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

beckhamyk18@163.com, yangmingshun@xaut.edu.cn, Yuanql@xaut.edu.cn

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.

Advanced Science and Technology Letters Vol.121 (AST 2016), pp.125-130

http://dx.doi.org/10.14257/astl.2016.121.23

ISSN: 2287-1233 ASTL Copyright © 2016 SERSC

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

1600×1395×1395 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

Workbench

Beam

Spindle box

Right column

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 = 1.69×105 Mpa,

poisson's ratio μ = 0.286, density ρ = 7.12×10-9

T/mm3. Model the appearance of the

overall size is 906×560×420 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 4592. 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).

Advanced Science and Technology Letters Vol.121 (AST 2016)

126 Copyright © 2016 SERSC

Left plate

Hole 1

Hole 3

Steel plate

Hole 2

Hole 4

Fig. 2. Model for the beam

(a) 1st 766.11Hz (b) 2nd 941.22Hz

(c) 3rd 1513.8Hz (d) 4th 1532.5Hz

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=766.11 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 0.021 Mpa, as shown in the Figure 4.

Advanced Science and Technology Letters Vol.121 (AST 2016)

Copyright © 2016 SERSC 127

(a) Displacement nephogram (b) Equivalent stress nephogram

Fig. 4. Static deformation picture

Maximum deformation is 0.0010909 mm, the maximum equivalent stress is

0.57085 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

Advanced Science and Technology Letters Vol.121 (AST 2016)

128 Copyright © 2016 SERSC

Fig. 6. Beam after topology optimization

After optimization of beam of first-order natural frequency f=772.18 Hz, the

maximal displacement of beam is 0.0011189 mm, the maximum equivalent stress is

0.42119 Mpa, the mass is 204.37 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

)mm002.0( maxmax , the maximum equivalent stress

)Mpa1( maxmax ), natural frequency

f( Hz770f ), 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 191.71kg, the maximal displacement is

Advanced Science and Technology Letters Vol.121 (AST 2016)

Copyright © 2016 SERSC 129

0.0010667mm and the maximum equivalent stress is 0.50217 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 0.50217Mpa, which is far less than the allowable stress

of material. And the maximal displacement is only 0.0010667mm, 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. 51475366, 51475146) and Key Laboratory of

Scientific Research Projects of Shan'xi Educational Committee (Grant No. 12JS072).

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130 Copyright © 2016 SERSC