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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