1-20 of 134 Search Results for

time-temperature superposition

Sort by
Image
Published: 15 May 2022
Fig. 15 Schematic of time-temperature superposition to create a master curve for cure. T g , glass transition temperature; T , temperature; a T , shift factor More
Image
Published: 15 May 2022
Fig. 14 Time-temperature superposition principle illustrated with polyisobutylene data. Reference temperature of the master curve is 25 °C (77 °F). Insert graph shows the amount of curve shifting required at different temperatures. Source: Ref 14 More
Image
Published: 15 May 2022
Fig. 16 Superposition of the glass transition temperature ( T g ) versus ln(time) data from Fig. 14 to form a master curve at a reference temperature of 140 °C (285 °F). The vitrification temperatures are indicated on the master curve: ⊡, 100 °C (212 °F); ◆, 120 °C (250 °F) ◘ 140 °C (285 °F More
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006934
EISBN: 978-1-62708-395-9
.... Then, the widely used models to simulate the service life of polymers are highlighted. These include the Burgers power-law model, the Findley power-law model, the time-temperature superposition (or equivalence) principle (TTSP), and the time-stress superposition principle (TSSP). The Larson-Miller parametric...
Series: ASM Desk Editions
Publisher: ASM International
Published: 01 November 1995
DOI: 10.31399/asm.hb.emde.a0003024
EISBN: 978-1-62708-200-6
..., and the effect of viscoelasticity on the test methods used. Two common ways of evaluating viscoelasticity of plastics are by means of creep experiments and dynamic mechanical experiments. Graphic or tabular analysis of test data, time-temperature superposition, and empirical correlation methods are commonly...
Image
Published: 01 November 1995
Fig. 32 Generation of temperature-dependent shift factor, a T . (a) Data plot. (b) Construction of master curve. (c) Time-temperature superposition plot More
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006941
EISBN: 978-1-62708-395-9
... often cannot be considered to behave, even at room temperature, as purely elastic materials. Several superposition principles can be used to extrapolate short-term test data to a longer period of material property behavior. These include the Boltzmann superposition principle, the time-temperature...
Image
Published: 01 February 2024
Fig. 16 Superposition of cooling curves obtained along a Jominy test bar on the time-temperature-transformation (TTT) curve of steel. Note fastest cooling on the water-quenched end, yielding a martensitic microstructure, and slowest cooling on the air-quenched end, yielding a pearlitic More
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006909
EISBN: 978-1-62708-395-9
... with slope E a / R , which can, with caution, be extrapolated: (Eq 2) ln ( K ( T ) ) = ln ( A ) − E a / RT The Arrhenius relation is generally preferred to time-temperature superposition (see subsequent text) for assessing temperature effects; however...
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006929
EISBN: 978-1-62708-395-9
...) with Arrhenius plot of shift factor. a T , amount of curve shift. Source: Ref 31 Fig. 14 Time-temperature superposition principle illustrated with polyisobutylene data. Reference temperature of the master curve is 25 °C (77 °F). Insert graph shows the amount of curve shifting required at different...
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006930
EISBN: 978-1-62708-395-9
... in.). This is referred to as Method B. The time of descent number ( t B ) can be converted to the melt flow rate in Method A ( MFR A ) by the following relationship ( Ref 6 ): (Eq 2) M F R A = 1089 * ρ m e l t / t B where ρ melt is the melt density at the test temperature in grams...
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006924
EISBN: 978-1-62708-395-9
... in Fig. 12 and 13 . DGEBA, diglycidylether of bisphenol A; PACM, 4,4’-diaminodicyclohexyl methane. Source: Ref 26 Time-temperature-superposition kinetics offers a convenient way to concisely summarize these observations. It applies to cure reactions that can be described with reasonable...
Series: ASM Handbook
Volume: 22A
Publisher: ASM International
Published: 01 December 2009
DOI: 10.31399/asm.hb.v22a.a0005411
EISBN: 978-1-62708-196-2
... Abstract The overarching goal of life-prediction research is to develop models for the various types of time dependencies in the crack-tip damage accumulation that occur in materials subjected to elevated temperatures. This article focuses on describing the models based on creep, oxidation...
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006933
EISBN: 978-1-62708-395-9
...-temperature superposition to project behavior over time. Example 3 in this article illustrates the use of creep modeling. Aging and Degradation Changes in the mechanical properties of plastic resins that arise from molecular degradation or aging can be evaluated via DMA. Such changes can significantly...
Series: ASM Desk Editions
Publisher: ASM International
Published: 01 November 1995
DOI: 10.31399/asm.hb.emde.a0003025
EISBN: 978-1-62708-200-6
... must consider viscoelasticity. One method useful for obtaining long-term design data is the time-temperature superposition principle, which states that the mechanical response at long times at some particular temperature is equivalent to the mechanical response at short times but at some higher...
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006928
EISBN: 978-1-62708-395-9
... that involves long-term loading. Under viscoelastic conditions, one method useful for obtaining long-term design data is the time-temperature superposition principle. This principle states that the mechanical response at long times at some particular temperature is equivalent to the mechanical response...
Series: ASM Handbook
Volume: 4B
Publisher: ASM International
Published: 30 September 2014
DOI: 10.31399/asm.hb.v04b.a0005936
EISBN: 978-1-62708-166-5
..., the development of the internal stresses leading to the final residual stress state at room temperature is very complex. Therefore, this article takes a step-by-step approach to the development of internal stresses, while at the same time endeavoring to make the connection with distortion, showing...
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006944
EISBN: 978-1-62708-395-9
... of the experiment, the apparent modulus of the material is observed to change. These changes are predictable using the time-temperature superposition principle. The horizontal shift produced by changing temperature can be calculated using the Williams-Landel-Ferry (WLF) equation ( Ref 2 ): (Eq 4) log a T...
Series: ASM Handbook
Volume: 4B
Publisher: ASM International
Published: 30 September 2014
DOI: 10.31399/asm.hb.v04b.a0005947
EISBN: 978-1-62708-166-5
... an influence. These desired or undesired modifications of the surface layer also lead to a density change. Phase transformations and precipitation processes also have an influence on the density. These processes are governed by the (local) chemical composition and the process-dependent temperature-time...
Series: ASM Handbook
Volume: 17
Publisher: ASM International
Published: 01 August 2018
DOI: 10.31399/asm.hb.v17.a0006446
EISBN: 978-1-62708-190-0
...-detection methods are based on this general principle and differ only in the practical realizations of how superposition is enacted. Harmonics Generation Assume that the response r ( t ) of a nonlinear system to a given excitation e ( t ) can be expressed in the time domain as: (Eq 10) r ( t...