MSE Seminar: Zhong Chen, Shear Fracture of Advanced High Strength Steels

PhD candidate advised by Dr. Robert Wagoner, Department of Materials Science and Engineering, The Ohio State University

All dates for this event occur in the past.

264 MacQuigg Labs
105 W. Woodruff Ave.
Columbus, OH 43210
United States

Abstract 

Shear fracture, the failure of metal sheets during forming in tight-bending areas, has been shown to be mainly a result of plastic localization for most advanced high strength steels (AHSS) which have been used widely in automotive industry. Such fractures are poorly predicted by traditional industrial methods like finite element modeling (FEM) and forming limit diagrams (FLDs). In order to resolve the problem, the sensitivity of simulated shear-fracture formability to material and process parameters was determined using FEM with a variety of constitutive models, element sizes, and friction coefficients. Two types of shear fracture process were simulated. (1) Draw-bend fracture (DBF) tests are laboratory analogs producing shear fracture; they provide experimental validation but introduce complexity due to varying strain state and unavoidable transitions between shear fracture and tensile fracture. (2) Plane-strain (PS) draw-bend fracture simulations are more similar to “real-world” forming conditions; they simplify the modeling (fixed strain state, no transitions) but no corresponding full-scale laboratory experiments currently exist. It turns out that the study results can recommend ways to modify such techniques to accommodate advanced high strength steels, as well as give guidance to alloy designers in terms of which constitutive parameters are most important in avoiding shear fracture, and which are relatively unimportant. 

Bio

Currently Zhong Chen is a Ph.D. student of Prof. Robert H. Wagoner in the Department of Material Science and Engineering at The Ohio State University. His research interests include lightweight materials for automotive applications (advanced high strength steels and aluminum alloys), finite element analysis, and sheet metal forming. Research sponsors range from GM, CHRYSLER, TOYOTA, POSCO, AUTO/STEEL PARTNERSHIP, etc. Also, Zhong received many honors. In 2013, he was honored as automotive R&D delegation to visit and study in Germany (headquarter of BMW, Benz, Bosch and RWTH Aachen University). In 2007, he was honored as National Merit Scholarship, which was awarded to only 0.4% of college students throughout the country.

In his spare time, Zhong likes to play guitar, go swimming and reading.