文献翻译原文在冲压过程模拟产品和工艺设计最新应用Word下载.docx

1、 （1） to optimize the product design by analyzing formability at the product design stage and （2） to reduce the tryout time and cost in process design by predicting the deformation process in advance during the die design stage. For each of these objectives, two kinds of FE-simulations are applied. P

2、am-Stamp, an incremental dynamic-explicit FEM code released by Engineering Systems Intl, matches the second objective well because it can deal with most of the practical stamping parameters. FAST_FORM3D, a one-step FEM code released by Forming Technologies, matches the first objective because it onl

3、y requires the part geometry and not the complex process information.In a previous study, these two FE codes were applied to complex-shaped parts used in manufacturing automobiles and construction machinery. Their capabilities in predicting formability issues in stamping were evaluated. This paper r

4、eviews the results of this study and summarizes the recommended procedures for obtaining accurate and reliable results from FE simulations.In another study, the effect of controlling the blank holder force （BHF） during the deep drawing of hemispherical, dome-bottomed cups was investigated. The stand

5、ard automotive aluminum-killed, drawing-quality （AKDQ） steel was used as well as high performance materials such as high strength steel, bake hard steel, and aluminum 6111. It was determined that varying the BHF as a function of stroke improved the strain distributions in the domed cups.Keywords: St

6、amping; Process ;stimulation; Process design1. IntroductionThe design process of complex shaped sheet metal stampings such as automotive panels, consists of many stages of decision making and is a very expensive and time consuming process. Currently in industry, many engineering decisions are made b

7、ased on the knowledge of experienced personnel and these decisions are typically validated during the soft tooling and prototyping stage and during hard die tryouts. Very often the soft and hard tools must be reworked or even redesigned and remanufactured to provide parts with acceptable levels of q

8、uality.The best case scenario would consist of the process outlined in Fig. 1. In this design process, the experienced product designer would have immediate feedback using a specially design software called one-step FEM to estimate the formability of their design. This would allow the product design

9、er to make necessary changes up front as opposed to down the line after expensive tooling has been manufactured. One-step FEM is particularly suited for product analysis since it does not require binder, addendum, or even most process conditions. Typically this information is not available during th

10、e product design phase. One-step FEM is also easy to use and computationally fast, which allows the designer to play “what if” without much time investment.Fig. 1. Proposed design process for sheet metal stampings. Once the product has been designed and validated, the development project would enter

11、 the “time zero” phase and be passed onto the die designer. The die designer would validate his/her design with an incremental FEM code and make necessary design changes and perhaps even optimize the process parameters to ensure not just minimum acceptability of part quality, but maximum achievable

12、quality. This increases product quality but also increase process robustness. Incremental FEM is particularly suited for die design analysis since it does require binder, addendum, and process conditions which are either known during die design or desired to be known.The validated die design would t

13、hen be manufactured directly into the hard production tooling and be validated with physical tryouts during which the prototype parts would be made. Tryout time should be decreased due to the earlier numerical validations. Redesign and remanufacturing of the tooling due to unforeseen forming problem

14、s should be a thing of the past. The decrease in tryout time and elimination of redesign/remanufacturing should more than make up for the time used to numerically validate the part, die, and process. Optimization of the stamping process is also of great importance to producers of sheet stampings. By

15、 modestly increasing ones investment in presses, equipment, and tooling used in sheet forming, one may increase ones control over the stamping process tremendously. It has been well documented that blank holder force is one of the most sensitive process parameters in sheet forming and therefore can

16、be used to precisely control the deformation process.By controlling the blank holder force as a function of press stroke AND position around the binder periphery, one can improve the strain distribution of the panel providing increased panel strength and stiffness, reduced springback and residual st

17、resses, increased product quality and process robustness. An inexpensive, but industrial quality system is currently being developed at the ERC/NSM using a combination of hydraulics and nitrogen and is shown in Fig. 2. Using BHF control can also allow engineers to design more aggressive panels to ta

18、ke advantage the increased formability window provided by BHF control.Fig. 2. Blank holder force control system and tooling being developed at the ERC/NSM labs.Three separate studies were undertaken to study the various stages of the design process. The next section describes a study of the product

19、design phase in which the one-step FEM code FAST_FORM3D （Forming Technologies） was validated with a laboratory and industrial part and used to predict optimal blank shapes. Section 4 summarizes a study of the die design stage in which an actual industrial panel was used to validate the incremental F

20、EM code Pam-Stamp （Engineering Systems Intl）. Section 5 covers a laboratory study of the effect of blank holder force control on the strain distributions in deep drawn, hemispherical, dome-bottomed cups.2. Product simulation applicationsThe objective of this investigation was to validate FAST_FORM3D

21、, to determine FAST_FORM3Ds blank shape prediction capability, and to determine how one-step FEM can be implemented into the product design process. Forming Technologies has provided their one-step FEM code FAST_FORM3D and training to the ERC/NSM for the purpose of benchmarking and research. FAST_FO

22、RM3D does not simulate the deformation history. Instead it projects the final part geometry onto a flat plane or developable surface and repositions the nodes and elements until a minimum energy state is reached. This process is computationally faster than incremental simulations like Pam-Stamp, but

23、 also makes more assumptions. FAST_FORM3D can evaluate formability and estimate optimal blank geometries and is a strong tool for product designers due to its speed and ease of use particularly during the stage when the die geometry is not available.In order to validate FAST_FORM3D, we compared its

24、blank shape prediction with analytical blank shape prediction methods. The part geometry used was a 5in. deep 12in. by 15in. rectangular pan with a 1in. flange as shown in Fig. 3. Table 1 lists the process conditions used. Romanovskis empirical blank shape method and the slip line field method was u

25、sed to predict blank shapes for this part which are shown in Fig. 4. Fig. 3. Rectangular pan geometry used for FAST_FORM3D validation.Table 1. Process parameters used for FAST_FORM3D rectangular pan validation Fig. 4. Blank shape design for rectangular pans using hand calculations. （a） Romanovskis e

26、mpirical method; （b） slip line field analytical method.Fig. 5（a） shows the predicted blank geometries from the Romanovski method, slip line field method, and FAST_FORM3D. The blank shapes agree in the corner area, but differ greatly in the side regions. Fig. 5（b）（c） show the draw-in pattern after th

27、e drawing process of the rectangular pan as simulated by Pam-Stamp for each of the predicted blank shapes. The draw-in patterns for all three rectangular pans matched in the corners regions quite well. The slip line field method, though, did not achieve the objective 1in. flange in the side region,

28、while the Romanovski and FAST_FORM3D methods achieved the 1in. flange in the side regions relatively well. Further, only the FAST_FORM3D blank agrees in the corner/side transition regions. Moreover, the FAST_FORM3D blank has a better strain distribution and lower peak strain than Romanovski as can b

29、e seen in Fig. 6.Fig. 5. Various blank shape predictions and Pam-Stamp simulation results for the rectangular pan. （a） Three predicted blank shapes; （b） deformed slip line field blank; （c） deformed Romanovski blank; （d） deformed FAST_FORM3D blank.Fig. 6. Comparison of strain distribution of various

30、blank shapes using Pam-Stamp for the rectangular pan. （a） Deformed Romanovski blank; （b） deformed FAST_FORM3D blank.To continue this validation study, an industrial part from the Komatsu Ltd. was chosen and is shown in Fig. 7（a）. We predicted an optimal blank geometry with FAST_FORM3D and compared it with the experimentally developed blank shape as shown in Fig. 7（b）. As seen, the blanks are similar but have some differences.Fig. 7. FAST_FORM3D simulation results for instrument cover validation. （a） FAST_FORM3Ds fo