| Summary: | Numerical simulation by finite element method has become a powerful tool in
preventing the unwanted effects of sheet metals technological processing. One of the
most important problems in sheet metal forming is the compensation of springback.
When stamped sheet components are removed from the forming tools, the residual
internal stresses will relax, and a new equilibrium state will be reached. As a result, the
final shape of the drawn part will deviate from the shape imposed by the forming tool.
This phenomenon is known as springback. Springback phenomenon theoretically
exists for anything kind of deep drawing or stamping process. In fact it is a well known
and unwanted characteristic of every process that involves plastic deformations on
elastic metals.
To improve the accuracy of the formed parts, the die surfaces are required to be
optimized so that after springback the geometry falls at the expected shape. Two
methods of die compensation can be applied for this purpose; ~is~lacement~djustment
(DA) and Karafillis and Boyce (K&B) methods. They are the so called spring-back compensation and spring-forward compensation. Both are based on an iterative
procedure. The die compensation were studied by applied of both DA and K&B
method. DA converges rapidly but its iterations may oscillate and K&B converges
more slowly but iterations show steadily decreasing error. The combination of K&B
1 method and DA were applied with an improvement of the adjustment direction from
y direction in original DA method to a normal vector of the surface to maintain the
surface gap of lower and upper surface in a consistent way. The initial development of
the hybrid algorithm is presented, a numerical test results on a simple model are also presented to support.
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