| Autor: |
Statnik ES; HSM Laboratory, Center for Digital Engineering, Skoltech, 121205 Moscow, Russia.; 'Luch' Laboratory, National University of Science and Technology MISiS, 119049 Moscow, Russia., Salimon AI; HSM Laboratory, Center for Digital Engineering, Skoltech, 121205 Moscow, Russia.; 'Luch' Laboratory, National University of Science and Technology MISiS, 119049 Moscow, Russia., Gorshkova YE; 'Luch' Laboratory, National University of Science and Technology MISiS, 119049 Moscow, Russia.; Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, 141980 Dubna, Russia.; Institute of Physics, Kazan Federal University, 420008 Kazan, Russia., Kaladzinskaya NS; Laboratory of Electron Probe Analysis, Department of Materials Research and Testing, SSI O.V. Roman Powder Metallurgy Institute, 220005 Minsk, Belarus., Markova LV; Laboratory of Electron Probe Analysis, Department of Materials Research and Testing, SSI O.V. Roman Powder Metallurgy Institute, 220005 Minsk, Belarus., Korsunsky AM; MBLEM, Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, UK. |
| Abstrakt: |
The reported study was devoted to the investigation of viscoelastic behavior for solid and porous ultra-high molecular weight polyethylene (UHMWPE) under compression. The obtained experimental stress curves were interpreted using a two-term Prony series to represent the superposition of two coexisting activation processes corresponding to long molecular (~160 s) and short structural (~20 s) time scales, respectively, leading to good statistical correlation with the observations. In the case of porous polymer, the internal strain redistribution during relaxation was quantified using digital image correlation (DIC) analysis. The strongly inhomogeneous deformation of the porous polymer was found not to affect the relaxation times. To illustrate the possibility of generalizing the results to three dimensions, X-ray tomography was used to examine the porous structure relaxation at the macro- and micro-scale levels. DIC analysis revealed positive correlation between the applied force and relative density. The apparent stiffness variation for UHMWPE foams with mixed open and closed cells was described using a newly proposed three-term expression. Furthermore, in situ tensile loading and X-ray scattering study was applied for isotropic solid UHMWPE specimens to investigate the evolution of internal structure and orientation during drawing and stress relaxation in another loading mode. |
