designing of an adjustable enlarger using the finite element method · 2021. 3. 6. · finite...

Fiabilitate si Durabilitate - Fiability & Durability No 1/ 2020 Editura “Academica Brâncuşi” , Târgu Jiu, ISSN 1844 – 640X

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DESIGNING OF AN ADJUSTABLE ENLARGER USING THE FINITE

ELEMENT METHOD

Lecturer PhD. eng. Alin NIOAŢĂ, Faculty of Engineering,

”Constantin Brâncuşi” University, [email protected]

ABSTRACT: Enlargers are tools designed for processing holes obtained by drilling with borers,

casting,forging, in order to increase their diameters. This paper shows improvements in the classic

cycle of research and design of cutting tools because it uses the finite element method in designing

adjustable tools, tools provided with interchangeable plates.

KEY WORDS: CATIA, cutting tools, enlarger, replaceable plates, forces.

1. INTRODUCTION

CATIA (Computer Aided Three Dimensional Interactive Applications) is a product of

Dassault Systemes, one of the most advanced integrated CAD/CAM/CAE platforms based on

the latest technologies in the informatic industry [1, 2, 3].

Basic functionalities [1, 2, 3]:

- advanced design of mechanical parts;

- interactive producing of the assemblies;

- automatic obtaining of projections of the current piece or ensemble;

- the possibility of designing in a parameterized way;

- allows designing the parts and assemblies directly in three dimensions, without first drawing

the sketches in two-dimensional representation;

- uses virtual prototypes that allow:

-testing of resistance to various stresses;

- verifying whether an assembly is dismountable or not;

-verifying if the mobility of components, relative to each other, does not generate

collisions;

- has modular structure.

2. MODELING OF THE PIECE

Adjustable enlargers with removable teeth are used for diameters over 80 mm and have

4 ... 8 teeth depending on the diameter of the tool. An example of an adjustable enlarger with

removable teeth is given in Figure 1[4].

mailto:[email protected]


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Fig.1 Enlarger with removable teeth

The body of the adjustable enlarger (figure 2), made of an alloy steel, is provided with

channels in which the changeable plates are assembled (figure 3).

Fig. 2 Enlarger body

Fig. 3 Replaceable plate

The adjustment of the plates for processing is done with the help of the cam (in fact

several cams depending on the number of plates) (figure 4). There is a graded vernier on the

cam that helps us determine the size for processing. The cams are designed so as to allow the

size of the enlarger to be changed with certain values [5, 6].


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Fig. 4 Cam

The plates and the cam are fixed by means of a lid (Figure 5) and screws.

Functional geometry is achieved by positioning the plates in the enlarger body

Fig. 5 Lid

3. FEM ANALYSIS

After solid modeling in the CATIA Part Design module, the piece is considered to be

made of a material (steel) having the following physical and mechanical properties, important

during the analysis: Young's module (2x1011

N / mm2), Poisson's coefficient (0.266), density

(7860 kg/m3), coefficient of thermal expansion (1.17x10-5

oK), allowable strength (2.5x10

8

N/m2) [7].

CATIA Generative Structural Analysis module is accessed from the Start - Analysis &

Simulation menu and set the static analysis type (Static Case), the specification tree

simultaneously showing the element with the same name [8, 9].

Although the CATIA program implicitly defines the network of nodes and elements

(discretization) , it is recommended to edit it and determine the size of the finite element


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(Size), the maximum tolerance between the discretized model and the actual model used in

the analysis (Absolute sag), the element type (Element type), and so on [8,9].

Subsequently, a restriction of Clamp type (supports, represented in blue) is applied to

the clamping surface (figure 6).

Fig. 6 Applying supports

The applied forces Fx, y (Figure 7) and Fz (figure 8) are positioned on the surfaces of

discharging and placement of the plates, exerting the values represented in the figure,

oriented according to the direction of the cutting forces. Thus, in the specification tree the

Elemental Distributed Force 1 becomes available, the force being specified by arrows on the

surface [3, 8, 9].

Fig. 7 Strong values Fx, Fy


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Fig. 8 Force values Fz

After establishing the restrictions and the loading, the effective step of the calculation

(analysis) follows. Pressing the Compute icon on the toolbar the All option is selected , the

first effect of the action being the update of the Static Case Solution element. After

completing the calculation, the user has the tools of the Image bar to view the results. The

specification tree is completed according to the inserted images. The figure shows the image

(by using the Von Mises Stress, Deformation, Main Stress and Precision tools),

corresponding to the calculation of the part model and the load considered, indicating that the

deformations are presented graphically slightly exaggerated in order to facilitate the stage of

establishing the conclusions of the analysis ( Figure 9, 10) [3, 8, 9].


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Fig. 9 Distribution mode: linear

Fig. 10 Distribution mode: logarithmic

In the figures (Figure 9, 10), the color palettes accompanying the result are shown on

the right side - Von Mises image. The lowest values of the tensions are at the bottom of the

pallete, and the maximum values at the top of it. The dialog box also contains the explicit

values, in the Extreme Values area, as follows: Min 0.519 x 106 and Max 1.110 x 10

7 N/m

2.

Thus, one can interpret the way in which the tensions are distributed on the piece according to

the colors displayed.

Analyzing the shades of colors in the linear distribution mode (Figure 9), we can

observe a variation of the tensions on the piece from 0 N/m2 to 7.74 x 10

6 N/m

2 and in the


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logarithmic distribution mode (figure 10) from 2.27 N/m2 to 2.21 x 10

7 N/m

2.

Given that the allowable strength of the material is 2.5 x 108 N/m

2, an initial conclusion

can be drawn that the piece model will withstand the distributed force applied.

4.CONCLUSIONS The designers of an enlarging tool with tangential changeable plates must take into

account that a correct design and modeling largely depends on the basic parameters of the

processing that the respective enlarger will perform: the precision and the quality of the

processed surfaces, the productivity and the cost of the processing.

Finite element analysis using the CATIA program is a modern method for studying

different contacts, allowing the determination of important parameters for the study of

different contacts. In the case of hertz contacts, accurate information on the state of stresses at

the contact level is obtained. The point contact analysis using the classical method (Hertz

theory) did not allow such accurate results to be obtained. Von Mises stress determination

allows a stress state analysis thus allowing for a correct quantification of this state and the

possibility of identifying the deterioration that occurs.

REFERENCES

[1] Ghionea, I.G. – CATIA v5 – culegere de aplicaţii pentru activităţi de laborator, format

electronic, Universitatea Politehnică Bucureşti, 2015;

[2] Ghionea, I.G. – CATIA v5 – aplicaţii ȋn inginerie mecanică, Editura BREN, Bucureşti,

2009;

[3] Ghionea, I.G. – Proiectare asistată ȋn CATIA v5 – elemente teoretice şi aplicaţii, Editura

BREN, Bucureşti, 2014;

[4] Nioață, A. – Proiectarea sculelor așchietoare, Editura ‖Academica Brâncuși‖, Târgu-Jiu,

2010.

[5] Rădulescu Constanţa, Cîrţînă Liviu Marius, Panait Alexandru - Analysis of the

stability of the technological process of making a piece on a machining center Part I -

Confereng 2017, Analele Universitatii ,,Constantin Brancusi,, din Targu-Jiu, Nr.3/2017,

Editura ―Academica Brâncuşi‖ ISSN 1842 – 4856, pag. 64-69;

[6] Rădulescu Constanţa, Cîrţînă Liviu Marius, Panait Alexandru - Analysis of the

stability of the technological process of making a piece on a machining center Part II -

Confereng 2017, Analele Universitatii ,,Constantin Brancusi,, din Targu-Jiu, Nr.3/2017,

Editura ―Academica Brâncuşi‖ ISSN 1842 – 4856, pag. 70-73;

[7] Tătar A., Bazele electrotehnicii, Editura Sitech Craiova, 2018, ISBN 978-606-11-6428-8,

pag. 217.

[8] Ciofu, F. - Hip implant analysis with CATIA, Revista Fiabilitate şi Durabilitate,

Nr.2/2017, ISSN 1844-640X, page 99-104.

[9] Ciofu, F. - Parametriated assisted design using CATIA, Revista Fiabilitate şi Durabilitate,

Nr.2/2019, ISSN 1844-640X, page 60-66.

designing of an adjustable enlarger using the finite element method · 2021. 3. 6. · finite...

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