creep behavior are discussed. The results show that tensile specific creep and creep rate of HPC at early ages were governed by the age at loading. The specific creep, creep coefficient and creep rate were larger at earlier loading ages, and decreased exponentially with age at loading. The tensile specific creep decreased with curing temperature, but the difference in creep due to different curing temperatures decreased with the age at loading, and could be ignored while concrete specimen being loaded after the age of 7 days.

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Mechanochemical reactions of some polyurethane elastomers. 3. Prediction of long-term uniaxial tensile creep using linear compliance as a basis

Colloid & Polymer Science ◽

10.1007/bf01412596 ◽

1986 ◽

Vol 264 (7) ◽

pp. 590-594 ◽

Cited By ~ 1

Author(s):

C. V. Oprea ◽

A. C. Constantinescu ◽

P. B�rsanescu

Keyword(s):

Tensile Creep ◽

Uniaxial Tensile ◽

Polyurethane Elastomers ◽

Mechanochemical Reactions ◽

Uniaxial Tensile Creep

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Secondary processes of poly(methyl methacrylate) and their activation energies as determined by shear and tensile creep compliance measurements

Journal of Polymer Science Part A-2 Polymer Physics ◽

10.1002/pol.1968.160060301 ◽

1968 ◽

Vol 6 (3) ◽

pp. 433-449 ◽

Cited By ~ 7

Author(s):

Edward V. Thompson

Keyword(s):

Methyl Methacrylate ◽

Creep Compliance ◽

Activation Energies ◽

Tensile Creep ◽

Poly Methyl Methacrylate

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Viscoelastic Finite Element Modeling of Bimodal High Density Polyethylene (HDPE) Piping Materials for Nuclear Safety-Related Applications

ASME 2010 Pressure Vessels and Piping Conference: Volume 6, Parts A and B ◽

10.1115/pvp2010-25715 ◽

2010 ◽

Cited By ~ 1

Author(s):

Do-Jun Shim ◽

Prabhat Krishnaswamy ◽

Yunior Hioe ◽

Sureshkumar Kalyanam

Keyword(s):

Finite Element ◽

Service Life ◽

High Density Polyethylene ◽

Viscoelastic Behavior ◽

Time Dependent ◽

Tensile Creep ◽

Uniaxial Tensile ◽

Fe Model ◽

Creep Tests ◽

Uniaxial Tensile Creep

The U.S. Nuclear Regulatory Commission (USNRC) has recently approved Relief Requests for the use of high density polyethylene (HDPE) piping in safety-related applications. The ASME Boiler and Pressure Vessel Code, meanwhile, has developed Code Case N-755 that defines the design and service life requirements for PE piping in nuclear plants though it has not as yet been approved by the USNRC. One of the issues of concern is premature failure of PE piping due to slow crack growth (SCG) that can initiate due to a combination of sustained loads, elevated temperatures, and a pre-existing defect. Understanding and predicting the SCG behavior is an essential step in developing a methodology for predicting the service life of PE piping. The first step in studying the failure process in a polymer under a constant sustained load is the selection of a suitable constitutive model to represent the time-dependent behavior of the material. In this paper, uniaxial tensile creep tests were performed for a bimodal HDPE (PE4710) piping material. This creep data was used to determine the viscoelastic material constants for this bimodal HDPE using a power-law creep model. These material constants were used in finite element (FE) analyses to study the viscoelastic behavior of the bimodal HDPE. As a first step, the FE model was verified by comparing the results from numerical simulations and experiments for a set of uniaxial tensile creep tests. The FE model was then applied to study the viscoelastic behavior of a SCG specimen. The time dependent stress and strain fields were investigated.

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