Optimization Design of Cold Roll-beating Experiment Device Based on ANSYS Workbench

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1 , pp Optimization Design of Cold Roll-beating Experiment Device Based on ANSYS Workbench Fanzhi Wei, Mingshun Yang, Qilong Yuan Faculty of mechanical and precision instrument engineering, Xi an University of Technology, Xi an, China Abstract. Cold roll-beating forming technology is an advanced plastic forming technology. In order to promote the further movement way of this technology research, a cold roll-beating experiment device is designed in this paper. Through the cold roll-beating process the beam plays the main role in bearing and positioning. A parametric model of the frame is built in ANSYS Workbench. Static and modal analysis is made according to the limiting working conditions to make sure the beam s stiffness whether meet the requirement or not in cold roll-beating process based on the result of analysis. The frame is optimized by Goal-Driven Optimization (GDO) function of ANSYS Workbench with topology optimization and shape optimization. After optimization improved, the frame s quality is reduced 20.4% to the original structure and its stiffness is also meet the requirement in cold roll-beating process. Keywords: Cold roll-beating, Experiment Device, Optimization Design, Workbench 1 Introduction With the development of modern plasticity forming technology, reducing plasticity forming equipment energy consumption and the forming force, and improving the producing flexibility and product accuracy has become the main innovation direction of plasticity forming technology [1-4]. As a plastic forming technology at ordinary temperatures, Cold roll-beating forming technology features in simple technology simplicity, low energy -consumption and high efficiency [5]. Cold roll-beating forming technology uses advantage of the characteristics of the metal plastic forming, with high speed rolling wheel beating striking the workpiece to force metal flowing, thus forming a plastic forming technology of partial load, no die, and no constraint free of parts contour [6]. In this paper, the ANSYS Workbench software is used to optimize the beam of the device. On the premise of meeting the mechanical properties of the device, minimizing the quality of the beam can reduce equipment tonnage and enhance the utilization ratio of materials. ISSN: ASTL Copyright 2016 SERSC

2 2. The Design of Cold Roll-beating Device Mechanical structural design of equipment should guarantee the security, stability, reliability, simplicity and feasibility. Figure 1 is a specific structure of the device. The overall size (length, width and height) of the cold roll-beating equipment is mm, which consists of beam, left and right columns, spindle box and spindle, workbench and base. Base is fixed on the ground, beam and the left column through the screw guiding, with the right column by dowel locating, motor and main spindle by the belt transmission. Before roll- beating process, adjusting screw and dowel to ensure beam at right height. And then rolling process, the worktable driven fixture and workpiece to the Y axis is the direction of feed at a certain speed, motor drives the spindle rotating to finish roll-beating. Motor Left column Beam Spindle box Right column Workbench Base Fig. 1. 3D models of cold roll-beating device 3 Modal and Static Analysis of the Device Beam The part of equipment beam is connected by welding, according to the Saint Venant s Principle, chamfering, rounded corners, holes, etc. are ignored. Finite element model of beam as shown in figure 2. Material of the beam is QT600-3, E = Mpa, poisson's ratio μ = 0.286, density ρ = T/mm 3. Model the appearance of the overall size is mm. Total mass is 240 kg. Adopt the method of the smart mesh divided into ANSYS Workbench, divided the total number of nodes are 9620, the total number of units are Model in ANSYS Workbench module modal analysis is carried out on the beam, get beam first to the fourth order natural frequency as shown in Figure 3(a)~(d). 126 Copyright 2016 SERSC

3 Left plate Hole 1 Hole 3 Steel plate Hole 2 Hole 4 Fig. 2. Model for the beam (a) 1 st Hz (b) 2 nd Hz (c) 3 rd Hz (d) 4 th Hz Fig. 3. Beam modal shape The highest speed in motor engineering v=5000 r/min, the biggest vibration frequency f=83.3hz. And the beam first-order natural frequency f= Hz, greater than the vibration frequency, so in the process of roll-beating, the beam does not produce resonance. Statics analysis was carried out on the beam, the plate on the left side and right side hole full constraints, In the process of roll-beating working extreme conditions, the load to the beam with mandrel surface convex platform the average pressure is Mpa, as shown in the Figure 4. Copyright 2016 SERSC 127

4 (a) Displacement nephogram Fig. 4. Static deformation picture (b) Equivalent stress nephogram Maximum deformation is mm, the maximum equivalent stress is Mpa. Thus, the beam low order natural frequency is larger than the vibration frequency of work, Dynamic stiffness is better, it won't produce resonance. When the beam under extreme conditions, the maximum deformation is small, the static stiffness is better. It will not affect the machining accuracy of deformation in the work. The beam under extreme conditions of equivalent press is lesser, far less than the yield limit of material of beam. But large mass makes the beam too bulky and optimization design is necessary. 4 The Optimal Design of the Beam Use shape Optimization module in ANSYS Workbench [7], and through the original finite element model of beam to divide mesh, load the same boundary conditions and loading in the static analysis, setting the Optimization goal mass reduction is 40%, through iterative calculation, the optimization results are obtained as shown in figure 5. Use 3D software improve the finite element model of beam as shown in figure 6 Fig. 5. Topological optimization results 128 Copyright 2016 SERSC

5 Fig. 6. Beam after topology optimization After optimization of beam of first-order natural frequency f= Hz, the maximal displacement of beam is mm, the maximum equivalent stress is Mpa, the mass is kg, as shown in figure 7. The optimization results show that beam mass reduce 14.8% after removing material, dynamic stiffness of beam has increased, but the static stiffness is almost not change, the ability of resistance to deformation and fracture is still strong. (a) The displacement nephogram (b) Equivalent stress nephogram Fig. 7. Static deformation picture Use the beam which after topology optimize model input the ANSYS Workbench of GDO module to optimize the sizes, the left plate and beam thickness as the design variables, use the frequency, maximum displacement and maximum equivalent stress as state variables, the minimum mass as objective function. Setting the left plate and crossbeam of thickness is 35 to 60 mm, the largest displacement of beam 0.002mm), the maximum equivalent stress max ( max 1Mpa) ), natural frequency max ( max f( f 770Hz ), through the interaction between various variables and iterative calculation, we can get three optimal design points. From the candidates it can be seen that the reasonable left plate thickness is 38~40mm, the crossbeam thickness about 48~50mm.Because the thickness of plate easy process after get round numbers, so in the beam model, when the left plate is 40mm, beam thickness is 50mm, state variables of beam satisfy boundary conditions that it get minimal mass. First order natural frequency f=778.91hz, the mass is kg, the maximal displacement is Copyright 2016 SERSC 129

6 mm and the maximum equivalent stress is Mpa. It can be concluded that: after topology optimization, the maximal displacement of beam and equivalent stress decreases, the first-order natural frequency increases, the rigidity get better and the mass decreased by 13.3%. Through the left plate and crossbeam size optimization, although the maximum equivalent stress increases, but the maximal displacement reduced, stiffness can meet the demand of processing, and the mass is decreased by 20.4%. 5 Summary Based on finite element analysis of beam, it is concluded that the first order natural frequency f=778.91hz work is greater than the vibration frequency f=83hz, the maximum equivalent stress is Mpa, which is far less than the allowable stress of material. And the maximal displacement is only mm, which can meet the accuracy requirement in the process of machining. The optimized structure mass is decreased by 20.4%. Acknowledgements. This topic of research is supported by National Natural Science Foundation of China (Grant No , ) and Key Laboratory of Scientific Research Projects of Shan'xi Educational Committee (Grant No. 12JS072). References 1. Min, N.Y., G.H. An, S. X. Chen, China Mechanical Engineering, 1, 11 (2000) 2. Cui F.K., Zhu W.J., Wang X.Q. and Zhang F.S., Journal of Henan Polytechnic University, 2, 31 (2012) 3. Amirkhaneou, S.: Materials& Design, 4, 32 (2011). 4. Neugebauera R., Bouzakisb, K. D.: CIRP Annals - Manufacturing Technology. 2, 60 (2011). 5. Zhang, L., Li, Y., Yang, M. S., Yuan, Q. L., Cui, F.K: Aerospace Materials & Technology, 6, 41 (2011). 6. Liu, X., Zhang, X. L., Cui, F. K., Machine Building & Automation, 6, 6 (2014). 7. Cheng, F.L., Chen, S.J.: Journal of Machine Design, 1, 29 (2012). 130 Copyright 2016 SERSC