Abstract and Research Summary Preliminary studies of the behavior of phase change materials (PCMs) in cement-based materials have provided important insights into factors influencing their behavior including: - The influence of the rate of temperature change on energy absorption and release, and, - The influence of the volume fraction of PCM on strength and deformability. While these studies have been tremendously insightful, they have been performed using only one type of PCM, i.e., having a fixed transition temperature (23-26C) and enthalpy of phase change (80 J/g). To better exploit and isolate the effects of energy absorption and release during phase change, these investigations need to be carried out for a wider range of PCMs, i.e., of different transition temperatures and enthalpies. However, experimental studies of this nature are laborious. Over the REU duration, it is sought to use finite element tools to simulate heat transfer and temperature distributions, in space and time, to better understand the influence of PCMs properties (i.e., transition temperature and enthalpy) and section geometry on the thermal response. In the first step, efforts will be made to develop and calibrate a working model which can replicate the thermal response of a reference system exposed to a defined temperature loading (Figure 1). This working model will then be validated for defined test cases wherein, either the specimen geometry, PCM properties or PCM dose are varied. On completion of the validation sequence, a series of parametric simulations will be carried out while systematically varying the imposed temperature cycle, section geometry and therein, the PCM properties and volume fraction. These determinations will help identify the optimum properties and PCM loading that can provide for the highest levels of energy absorption and release, in relation to the section geometry and imposed thermal cycle- a key activity to design and proportion (thermal) damage resistant concretes.
During the course of her graduate program, Ms. Sharma will work closely with the group of students in Structrual and Materials Engineering at ASU. Her academic background and leadership experience will be beneficially utilized in recruiting under-represented groups to the study of structural and materials engineering. It is observed that a large number of women in the civil engineering graduate program at ASU and elsewhere are in environmental and related areas. In structural engineering and materials area, the number is relatively low, primarily due to the lack of role models. The PI has already actively started efforts to include women and minorities in the materials research program (there are 3 women graduate students and 1 Hispanic undergraduate student in the 8 member graduate/undergraduate student body in the PIs laboratory). Ms. Sharmas association with the Society of Women Engineers (SWE), Math- Science Honors program, and Chi-Epsilon honor society will be used to invite under-represented and minority students from these groups to visit the laboratory and the graduate student symposium organized every year by SSEBE. This will provide these students an opportunity to observe first-hand the research activities ongoing in the School, meet with other faculty and graduate students, and potentially consider graduate study in these disciplines. She will also be introduced to the Western Alliance to Expand Student Opportunities (WAESO) which is dedicated to providing educational and research opportunities to students from under-represented and minority groups. She will be given an opportunity to closely work with (and mentor) an undergraduate student in the PIs group who was identified as an interested undergraduate researcher by WAESO. Ms. Sharma will be provided travel funding to American Concrete Institute (ACI) and Transportation Research Board (TRB) conferences to enrich her experience and to meet other potential graduate engineering students that can be recruited to ASU. Such conferences will also help her develop a collaborative network that will be beneficial in her future career.
|Effective start/end date||10/1/11 → 3/31/16|
- National Science Foundation (NSF): $352,004.00