FEM Analysis of Rebar Bending Machine

International Journal of Innovative Research in Advanced Engineering (IJIRAE) ISSN: 2349-2163 Issue 4, Volume 2 (April 2015) www.ijirae.com

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FEM Analysis of Rebar Bending Machine P.N.AWACHAT DIGVIJAY KEWALE DNYANESHWAR KALE Dept. of Mechanical engineer Dept. of Mechanical engineer Dept. of Mechanical engineer G.H. Raisoni Academy Of Engg.&Tech., G.H.Raisoni Academy Of Engg.&Tech., G.H.Raisoni Academy Of Engg.&Tech., Nagpur Nagpur Nagpur

Abstract — Finite element method is numerical technique for finding approximate solutions to boundary value problems for partial differential equations. It uses subdivision of whole problem into simpler parts, called finite elements, and variational methods from calculus of variations to solve problems by minimizing an associated error function. FEM analysis can be used in designing of bending machine. Reinforcement manufacturing received very little attention from the research Community. As the construction industry started to move towards more industrialized methods, the reinforcement manufacturing also began to adopt more industrialized method. The operation of the machine is numerically controlled by a computer (CNC), which determines the exact bending and cutting locations. The design is based on optimal design using non-linear finite element method, in which material non-linearity is considered and fabrication process is based on a rapid and efficient prototyping system using a CAD/CAM.

Keywords: - FEM, re-bar, CNC, CAD/CAM

I. INTRODUCTION: Nowadays the world is focusing into automation, Each and every work of human is reduced by a machine but

few areas like construction the usage of machines bending rods for stirrups which are used to withstand loads in beams and columns are not done by machine because the cost of machine is high and need skilled labours to operate Stirrup is an important reinforced element which acts as a shear reinforcement. Presently, stirrups are made manually, which suffers from many drawbacks like lack of accuracy, low productivity and resulting into severe fatigue in the operator. To reduce these drawbacks we use computer numerical control in rebar bending machine. The rebar production process begins with the design of the reinforced concrete element and ends with its fabrication.

II. ABOUT FEM (FINITE ELEMENT METHOD):

Finite element method is numerical technique for finding approximate solutions to boundary value problems for partial differential equations. The various models of machine can be obtained by finite element software ANSYS, taking into account the non-linear material properties of the reinforced mild steel bars. Currently finite element method is widely used to solve problems of continuous media mechanics. This is explained by wide versatility of the FEM and possibility of representing the most complex structures by finite elements of a simple configuration. The finite element method is developed to solve specific problems of determination the stress-strain state of bending deformation of bars with different boundary conditions, which is implemented on personal computer. The method is very useful when computer is used, as all of its algorithms are written in matrix form.

III. FEM ANALYSIS:

Finite element analysis is method which finds approximate solution to problem with the help of differential equations. The analysis can be done by dividing the part into N sections. Behaviour of rod under bending stress is given below by finite element method analysis calculations.

Fig. analysis of re-bar



Fig. FEM analysis of re-bar

E= 91 mpa (

Discretization diagram

Nodal displacement vector d= The element stiffness matrix for element 1 & 2 can be written as

K=

=

Similarly for

=

Global stiffness matrix K=

Applying boundary conditions;

=

0.4687 +22.6 = -21 22.6 + 2154.02 =0

Shear force and bending moment at each end at an individual member are obtained by

=7.247



=

Similarly, The calculations for the member 2 are; 0.46 0.46 -18.58

-24.31 +1707.68 -1394.94

u =

=

u =

For element 1

Fig. SFD & BMD diagram

For element 2

Fig. SFD & BMD diagram



IV. WORKING:

There are various bending machines available in industry, those works on hydraulic and pneumatic fluids. The basic assumption underlying this research is that the two ends of the rebar manufacturing process are computer-based or assisted. There are various components used in rebar bending machine, within which many more are electronics such as motor, microcontroller (89c51), printed circuit board, IC232 (MAX232), cable RS232. Power supply is given to controller (Microcontroller-89c51), and then signal is given to PCB (printed circuit board) at which max 232 step down to 5v from 15v. Also signal is given to motor. The signal from MAX 232 is further send to motor which perform bending. Finally the stirrups are formed by bending.

V. SUGGESTED NEW MODEL:

The working of this model is based on computer programming, which is fed into microcontroller (89c51). This is portable as it does not contain compressor or storage tank which is required in hydraulic or pneumatics. It efficiently bends the rod of about 8mm diameter. It finds wide range of applications in construction sites where manual work for bending stirrups is minimized. This works on both manual and automatic operations. The main advantage is this model is, fluctuating power or uneven power supply to system does not create any hazard to controlling system because the relay gets burst themselves which cause system stop. In this model, the angle can be bending in various angles.

Fig. CAD model of re-bar machine

VI. RESULT AND CONCLUSION: It saves man hour inputs for data handling, processing and programming the NC Machine. Flexibility in the manufacturing strategy, enabling the batches to be produced by building elements or any other sorting criterion. Enabling just-in-time delivery due to the elimination of errors and improved communication. It is portable machine as it does not contain any compressor or storage tank.It produces bend up to 8mm diameter.

VII. REFERENCES:

R. Navona, Y. Rubinovitzb and M. Cofflerc, Automation and Robotics in Construction XI D.A. Chamberlain (Editor) © 1994 Elsevier Science.

Kunal Sharma , Dr. V.N Bartaria International Journal of Advanced Technology & Engineering Research (IJATER) Finite element method basic concept and app Chemmakesava .R. Alavala, Chandrapatla & Belegundu, Bhavikatti

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FEM Analysis of Rebar Bending Machine