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
Filter
  • 1990-1994
  • 1980-1984  (5)
  • 1984  (5)
Source
Material
Years
  • 1990-1994
  • 1980-1984  (5)
Year
Keywords
  • 1
    Electronic Resource
    Electronic Resource
    A double-torsion study of the fracture of polyethersulphone (1984)
    Springer
    Journal of materials science 19 (1984), S. 3796-3805 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Fracture studies of polyethersulphone have been undertaken using the double torsion geometry, in particular to establish the effects of ageing and crack speed on fracture toughness. The stability of crack growth was found in all cases to be very dependent on initial notching. If by suitable techniques, e.g. fatigue, a craze was formed at the notch root the subsequent crack growth was found to be stable, with a craze ahead of the growing crack. Under these conditions only a slight dependence of fracture toughness on crack speed was observed, with no significant differences between material aged for 5 years at room temperature and freshly moulded samples. The dimensions of the observed craze were found to be very similar to those of crazes observed in a parallel study using compact tension geometry and lead to comparable values for craze stress and crack opening displacement. In many instances unstable crack growth was observed, often described as “stick-slip”. This was often associated with the absence of a craze at the crack tip, perhaps due to a damage zone created during razor notching. The initiation load and load for crack arrest were determined and used to calculate initiation and arrest values for the fracture toughness as a function of the applied deformation rate. It was found that these values converged at high crosshead speeds to a value independent of ageing, although for the freshly moulded material the initiation values were significantly higher, and the arrest values lower. Electrically conducting grids were used to establish that crack speeds up to 400 m sec−1 occur during stick-slip crack growth. A detailed discussion is presented of conditions required for stable and unstable crack growth in polyethersulphone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00552293
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    The fracture toughness of tough polyethylenes by a novel high pressure technique (1984)
    Springer
    Journal of materials science 19 (1984), S. 413-422 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The failure of two grades of polyethylene has been studied using the technique of torsion under superposed hydrostatic pressure. The behaviour of unnotched samples of both grades was ductile at all pressures and strain-rates. However, at sufficiently high pressures both grades of polyethylene (including a tough copolymer) failed in a brittle manner when a surface notch was exposed to a suitable pressure fluid. Measurement of fracture stresses for various notch depths lead to a value for a critical stress intensity factor at each of several pressures. A linear extrapolation was then used to estimate the critical stress intensity factor at atmospheric pressure to be 1.11±0.05 MN m−3/2 and 1.68±0.08 MN m−3/2 for the homopolymer and copolymer, respectively. An independent measurement at atmospheric pressure for the homopolymer using compact tension geometry yielded a value of 1.28±0.02 MN m−3/2 confirming the accuracy of the extrapolation procedure and that the effect of the environment on the behaviour was not substantial.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00553564
    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 fracture toughness of tough polyethylenes by a novel high pressure technique (1984)
    Springer
    Journal of materials science 19 (1984), S. 413-422 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The failure of two grades of polyethylene has been studied using the technique of torsion under superposed hydrostatic pressure. The behaviour of unnotched samples of both grades was ductile at all pressures and strain-rates. However, at sufficiently high pressures both grades of polyethylene (including a tough copolymer) failed in a brittle manner when a surface notch was exposed to a suitable pressure fluid. Measurement of fracture stresses for various notch depths lead to a value for a critical stress intensity factor at each of several pressures. A linear extrapolation was then used to estimate the critical stress intensity factor at atmospheric pressure to be 1.11±0.05 MN m−3/2 and 1.68±0.08 MN m−3/2 for the homopolymer and copolymer, respectively. An independent measurement at atmospheric pressure for the homopolymer using compact tension geometry yielded a value of 1.28±0.02 MN m−3/2 confirming the accuracy of the extrapolation procedure and that the effect of the environment on the behaviour was not substantial.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02403227
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    A double-torsion study of the fracture of polyethersulphone (1984)
    Springer
    Journal of materials science 19 (1984), S. 3796-3805 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Fracture studies of polyethersulphone have been undertaken using the double torsion geometry, in particular to establish the effects of ageing and crack speed on fracture toughness. The stability of crack growth was found in all cases to be very dependent on initial notching. If by suitable techniques, e.g. fatigue, a craze was formed at the notch root the subsequent crack growth was found to be stable, with a craze ahead of the growing crack. Under these conditions only a slight dependence of fracture toughness on crack speed was observed, with no significant differences between material aged for 5 years at room temperature and freshly moulded samples. The dimensions of the observed craze were found to be very similar to those of crazes observed in a parallel study using compact tension geometry and lead to comparable values for craze stress and crack opening displacement. In many instances unstable crack growth was observed, often described as “stick-slip”. This was often associated with the absence of a craze at the crack tip, perhaps due to a damage zone created during razor notching. The initiation load and load for crack arrest were determined and used to calculate initiation and arrest values for the fracture toughness as a function of the applied deformation rate. It was found that these values converged at high crosshead speeds to a value independent of ageing, although for the freshly moulded material the initiation values were significantly higher, and the arrest values lower. Electrically conducting grids were used to establish that crack speeds up to 400 m sec−1 occur during stick-slip crack growth. A detailed discussion is presented of conditions required for stable and unstable crack growth in polyethersulphone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02396953
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    The dependence of yield behavior on temperature, pressure, and strain rate for linear polyethylenes of different molecular weight and morphology (1984)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 22 (1984), S. 191-209 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The temperature, strain-rate, and pressure dependences of the yield stress have been determined for two polyethylene homopolymers of differing molecular weights and for a polyethylene copolymer. Samples were prepared by slowly cooling from the melt, and also by quenching in order to assess the effects of morphology on the yield behavior. The data have been analyzed on the basis of two Eyring processes acting in parallel. Comparison of all data sets reveals the existence in general of three distinct activated processes each with its own temperature, strain-rate, and pressure dependences. The relative contribution of each process is dependent on the molecular weight, morphology, etc. Also discussed is the relation of these three yield processes to the well-known loss processes of linear viscoelasticity.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1984.180220205
    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...