Arruda 9702884 The research component of this proposal is concerned with experimental testing, characterization and constitutive modeling of polymers. The strain rate and temperature dependent behavior of semicrystalline polymers is not well characterized nor completely understood. Existing models for semicrystalline polymers have not been developed in conjunction with a reasonable range of experiments for verification of actual material performance. There are many technologically important applications for this work, the relationship between polymer properties and part performance is one of today's major engineering challenges. The PI of this proposal is experienced in the design, implementation and analysis of mechanical tests and in traditional materials science characterization methods for polymers. The PI has also successfully developed internal variable based constitutive models of amorphous (glassy and rubbery) polymers that accurately predict their three dimensional response. The proposed work involves extensive mechanical testing and material characterization of semicrystalline polypropylene to relate the physical mechanisms associated with deformation to experimentally observed results. Also, this research will involve internal variable based constitutive modeling of the strain rate and temperature dependent behavior of semi-crystalline polypropylene. The goal of this work is a model that accurately predicts the experimental data. The specific objectives of the proposed study are: (i) to gain an understanding of the important and prominent deformation mechanisms in polypropylene over a range of strain rates and temperatures through mechanical testing and characterization, (ii) to determine the state of deformation dependence of polypropylene through tests on isotropic specimens in uniaxial compression, plane strain compression and tens ion, (iii) to study the evolution of structure with straining and quantifying structural state, (iv) to develop an internal variable based, three dimensional constitutive model of the deformation response and (v) to implement the model into a commercially available finite element package via a user defined material option for verification. The teaching component is outreach to middle school girls designed to foster continued interest in math and science based careers. The planned activity targets girls at a critical time in their education process when they begin to start believing they no longer are good at math and science. In middle school they are surrounded by influences against math and ;science careers for women. Girls fail to continue to elect math and science courses in adolescence which quickly steers them towards non-technical academic paths. To emerge from adolescence with confidence in their math and science abilities, girls need more encouragement to continue to elect advanced math and science courses. They need to understand the many varied career opportunities that rely on a solid math and science education. To become women with an interest in engineering careers, girls need to see women succeeding in their engineering careers. They need to hear from women engineers about the aspects of engineering they found appealing when the women made their career choices. And they need to learn engineering principles from women who are enthusiastic about the subject. The PI plans to develop, implement and evaluate an engineering career module that engages women faculty and undergraduates in teaching middle school girls about engineering. The module involves the PI going to middle schools in Washtenaw County, MI to highlight the research work of women at universities nationwide. It will provide opportunities for girls in the program to interact with these women through the internet and email. The girls in the program will also engage in design projects utilizing hands-on, team learning strategies that are attractive to girls. The importance of problem solving in society and the usefulness of math and science classes for future career opportunities will be stressed. Dissemination plans for this outreach activity include enlisting undergraduate women from the College of Engineering at Michigan to develop similar modules in various engineering disciplines, and sending the packaged modules to women engineering faculty at colleges and universities nationwide.
