This CAREER project will develop and validate a method to determine linearly and nonlinearly viscoelastic properties of time-dependent materials using nanoindentation technology. A nanoindenter will be used to determine the load or displacement as a function of time of a viscoelastic material for prescribed displacement or loading history. Analysis and numerical simulation of the material response will be performed to develop a method of analysis for extracting the surface local relaxation or creep functions. The method will allow the measurements of viscoelastic functions for very small amounts of materials such as thin films deposited on substrates used in microelectronics, very small structures such as Micro-Electrical-Mechanical-Systems (MEMS), gradient materials with material properties varying spatially, and heterogeneous materials such as human bones. This method will enable the measurements of viscoelastic properties on the sub-micron scale that cannot be determined from conventional material testing systems that are designed for bulk material samples
The educational activities are planned to fulfill the following objectives: (1) Involving more undergraduate students in research activities that allow them to experience the excitement in scientific research and discovery, as well as combining and using the knowledge they have acquired in different courses. (2) Introduce to the curriculum modern experimental techniques in mechanics, including the measurements of material properties on the sub-micron scale using nanoindentation. (3) Integrate the approach of Computer Aided Engineering into the Mechanical Design and Aerospace Structures courses, and introduce experimental content and manufacturing experience in the curriculum. (4) Develop graduate level courses that provide knowledge of mechanics to graduate students in the Web Handling Research Center, an Industry/University Cooperative Research Center at Oklahoma State University.
