CAREER: Faculty Early Career Development Program

ARRUDA 9702884本提案的研究部分涉及聚合物的实验测试、表征和本构模型。半结晶聚合物的应变速率和温度依赖行为还没有得到很好的描述，也没有完全了解。现有的半结晶聚合物模型还没有与验证实际材料性能的合理范围的实验相结合。这项工作有许多重要的技术应用，聚合物性能和部件性能之间的关系是当今主要的工程挑战之一。这项建议的PI在设计、实施和分析机械测试以及聚合物的传统材料科学表征方法方面经验丰富。PI还成功地开发了基于内部变量的非晶态(玻璃和橡胶)聚合物的本构模型，准确地预测了它们的三维响应。拟议的工作包括对半结晶聚丙烯进行广泛的力学测试和材料表征，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，这项研究还将涉及基于内变量的半结晶聚丙烯应变速率和温度依赖行为的本构建模。这项工作的目标是建立一个能够准确预测实验数据的模型。拟议研究的具体目标是：(I)通过力学测试和表征，了解聚丙烯在一定应变率和温度范围内的重要和显著的变形机制；(Ii)通过对各向同性试件进行单轴压缩、平面应变压缩和数十个离子的测试，确定聚丙烯的变形依赖状态；(Iii)研究结构状态的应变和量化结构的演变；(Iv)开发基于内变量的变形响应的三维本构模型；以及(V)通过用户定义的材料选项将该模型应用到商业上可用的有限元程序包中进行验证。教学部分是面向中学女孩的外展活动，旨在培养人们对数学和科学职业的持续兴趣。这项有计划的活动针对的是女孩在教育过程中的关键时刻，当她们开始认为自己不再擅长数学和科学时。在中学，她们受到了反对女性数学和理科事业的影响。女孩在青春期没有继续选择数学和科学课程，这很快就把她们引向了非技术性的学术道路。为了走出青春期，对自己的数学和科学能力充满信心，女孩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。为了成为对工程职业感兴趣的女性，女孩们需要看到女性在工程职业中取得成功。当女性做出职业选择时，她们需要听取女性工程师对工程方面的看法。他们需要从对这门学科充满热情的女性那里学习工程学原理。PI计划开发、实施和评估一个工程职业模块，让女教职员工和本科生参与向中学女孩教授工程知识。该单元涉及到密西西比州沃什滕诺县的中学，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。参加该计划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。课程将强调在社会中解决问题的重要性，以及数学和科学课程对未来职业机会的作用。这一推广活动的传播计划包括招募密歇根工程学院的本科生女性在不同的工程学科开发类似的模块，并将打包的模块发送给全国各地的学院和大学的女性工程教师。

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.