A lap is defined as surface to surface contact in the workpiece when the surface of the workpiece folds or collapses on itself. A lap appears as a seam in the surface of a forging that can extend into the interior of the forging.
One of the most powerful features of QForm2D/3D is its ability to precisely predict these kinds of forging defects. Laps are shown in 2D as a line extending into the forging and in 3D as a cloud of red spots that not only show the shape of the lap on the surface of the forging, but extend into the forging to show you the exact shape and depth of the lap extending into the forging. QForm will show the formation of the lap and continue the simulation to show the final location of the lap in the finished forging with a high degree of accuracy.
QForm's completely automated code generates adaptive mesh for even the most complicated deformed billet surfaces including situations when the surface collapses and a lap appears.The program automatically detects areas where laps are likely to occur and locally increases the mesh density in these areas so that laps will be indicated with the highest degree of precision. Surface to surface contact is treated automatically and the lap surface is clearly shown by a cloud of red spots. These spots show the defect location and its depth. By these means the program traces the defects through the sequence of blows and shows the location of the defects in the finish product.
The animations on the right show some examples of lap detection in QForm.
Examples of laps in QForm
The following sequence shows an arm forging when several laps appear due to improper die design. The user can clearly see where and when the laps are initiated and how they propagate inside of the forged part body.
(The color is showing effective strain)
The laps appearing in the forged arm are highlighted by red dots.