SCHOOL OF TECHNOLOGY

TUNKU ABDUL RAHMAN COLLEGE

KUALA LUMPUR

ACADEMIC YEAR 2011/2012

TITLE: FINITE ELEMENT ANALYSIS ON WEAR OF SPUR GEAR

AND STRAIGHT BEVEL GEAR BY USING CAD

SOFTWARE

Prepared by:

NAME : LAW SOON KEAT

COURSE : ADVANCE DIPLOMA IN MECHANICAL AND

MANUFACTURING ENGINEERING YEAR 2 (AME 2)

ID No. : 10WTA08498

NAME OF DIVISION : FINITE ELEMENT ANALYSIS

SUPERVISOR : MR. CHOY HAU YAN

Proposal for the final year project

Title: Finite element analysis on wear of spur gear and straight bevel gear by using CAD

software.

1. Introduction

This project will addresses the problem of the wear development of gear teeth surface.

This project will carry out both the theoretical side of wear on gear flanks and the

experimental aspects of the problem.

1.1 Background

Gears are about as old as any of the machinery of mankind. At first time over 3000 years

ago primitive gears first meshed with each other and transmitted rotary motion. Early

gears were made from wood with cylindrical pegs for cogs and were often lubricated with

animal fat grease. Gears were also used in wind and water wheel machinery for

decreasing or increasing the provided rotational speed for application to pumps and other

powered machines. An early gear arrangement used to power textile machinery is

illustrated in the following figure. The rotational speed of a water or horse drawn wheel

was typically too slow to use, so a set of wooden gears needed to be used to increase the

speed to a usable level.

In the fourth century, BC Aristotle wrote about wheels using friction between smooth

surfaces to transmit motion. The earliest gears were of wooden and had teeth of really

engaging pins. The early Greeks made use of metal gears with wedge shaped teeth. The

Romans made considerable use of gears in their mills. In middle age stone gears were

used in Sweden.

The industrial revolution in Britain in the eighteen-century saw an explosion in the use of

metal gearing. A science of gear design and manufacture rapidly developed through the

nineteenth century.

Figure 1.1: Types of gears

1.2 Problem statement

In the industry field, the usage of gears are very wide, from the internal parts such as

gearbox to external parts like shaft to transmit power from point one to another.

Eventually, the number of times for diagnogstic of the gear were increased dramatically.

Hence, diagnogstic have to carried out to avoid the machinery failure, yet the cost for

running diagnogstic for a gear is very expensive and time consuming. Perhaps, the

enhencement of technology enable engineer to change the particular piece of gear in the

machine. The process of changing of gear could be very complicated and expensive. The

occurances of failer in gear will direct reflect onto production of a factory.

Gear manufacturers have so far been ocupied with failures due to root stresses, surface

pressures and hardening carcks. From the failures as mention above, surface fatigue is a

know problem and the cure is to build with better materials, smoother surfaces, heat

treatments etc. Here the questions is coming in: how will mild wear affect the surface

pressure and indirectly the fatigue limit? How is the transmission error under load

affected?

Normally, wear is treated using blunt approximations and without reflecting on the

effects of wear on the working behaviour of the gears. Wear analysis of tested gear is

commonly carried out using a scale to indicate the degree of wear. This work differs in

that sense due to its relatively sharp focus on the mild wear of gear surfaces and its

consequences. The experimental analysis was conducted using top-of-the-line equipment,

tielding interesting results as to wear distribution over the tooth surface. Some of the

results presented here are not new, since many engineers have worked with gears without

really focusing on the wear aspect.the fact the the gear teeth wear alot at the root and the

process can be fast is not revolutionary. The question coming in is: how fast and how

much does it wear and can be predicted?

1.3 Objective

1) To test on the stiffness of the gear tooth on both spur gear and straight bevel gear by

using CAD software.

2) To calculate as acurately as possible the time dependent wear development of gear

teeth flanks.

1.4 Scope of project

There is few of principle causes for gear failure: an error of design, application error,

manufacturing error. Design errors may be due to causes like improper gear geometry,

use of wrong materials, quality, lubrication and other specifications. In this project we are

going into the wear failure which is takes place with the metal gradually wearing away

from the contact points of the gear teeth. It takes place in an unifrom manner. With the

CAD software we are using, we were able to determine the surface deformation to the

breakage of the gear tooth.

This project will carry out the involute form of gear tooth which is commonly used in the

industry field of spur gear and straight bevel gear. The gear will follow by industrial

standard base on RS40-1B type.

The test will run on gear ratio of 1:1 of both gears on different rpm.

1.5 Methodology

With the cheap computing power has enabled a simulation where the development of the

wear over time can be monitired, more refined models of wear and surface interaction

can be used.

FEA consists of a computer model of a material or design that is stressed and analyzed

for specific results. It is used in new product design, and existing product refinement. A

company is able to verify a proposed design will be able to perform to the client's

specifications prior to manufacturing or construction. Modifying an existing product or

structure is utilized to qualify the product or structure for a new service condition. In case

of structural failure, FEA may be used to help determine the design modifications to meet

the new condition.

By using the FEA method in the CAD software we could carry out the data for the design

of the bevel gear tooth, hence to increase the efficiency and the reliability by giving

further improvement.

1.5 Project planning

Semester 1

Task Week

1 2 3 4 5 6 7 8 9 10 11 12 13 14

Literature Review

Proposal Approval

Design The Project And Task

Research Infomation

Program Planning

Materials Research

Discuss Problem

Write Project Process Report

Semester 2

Task Week

1 2 3 4 5 6 7 8 9 10 11 12 13 14

Submission of Project Process Report and Presentation

Programme Software

Debug & Test Run

Project Dissertation

Submission of Draft Dissertation

Reference

1. http://sourcing.indiamart.com/engineering/articles/gear-failure/

2. http://chestofbooks.com/crafts/machinery/Shop-Practice-V2/Involute-Gears.html

3. http://www.efunda.com/designstandards/gears/gears_history.cfm

4. http://pdf.directindustry.com/pdf/tsubakimoto-chain/tsubaki-sprockets-couplings/5083-121290-_14.html