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IJMET 10 04 032

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International Journal of Mechanical Engineering and Technology (IJMET)
Volume 10, Issue 04, April 2019, pp. 322-331. Article ID: IJMET_10_04_032
Available online at http://www.iaeme.com/ijmet/issues.asp?JType=IJMET&VType=10&IType=4
ISSN Print: 0976-6340 and ISSN Online: 0976-6359
© IAEME Publication
Scopus Indexed
MODELLING AND ANALYSIS OF ROTOR
BRAKING SYSTEM
K Srinivasa Rao
Assistant Professor, Department of Mechanical Engineering,
Velagapudi Rama Krishna Siddhartha Engineering College, Vijayawada-520007, A.P. India
U V Narayana Rao
Assistant Professor, Department of Civil Engineering
Velagapudi Rama Krishna Siddhartha Engineering College, Vijayawada-520007, A.P. India
G Sridhar Babu and M Rajesh
Assistant Professor, Department of Mechanical Engineering,
Velagapudi Rama Krishna Siddhartha Engineering College, Vijayawada-520007, A.P. India
ABSTRACT
A brake is a mechanical device which simulated frictional safety is connected to
moving machine part, to stop the movement of a machine. At present performing this
function, the brakes take in either kinetic energy of the moving part or the potential
energy surrendered by items being brought down by lifts and so forth. The energy
absorbed by the brakes is scattered as heat. Disc brake is a recognizable automobile
application where they are utilized broadly for car and bike wheels. The disc is
sandwiched between two pads activated by cylinders backed in a calipers mounted on
the stud shaft. At the point when the brake lever is pressed using pressurized hydraulic
pressurized fluid is constrained into the chambers pushing the contradicting cylinders
and brake pads into frictional contact with the disc. The frictional heat produced amid
braking application can result in various negative impacts on the brake assembly, for
example, brake blur, untimely wear, thermal splits and disc thickness variation (DTV).
The main purpose of this project is Optimization of Automotive Brake Disc and analysis
the unsteady state thermal behaviour of the dry contact between the brake disc and pads
during the braking phase. The thermal-structural analysis to determine the deformation
and the Von Misses stresses established in the disc. The objective of the project is the
design, analysis and optimization of disc brake using Ansys. The brake disc is designed
by a 3Dmodelling software CATIA V5R20 and we analyse structural and thermal
conditions on disc brake using ANSYS 15.
Keywords: Brake, Cylinder Thermal Stresses, wear resistance.
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Modelling and Analysis of Rotor Braking System
Cite this Article: K Srinivasa Rao, U V Narayana Rao and G Sridhar Babu and M
Rajesh, Modelling and Analysis of Rotor Braking System, International Journal of
Mechanical Engineering and Technology, 10(4), 2019, pp. 322-331.
http://www.iaeme.com/IJMET/issues.asp?JType=IJMET&VType=10&IType=4
1. INTRODUCTION
1.1. BRAKE
A brake is a contact mechanical device for changing over the momentum or kinetic energy of
the moving vehicle into heat by method for rubbing. It is obliged to stop or ease off the vehicle
in the briefest conceivable separation when needed to do so. Braking of a vehicle relies on the
static function that demonstration in the middle of tires and street surface. Brakes take a shot at
the following standard to stop the vehicle: "The kinetic energy because of movement of the
vehicle is scattered as heat energy because of contact between moving parts (wheel or wheel
drum) and stationary parts of the vehicle (brake shoes)". The heat energy so produced because
of use of the brakes is dispersed into the air. Brakes work most successfully when they are
connected in a way so the wheels don't bolt totally, yet keep on moving without slipping on the
surface of the street. The whole time, the brakes take in either kinetic energy of the moving part
or the potential energy surrendered by articles being brought down by lifts, and so on. The
energy absorbed by the brakes is scattered as heat. This heat is dispersed into the encompassing
air to stop the vehicle, so the slowing mechanism ought to have the following prerequisites:
1. The brakes are solid enough to stop the vehicle inside a base Distance.
2. The driver ought to have fitting control over the vehicle amid braking, not to slip.
3. The brakes must have great against blur aspects.
4. The brakes ought to have great against wear properties
1.2. MECHANICAL BRAKES
The mechanical brakes, according to the direction of acting force, may be divided into the
following two groups, a) Radial brakes b) Axial brakes
1.2.1. RADIAL BRAKES
In these brakes, the force acting on the brake drum is in radial direction. The radial brakes may
be sub-divided into external brakes and internal brakes. According to the shape of the friction
element, these brakes may be block or shoe brakes and band brakes. E.g. block brakes and band
brakes.
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K Srinivasa Rao, U V Narayana Rao and G Sridhar Babu and M Rajesh
1.2.2. AXIAL BRAKES
In these brakes, the force acting on the brake drum is in axial direction. The axial brakes may
be disc brakes and cone brakes. The analysis of these brakes is similar to clutches. E.g. Disc
brakes, Cone brakes.
1.3. WORKING OF DISC BRAKES
Disc brakes are responsible for stopping your vehicle. They consist of three main parts: brake
pads, a caliper, and a rotor. Brake pads are located on each side of the rotor and are actually
pushed against the rotor to stop the wheel and thereby stop your vehicle. The pads create the
necessary friction to stop the vehicle. The caliper is a device located over the top of the rotor
and contains both brake pads. There are two types of calipers: floating calipers and fixed
calipers. A floating caliper can compress itself and contains only one piston. When the brakes
are applied, brake fluid will force the piston into the brake pad, which will press against the
rotor. Then, the other side of the caliper will press the other brake pad against the rotor to stop
the wheel and vehicle. A fixed caliper doesn’t move; so, it contains two pistons located on each
side of the rotor.
Now a days the disc brakes are of different types according to their geometry and size. The
shape and size varies from industry to industry, but mostly they are classified into two types
solid disc and ventilated discs. In solid discs the heat dissipation is lower than ventilated disc.
For two wheeler vehicles the solid discs are avoided due to their low heat dissipation, so we use
ventilated discs. Coming to the heavy vehicles, at first solid disc brakes are used later some
modification are done , so that a fin like structures are provided for in the middle for the disc
for air flow to dissipate the heat
Figure 1.5 Solid and Ventilated Discs
2. DESIGINING
The models all are of solid modeling type, the first four models dimensions are as follows, here
outer radius is 240mm is same for all the discs. The thickness we had taken is 5mm the inner
radius changes form disc to disc , because for the material optimization we consider different
changes.
2.1. Model 1
This is one of the existed model , we can observed this model in some bikes. As we know that
ventilated rotor disc are used for the better heat dissipation. In this model the holes are provide
for that reason, so that air passes through out the surface of the disc and the temperature is
reduced.
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Modelling and Analysis of Rotor Braking System
2.2. Model 2
In this model curved slots are provided for better cooling of the disc rotor ,so that we can reduce
the stress developed in the rotor. So the durability of the disc can be increased ,it is the exact
idea behind this model design. To optimize the material internal shape is modified as shown in
the above fig
2.3. Model 3
It is modified form the model 2 , the reason behind this is discussed in the next chapter
2.4. Model 4
This model is designed base on the analytical results obtained for previous models we had
designed. The inner radius is 140mm, this design is so what similar to the latest trending designs
of disc rotors of disc brakes which are available in the market. All the model which we are
draw in the catia are related to the two wheeler vehicles.
2.5. Model 5
This model is related to the four wheeler vehicles. In this we also design the existinig models
of the heavy vehicles disc brakes; here we try to compare the models which were in the used in
the present vehicles like cars. In this project we try to investigate the best model among them.
Coming to the design the outer radius is 320 it is common for all the models. Dimensions 320
x 32 mm , Height 77mm, Wear limit 30mm thick for ventilated discs, 20mm for solid disc
3. DESIGN OF VENTILATED DISC
The ventilated type disc rotors the difference in the models are model 5 has hole which are
proved for air flow provided in it like ventilated disc .The first step in analysis is modeling, that
part is completed. The model which was generated in catia can't open in ansys workbench, so
we have convert that model files into .igs format.
Design of Model 1
Design of Model 4
Design of Model 2
Design of Model 5
Design of Model 3
Design of Ventilated Disc
4. MESHING
Meshing is one of the major part which should be observed in the analysis, In computational
solutions of partial differential equations, meshing is a discrete representation of the geometry
that is involved in the problem. Essentially, it partitions space into elements (or cells or zones)
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K Srinivasa Rao, U V Narayana Rao and G Sridhar Babu and M Rajesh
over which the equations can be approximated. Zone boundaries can be free to create
computationally best shaped zones, or they can be fixed to represent internal or external
boundaries within a model. Three-dimensional meshes created for finite element analysis need
to consists of of tetrahedral, pyramids, prisms or hexahedra The procedure for generating a
mesh of nodes and elements consists of three main steps:
1 Set the element attributes .2 Set mesh controls (optional, ANSYS offers a large number
of mesh controls, which you can choose from to suit your needs). 3. Generate the mesh.
As we can see for the above figure ,in that meshing the major part of elements are the
pyramidal shaped elements, it is five nodal pyramidal element. Similarly other models are
meshed in the same way, so can observe nearly same kind of mesh in them. After giving all the
attributes to the models they are solved by taking the required terms which are to be calculated.
By clicking the solve option in the ansys workbench, so we can derive the solution or results
from the models
5. RESULTS AND DISCUSSIONS
The main aim is to develop a new design by comparing the results of an existing model to the
model which we have designed, so all the models are tested for same conditions. The results
which are obtained are discussed in this chapter. Here two types of analysis are done on first
four models which were designed, they are structural and thermal. Let first discussed about the
structural, in structural we find the vonmises stress and the deformation
6. STRUCTURAL ANALYSIS
In order to apply the conditions of pressure and temperature on the rotor surface we made a
extrusion equal to the thickness of the rotor on its surface and slice the extrusion. The surface
which is extruded is exposed to the loads. The loads that we make use here are Pressure of
0.1Mpa and a thermal condition of 120 degrees on that extruded part. A rotational velocity of
the disc is taken to be 50 radians/sec. By applying the given conditions the following results are
obtained.
6.1. Model: 1
Figure Equivalent stress :
Figure Total deformation
Above analysis results are the existing model results, results obtained for the load we have
applied for the model are ; equivalent stress , deformation. Here the maximum stress are seen
at the ventilated holes because of the stress concentration factor it exists at the holes. Maximum
deformation is the area around where the braking force is applied this is due to the compression
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Table Results of Model 1
Deformation - mm
Stress
-Mpa
Minimum
0
2.62
Maximum
0.095
345.45
6.2. Model:2
Figure Equivalent stress
Figure Total deformation
Table Results of Model 2
Deformation - mm
Stress(von-mises) Mpa
Minimum
0
0.026
Maximum
0.071
185.26
6.3. Model:3
Because of the second model is failed we go for some geometric modification, as previously
discussed that due cantilever effect the model is failed so we provided some support at the end
of the slot which were on the disc by adding material. And the results for this In this model as
we observed that the maximum stress obtained is equal to the stress in the first model and the
minimum stress reduced compare to the existed model i.e first model .As in the second model
failure occurs due to the deformation, in this model there is a slight deformation. Due increase
in stress and slight deformation this model is also considered as failed.
Table Results of Model 3
Deformation
-mm
Stress(von-mises)- Mpa
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Minimum
0
0.057
327
Maximum
0.031
346.56
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K Srinivasa Rao, U V Narayana Rao and G Sridhar Babu and M Rajesh
6.4. Model:4
Figure Equivalent Stress
Figure Total deformation
The models 2,3 are failed so that we rethink a new design , this idea is by seeing some of
latest designed available in the market. This is also analyse under same conditions as of previous
models. The results are as follows
Table Results of Model 4
Deformation
- mm
Stress(von-mises)- Mpa
Minimum
0
0.102
Maximum
0.033
308.45
The results which are obtained for this model has 10% reduction in the maximum stress
than first model, the minimum stress are also reduced as well. Coming to the deformation
models 2,3 are failed due to deformation but in this model the deformation is very low and
negligible. It is good model and passed the analysis. The maximum stress is seen in the holes
where the braking force is applied, the actual stress or average stress is about. Results of all the
models are tabulated as follows and compared:
Table Comparison of Stress
Model
Model 1
Model 2
Model 3
Model 4
Material
Gray cast iron
Gray cast iron
Gray cast iron
Gray cast iron
Min.Stress (Mpa)
2.46
0.024
0.05
0.102
Max.stress(Mpa)
345.45
185.26
346.56
308.45
Avg. Stress (Mpa)
173.955
92.642
173.305
154.27
Table Comparison of deformation
Model
Material
Min.Deformation
Max.Deformation
Model 1
Gray cast iron
0
0.095mm
Model 2
Model 3
Model 4
Gray cast iron
Gray cast iron
Gray cast iron
0
0
0
0.031mm
0.071mm
0.033mm
Status
Negligible
deformation
Deformed
Deformed
Not deformed
7. THERMAL ANALYSIS
The analysis which was performed is transient thermal analysis, in this analysis we find out the
heat flux and temperature distribution in the rotor. Temperature are developed in the rotors are
due to the friction between the brake pads and the disc when the brake is applied .Heat flux or
thermal flux is the rate of heat energy transfer through a given surface, per unit time. As the
heat flux value is high heat transfer will increases
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7.1. Model:1
Figure Temperature distribution
Figure Heat flux
Figure Temperature distribution
Figure Heat flux
7.2. Model 2
7.3. Model: 3
Figure Temperature Distribution
7.4. Model: 4
Figure Temperature Distribution
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7.5. Model: 5
Figure Equivalent Stress
Figure Total deformation
7.6. Model:6
Figure Equivalent Stress
Figure Total deformation
Figure Equivalent Stress
Figure Total deformation
7.7. Model:7
8. CONCLUSION
Conclusion is the crucial part of a project or any work. By analysing the results we come to the
conclusion that the model 4 is much optimised and the stress, deformation, heat flux,
temperature distribution produced are less compared to the existed model i.e model 1. So we
can say that this model is best among the all others in all aspects we were considered. We came
to this conclusion by comparing the values of existed model which was analysis under the same
conditions where the other models are analysed .In this work we conducted structural and
thermal analysis. On the base of the value obtained in the analysis, we conclude that model 4 is
the optimized model, had a better strength too.
Coming to other models that are use for four wheeler vehicles, here we try to find out the
which one is the best among the three existing models which we taken for analysis. In this we
done the structural analysis on the models, by considering the stress, deformation and
temperature gradient we concluded that model 7 is better than the others. Even though the model
6 having less stress and deformation value it has low cooling capacity, as the temperature
decreases the thermal stress also decreases. Model 7 has better ventilated system than model 6,
so we chosen model 7 is better than other models
REFRENCES
[1]
Design of Machine Elements By V. B. Bhandar, Third Edition, Mcgraw Hill Education,
[493]. pp. 75–78.
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Modelling and Analysis of Rotor Braking System
[2]
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[5]
[6]
[7]
[8]
[9]
Swapnil R. Abhang, D.P.Bhaskar, ‘‘Design and Analysis of Disc Brake, IJETT – Volume
8 Number 4- Feb 2014,[165]
Manjunath T V, Dr Suresh P M, ‘‘Structural and Thermal Analysis of Rotor Disc of Disc
Brake’’ IJIRSET, ISSN: 2319-8753Vol. 2, Issue 12, December 2013.
Kenneth Domond ‘‘Brake Rotor Design and Comparison using Finite Element Analysis:
An Investigation in Topology Optimization’’,2010
J.Slavic, M.D. Bryant and M. Boltezar (2007), "A new approach to roughness-induced
vibrations on a slider.", J. Sound and Vibration, Vol. 306, Issues 3–5, 9 October 2007,pp.
732–750.
Thoms, E. (1988), "Disc brakes for heavy vehicles", IMechE, pp. 133–137.
Stringham, W. et al. (1993), "Brake roughness – disc brake torque variation", disc distortion
and vehicle response, SAE Technical Paper Series, no.
Jacobsson, H. (1997), "Wheel suspension related disc brake judder", ASME, no.
DETC97/VIB-4165, pp. 1–10
Jacobson, H. (1996), "High speed disc brake judder – the influence of passing through
critical speed", In EuroMech – 2nd European Nonlinear Oscillations Conference, Prague,
no. 2, pp. 75–78.
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