An Alteration of the Time-Temperature Superposition Principle to Account for Environmental Degradation in Fibre Reinforced Plastics

The approach suggested in this analysis stems from basic material science laws and considers that any environmental degradation of polymer composites ultimately consists in chemical link and cohesion force alteration. Such alteration leads to the modification of material viscoelastic characteristics that can be measured through stress relaxation or creep. Then the analysis deals with the applicability of the time-temperature shift principle for prediction test in cases involving environmental degradation. It is demonstrated that the shift factor as determined from Arrhenius Law needs to incorporate an additional term to account for the variation of the activation energy of the chemical and physical degradation. The method leads to excellent prediction of the time and environment dependent material strength.

Time–Temperature Superposition for Asphalt Mixtures with Growing Damage and Permanent Deformation in Compression

Transportation Research Record Journal of the Transportation Research Board ◽

10.3141/1832-20 ◽

2003 ◽

Vol 1832 (1) ◽

pp. 161-172 ◽

Cited By ~ 27

Author(s):

Yanqing Zhao ◽

Y. Richard Kim

Keyword(s):

Permanent Deformation ◽

Superposition Principle ◽

Asphalt Mixture ◽

Temperature Shift ◽

Shift Factor ◽

Compression Tests ◽

Loading Test ◽

Time Temperature Superposition ◽

The objective in this study was to check the validity of the time–temperature superposition principle for hot-mix asphalt (HMA) with growing damage and viscoplastic strain in the compression state, which is essential for the permanent deformation characterization of HMA. Constant crosshead rate compression tests were conducted at temperatures between 25°C and 55°C, and data were analyzed to construct the stresslog reduced-time master curves for various strain levels. Research results indicate that HMA with growing damage remains thermorheologically simple in the temperature range used in this study and that the time–temperature shift factor is only a function of temperature and is independent of the strain level. Two types of tests, the repeated creep and recovery test and the cyclic sinusoidal loading test, were performed in this study to validate the time–temperature superposition in loading histories commonly used in asphalt mixture testing. The results further confirm that the time–temperature superposition is valid for HMA with growing damage and permanent deformation and that the response of HMA depends only on the reduced loading history.

Temperature Correction of Backcalculated Moduli and Deflections Using Linear Viscoelasticity and Time-Temperature Superposition

Transportation Research Record Journal of the Transportation Research Board ◽

10.3141/1570-13 ◽

1997 ◽

Vol 1570 (1) ◽

pp. 108-117 ◽

Cited By ~ 6

Author(s):

Sun Woo Park ◽

Y. Richard Kim

Keyword(s):

Linear Viscoelasticity ◽

Superposition Principle ◽

Asphalt Mixture ◽

Temperature Shift ◽

Relaxation Modulus ◽

Analytical Description ◽

Shift Factor ◽

Temperature Correction ◽

Time Temperature Superposition

New analytical procedures for temperature correction of backcalculated asphalt concrete moduli and surface deflections were developed based on the theory of linear viscoelasticity and the time-temperature superposition principle and verified using falling weight deflectometer data and field temperature measurements. The new correction procedures explicitly utilize the thermorheological properties of the asphalt mixture. The resulting temperature-modulus correction factors depend only on the relaxation modulus and time-temperature shift factor of the mixture. The temperature-deflection correction factor depends on both the material properties and the layer thicknesses of the pavement section. Emphasis has been placed on the analytical description of the mixture’s thermoviscoelasticity responsible for temperature effects on mixture modulus and pavement deflection. A mechanistic framework for dealing with temperature correction problems for asphalt pavement has been introduced.

Rubber aging life prediction based on interpolation and improved time-temperature superposition principle

Materials Research Express ◽

10.1088/2053-1591/ac45ba ◽

2021 ◽

Author(s):

Kunheng Li ◽

Zhiyong Chen ◽

Wenku Shi

Keyword(s):

Life Prediction ◽

Room Temperature ◽

Superposition Principle ◽

Accelerated Aging ◽

Shift Factor ◽

Performance Degradation ◽

Polymer Materials ◽

Time Temperature Superposition ◽

Abstract With focus on quickly and accurately predicting and evaluating the aging performance degradation of rubber at room temperature, the pseudo-failure life at each different acceleration temperature is proposed to be calculated by interpolation method based on indoor high temperature accelerated aging data, and on the basis of the obtained pseudo-failure life.By introducing the time–temperature equivalence principle, a shift factor obeying to an Arrhenius law is derived, and master curves are built as well for the compression set as for the ultimate mechanical properties.The concept of the sum of squares of dispersion coeﬀicient errors is proposed to evaluate the prediction accuracy.Meanwhile a quantitative calculation method that considers the effect of temperature on the performance degradation curve and the shift factor is innovatively proposes.The results show that the proposed optimization method based on the traditional time-temperature superposition principle can quickly process the aging life at room temperature, and the prediction results are distributed within the 3-fold dispersion line, which can well meet the engineering requirements. The reduction of the DSC value from 1.4164 to 1.0828 further demonstrates the effectiveness of the proposed method above. This method can provide some reference for other related polymer materials accelerated aging data processing and life prediction.

Application of TTSP to wood-development of a vertical shift factor

Holzforschung ◽

10.1515/hf-2016-0081 ◽

2017 ◽

Vol 71 (1) ◽

pp. 51-55 ◽

Cited By ~ 3

Author(s):

Fuli Wang ◽

Tianlai Huang ◽

Zhuoping Shao

Keyword(s):

Stress Relaxation ◽

Master Curve ◽

Goodness Of Fit ◽

Superposition Principle ◽

Relaxation Curve ◽

Shift Factor ◽

Vertical Shift ◽

Wood Development ◽

Abstract The applicability of the time-temperature superposition principle (TTSP) to wood has been investigated aiming at the prediction of long-term mechanical properties of wood by both horizontally and vertically shifting of short-term stress relaxation data obtained by experiments. The expression of TTSP considering the vertical shift factor (bT) for wood is proposed the first time. The results showed that: (1) TTSP applied to poplar and the master curve that was obtained from 1 h of tests at 283.2, 303.2, 320.2, 343.2, and 363.2 K in a relative humidity (RH) of 60% could predict the stress relaxation behavior for approximately 42 years at 283.2 K and 60% RH. (2) There was a linear correlation between lgaT and T-1, lg aT=6590.40 T-1-23.64 (R2=0.994), which followed the Arrhenius equation well, while the apparent activation energy was 34.6 kcal mole-1. (3) The bT had a linear relationship with temperature, and the relation was lgbT=0.0013T-0.37 (R2=0.999). (4) The long-term relaxation curve of the long-term verification test had high goodness of fit with the master curve. The results can be interpreted that the TTSP expression considering the bT proposed in this paper is rational.

FRP for Marine Application

10.5772/intechopen.101332 ◽

2021 ◽

Author(s):

Bikash Chandra Chakraborty

Keyword(s):

Vinyl Ester ◽

Sea Water ◽

Superposition Principle ◽

Marine Corrosion ◽

Sulfate Reducing ◽

Specific Strength ◽

Reinforced Plastics ◽

Marine Application ◽

Reinforced Cement ◽

Fiber Reinforced Plastics (FRPs) are widely used in marine sector owing to their high specific strength and resistance to marine corrosion. For naval application, additional advantages are transparency to radar wave and better vibration damping than metals. The use of various FRPs in off-shore structures and marine vessels needs analysis of desired properties considering the types of matrices and fiber. The common consideration is effect of sea water on the properties of the FRP. This chapter gives a brief on use of different FRPs in various areas such as off-shore pillars, Reinforced Cement Concrete (RCC) enclosers, primary and secondary marine components. A brief discussion is included here on diffusion models and estimation of durability by a time-temperature superposition principle applied to water ingress and corresponding change in mechanical strength of FRPs with examples. The effect of microbial activity on the damage of FRP is not very much reported in literature. It is known that sulfate-reducing bacteria (SRB) are the most damaging microbes for FRP. In conclusion, it is highlighted that vinyl-ester-based FRPs using glass and carbon fibers are best for marine application. To determine the realistic service life in marine environment, Vinyl Ester- FRP (VE-FRP) are to be simultaneously studied for damage due to sea water and the microbes such SRB.

Integration of Atomistic Simulation with Experiment Using Time−Temperature Superposition for a Cross-Linked Epoxy Network

10.26434/chemrxiv.8326172 ◽

2019 ◽

Author(s):

Ketan Khare ◽

Frederick R. Phelan Jr.

Keyword(s):

Master Curve ◽

Glassy State ◽

Superposition Principle ◽

Quantitative Comparison ◽

Time Shift ◽

Data Sets ◽

Epoxy Network ◽

Time Temperature Superposition ◽

<a></a><a>Quantitative comparison of atomistic simulations with experiment for glass-forming materials is made difficult by the vast mismatch between computationally and experimentally accessible timescales. Recently, we presented results for an epoxy network showing that the computation of specific volume vs. temperature as a function of cooling rate in conjunction with the time–temperature superposition principle (TTSP) enables direct quantitative comparison of simulation with experiment. Here, we follow-up and present results for the translational dynamics of the same material over a temperature range from the rubbery to the glassy state. Using TTSP, we obtain results for translational dynamics out to 10<sup>9</sup> s in TTSP reduced time – a macroscopic timescale. Further, we show that the mean squared displacement (MSD) trends of the network atoms can be collapsed onto a master curve at a reference temperature. The computational master curve is compared with the experimental master curve of the creep compliance for the same network using literature data. We find that the temporal features of the two data sets can be quantitatively compared providing an integrated view relating molecular level dynamics to the macroscopic thermophysical measurement. The time-shift factors needed for the superposition also show excellent agreement with experiment further establishing the veracity of the approach</a>.