3 results listed
Hydroforming has been increasingly exploited by automotive industry due to several advantages such as more homogeneous deformation of workpiece, uniform thickness distribution, better surface properties due to lack of forming tool – workpiece contact interaction, etc. Advanced High Strength Steels (AHSS), on the other hand, have unique properties that make them prominent near-future solution in lightweighting, and improved safety efforts for auto industry. Current study, is aimed for investigating the hydroformability of DP 600, DP 800, and TRIP 780 advanced high strength steel (AHSS) grades at room temperature. To this goal, FEA of hydroforming process was modeled in which AHSS sheets were hydroformed into a closed die cavity with a non-axisymmetric geometry. 3D FE model of hydroforming process was established and validated with commercial FEA package Ls-Dyna. Process parameters (e.g. hydroforming pressure, blank holder force, etc.) were optimized using Ls-Opt, an artificial neural network (ANN) based optimization module integrated into Ls-Dyna, to compare the formability of AHSS steels. Thickness reduction (TR) of formed sheets and die cavity filling ratio (CFR) were taken as control parameters. Optimum hydroformability was obtained with the combination of 800 kN blank holder force and 25 MPa hydraulic pressure. Moreover, DP 600 has shown the highest hydroformability when TR and CFR values were compared.
International Iron & Steel Symposium
UDCS
Doğan ACAR
Ömer Necati CORA
In the current study, enhancement of formability of AA 5754-O aluminium alloy sheets via double-sided
hydroforming process is investigated. Double-sided hydroforming process is a manufacturing process which
increases the formability and surface quality of the workpiece. Hydraulic bulge experimental results obtained in
authors’ earlier studies and tensile tests of AA 5754-O sheets were used as reference in the construction and
validation of finite element (FE) model for double-sided hydroforming process. Dome height and sheet thickness
distribution of formed workpiece in both hydraulic bulging and double-sided hydroforming was used formability
evaluation criteria. Furthermore, applied pressure values for both side of the workpiece is optimized in order to
achieve even higher formability. Constructed FE model showed good agreement with experimental data. Results
showed that double-sided hydroforming resulted with higher formability when compared to hydraulic bulging.
International Symposium on Light Alloys and Composite Materials
UHAKS
Doğan ACAR
Ömer Necati CORA
Erosion shield is an add-on structural component which is used to reduce the effect of solid particle
erosion (SPE) on helicopter rotor blade especially during take-off and landing of helicopters. Current study aimed
for revealing the erosion resistance performance of Ti-6Al-4V alloy erosion shield material under different erodent
impact velocities (70, 150 and 200 m/s) and impact angles (20°, 30°, 45°, 60° and 90°). Crushed and sharp-edged
quartz sand particles in 250 µm nominal diameter were used as erodent. Experiments were performed per MIL-
STD-3033 standard. Maximum erosion rate was obtained at 20° impact angle while it increases with increasing
impact velocity.
International Symposium on Light Alloys and Composite Materials
UHAKS
Doğan ACAR
Ömer Necati CORA