Long-term creep behavior of SU-8 membranes: Application of the time–stress superposition principle to determine the master creep compliance curve

2008 ◽  
Vol 142 (1) ◽  
pp. 242-249 ◽  
Author(s):  
B. Schoeberle ◽  
M. Wendlandt ◽  
C. Hierold
Keyword(s):  
Creep Behavior ◽  
Creep Compliance ◽  
Superposition Principle ◽  
Time Stress ◽  
Compliance Curve ◽  
Stress Superposition ◽  
Term Creep

Effect of Stress-Induced Damage Evolution on Long-Term Creep Behavior of Nonlinear Viscoelastic Polymer

2006 ◽  
Vol 324-325 ◽  
pp. 731-734 ◽  
Author(s):  
Rong Guo Zhao ◽  
Wen Bo Luo ◽  
Chu Hong Wang ◽  
Xin Tang
Keyword(s):  
Methyl Methacrylate ◽  
Temperature Stress ◽  
Creep Behavior ◽  
Damage Evolution ◽  
Creep Compliance ◽  
Superposition Principle ◽  
Nonlinear Viscoelastic ◽  
Compliance Curve ◽  
Term Creep

The mechanical behaviors were investigated by nonlinear creep tests of poly(methyl methacrylate) under different temperatures. The test duration was 4000 seconds. The corresponding temperature shift factors, stress shift factors and temperature-stress shift factors were obtained according to time-temperature superposition principle, the time-stress superposition principle and the time-temperature-stress superposition principle (TTSSP). The master creep compliance curve up to about 1-month at a reference temperature 22 degrees centigrade and a reference stress 14 MPa was constructed, and the effect of stress-induced damage evolution on the long-term creep behavior of polymeric material was accounted. It was shown that TTSSP provides an effective accelerated test technique in the laboratory, the results obtained from a short-term creep test of poly(methyl methacrylate) specimen at high temperature and stress level can be used to construct the master creep compliance curve for prediction of the long-term mechanical properties at relatively lower temperature and stress level, and the master creep compliance curve with damage considered can be applied to accurately characterize the long-term creep behavior of nonlinear viscoelastic polymer.

Time-Temperature-Stress Superposition Principle: Brief Description and Application to Polymer Creep Behavior

2012 ◽  
Vol 602-604 ◽  
pp. 681-684
Author(s):  
Yong Hua Li ◽  
Cheng Kai Jiang
Keyword(s):  
Temperature Stress ◽  
Stress Level ◽  
Creep Behavior ◽  
Physical Aging ◽  
Superposition Principle ◽  
Nonlinear Creep ◽  
Stress Superposition ◽  
Lower Temperature ◽  
Term Creep

A new accelerated characterization model for creep performances was briefly introduced first, which considers both the effects of temperature and stress level, named time-temperature- stress superposition principle (TTSSP). TTSSP assumes that the influence of stress level on the intrinsic time is similar to that of temperature for the creep behavior, as well as damage and physical aging. The creep curves at different state can be shifted into a master curve at reference state using TTSSP. Then the long-term creep behavior of viscoelastic materials at lower temperature and/or stress level can be predicted from the short-term ones. Finally, TTSSP was used to investigate the nonlinear creep behavior of high-density polyethylene (HDPE). It was shown that the long-term creep behavior of HDPE can be predicted successfully.

scholarly journals The influence of physical ageing on the in-plane shear creep compliance of 5HS C/PPS

2019 ◽  
Vol 24 (2) ◽  
pp. 197-220
Author(s):  
E. R. Pierik ◽  
W. J. B. Grouve ◽  
M. van Drongelen ◽  
R. Akkerman
Keyword(s):  
Creep Compliance ◽  
Superposition Principle ◽  
Woven Fabric ◽  
Tensile Creep ◽  
Physical Ageing ◽  
Creep Response ◽  
Structural Applications ◽  
Term Creep ◽  
Over Time

Abstract Thermoplastic polymer-matrix composites, such as carbon woven fabric reinforced poly(phenylene sulphide) (C/PPS), are increasingly used in the aircraft industry. Primary structural applications, however, are limited due to uncertainty concerning the long-term behaviour. Recent work indicated a progressive creep response over time, which would render these materials unusable for such applications. However, the effect of physical ageing was neglected, which is well known to alleviate the creep behaviour and hence physical ageing is rigorously included in this study on the long-term creep response of C/PPS. Short-term tensile creep tests in the bias direction were performed at temperatures of 50, 60, 65, 70, 75 and 80$^{\circ}\mbox{C}$ C ∘ to obtain a master curve using the time–temperature superposition principle. Ordinary horizontal shifting failed to produce a smooth curve and therefore three alternative approaches were used and compared. The physical ageing rate was, however, characterised with horizontal shifting only at 50$^{\circ}\mbox{C}$ C ∘ and was implemented by means of the effective time theory (Struik, 1977) to correct the momentary master curves for the influence of physical ageing. The resulting predictions are more realistic and demonstrate that the structural changes in a material reduce the creep rate over time. Hence, the long-term creep compliance tends to increase asymptotically towards a finite value, in contrast to the unbounded momentary response.

Time-Temperature-Stress Equivalence Applied to Accelerated Characterization of Creep Behavior of Viscoelastic Polymer

2007 ◽  
Vol 353-358 ◽  
pp. 1386-1389 ◽  
Author(s):  
Rong Guo Zhao ◽  
Wen Bo Luo ◽  
Chu Hong Wang ◽  
Xin Tang
Keyword(s):  
Temperature Stress ◽  
Stress Level ◽  
Creep Compliance ◽  
Superposition Principle ◽  
Test Duration ◽  
Nonlinear Creep ◽  
Creep Tests ◽  
Test Technique ◽  
Compliance Curve ◽  
Stress Superposition

Temperature induced change, and stress induced change as well, in intrinsic timescale were investigated by nonlinear creep tests on poly(methyl methacrylate). With four different experimental temperatures, from 14 to 26 degrees centigrade, time-dependent axial elongations of the specimen were measured at seven different stress levels, from 14 MPa to 30 MPa, and modeled according to the concept of time-temperature-stress equivalence. The test duration was only 4000 seconds. The corresponding temperature shift factors, stress shift factors and temperature-stress shift factors were obtained according to the time-temperature superposition principle (TTSP), the time-stress superposition principle (TSSP) and the time-temperature-stress superposition principle (TTSSP). The master creep compliance curve up to about two-year at a reference temperature 14 degrees centigrade and a reference stress 14 MPa was constructed by shifting the creep curves horizontally along the logarithmic time axis using shift factors. It is shown that TTSSP provides an effective accelerated test technique in the laboratory, the results obtained from a short-term creep test of PMMA specimen at high temperature and stress level can be used to construct the master creep compliance curve for prediction of the long-term mechanical properties at relatively lower temperature and stress level.

Creep Behavior of Building Silicone Sealant under Long-Term External Loading and its Time-Stress Equivalence

2014 ◽  
Vol 633 ◽  
pp. 451-454
Author(s):  
Xiao Gen Liu ◽  
Yi Wang Bao ◽  
Xiu Fang Wang
Keyword(s):  
Creep Curve ◽  
Creep Behavior ◽  
External Loading ◽  
Nonlinear Creep ◽  
Creep Tests ◽  
Time Stress ◽  
Silicone Sealant ◽  
Term Creep ◽  
Term Performance

The main mechanics behavior character of building silicone sealant is its time dependence£¬which lies in the existence of the interior timepiece or the characteristic time. The creep behaviors were fundamental to evaluating the long-term performance of the building silicone sealant under long-term external loading. A series of creep tests of building silicone sealant were conducted in the laboratory under different combinations of external loads, the characteristics of the creep curve were obtained. In this work, the creep behaviors of building silicone sealant were also investigated under various temperatures at invariable stress. The test measurements show that the creep behavior of building silicone sealant are nonlinear, Nonlinear creep behavior is analyzed by means of the equivalence principle of time-stress, the main creep curve under reference stress was obtained by fitting with the viscoelastic rheological model. So the long-term creep behavior of the building silicone sealant under lower stress can be predicted by short-term creep behavior under higher stress.

The Creep Behavior of Wood-Polymer Composites

2013 ◽  
Vol 815 ◽  
pp. 632-638
Author(s):  
Yuan Zhu ◽  
Pei Ying Liu ◽  
Zhi Hong Jiang
Keyword(s):  
Power Law ◽  
Creep Behavior ◽  
Creep Compliance ◽  
Burgers Model ◽  
Wood Polymer ◽  
Different Temperatures ◽  
Linear Viscoelastic ◽  
Term Creep ◽  
Long Term Behavior

The creep behavior of WPCs needs to be addressed when developing and using this kind of materials. In this paper, the creep behavior of WPCs under linear viscoelastic region was investigated at different temperatures and bamboo flours levels. The creep compliance increase with the rise of temperature, the addition of bamboo flour has a positive effect on the creep behavior. Burgers model, Findley power law and TTSP were used to predict the long-term behavior of this kind material. Finely power law can well describe the creep properties of WPCs while Burgers model begins to diverge from measured data at about 100min. The application of TTSP was used to create master curve covered more than 108 from 30-min short-term creep compliance curves.

scholarly journals Time–Temperature–Plasticization Superposition Principle: Predicting Creep of a Plasticized Epoxy

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1848 ◽  
Author(s):  
Andrey E. Krauklis ◽  
Anton G. Akulichev ◽  
Abedin I. Gagani ◽  
Andreas T. Echtermeyer
Keyword(s):  
Glass Transition ◽  
Creep Behavior ◽  
Superposition Principle ◽  
Matrix Material ◽  
Epoxy Compound ◽  
Polymer Materials ◽  
Short Term ◽  
Term Creep ◽  
Short Term Creep

Long-term creep properties and the effect of water are important for fiber reinforced polymer (FRP) composite materials used in offshore applications. Epoxies are often used as a matrix material in such composites. A typical design lifetime of offshore FRP structures is 25 or more years in direct contact with water leading to some deterioration of the material properties. Knowing and predicting the extent of the material property deterioration in water is of great interest for designers and users of the offshore FRP structures. It has been established that the time–temperature superposition principle (TTSP) is a useful tool for estimating changes in properties of polymer materials at long times or extreme temperatures. In this work, a time–temperature–plasticization superposition principle (TTPSP) is described and used for predicting the long-term creep behavior of an epoxy compound. The studied epoxy does not degrade chemically via hydrolysis or chain scission but is negatively affected by plasticization with water. The methodology enables prediction of the long-term viscoelastic behavior of amorphous polymers at temperatures below the glass transition (Tg) using short-term creep experimental data. The results also indicate that it is possible to estimate the creep behavior of the plasticized polymer based on the short-term creep data of the respective dry material and the difference between Tg values of dry polymer and plasticized polymer. The methodology is useful for accelerated testing and for predicting the time-dependent mechanical properties of a plasticized polymer below the glass transition temperature.

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