Course Project Report submitted in partial fulfillment of the requirement for the

FEA Course project of

FOURTH YEAR OF ENGINEERING

IN

MECHANICAL

Under the guidance of

(Prof. Mandar Damle)

Submitted by

Pranav Sawant

Shalem Shelke

DEPARTMENT OF MECHANICAL ENGINEERING

DON BOSCO INSTITUTE OF TECHNOLOGY

PREMIER AUTOMOBILES ROAD, KURLA (W) – 400070

UNIVERSITY OF MUMBAI

(2014-2015)

UNIVERSITY OF MUMBAI

2014-2015

Project Title : FINITE ELEMENT ANALYSIS OF A BEVEL GEAR

Institute Name : Don Bosco Institute Of Technology

Institute Address : Premier Automobiles Road,

Kurla (West), Mumbai - 400070

Department : Mechanical Engineering

Internal Guide : Prof. Mandar Damle

Project Group Members:

Sr no Roll no Names

1 63 Pranav Sawant

2 65 Shalem Shelke

Date of Submission : 16/04/2015

Approved By : __________________

Prof. Mandar Damle

Department of Mechanical Engineering

Don Bosco Institute of Technology

FEA COURSE PROJECT

Finite Element Analysis Of A Bevel Gear April 10

2015 Finite Element Analysis of stress concentration in 3D model of a Bevel Gear is

obtained using ANSYS Workbench, for analysis of Gear failure in a differential.

Acknowledgement:

We would like to express our deepest appreciation to all those who provided us the possibility to complete this

report. A special gratitude we give to our project manager, Mr. Mandar Damle, whose contribution in

stimulating suggestions and encouragement, helped us to coordinate our project, especially in writing this

report.

Furthermore we would also like to acknowledge with much appreciation the crucial role of the staff, who gave

us the permission to use all required equipment and the necessary materials to complete the given task. Last but

not least, many thanks go to our colleague and friend Mr. Sanil Mhatre who has invested his effort in guiding us

in achieving our goal.

Table Of Contents:

Sr No. Topic Page No.

1) Introduction 6

2) Problem Definition 6

3) Theory And Objective 7

4) Selection Of Material 8

5) Gear Modelling 9

6) FEA Simulation 10

7) Results 13

8) Conclusion 13

9) References 14

List Of Figures:

Fig. 1 CAD Model (Solidworks)

Fig. 2 Selection of fixed support

Fig. 3 Application of force

Fig. 4 Total Deformation

Fig. 5 Equivalent Stress

Fig. 6 Safety Factor

1.) Introduction:

Gears are commonly used for transmitting power. They develop high stress concentration at the root and the

point of contact. The repeated stressing on the fillets causes the fatigue failure of gear tooth. The main objective

of this study is to analyze stress concentration at the gear tooth under consideration. A finite element model of

Bevel gear with a segment a tooth is considered for analysis, and stress concentration is introduced on gear

tooth for analysis.

Gears are used for a wide range of industrial applications. They have varied application starting from textile

looms to aviation industries. They are the most common means of transmitting power. They change the rate of

rotation of machinery shaft and also the axis of rotation. For high-speed machinery, such as an automobile

transmission, they are the optimal medium for low energy loss and high accuracy.

2.) Problem Definition:

The function of a Gear pair, is to convert input provided by prime mover into an output with lower speed and

corresponding higher torque.

A pair of bevel gears transmit 7.5kW at 300rpm having pressure angle 20 degrees.

Tangential Load, Pt = 3789.4N

Radial Load, Pr = 1103.38N

Axial Load, Pa = 827.54N

3.) Theory And Objective:

Toothed gears are used to transmit the power with high velocity ratio. During this phase, they encounter high

stress at the point of contact. A pair of teeth in action is generally subjected to two types of cyclic stresses: i)

Bending stresses inducing bending fatigue ii) Contact stress causing contact fatigue. Both these types of stresses

may not attain their maximum values at the same point of contact. Failure of Differential gears is uncommon

and rare as they are usually designed with high factors of safety. In this analysis we will analyze the Equivalent

stress acting on the gear tooth, considering a relevant problem in the “Design of Machine Elements”, page 718,

ex 19.1, by V.B. Bhandari as a reference.

4.) Selection Of Material:

Material selected for Bevel Gear is structural steel and the properties of material are given below:

Structural Steel Constants:

Structural Steel Compressive Yield Strength:

Structural Steel Tensile Yield Strength:

5.) Gear Modelling:

The CAD model of the Bevel Gear was done in Solidworks. And the Fixed Support was selected, as shown in

Fig. 2

Fig. 1

Fig. 2

6.) ANSYS Simulation:

In order to analyze the gear tooth, a tangential load of 3789.4 newton force, a radial load of 1103.38 newton

force and an axial load of 827.54 newton force, were used as loads. [1]

Fig. 3

The Bevel Gear tooth was loaded in the following manner:

Radial Force:- Fx = 1103.4 N

Axial Force:- Fy = -827.54 N

Tangential Force:- Fz = 3789.4 N

Fig. 4

Fig. 5

Fig.6

7.) Results:

Object Name Total Deformation Equivalent Stress

State Solved

Scope

Scoping Method Geometry Selection

Geometry All Bodies

Definition

Type Total Deformation Equivalent (von-Mises) Stress

By Time

Display Time Last

Calculate Time History Yes

Identifier

Suppressed No

Results

Minimum 0. mm 9.6994e-003 MPa

Maximum 9.6866e-003 mm 19.119 MPa

8.) Conclusion:

The above Result shows, that the maximum stress induced on the face of the tooth in contact, 19.119MPa, is

much lesser than the Yield Strength, 250Mpa (4), of the material selected.

Furthermore, the minimum Factor of Safety is 13.076, while the maximum is 15.

This is much higher than the Factor Of Safety selected for design of Bevel gear, which is usually in the range of

3-5.

Thus the analysis showed minimal Stress and Total Deformation, which validates our objective.

9.) References :

1. V.B.Bhandari, “Design Of Machine Elements”, 3rd

Edition (2010)

2. PSG Design Data Book

3. R. S. Khurmi, “Strength of materials,” 23rd Edition Chapter 33 (2009)