Formability of Aluminum AA5754 Using Electrohydraulic Forming Process.

Conventional sheet metal forming processes have problems like low formability, non-uniform strain distribution, spring back, wrinkling, etc. High velocity processes like electrohydraulic forming can deform sheets at high strain rate and have capability to tackle such problems associated with conventional forming operations to a greater extent. Forming limit diagram (FLD) characterizes sheet deformation as measure of formability. Punch stretch test (PST) can assess formability of sheet in conventional low strain rate process, but no standard method is available to determine FLD at high strain rate. So in the present work, an experimental setup has been developed to characterize sheets at high strain rate using hydraulic forming process with a 40 kJ capacitor bank. A similar corresponding standard setup for punch stretch test is also developed for comparative study of formability with respect to dome height, forming limit curve, and strain distribution. Formability of aluminum alloy AA5754 is determined at quasi-static and high strain rates, and comparative analysis is reported for whole state of strain using dog bone samples of width ranging from 10 to 120 mm. An estimate of electrohydraulic forming parameters for high strain test of the Al alloy using the given setup is also determined. Study of comparative strain distribution behavior of samples of different widths is also carried out. Comparative analysis shows that there is an improvement in formability and strain distribution behavior of the alloy deformed using EHF as compared to PST. [ABSTRACT FROM AUTHOR]