| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1987: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1986: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Research Abstract |
There are many kinds in shapes and materials in products of extrusion, forging, etc., and temperature of material and working speed must be controlled rigorously, especially in forming of non-ductile materials, eg. titanium alloys. In such situation, numerical analysis seems to be effective for estimation of strain or temperature of a work at the stage of designing dies. However, same difficulties remain yet in usual finite element method (FEM).
In this research, a new method of analysis is proposed. First, a deforming region is devided into thin sub-regions, by referring to strain distribution obtained by a model experiment. Secondly, deformations of these sub-regions are analysed by the use of FEM. Finally, those solutions are combined and the solution of 3-D deformation is estimated.
Non-axisymmetric, backward extrusion is dealt with as an example. The pattern of division possibly causes some errors in the solution, so the following two methods of division are discussed.
In the first method, strain measurement is done in the cross section at the part after extrusion and principal strain lines, distributed approximately in radial direction, are obtained. Then, stream surfaces, containing principal strain lines, are used for division; shear strain across these surfaces is rather small and interference of deformation between neighboring sub-regions seems to be small.
In the second method, deviding surfaces are assumed to be planes and no experimental information is applied to, this time. This method is rather rough but it was found that a reasonable solution is obtained in the situation that there are many symmetric surfaces as in the extrusion with a punch of square section.
Consequently, the latter method of division is useful in the deformation not far from axi-symmetric one, whereas the former method should be applied to, when considerable circumferential flow occurs.
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