模具設計外文翻譯--對渦輪增壓器葉輪和齒環(huán)的鍛造加工過程進行模具優(yōu)化設計（英文）

1、Optimization of Die Design for Forging a Turbo-Charger Impeller and a Ring Gear Using Process Simulation Jay Gunasekera, PhD, DSc, PE, Professor of Mechanical Engineering, Ohio University, USA, Mazyad Al-Moheib and Fahad

2、 Al-Mufadi, Former PhD students at Ohio University, USA SYNOPSIS: The objective of this project was to optimize the preform and final die design for two complex automotive forged products (a turbine impeller and a ring

3、gear) for two different forging companies in the US. The turbine impeller has to have a minimum effective plastic strain of 0.5 in order to increase the toughness and resist fracture due to the very high centrifugal st

4、resses. It is also important to distribute the strain and the grain size as uniformly as possible throughout the finished forged part, so as to achieve the best mechanical properties for the Al 2618 turbine wheel. Opt

5、imization of grain size was performed by determining optimal temperature and average strain rate (by the use of Zener-Hollomon Parameter). The second project was to optimize the die design for a steel Ring Gear, so as t

6、o reduce the number of forging stages and also reduce the material wastage due to excessive flash. The software used was MSC.SuperForge, the predecessor of Simufact.forming, which is capable of checking the die filling,

7、 defect formation and die contact in the final stage. It can also determine and display a variety of useful parameters such as; the effective plastic strain, effective strain rate, effective stress, material flow, tempe

8、rature, force-time relationship and final shape by using Superforge-FV (Finite Volume) simulation. It is concluded that the software can be effectively used to optimize the forging process to maximize the mechanical str

9、ength, minimize material scrap for example Lee et al. [4] used UBET to analyze the forging load, die filling, and the effective strain for forgings with and without flash gap. The program was applied to both axisymmet

10、ric and non-axisymmetric closed die forging as well as plane strain closed die forging with rib-web type cavity. The results obtained from this study were compared with experimental results in which, a good agreement wa

11、s achieved. A pre-form design approach that incorporates both FEM-based forward simulations and UBET-based backward simulations was developed by Liu, et al. [5]. Bramley, [6], has employed TEUBA, which is a UBET-based

12、computer program for the process of forging pre-form design using reverse simulations. This approach is based on reversing the flow by starting from the desired final shape with the die velocities reversed in such a way

13、 that the material at the end of the deepest die cavity is considered to have a free boundary and material flows backward up to certain time step where the dies are separated from the billet, which gives the pre-form of

14、the process. A finite element-based inverse die contact tracking method to design the perform die shapes of a generic turbine-disk forging process was used by Zhao, et al. [7]. Finally, M. Mohelib and J.S. Gunasekera

15、 [8] used UBET for backward simulation in Ring Rolling and for forging a Ring Gear. The Ring Gear project is reported in this paper. The theory of UBET can be found in a number of excellent publications and will not be

16、 repeated here. 2. TURBINE WHEEL ANALYSIS [1] The development of Finite Element Analysis (FEA) techniques has provided an important link between advances in die and equipment design and an improved understanding of mater

17、ials behavior. Inputs to the FE codes include the characteristics of the work piece material (flow stress and thermal properties) and the tool/work piece interface (friction and heat transfer properties), as well as work

18、 piece and tooling geometries. Typical outputs include predictions for forming load, strain, strain rate and temperature contour plots, and tooling deflections. The method of study for this model is: 1. The models are fi

19、rst made in CAD software such as SOLID EDGE for the billets and for preform (upsetting dies) as well as closed die forging in both the upper and lower dies. This model is exported for three-dimensional FEA techniques suc

20、h as FV (Finite Volume) analysis (simulation) of actual die forging of the rotating part with SUPERFORGE [9] to find flaws in the design of the preform. 2. To focus on optimizing the preform design. 3. To define the best

21、 preform design and finished work piece based on optimization results and to verify the applicability of this method. One of the most important aspects of the closed-die forging process is the design of preforms (or blo

22、ckers) to achieve adequate metal distribution. With the proper preform design, defect-free metal flow and complete die fill can be achieved in the final forging operation and metal losses into flash can be minimized. The