Accurate Prediction Approach of 3D Trimming Line for Auto Panel Part

Abstract

It is difficult to obtain 3D trimming line using traditional prediction methods for auto panel parts. An initial geometrical development method with element layer is proposed based on one step inverse analysis theory for this problem. The flange mesh can be unfold onto the die surface layer by layer according to nodal adjacent element relation, then the above development mesh is smoothed by mesh smoothing method with sliding constraint surface in order to delete overlap and distorted mesh, the 3D initial mesh can be obtained for one step inverse analysis method. The accurate 3D trimming line of auto panel part can be achieved by plasticity iteration of one step inverse analysis. A typical real part of 3D trimming line prediction is selected to prove this method, the comparison results between the simulated and experimental values show that this method has enough precision and can handle complex parts, satisfies the engineering practical demands.

Trimming line development method of auto panel part with undercutting flange

“…But it can only develop the quasi-vertical walls and cannot unfold the undercutting flanges. Chung and Bao [12,13] develop the undercutting flanges by geometrical unfold method layer by layer. However it needs to smooth the mesh after each step and leads to low efficiency for the complicated undercutting flanges.…”

“…The new geometrical development method in triangle mesh parameterization way adopts the theory presented in literature [13]: utilizing geometric intrinsic properties of triangles to represent the shape of a triangle. Fig.…”

“…But this method needs to remedy mesh distortion many times by the energy minimization technique during development process. Bao used a similar way as Chung to get the initial guess mesh and the mesh smoothing is needed to be improved [13].…”