TYPES OF DAMAGE IN PIN-LOADED ALUMINUM PLATE AND...

TYPES OF DAMAGE IN PIN-LOADED ALUMINUM PLATE AND OTHER

MATERIAL

MOHAMMAD AFIFI B. MOHAMMAD

A report submitted in partial fulfilment of the

requirements for the award of the degree of

Bachelor of Mechanical Engineering

Faculty of Mechanical Engineering

UNIVERSITI MALAYSIA PAHANG

NOVEMBER 2009

UNIVERSITI MALAYSIA PAHANG

FACULTY OF MECHANICAL ENGINEERING

We certify that the project entitled Types of Damage in Pin-Loaded Aluminum Plate and

Other Material is written by Mohammad Afifi B. Mohammad. We have examined the final

copy of this project and in our opinion; it is fully adequate in terms of scope and quality for

the award of the degree of Bachelor of Engineering. We herewith recommend that it be

accepted in partial fulfillment of the requirements for the degree of Bachelor of Mechanical

Engineering.

(name of panel member)

Examiner Signature

SUPERVISOR’S DECLARATION

I hereby declare that I have checked this project and in my opinion, this project is adequate

in terms of scope and quality for the award of the degree of Bachelor of Mechanical

Engineering.

Signature :

Name of Supervisor : MR. LEE GIOK CHUI SMN., KMN.

Position :

Date :

STUDENT’S DECLARATION

I hereby declare that the work in this project is my own except for quotations and

summaries which have been duly acknowledged. The project has not been accepted for any

degree and is not concurently submitted for award of other degree.

Signature :

Name : MOHAMMAD AFIFI B. MOHAMMAD

ID Number : MA 06074

Date :

To my Beloved Father and Mother

ACKNOWLEDGEMENTS

First of all, I am very gratefully to Allah swt for giving me strength and ability to complete this thesis. I would like to acknowledge and extend my heartfelt gratitude to the Mr. Lee Giok Chui who has made the completion of this thesis. This thesis could not have been written without Mr. Lee Giok Chui who not only served as my supervisor but also encouraged and challenged me throughout my academic program. He guided me through the dissertation process, never accepting less than my best efforts.

For this research, experiments were essential. I did a lot of experiments at mechanics lab and I would like to thank Mr Jamiludin as mechanics lab instructor for his valuable knowledge and guidance that he gave to me to handle the universal testing machine.

I also wish to express sincere appreciate to the lecturers, technical staff of Faculty Mechanical Engineering, University Malaysia Pahang for their teaching and help during the period of the project. My fellow postgraduate students and friends should also be recognized for their support.

Last, but not least, I thank to my family especially my parents, Mr. Mohammad Abdul Rahim and Mdm. Noor Zariyoum Mohammad have been an inspiration throughout my life. They have always supported my dreams and aspirations. They did a fine job raising me. I’d like to thank them for all they, and all they have done for me. My elder sisters, Noor Zariza, Noor Zariyani, Noor Zariyati and younger sister Noor Afifah for sharing their experience of the dissertation writing endeavor with me, for listening to my complaints and frustrations, and for believing in me.

ABSTRACT

The investigation is about the types of damage in pin loaded aluminum plate and mild steel plate. The experiment had done using various dimensions of the specimens by varying the edge distance to hole diameter ratio (E/D) and width size to hole diameter ratio (W/D). There are three types of mechanical joint failure that has been studied in this research which known as normal or net-tension failure, shear-out failure, and bearing failure. The specimens were tested using universal testing machine. The movement for upper crosshead of the testing machine will be stopped when the failure mode under investigation was seen on the specimen. For each specimen, the failure load was taken and determined from the load vs. displacement graph which is obtained from the computer that connects with the universal testing machine. The differences dimensions of the specimens give different value of failure load and some changing on the failure mode occurred on the specimens. Bearing failure which is preferred in this investigation due to less hazard and damage compared with normal and shear-out failure only occurred when W/D=4 for aluminum plate and W/D equal to 3 and 4 for mild steel plate. Finally, the graph of failure load vs. E/D ratio can be used to determine the optimum value of W/D ratio in designing field to avoid failure that will cause any disaster.

ABSTRAK

Kajian adalah mengenai jenis-jenis kerosakan pada kepingan aluminium dan besi lembut dengan pin berbeban. Eksperimen ini dijalankan menggunakan model kepingan berlainan saiz dengan mengubah nisbah jarak tepi dengan diameter lubang (E/D) dan nisbah kelebaran dengan saiz diameter lubang (W/D). Terdapat tiga jenis kegagalan sambungan mekanikal yang dikaji dalam penyelidikan ini yang mana dikenali sebagai kegagalan normal atau net-ketegangan, kegagalan ricih keluar dan kegagalan sudut.Spesimen diuji denan menggunakan mesin uji universal. Gerakan untuk kepala pemegang bahagian atas mesin uji akan diberhentikan apabila kegagalan yang dikaji dapat dilihat pada spesimen. Untuk setiap specimen, nilai beban yang menyebabkan kegagalan diambil dan ditentukan daripada graf beban melawan sesaran yang diperolehi dari computer yang disambung pada mesin uji universal. Perbezaan saiz pada setiap spesimen memberikan nilai yang berbeza untuk beban kegagalan dan beberapa perubahan pada jenis kegagalan yang berlaku pada spesimen. Kegagalan sudut yang mana lebih dipilih dalam penyelidikan ini kerana kurang bahaya dan keroskan jika dibandingkan dengan kegagalan normal dan ricih keluar hanya berlaku apabila W/D=4 untuk plat aluminium dan W/D adalah 3 dan 4 untuk plat besi lembut. Akhirnya, graf beban kegagalan melawan nisbah E/D boleh digunakan untuk menentukan nilai optimum nisbah W/D dalam bidang reka bentuk untuk mengelakkan kegagalan yang akan menimbulkan bencana.

TABLE OF CONTENTS

Page

SUPERVISOR’S DECLARATION ii

STUDENT’S DECLARATION iii

DEDICATION iv

ACKNOWLEDGEMENTS v

ABSTRACT vi

ABSTRAK vii

TABLE OF CONTENTS viii

LIST OF TABLES xi

LIST OF FIGURES xii

LIST OF SYMBOLS xvi

LIST OF ABBREVIATIONS xvi

CHAPTER 1 : INTRODUCTION

1.1 Introduction 1

1.2 Problem Statement 2

1.3 Objectives 2

1.4 Scopes 3

CHAPTER 2 : LITERATURE REVIEW

2.1 Introduction 4

2.2 Failure 5

2.2.1 Ultimate Failure 52.2.2 Mechanical Joint Failure 7

2.3 Mechanical Joint 9

2.3.1 Pins 10

2.4 Previous Studies

2.4.1 An experimental investigation into the progression of damage 10 in pin-loaded fibre metal laminates

2.4.2 Effects of geometric parameters on failure behavior in laminated 11composite plates with two parallel pin-loaded holes

2.4.3 Failure analysis of woven laminated glass–vinylester 14composites with pin-loaded hole

2.4.4 Other Studies 17

2.5 Materials 18

2.5.1 Aluminum 182.5.2 Mild Steel 18

CHAPTER 3 : METHODOLOGY

3.1 Introduction 20

3.2 Project flow chart 21

3.3 Preparation of specimens 22

3.4 Universal testing machine 24

CHAPTER 4 : RESULT AND DISCUSSION

4.1 Introduction 26

4.2 Analyzing the Aluminum plates 26

4.2.1 Aluminum (165x10mm) 274.2.2 Aluminum (165x15mm) 284.2.3 Aluminum (165x20mm) 30

4.2.4 Aluminum (170x10mm) 314.2.5 Aluminum (170x15mm) 334.2.6 Aluminum (170x20mm) 344.2.7 Aluminum (175x10mm) 364.2.8 Aluminum (175x15mm) 374.2.9 Aluminum (175x20mm) 394.2.10 Aluminum (180x10mm) 404.2.11 Aluminum (180x15mm) 424.2.12 Aluminum (180x20mm) 43

4.3 Analyzing the Mild Steel plates 44

4.2.1 Mild Steel (165x10mm) 454.2.2 Mild Steel (165x15mm) 464.2.3 Mild Steel (165x20mm) 484.2.4 Mild Steel (170x10mm) 494.2.5 Mild Steel (170x15mm) 514.2.6 Mild Steel (170x20mm) 524.2.7 Mild Steel (175x10mm) 544.2.8 Mild Steel (175x15mm) 554.2.9 Mild Steel (175x20mm) 574.2.10 Mild Steel (180x10mm) 584.2.11 Mild Steel (180x15mm) 604.2.12 Mild Steel (180x20mm) 61

4.4 Result 63

4.4.1 Aluminum 634.4.2 Mild Steel 64

4.5 Discussion 65

CHAPTER 5 : CONCLUSIONS AND RECOMMENDATIONS

5.1 Conclusions 70

5.2 Recommendations 71

REFERENCES 72

LIST OF TABLES

Table No. Title Page

2.1 Title and finding of previous study 17

2.2 Typical values of some physical properties of metals 19

3.1 Table of vary E/D and W/D for both type of specimen 23

4.1 Result for Aluminum Plate 63

4.2 Result for Mild Steel Plate 64

LIST OF FIGURES

Figure No. Title Page

2.1 Net-Tension Failure 7

2.2 Shear-Out Failure 7

2.3 Bearing Failure 8

2.4 Failure modes under investigation 8

2.5 Pin-bearing test configuration and typical joint geometry 11

2.6 Geometry of the experiment 12

2.7 Failure modes in experimental study (a) shear-out, (b) bearing, (c) bearing and shear-out and (d) bearing and net-tension

13

2.8 Experiment setup for pin joint testing 15

2.9 Load–displacement curves for pin-loaded glass–vinylester composite plates

16

3.1 Flow chart of the project 21

3.2 Geometry of the aluminum / mild steel plate with a circular hole, subjected to pin

22

3.3 Experimental setup for the pinned-joint fixture 24

4.1 Graph 1 : Load(kN) versus Displacement(mm) (Al 165x10mm) 27

4.2 Specimen and Failure Occur (Al 165x10mm) 27



















4.21 Graph 11: Load(kN) versus Displacement(mm) (Al 180x15mm) 42




4.25 Graph 13 : Load(kN) versus Displacement(mm) (Ms 165x10mm) 45

4.26 Specimen and Failure Occur (Ms 165x10mm) 45























4.49 Graph 25 : Failure Load vs E/D [Al-W/D=2] 65



4.52 Graph 28 : Failure Load vs E/D [Ms-W/D=2] 67



LIST OF SYMBOLS

L : Length of the plate

P : Load by Universal Testing Machine

E : Distance between centre of hole and edge of the plate

W : Width of the plate

D : Diameter of the plate

t : Thickness of the plate

LIST OF ABBREVIATIONS

FML : Fiber Metal Laminates

FEA : Finite Element Analysis

Al : Aluminum

Ms : Mild Steel

CHAPTER 1

INTRODUCTION

1.1 INTRODUCTION

Mechanical joining using pin or a rivet is one method for joining parts. The

pin-joint structure is one of the important members of aerospace vehicles. There are many

reasons to be careful in dealing with these structure members, because of the possibility of

serious failures such as crack due to stress concentration induced by contact phenomenon.

Many researchers have dealt with pin-joint structures. In most cases, the contact condition

is the issue of these joint structures, while many other design parameters such as friction,

interference-fit, and clearance-fit also affect the structural safety. The interference-fit pin-

joint is a member whose diameter of the pin is larger than that of the hole, and the clearance

fit is the opposite case. To solve the contact problem of pin-joint structures, various

analytic solutions and numerical methods such as the finite element method can be used.

The difficulty with this method is that the presence of a hole in a plate subjected to external

loading introduces a disturbance in the stress field. Stress concentrations are generated in

the nearest area of the hole making the joint a weak one.

The example of material that usually used in pin joined situation on aerospace is

composite material. Composite materials are becoming more popular and are used in

almost all fields due to their high strength to weight ratio, good fatigue resistance, corrosion

resistance etc. compared to metals. They are used for aircraft structures to golf clubs,

electronic packaging to medical equipment, and space vehicles to home buildings due to

their good mechanical properties. In the practical use of composite structures certain

discontinuities like holes and cutouts arise while joining by rivets or pins.

However, because of composite material that have expensive price and it is hard to

make, the aluminum and mild steel plate will be used in this research. Aluminum is a

common sheet metal that usually has in composite plate combined with other type of fiber.

The common failure modes in mechanical joint will be examined. Failure in mechanical

joint can be classified into three types that are bearing, shear out and net-tension or normal.

So, types of damage in pin-loaded aluminum plate and mild steel plate will be examined

whether it is bearing, shear out, net tension or combination of these.

1.2 PROBLEM STATEMENT

In mechanical joint, we need to find the correct point where the hole of joint such as

rivet or pin that is suitable for the part. It is important to avoid from any incident that cause

of the joint such as in aerospace technology. The location where the part join need to be at

best point where if the failure happened, it will not cause any disaster such as bearing

failure. So the ratio E/D and W/D [refer to Figure 3.2] is important and needed to find the

correct location where the part can be jointed and analyze the failure that occur at the point.

1.3 OBJECTIVES

To investigate the type of mechanical joint failure (net-tension, bearing and shear

out) in pin loaded aluminum plate and mild steel plate.

Investigate failure load in an aluminum plate, with a circular hole, which is

subjected to a traction force by a pin.

1.4 SCOPES

Vary the edge distance to hole diameter (E/D) and width to diameter (W/D) ratios

[refer to Figure 3.2].

Using aluminum plate and mild steel plate with same thickness that is 2mm.

CHAPTER 2

LITERATURE REVIEW

2.1 INTRODUCTION

In many fields such as Airbus A380 design and manufacturing, there exist codes

and standard that are put in place by various agencies that must followed by all designers

and manufactures. Regardless of the extreme care taken in design, manufacturing, and

material selection for machines and components, failure are unavoidable, resulting in loss

of property and unfortunately, sometimes, life. Every engineer should be completely

familiar with the concept of failure of materials and able to extract information from a

failed component as to the causes of failure. Responsible operating practice, good

maintenance and through periodic inspection of the fracture – critical components are the

best ways to avoid failures.

Materials engineers are frequently involved in choosing inspection intervals and

techniques. (The Science and Design of Engineering Materials, 2nd edition). In most cases

scientists and engineers carefully analyze the failed component to determine the cause of

failure. The information gained is used to advance safe performance and minimize the

possibility of failure through improvements in design, manufacturing process, and materials

synthesis and selection.

2.2 FAILURE

Failure may be defined as inability of a material or a component to :

- perform the intended function

- meet performance criteria although it may still be operational

- perform safely and reliably even after deterioration.

Yielding, wear, buckling (elastic instability), corrosion and fracture are examples of

situations in which component has failed. Engineers are deeply aware of the possibility of

fracture in load-bearing component and its potentially detrimental effort on productivity,

safety, and other economical issues. As a result of all design, manufacturing, and materials

engineers use safety factors in their initial analysis to reduce the possibility of fracture by

essentially overdesigning the component or machine. [1]

2.2.1 Ultimate Failure

In mechanical engineering, ultimate failure describes the breaking of a material. In

general there are two types or failure: fracture and buckling. Fracture of a material occurs

when either an internal or external crack elongates the width or length of the material. In

ultimate failure this will result in one or more breaks in the material. Buckling occurs when

compressive loads are applied to the material and instead of cracking the material bows.

This is undesirable because most tools that are designed to be straight will be inadequate if

curved. If the buckling continues the material will create tension on the inner side of the

material and compression on the outer part, thus fracturing the material.

In engineering there are multiple types of failure based upon the application of the

material. In many machine applications any change in the part due to yielding will result in

the machine piece needing to be replaced. Although this deformation or weakening of the

material is not the technical definition of ultimate failure, the piece has failed. In most

technical applications pieces are rarely allowed to reach their ultimate failure or breakage

point, instead for safety factors they are removed at the first signs of significant wear.

There are two different types of fracture brittle and ductile. Each of these types of

failure occurs based on the material's ductility. Brittle failure occurs with little to no plastic

deformation before fracture. An example of this would be stretching a clay pot or rod, when

it is stretched it will not neck or elongate merely break into two ore more pieces. While

applying a tensile stress to a ductile material, instead of immediately breaking the material

will instead elongate. The material will begin by elongating uniformly until it reaches the

yield (engineering) point, then the material will begin to neck. When necking occurs the

material will begin to stretch more in the middle and the radius will decrease. Once this

begins the material has entered a stage called plastic deformation. Once the material has

reached its ultimate tensile strength it will elongate more easily until it reaches ultimate

failure and breaks.

There are numerous methods to improve the strength of a material and therefore

increase its ultimate failure point. Cold working a material is done by plastically deforming

a material below its recrystallization temperature. This is most commonly seen by

manufacturers hammering a material at room temperature. Hot working is any plastic

deformation that is done above the recrystallization temperature. Cold working remains less

effective because it is done below the recrystallization factor, but also remains more

accurate. Because of thermal expansion and contraction of a material when heated hot

working adds additional strength but also adds a rougher surface due to oxidization.

Heat treatment of a material is when the material is heated to extreme temperatures

and quenching the material in water to cool it quickly. By heating the material to these very

high temperatures the materials atomic structure is capable of being altered into a stronger

material. This will also hopefully remove any cracks or deformations that will weaken a

material. These cracks will weaken a material because they focus the stress or strain of a

material to a particular point.

2.2.2 Mechanical Joint Failures Modes

Net-Tension Failure

Net-tension failure or normal failure involves a fracture across the width of the

joint, as illustrated in Figure 2.1, and normally occurs when the W/D ratio is small.

Figure 2.1: Net-Tension Failure

Shear-Out Failure

Shear-out failure occurs when a plug of material separates from the laminate ahead

of the pin, as shown in figure 1 and normally occurs when the E/D ratio is small (or in

conventional composites, if an excessive amount of 0° plies are used). Shear- out failure

can therefore occur after some bearing damage has initiated.

Figure 2.2: Shear-Out Failure

TYPES OF DAMAGE IN PIN-LOADED ALUMINUM PLATE AND...

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