International Journal of Electrical Electronics Computers & Mechanical Engineering (IJEECM)
ISSN: 2278-2808
www.ijeecm.org Volume 9 Issue 11 ǁ Nov. 2019
IJEECM journal of Mechanical Engineering (ijeecm-jme)
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Topology Optimization of Gear Box using ANSYS
P Chandra Rao
1, M Anil Kumar
2, M Nirmal Devi Kiran
3
1,2,3 Mechanical Engineering Department,
1,2,3 , KIET Group of Institutions, Kakinada, East Godavari (Dt), A.P., India
Abstract: In mechanical transmission systems, gears play
major role in transmitting the mechanical power. They
operate under high torques or high rotations. these gears
are designed with stand stress and forces exerted while
operating. A Gear box provide torque multiplication
which is widely used in various applications. The aim of
this paper is to reduce weight of the conventional gear
box without compromising the efficiency by using
topology optimization techniques from ANSYS software.
Gearbox is designed using PTC CREO parametric and
exported to ANSYS. After performing the topology
optimization again, the gear box is redesigned and final
analysis is performed. Conventional structural steel is
selected as material. Analysis is carried out on optimized
gear and regular gear. Then by comparing the results
the conclusion for optimized gear is selected.
Index Terms— Gear box, PTC CREO, ANSYS.
I. INTRODUCTION
Spur Gears are the most frequently used drive transmission
in many applications. They are designed using standard
procedure which considers certain parameters. These design
parameters lead to heavy gears. The weight of gears can be
reduced using topology optimization which over designing
of gears can be avoided. The increase in rotational inertia
caused by the weight which decreases the efficiency at the
initiation of a transmission drive. The aim here is to reduced
the weight of a simple spur gear of a simple 2-stage
compound gear train using ANSYS. ANSYS topology
optimization software which is an iterative process keeping
a targeted factor of safety limit and removing nodes from
body one at a time. If the factor of safety limit is reached
then node is returned to its previous position. This is a FEM
optimization procedure which ANSYS software used to
optimize the gear.
In this study, gears from gear set are analyzed for static
loading under the application of tangential load resulting
from maximum torque in the given application. After
studying the stress distribution on baseline gears, weight
reduction areas are identified on given gears and
geometrical features are added on the gear to reduce the
weight. Static analysis is conducted on the optimized gears
under the application of same loading and comparative
results are presented about stress distribution between
baseline and optimized gears and weight reduction is
outlined for each gear of gear set.
II. LITERATURE SURVEY
Mathematical approach that optimizes the material -layout
within a given design space is topology optimization. The
variations of under a given set of loads and boundary
conditions keeping the predefined requirements and results
are obtained. Engineers use topology optimization is find
the best design for new concepts and components.
Implementing the finite element methods for the analysis of
Topology optimization, which the technique uses
topological derivatives, level sets, genetic algorithms, and
the methods of moving asymptotes, optimality criteria
method. [2]
Topology optimization is used at the concept level of the
design process to arrive at a conceptual design proposal that
is the fine-tuned for performance and manufacturability.
The ease of manufacturing process and performance of a
component can be increased at concept level by
optimization of design at proposal stage. This results a
better component which saves time and cost while
developing conceptual design where reduction of overall
cost is observed.
Although, topology optimization makes a optimal
component there are still manufacturing constraints which
restricts the component being develop using this technique
and may be expensive in some cases. If we can overcome
these challenges, a better component is manufactured. [2]
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III. SYSTEM DESCRIPTION
Calculation of Forces:
Power(P)= 100KW
Speed (N) = 1500rpm
Torque =60×106×𝑃
2×𝜋×𝑁 =636942.6N.mm
Tangential force(pt) =2×t
𝑚×𝑧 =3216.88N
Lewis Bending stress equation(σb)=
σb =𝑝𝑡
𝑀×𝑏×𝑦 =20.5 N/𝑚𝑚2
Table.1
Gear Dimensions
Type of gear spur gear
No.of teeth(z) 66
Pitch circle dia 407.41mm
Module(m) 6
Width(b) 50mm
Factor of safety 0.4
Pressure angle 20
Table.2
Material Properties
Material Specifications Values
Density 7800 Kg/m3
Modulus of Elasticity 210Gpa
Possion Ratio 0.3
Ultimate Tensile
Strength
280 N/mm2
Tensile Yield Strength 560 mm2
IV. OVERALL METHODOLOGY
Conventional Numerical topology optimization is not
carried out in this analysis. ANSYS software which is based
on the Numerical finite element method (FEM).
Regular design parameters of spur gear are used to design
the gear and initial analysis performed by applying loads
and constraints.
Using stress and deformation data topology optimization is
carried out.
Based on the suggestions given by the topology
optimization tool in ANSYS, the gear is re designed using
PTC CREO.
Material is removed as suggested and empty space is filled
using lattice structures. Then analysis is performed using
same loads and constraints and studying the results.
Fig.1: Non optimized gear
Fig.2: Optimized gear
Fig.3: Gear box assembly
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V. SUMMARY OF RESULTS
Validation of designed models are performed by calculating
the forces which are applied on it and verifying values to
ensure the design within safety limits. These calculated
forces and constraints are applied on the model in ANSYS
software. The material used in analysis is structural steel in
both cases. The calculated tangential force of 3216.88 N is
applied on the tooth of the gear and effects are observed and
compared in regular and optimize designs.
Fig.4: Gear 1 meshed
Fig.5: Total deformation
Fig.6: Topology optimization result
Fig.7: Optimized gear
Fig.8: Optimized gear meshed
Fig.9: Optimized gear Equivalent stress
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Fig.10: Optimized gear total deformation
Material Regular
Gear
Regular
Gear
Optimised
Gear
Optimised
Gear
Min Max Min Max
Total
Deformatio
n
0 mm 0.01416
5 mm
0 0.076965
mm
Equivalent
Strain
1.3059e
-10
mm/m
m
8.7649e
-5
mm/mm
4.1129e-9
mm/mm
0.0002015
5 mm/mm
Von
Misses
Stress
2.1837e
-5 MPa
17.197
MPa
0.0003739
6 MPa
39.895
MPa
Mass 0 50.713
kg
0 31.659 kg
load 0 3216.9
N
0 3216.9 N
VI. CONCLUSION
After carrying initial structural analysis and topology
optimization using ANSYS on regular gear and based on the
optimization results the gear is re designed inserting lattice
structures using PTC CREO. After re analyzing under same
loads the results are compared. Although very small
increase in deformation, strain and stress, all which are in
acceptable limits. The aim of the experiment is achieved
which mass of the gear reduced by 19.054 Kg. The gear is
designed by using beam strength criteria analytical
calculations and bending stress obtained which are in
acceptable limits and designed gear is safe.
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