caa a22 4500 463221788 CHVBK 20180405153214.0 cr unu---uuuuu 170326e20070801xx s 000 0 eng 10.1007/s10853-006-1108-2 doi (NATIONALLICENCE)springer-10.1007/s10853-006-1108-2 A fatigue-to-creep correlation in air for application to environmental stress cracking of polyethylene [Elektronische Daten] [Ravi Ayyer, Anne Hiltner, Eric Baer] The present study was undertaken to determine whether the correlation between fatigue and creep established for polyethylene in air could be extended to environmental liquids. Fatigue and creep tests under various conditions of stress, R-ratio (defined as the ratio of minimum to maximum load in the fatigue loading cycle), and frequency were performed in air and in Igepal solutions. The load-displacement curves indicated that stepwise fatigue crack growth in air was preserved in Igepal solutions at 50°C, the temperature specified for the ASTM standard. In air, systematically decreasing the dynamic component of fatigue loading by increasing the R-ratio to R=1 (creep) steadily increased the lifetime. In contrast, the lifetime in Igepal was affected to a much smaller extent. The fatigue to creep correlation in air was previously established primarily for tests at 21°C. Before testing the correlation in Igepal, it was necessary to establish the correlation in air at 50°C. Microscopic methods were used to verify stepwise crack growth by the sequential formation and breakdown of a craze zone, and to confirm the fatigue to creep correlation. The crack growth rate under various loading conditions was related to the maximum stress and R-ratio by a power law relationship. Alternatively, a strain rate approach, which considered a creep contribution and a fatigue acceleration factor that depended only on strain rate, reliably correlated fatigue and creep in air at 50°C under most loading conditions of stress, R-ratio and frequency. The exceptions were fatigue loading under conditions of R=0.1 and frequency less than 1Hz. It was speculated that compression and bending of highly extended craze fibrils were responsible for unexpectedly high crack speeds. Springer Science+Business Media, LLC, 2007 Ayyer Ravi Department of Macromolecular Science, and Center for Applied Polymer Research, Case Western Reserve University, 44106, Cleveland, OH, USA aut Hiltner Anne Department of Macromolecular Science, and Center for Applied Polymer Research, Case Western Reserve University, 44106, Cleveland, OH, USA aut Baer Eric Department of Macromolecular Science, and Center for Applied Polymer Research, Case Western Reserve University, 44106, Cleveland, OH, USA aut Journal of Materials Science Kluwer Academic Publishers-Plenum Publishers; http://www.springer-ny.com 42/16(2007-08-01), 7004-7015 0022-2461 42:16<7004 2007 42 10853 https://doi.org/10.1007/s10853-006-1108-2 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10853-006-1108-2 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Ayyer Ravi Department of Macromolecular Science, and Center for Applied Polymer Research, Case Western Reserve University, 44106, Cleveland, OH, USA aut NATIONALLICENCE 700 1- Hiltner Anne Department of Macromolecular Science, and Center for Applied Polymer Research, Case Western Reserve University, 44106, Cleveland, OH, USA aut NATIONALLICENCE 700 1- Baer Eric Department of Macromolecular Science, and Center for Applied Polymer Research, Case Western Reserve University, 44106, Cleveland, OH, USA aut NATIONALLICENCE 773 0- Journal of Materials Science Kluwer Academic Publishers-Plenum Publishers; http://www.springer-ny.com 42/16(2007-08-01), 7004-7015 0022-2461 42:16<7004 2007 42 10853 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer