Model for prediction of temperature distribution in workpiece for surface grinding using fea

International Journal of Advanced Research in Engineering and TechnologyRESEARCH IN –
INTERNATIONAL JOURNAL OF ADVANCED (IJARET), ISSN 0976
6480(Print), ISSN 0976 – 6499(Online) Volume 3, Number 2, July-December (2012), © IAEME
ENGINEERING AND TECHNOLOGY (IJARET)

ISSN 0976 - 6480 (Print) IJARET
ISSN 0976 - 6499 (Online)
Volume 3, Issue 2, July-December (2012), pp. 207-213
© IAEME: www.iaeme.com/ijaret.asp
©IAEME
Journal Impact Factor (2012): 2.7078 (Calculated by GISI)
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MODEL FOR PREDICTION OF TEMPERATURE DISTRIBUTION IN
WORKPIECE FOR SURFACE GRINDING USING FEA

Gunwant D.Shelake1, Harshal K. chavan2, Prof. R. R. Deshmukh3, Dr. S. D. Deshmukh4
4
Dept. of Mechanical Engineering, JNEC, Aurangabad, MH. India,4sdeshmukh47@rediffmail.com
1
M.E.(Mfg.) ,2Dept. of Mechanical Engineering ,JNEC, Aurangabad, MH.
India,1gunwantshelake@gmail.com

2
M.E.(Mfg.) ,2Dept. of Mechanical Engineering ,JNEC, Aurangabad, MH. India,
harshal.k.chavan@gmail.com

3
Dept. of Mechanical Engineering., JNEC, Aurangabad, MH. India3prithardeshmukh@gmail.com

ABSTRACT
Thermal damage and residual stresses [1] are responsible for defects in grinding process, so
it is important to study the factors which affect grinding temperatures. This paper presents an
overview of effect of various grinding parameters on grinding temperature. Then general
analytical approach consists of modeling the grinding zone as a heat source which moves
along the work piece surface. A critical factor for calculating grinding temperatures is the
energy distribution [2], which is the fraction of the grinding energy transported as heat to the
work piece at the grinding zone.. In this paper, a finite element thermo mechanical model for
the calculation of effect of temperature by a surface grinding process on a steel work piece
(AISI 52100) is presented. A model giving the energy conducted as heat in the work piece as
a function of the grinding wheel [3] speed, the work piece speed, and the cutting depth is
proposed
Keywords: Thermal damage, temperature distribution, finite element model

207

International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –

I. INTRODUCTION
The amount of energy per unit volume of material being removed from the work piece during
grinding is very large. This energy is converted entirely almost into heat, causing a significant
rise in the work piece temperature and, therefore thermal damage. In order to analyze this
extensive work has been performed pertaining to the modeling and simulation of grinding.
Thermal modeling that can predict the temperature rise within the work piece have been
developed. A 2D model was used, with the grinding width large with respect to its length.
However, this model is based on the assumption that the total grinding energy is entirely
absorbed by the work piece, whilst in reality the total grinding energy is distributed not only
in the work piece but also in the grinding wheel, the chip, and the coolant [4]. The finite
element method[5] has been employed for modeling the grinding process, in order to achieve
a greater accuracy and more reliable results. In the present paper, a novel finite element
thermal model is reported, which allows for the calculation of the grinding temperatures and
their distribution within the work piece. The maximum temperature on the surface and the
temperature fields developed in the subsurface of the work piece during grinding can be
theoretically predicted using the model [6].

II. KINEMATICS OF GRINDING
Fig. 1 shows a schematic representation of a grinding process. Here a wheel rotating with a
surface velocity of Vs moves against the surface of workpiece with relative velocity of Vwp.
During the process an amount of a i.e .depth of cut is removed from the surface. The contact
length between wheel and workpiece is calculated from equation (1)in which lc is contact
length, ds is diameter of wheel and a, as mentioned before is depth of cut that is removed in
one pass. The heat flux [7] that exerts to the workpiece during grinding can be calculated
from equation (2) where q is heat flux into the workpiece, ε is percentage of heat flux
entering into the workpiece, Ft is tangential force that produced during engagement of wheel
and workpiece and b is the grinding width. The proportion of heat flux entering the
workpiece can be calculated by equation (3) where uch is the energy required for chip
formation having a constant value of 13.8 J/mm3 for grinding all ferrous materials and u is
the total specific energy required for grinding [8],

208


Fig. 1 schematic representation of a grinding

III. THERMAL MODELING OF GRINDING
The grinding wheel is considered to be a moving heat source, see Fig. 1. The heat source is
characterized by a physical quantity, the heat flux, q, that represents the heat entering an area
of work piece per unit time and is considered to be of the same density along its length,
which is taken equal to the geometrical contact length, lc, which is calculated from the
relation [9]
݈௖ = ඥሺܽ. ݀௦ ሻ (1)
Where a is the depth of cut and ds is the diameter of the grinding wheel.

Fig. 2. Suggested thermal finite element model for surface grinding

The real contact length is expected to be larger to the deflection of the grinding wheel and the
workpiece in the contact area. Assuming the geometrical and real contact lengths are
considered to be equal. The heat flux can be calculated from the following equation
௙′ ೟ ௩ೞ
‫߳ = ݍ‬ ௟೎
(2)

Where, ϵ is the percentage of heat flux entering the workpiece,

209


f′୲ = the tangential force per unit width of the workpiece,
vs =the peripheral wheel speed and lc = the geometrical contact length.

The proportion of the heat flux entering the workpiece can be calculated by a formula
suggested by Malkin for grinding with aluminum oxide wheels, as
௨೎೓
߳ =1− ௨
(3)

where‫ݑ‬௖௛ is the energy required for chip formation, having aconstant value of about 13.8 J
/mm3 for grinding all ferrous materials, and u is the total specific grinding energy required for
grinding, calculated from
୤′ ୴
u = ୟ୴ ౩
౪
(4)
౭

where v୵ is the workspeed. Note that, in both Eqs (2) and (4), the value of Ft is required in
order to calculate the heat flux and the total specific grinding energy, respectively; it can be
calculated from
୮′ ౪
f′୲ = ୴౩
(5)

Where Pt is the power per unit width of the workpiece, which was measured during the
testing of the different grinding wheels. Therefore, from Eqs (2)–(5), the heat flux can be
calculated for every case. The kind of modeling suggested in this paper is suitable for a
grinding process with a very small depth of cut, since there is no modeling of the chip. In any
other case, other assumptions must be made for the chip in order to provide a valid model,
since the heat carried away by the chip cannot be neglected. Furthermore, the two coefficients
of the work piece material that are related to temperature, i.e. the thermal conductivity and
the specific heat capacity, along with the density of the work piece must be inserted as inputs
to the program. For the material used in the wheel testing, those quantities were taken from
the FEM program data bank. The first two were considered to be temperature dependent [10].

IV. FINITE ELEMENT MODEL
The process of grinding is carried out by movement of the grinding wheel against a stationary
workpiece. During this process, surface of work piece comes into contact with abrasive
grains of grinding wheel and a certain amount of material is removed from it. At any defining
moment contact occurs in a specific length of work piece called contact length in which
thermal exchange and mechanical forces are introduced into the workpiece. The problem of

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grinding can be described by moving an appropriate heat flux and mechanical forces on the
top surface of work piece, mathematically .A two dimensional model was used to simulate
movement of heat flux on the surface of work piece using the ANSYS [11] finite element
analysis package. Since loading and geometry remains unchanged in the third direction, a two
dimensional plane strain model would be appropriate for obtaining temperature and stress
field. The finite element mesh is shown in Fig. 2. AISI 52100 bearing steel which is widely
used for grinding was considered for work piece material. Thermal analysis was carried out,
step by step, by exerting calculated heat flux into the contact length.
Assumptions made in finite element models are
• Grinding process is transient in nature.
• Material is homogeneous and isotropic
• Material properties [12] are assumed to be linear.

V. RESULTS
Figure 3a, 3b & 3cshows temperature results when the wheel is approximately at the center of
workpiece. From figure 3a &3b we can say that maximum temperature occurs at the trailing
edge but due to ambient there is no temperature rise after the trailing edge. Fig 3c shows the
plot of temperature versus depth at a distance x=0.Due to the coolant on the top surface
maximum temperature occurs in the sub-surface. Figure 3d shows the temperature
distribution when the wheel is about to leave the workpiece surface. Fig shows that maximum
temperature occurs when wheel is about to leave the workpiece surface

Fig 3a Temperatures counter at the surface Fig 3b Temperature counter at y=-0.1mm

211


Fig 3c temperature versus depth at X=0 Fig 3e Temperature profile on the surface

Fig 3d Temperature distribution in grinding

VI. CONCLUSION

It can be concluded that the Finite Element Model yields a good understanding of the process
and aids to make suitable changes to process parameters to affect the desired thermal loading
and which may hence affect the residual stresses [13] in the model. Further, recently there has
been some work related to the use of grinding (HSG to be exact) for causing heat treatment
owing to the substantial heat generated and high temperature on the ground surface, the finite
element model can aid to decide suitable parameters (speed, feed) to determine the best
course for attaining such heat treatment. The model also incorporates cooling effects (through
surface convection) which can be used to compare the cooling effectiveness of the coolants to
be used. Since high temperature occurs at the trailing edge of the grind interface (also called
as the burnout effect), one must ensure that large amount of coolant is used and that it
penetrates the grind zone to be effective.

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REFERENCES
[1] R. J. Gu, M. Shillor,G. C. barber,T. Jen,July 2003:Thermal Analysis of the Grinding
Process.
[2] Bin Shen1,Albert J. Shih,Guoxian Xiao, June 2011:A Heat Transfer Model Based on
Finite Difference Method for Grinding.
[3] T. Brockhof, January 10, 1999: Grind-Hardening: A Comprehensive View.
[4] Maklin S., 1989, Grinding Technology: Theory and Application of Machining with
Abrasive, SME,Dearbon.
[5] D.A.Doman, A.Warkentin, R.Bauer, 1November 2008: Finite element modeling
approaches in grinding.
[6] Snoeys ,R., Maris, M and Peters , J., 1978,”Thermally Induced Damages in Grinding,”
Annals of the CIRP, p.571
[7] Aaron Walsh, February, 2004 :Mathematical Modelling Of The Crankshaft Pin Grinding
Process.
[8] Guo, C. And Malkin, S., 1994, " Analytical and Experimental Investigation of Burnout in
Creep-Feed Grinding
[9] Kohli, S.P., Guo, C., Malkin, S., 1995, "Energy Partition for Grinding with Aluminium
Oxide and CBN Abrasive wheels", ASME Journal of Engineering for Industry, Vol.117, pp.
160-168
[10] Jaeger J. “Moving Sources of Heat and Temperature at Sliding Contacts," Proc. Of the
Royal Society of New South Wales, Vol. 76,1942, pp. 203-224
[11] Ansys user manual 13.1 2010
[12] P.N. Moulik1, H.T.Y. Yang2, S. Chandrasekar*,10 February 2000 :Simulation of
thermal stresses due to grinding.
[13] Hédi Hamdi∗, Hassan Zahouani, Jean-Michel Bergheau,26 February 2003:Residual
stresses computation in a grinding process.

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Model for prediction of temperature distribution in workpiece for surface grinding using fea

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Model for prediction of temperature distribution in workpiece for surface grinding using fea