Date of Award

7-11-2015

Degree Type

Thesis

Degree Name

M.A.Sc.

Department

Mechanical, Automotive, and Materials Engineering

First Advisor

Green, Daniel

Keywords

DP600, Electrohydraulic forming, Formability, Improvement, Mechanisms, non-linear strain path

Rights

CC BY-NC-ND 4.0

Abstract

The objectives of this thesis are to quantify the increase in formability of DP600 steel sheets in electrohydraulic die forming (EHDF) and describe the mechanisms that lead to a formability enhancement. Marciniak tests and EHDF tests were conducted to obtain the conventional and EHDF forming limit curves of this sheet material, respectively. EHDF tests with a V-shaped die indicated that, globally, there was no formability improvement; however a 100% improvement was achieved locally near the apex of the specimen. A formability enhancement of over 75% can be achieved in EHDF with a conical die, provided the discharge energy is sufficient (≥12.5 kV). Numerical simulations of these tests showed that the combination of high strain rate and inertial effects helps to delay the onset of necking prior to the sheet contacting the die. But contact phenomena play an even more significant role to improve sheet formability by decreasing the stress triaxiality.

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