Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Some phenomenological relaxation rate equations based on Bose–Einstein similar kinetics (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 72 (1992), S. 5179-5186 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The possibility of describing transient phenomena associated with flow and consolidation of solids, such as stress relaxation or physical aging, in terms of a kinetic mechanism comprising spontaneous and induced events is discussed. The starting point is the differential equation dn(overdot)/dt=−an(overdot)[1−(b/a)n(overdot)], with n denoting the number of relaxed entities and n(overdot)=dn/dt (a,b are constants, t is time), yielding an n(overdot)(t) function reminiscent of a Bose–Einstein distribution. The corresponding n(t) relation describes the linear variation of n with log t, and the exponential dependence of n(overdot) on n, as often found experimentally. Replacing n(overdot) in the starting equation by the relative rate n(overdot)/n yields a power-law-type n(overdot)(n) dependence. A further modification, where the induction term n(overdot)/n is not linear but raised to a power (approximately-greater-than)1, finally produces a generalized version of the stretched exponential. When interpreted formally in terms of a spectrum of relaxation times τ, all three equations produce response functions with discrete τ distributions, provided a≠0.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.351998
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Volume changes during stress relaxation in polyethylene (1995)
    Springer
    Rheologica acta 34 (1995), S. 182-195 
    Details
    ISSN: 1435-1528
    Keywords: Stress dilatometry ; polyethylene ; stress relaxation ; Grüneisen parameter ; physical ageing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Abstract This paper presents the results of an experimental study of the stress relaxation behaviour of PE where the focus was on determination of the volume changes taking place during the relaxation process. The dimensions of the samples were followed using a specially designed non-disturbing extensometer. The extensometer data were confirmed in experiments where the volume was measured with a specially designed liquid stress dilatometer. The bulk of the results was obtained with LDPE and LLDPE. High density polyethylene was shown to behave similarly. The decrease in volume, corresponding to an increasing Poisson's ratio, during relaxation was approximately linear with log time. Volume vs. stress diagrams were linear; the values of the apparent bulk modulus calculated from them were only slightly higher than those obtained from the stress-strain curves. Grüneisen parameter was measured and compared with reported values. Possible similarities between the volume change during stress relaxation and that occuring during the process of physical ageing are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00398438
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    The Craze Growth Response in Stress Relaxation Conditions for a Styrene-Acrylonitrile Copolymer during Physical Aging (2000)
    Springer
    Mechanics of time-dependent materials 4 (2000), S. 231-255 
    Details
    ISSN: 1573-2738
    Keywords: craze growth ; crazing ; physical aging ; stress relaxation ; styrene-acrylonitrile copolymer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Craze growth in a styrene-acrylonitrile copolymer (SAN) wasstudied as a function of time after a quench (physical aging) at fourdifferent temperatures between 22 and 60°C. Thecraze growth experiments were performed in stress relaxation conditions.The craze length was found to grow linearly on a logarithmic loadingtime scale. A transition in the logarithmic growth rate was found tooccur on the logarithmic aging time scale. The transition was observedas a change in rate from high to approximately five times slower andoccurred over a relatively narrow range of aging times. The growth ratein the slow growth regime was relatively insensitive to temperature forall four temperatures studied. The transition was found to move toshorter aging times as temperature increases. Although the craze lengthbetween crazes in a sample could differ to a large extent, the growthrates themselves, were found to vary only within a±20% band.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009826600060
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...