CAREER: Relating Fundamental Viscoelastic Material Properties and Strengths Measured Using Various Testing Geometries

摘要粘弹性材料的应用十分广泛，对粘弹性材料进行性能表征和损伤生长预测是有效利用粘弹性材料的重要手段。蠕变柔度和抗拉强度是粘弹性材料通常测量的性能；由于材料的固有速率依赖性，它们被表示为时间或加载速率的函数。大多数粘弹性材料也依赖于温度；为了充分表征材料，必须在一定的加载速率和温度范围内进行测试。有许多类型的测试，在实验室中用于测量粘弹性材料的行为。在这个时候，没有办法将使用这些不同的测试几何形状收集的粘弹性材料行为的知识联系或联系在一起。该学院的早期职业发展（Career）研究和教育提供了一种方法，用于开发使用各种测试几何形状测量的粘弹性材料特性之间的本构关系。它将侧重于发展轴向和间接张力测试之间的关系，这是两种最广泛使用的测试方法。三轴，梁弯曲和半圆弯曲方法也将进行评估。数字图像相关（DIC）方法是一种用于测量全场位移的非接触技术，将用于捕获在每个测试几何形状中产生的非均匀应变场。分析应力和应变场和损伤增长模式将在每个几何形状上进行。拟议的教育和推广活动与研究计划内在地联系在一起：(1)有效地向评估粘弹性材料的政府机构、行业和研究人员以及依赖这些材料性能的公众传播研究成果；(2)在工程课堂中整合技术和培养发现的激情，以鼓励终身学习和支持研究活动；(3)教育公众工程师在社会中扮演的重要角色，吸引年轻人从事工程专业。将探讨PI和学生在大众媒体和技术会议上展示研究成果的机会。在课堂上，重点将放在开发动手活动，让学生在测量和分析与拟议项目相关的实际测试数据时获得工程研究的感觉。诸如虚拟实验室和使用联机数据库等技术的综合将是拟议活动的关键部分。一个研究团队的方法将被实施，包括本科生和研究生在一个重要的指导和研究经验。在进行个人研究的同时，每个学生都将为整个团队的努力做出贡献。将建立一个指导系统，以帮助建立和加强团队的研究计划。将作出重大努力，从代表性不足的群体中招收本科生和研究生，并将他们纳入研究小组。

AbstractViscoelastic materials are widely used and characterizing the material behavior and predicting damage growth are very important for effective use of these materials. The creep compliance and tensile strength are properties that are commonly measured for viscoelastic materials; they are expressed as a function of time or rate of loading because of the inherent rate dependency of the material. Most viscoelastic materials are also temperature dependent; to fully characterize the material, testing must be performed at a range of loading rates and temperatures. There are numerous types of tests that are used in the laboratory to measure viscoelastic material behavior. At this time, there is no way to link or tie together the knowledge ofviscoelastic material behavior gathered using these different test geometries.This Faculty Early Career Development (CAREER) research and education offers an approach todeveloping constitutive based relationships between the viscoelastic material properties measured using various test geometries. It will focus on developing a relationship between axial and indirect tension testing, two of the most widely used test methods. The triaxial, beam bending, and semi-circular bending methods will also be evaluated. The digital image correlation (DIC) method, a non-contact technique for measuring full field displacements, will be used to capture the non-uniform strain fields that are induced in each of the test geometries. Analysis of the stress and strain fields and damage growth patterns will be performed on each of the geometries.The proposed educational and outreach activities are intrinsically linked to the research plan to: (1) effectively disseminate research results to government agencies, industries, and researchers that evaluate viscoelastic materials as well as the general public that depend upon the performance of these materials; (2) integrate technology and foster the excitement of discovery in the engineering classroom to encourage lifelong learning and support research activities; and (3) educate the general public on the important roles engineers play in society and attract young people to the engineering profession. Opportunities for the PI and students to present research results in mass media outlets as well as technical meetings will be explored. In the classroom, emphasis will be placed on developing hands-on activities that allow the students to get a feel for engineering research while measuring and analyzing actual test data related to the proposed project. The integration of technology such as virtual laboratories and use of online databases will be a key part of the proposed activities. A research team approach will be implemented to include both undergraduate and graduate students in a significant mentoring and research experience. Every student will contribute to the overall team effort while conducting individual research. A system of mentoring will be established to help build and enhance the team's research program. A significant effort will be made to recruit students from underrepresented groups at both the undergraduate and graduate levels and incorporate them into the research team.