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

University Of New Hampshire, Durham NH

Investigators

Abstract

Abstract Viscoelastic 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 of viscoelastic material behavior gathered using these different test geometries. This Faculty Early Career Development (CAREER) research and education offers an approach to developing 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.