Open AccessPADDLE SHAPE OPTIMIZATION FOR HOLE-FLANGING BY PADDLE FORMING THROUGH THE USE OF A PREDEFINED STRAIN PATH IN FINITE ELEMENT ANALYSIS
Author(s) -
Lemopi Isidore Besong,
Johannes Buhl,
Markus� Bambach
Publication year - 2019
Publication title -
journal of machine engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.588
H-Index - 7
eISSN - 2391-8071
pISSN - 1895-7595
DOI - 10.5604/01.3001.0013.2226
Subject(s) - paddle , flange , finite element method , flanging , structural engineering , materials science , dimensionless quantity , geometry , mechanics , composite material , engineering , mathematics , physics
This research investigates a novel hole-flanging process by paddle forming through the use of finite element (FE) simulations. Paddles of different shapes rotating at high speeds were used to deform clamped sheets with pre-drilled holes at their centers. The results of the simulations show that the paddle shape determines the geometry and principal strains of the formed flanges. A convex-shaped paddle forms flanges with predominant strains in the left quadrant of the forming limit diagram (FLD). However, the convex paddle promotes unwanted bulge formation at the clamped end of the flange. A concave paddle forms flanges with no bulge but the principal strains of elements in the middle section of the flange are in the right quadrant of the FLD which indicates an increased probability for crack occurrence. An optimization of the paddle shape was conducted to prevent bulging at the clamped end while avoiding crack occurrence. The paddle shape was optimized by mapping the deformation of some elements along the flange length to a pre-defined strain path on the FLD while maintaining the bulge height within the desired geometric tolerance. The radii and lengths of the paddle edge were varied to obtain an optimum paddle shape.