CAREER: Faculty Early Career Development Program

该提案的研究部分涉及聚合物的实验测试、表征和本构建模。半晶聚合物的应变速率和温度依赖行为尚未被很好地表征或完全理解。现有的半结晶聚合物模型尚未与合理范围的实验相结合，以验证实际材料性能。这项工作在技术上有许多重要的应用，聚合物性能和零件性能之间的关系是当今主要的工程挑战之一。该提案的PI在机械测试的设计，实施和分析以及聚合物的传统材料科学表征方法方面经验丰富。PI还成功开发了基于内部变量的非晶态（玻璃状和橡胶状）聚合物的本构模型，该模型可以准确预测其三维响应。拟议的工作包括广泛的力学测试和半结晶聚丙烯的材料表征，以将与变形相关的物理机制与实验观察结果联系起来。此外，本研究将涉及基于内部变量的半结晶聚丙烯应变速率和温度依赖行为的本构模型。本工作的目标是建立一个能准确预测实验数据的模型。建议研究的具体目标如下：(1)通过力学测试和表征，了解聚丙烯在应变速率和温度范围内的重要和突出的变形机制；(2)通过对各向同性试样在单轴压缩、平面应变压缩和数十离子下的试验，确定聚丙烯的变形依赖状态；(3)研究结构随应变的演变并量化结构状态。（iv）开发一个基于内部变量的三维变形响应本构模型；(v)通过用户自定义的材料选项将该模型实现到商用有限元软件包中，以供验证。教学部分是延伸到中学女生，旨在培养对数学和科学为基础的职业的持续兴趣。这项计划中的活动针对的是处于教育过程关键时期的女孩，她们开始相信自己不再擅长数学和科学。在中学，他们被数学和数学的影响所包围；女性的科学事业。女孩在青春期没有继续选择数学和科学课程，这很快使她们走上了非技术的学术道路。为了对自己的数学和科学能力充满信心地走出青春期，女孩们需要更多的鼓励来继续选择高等数学和科学课程。他们需要了解依赖于扎实的数学和科学教育的许多不同的职业机会。要想成为对工程事业感兴趣的女性，女孩们需要看到女性在工程事业上取得成功。他们需要从女工程师那里听到她们在选择职业时觉得有吸引力的工程方面。他们需要从对这门学科充满热情的女性那里学习工程原理。PI计划开发、实施并评价由女教师和女大学生参与的初中女生工程教育的工程事业模块。该模块包括PI前往密歇根州华盛顿诺县的中学，以突出全国大学中女性的研究工作。它将为项目中的女孩提供通过互联网和电子邮件与这些妇女互动的机会。该项目中的女孩还将参与设计项目，利用对女孩有吸引力的动手和团队学习策略。将强调解决问题在社会中的重要性以及数学和科学课程对未来职业机会的有用性。这项外联活动的传播计划包括招募密歇根工程学院的女本科生，在不同的工程学科中开发类似的模块，并将打包的模块发送给全国高校的女工程教员。

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.