Quantifying deformation and energy dissipation of polymeric surfaces under localized impact

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• 作者：Georgios Constantinides ; Catherine A. Tweedie ; Doria M. Holbrook ; Patrick Barragan ; James F. Smith ; Krystyn J. Van Vliet1
• 关键词：Polymers ; Impact ; Nanoindentation
• 刊名：Materials Science and Engineering ; A
• 出版年：2008
• 期刊代码：61_09215093
• 类别：ms
• 出版时间：20 August 2008
• 卷：489
• 期：1-2
• 页码：403-412
• 文件大小：923 K

摘要

The mechanical response of polymeric surfaces to concentrated impact loads is relevant to a range of applications, but cannot be inferred from quasistatic or oscillatory contact loading. Here we propose and demonstrate a set of quantitative metrics that characterizes the ability of polymers to resist impact deformation and dissipate impact energy, as well as the strain rate sensitivity of these materials to contact loading. A model which incorporates nonlinear material behavior is presented and can predict the experimentally observed deformation behavior with high accuracy. The micrometer-scale impact response of several polymers has been investigated in the velocity range of 0.7–1.5 mm/s. Two semi-crystalline polymers – polyethylene (PE) and polypropylene (PP) – characterized above the corresponding glass transition temperature coration:none; color:black" href="/science?_ob=MathURL&_method=retrieve&_udi=B6TXD-4RKMJ35-2&_mathId=mml36&_user=1067359&_cdi=5588&_rdoc=49&_acct=C000050221&_version=1&_userid=10&md5=4dd3eae277d7c967952d46506c4f98e0" title="Click to view the MathML source" alt="Click to view the MathML source">T_g, and four fully amorphous polymers characterized well below coration:none; color:black" href="/science?_ob=MathURL&_method=retrieve&_udi=B6TXD-4RKMJ35-2&_mathId=mml37&_user=1067359&_cdi=5588&_rdoc=49&_acct=C000050221&_version=1&_userid=10&md5=ea7f8b2d8eae3960c8b16b7dc5cb6979" title="Click to view the MathML source" alt="Click to view the MathML source">T_g– polystyrene (PS), polycarbonate (PC), and low and high molecular weight poly(methyl methacrylate) or PMMA termed commercially as Lucite^® (LU) and Plexiglas^® (PL) – have been considered. In an inverse application, the model and experimental method provide a tool for extracting the relevant material quantities, including energy dissipation metrics such as the coefficient of restitution coration:none; color:black" href="/science?_ob=MathURL&_method=retrieve&_udi=B6TXD-4RKMJ35-2&_mathId=mml38&_user=1067359&_cdi=5588&_rdoc=49&_acct=C000050221&_version=1&_userid=10&md5=ba8c4afaeebca99b8e980caf3898c431" title="Click to view the MathML source" alt="Click to view the MathML source">e. This approach can be used to determine quantitatively the impact energy absorption of polymer surfaces at elevated temperatures through coration:none; color:black" href="/science?_ob=MathURL&_method=retrieve&_udi=B6TXD-4RKMJ35-2&_mathId=mml39&_user=1067359&_cdi=5588&_rdoc=49&_acct=C000050221&_version=1&_userid=10&md5=3eb7d33e31b405ee538bbc2d4da74790" title="Click to view the MathML source" alt="Click to view the MathML source">T_g, as demonstrated for PS and PC over the range of 20–180 coration:none; color:black" href="/science?_ob=MathURL&_method=retrieve&_udi=B6TXD-4RKMJ35-2&_mathId=mml40&_user=1067359&_cdi=5588&_rdoc=49&_acct=C000050221&_version=1&_userid=10&md5=af7f7bf3a53ea4a40613741aa5c3b6e9" title="Click to view the MathML source" alt="Click to view the MathML source">°C.