Mechanical and Civil Engineering Seminar

Abstract: Polymer additive manufacturing (AM) is mainly relegated to the space of rapid prototyping. In this talk, new approaches for transitioning polymer AM to end-use parts will be discussed. Common processing-structure-failure relationships in extrusion-based AM of both thermosetting and thermoplastic parts will be elucidated. Carbon fiber has been identified as a potential solution to overcome several shortcomings of polymer AM, where it improves polymer properties, reduces the time required to manufacture functional parts, and lowers warping to lead to a larger build envelop. The effects of carbon fiber reinforcement on the processability, structure, and properties of AM parts will be described. Despite several advantages, AM composites suffer low interlaminar mechanical properties due to poor layer-to-layer adhesion and voids. Failure mechanics of AM composites will be explained, and new post-processing methods and AM technologies to alleviate their poor interlaminar performance will be introduced. From a structural standpoint, AM allows for the implementation of specially designed fiber placement within the parts. With a knowledge of the loading profile, parts with unprecedented performance can be designed and manufactured. In this regard, a framework for the design optimization of AM composite parts will be introduced and demonstrated for a few benchmark problems.

Bio: Dr. Mehran Tehrani is an Assistant Professor in the Walker Department of Mechanical Engineering at the University of Texas at Austin. Dr. Tehrani's research focuses on advanced multifunctional composites and lies at the intersection of advanced manufacturing, materials science, and mechanics. Examples of his current projects include additively manufactured polymer composites, metal-nanocarbon hybrid conductors, multi-material additive/subtractive manufacturing, automated fiber placement, and graphene-based structural composites. He is a core faculty in the Advanced Manufacturing and Design Area and the Additive Manufacturing Initiatives within the department.

Before joining UT-Austin, Dr. Tehrani was an assistant professor in the Department of Mechanical Engineering at the University of New Mexico (2014-2019). Dr. Tehrani obtained his B.Sc. in Mechanical Engineering from Sharif University of Technology in 2007, M.Sc. in Mechanical Engineering from the University of New Mexico in 2009, and Ph.D. in Engineering Mechanics from Virginia Tech in 2012.  His research and teaching awards include the National Science Foundation CAREER award (2019), Office of Naval Research YIP award (2018), Air Force Research Laboratory Summer Faculty Fellowship (2016), Perkin-Elmer Award from the Composite Division @Society of Plastic Engineers (2012), and Virginia Tech Entrepreneur Challenge Award (2012).