UNIVERSITI TEKNOLOGI MARA

DYNAMIC CHARACTERIZATION OF FIBREREINFORCED COMPOSITE (S-GLASS) IN

RIGID ARMOURED VEHICLE

ABD HALIM HAJI IDRIS

Thesis submitted for the fulfilment of the requirementsfor the degree of

Master of Science

Faculty of Mechanical Engineering

August 2006

ABSTRACT

This thesis describes the identification of dynamic properties and characteristics of S-

Glass composite material which is used as spall liner in armoured tank. To achieve

this, the project puts its focus on analytical approach, numerical method and finally

an experimental method using modal testing .

The analytical approach utilised the Ritz method. Finite element method using

LUSAS software was employed in the approximation numerical approach. The

experimental work carried out focused on transient testing of a plate membrane.

In this study, it was observed that the natural frequencies obtained from the

experiment and analytical analyses (1C3F) were closely matched. However for other

boundary conditions the natural frequencies did not match even though the modes

shapes were similar.

For future works similar study can be carried out but the plates for testing have to be

produced under controlled conditions. This is to ensure that the material properties

are measured for specific bonding and grain orientation as well as fabrication

process.

Candidate's Declaration

I declare that the work in this thesis was carried out in accordance with the

regulations of Universiti Teknologi MARA. It is original and is the result of my own

work, unless otherwise indicated or acknowledged as referenced work. This topic has

not been submitted to any other academic institution or non-academic institution for

any other degree or qualification.

In the event that my thesis be found to violate the conditioned mentioned above, I

voluntarily waive the right conferment of my degree and agree be subjected to the

disciplinary rules and regulations of Universiti Teknologi MARA.

Name of Candidate

Candidate's ID No.

Programme

Faculty

Thesis Title

Signature of Candidate

Date

ABD HALIM BIN HAJI IDRIS

2000527048

MASTER OF SCIENCE

MECHANICAL ENGINEERING

DYNAMIC CHARACTERIZATION OF FIBRE

REINFORCED COMPOSITE (S-GLASS) IN RIGID

ARMOURED VEHICLE

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TABLE OF CONTE NTS

TITLE PAGE

ABSTRACT

CANDIDATE'S DECL ARATIO N

ACKNOWLEDGEMENTS

TABLES OF CONTENTS

LIST OF TABLES

LIST OF FIGURES

LIST OF PLATES

NOMENCLATURE

Chapter 1: Introduction

1.1. Background

1.2. Problem Statement

1.3. Objective

1.4. Scopes of Study

Chapter 2: Mathematical Background

2.1. Introd uction

2.2. Tran sverse vibration of Plates

2.3. Rectangular Plate

2.4. Transve rse vibration of membrane

2.5. Rectangular membranes

2.6. Applicati on of Ritz Method

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CHAPTER 1

INTRODUCTION

1.1 Background

The advent of high strength and light weight composite materials and newly

developed resin materials have radically changed the concepts of advanced

space structure and Armoured vehicles [I]. This high strength - to-weight or

modulus-to-weight ratios of composites could also result in lighter structural

components with lower operating costs and better maintenance history. Since,

most current space structures , unmanned vehicles, aircraft structures and high

performance defence vehicles are designed to be robust ; designers have been

quick to realize the advantages of this advanced material.

In response to this, the United State Army Tank-Automotive Command

(TACOM) had been evaluating alternative lighter weight materials such as

titanium alloys and ceramic tile/polymer-matrix composites (PMCs) that are

currently the only practical possibilities for lighter-weight structural armour

applications [2]. The alloys do have disadvantages when a spall liner] is

required that there are relatively to fabrication example machining and

welding. Although PMCs offer some advantages for example freedom from

spalling against chemical threats, a quieter operator environment and a high

mass efficiency against ball and fragment ballistic threats. Nevertheless, spall

liners have been identified as providing improved protection for the tank

crews but they still have a number of problems.

I A layer of lead-impregnated plastic foam, which is used to line the interior surfaces ofannouredvehicles to absorb the energy of fragments produced by penetrat ive attacks. It also acts as a radiationshield.

DYNAMIC CHARACTERIZATION OF FIBRE REINFORCED COMPOSITE (S-GLASS) IN RIGID ARMOURED VEHICLEABSTRACTCANDIDATE'S DECLARATIONACKNOWLEDGEMENTSTABLES OF CONTENTSLIST OF TABLES5.1 Parameter of the theoretical composite plate5.2 The mode shape of model-i that is clamped along one edge (1C3F) and measured at the centre of plate5.3 Natural frequencies of sample-i at various boundary conditions6.1 Natural frequencies for panel-I (4C) - hit on related points6.2 Damping loss factor - hit on related points6.3 Natural Frequencies of three panels6.4 Natural frequencies of three different samples - hung with bungee6.5 Natural frequency of panel 2 with different boundary condition7.1 Comparison data of natural frequencies through experimental and analysis.7.2 Comparison data of natural frequencies through experimental and analysis.7.3 Comparison data of natural frequencies through experimental and analysis.7.4 Comparison data of natural frequencies through experimental and analysis.7.5 Comparison data of Natural frequencies through experimental and analysis.

LIST OF FIGURES1 Figure l.1: Flow Chart2 Figure 2.1: A plate with a uniform thickness 'h'3 Figure 2.2: The plane of the membrane4 Figure 2.3: Square membrane5 Figure 3.1: Example of anti-symmetric angle-ply laminates. Although the ply orientations are anti-symmetric about the middle surface, the material distribution is symmetric6 Figure 3.2: Composite sandwich structure7 Figure 4.1: Excitation to the structure8 Figure 4.2: Typical Accelerometer frequency Response9 Figure 4.3: Typical mould construction10 Figure 4.4: Clamped-free-free-free (1C3F) support11 Figure 4.5: Clamped- Clamped —free-free (2C2F) support12 Figure 4.6: Clamped- Clamped - Clamped -free (3C1F) support13 Figure 4.7: Four Clamped (4C) support14 Figure 4.8: Free-free-free-free15 Figure 4.9: Arrangement of instrumentation for the vibration measurement16 Figure 4.10: Grid layout of nodes17 Figure 4.11: Response Function versus Frequency18 Figure 5.1: Finite element node numbering19 Figure 5.2: Mode shapes of plate20 Figure 5.3: Shape of specimen is to be tested21 Figure 5.4: An edge of simulated plate (model-1) constraint.22 Figure 5.5: An edge of simulated plate (model-2) constraint23 Figure 5.6: An edge of simulated plate (model-3) constraint.24 Figure 5.7: Graphs of simulated model-i at various boundary conditions25 Figure 5.8: 10 numbers of mode shape for sample-i - (I C317)26 Figure 6.1: Reciprocal theorem27 Figure 6.2: Experimental set up for the generations of FRFs28 Figure 6.3: Natural Frequencies for panel-i (4C)29 Figure 6.4: Natural Frequency for panel-i (4C) -hit on their points put together30 Figure 6.5: Three different samples of plate- signal at point 5 and hit point 631 Figure 6.6: Natural Frequency for panel-i (417) - hit on point 632 Figure 6.7: Natural Frequency for panel-2 (417) - hit on point 633 Figure 6.8: Natural Frequency for panel-3 (417) - hit on point 634 Figure 6.9: Results obtained from three plates put together in one graph35 Figure 6. 10: Natural Frequency obtained for different application of boundary conditions36 Figure 6.11: Resonance detail37 Figure 6.12: Nyquist plot of single mode38 Figure 7.1: Natural frequencies of panel/sample 1 - (I OF)39 Figure 7.2: Measured and predicted natural frequencies of sample 1 - (1C3F)40 Figure 7.3: Natural frequencies of panel/sample 3 - (2C2F)41 Figure 7.4: Measured and predicted natural frequencies of sample 3 - (2C2F)42 Figure 7.5: Natural frequencies of panel/sample 2 - (3C1F)43 Figure 7.6. Measured and predicted natural frequencies of sample 2 - (3C1F)44 Figure 7.7. Natural frequencies of sample 3 - (4C)45 Figure 7.8. Natural frequencies of panel 3 - (4F)46 Figure 7.9: Mode shape of the mode I - panel 1 (1 OF)47 Figure 7.10: Mode shape of the mode 2 of panel-i - (I OF)48 Figure 7.11: Mode shape of the mode 3 of panel-i —(IOF)

LIST OF PLATES4.1 Designed Mounting of Plate4.2 Adjustable Mounting (One Clamp)4.3 Adjustable Mounting (Two Clamp)4.4 Adjustable Mounting (Three Clamp)4.5 Adjustable Mounting (Four Clamp)4.6 Composite plate - hang (4F)

NOMENCLATUREChapter 1: Introduction1.1. Background1.2. Problem Statement1.3. Objective1.4. Scopes of Study

Chapter 2: Mathematical Background2.1. Introduction2.2. Transverse vibration of Plates2.3. Rectangular Plate2.4. Transverse vibration of membrane2.5. Rectangular membranes2.6. Application of Ritz Method

Chapter 3: Literature survey3.1. Introduction3.2. Composite materials3.2.1 Testing on assemblies of structures3.2.2 Modelling data3.2.3 Free Vibration3.2.4 Lamination Parameter3.2.4. [a] Lamination3.2.4. [b] Stiffened laminated3.2.4. [c] Twisted Plate3.3. Experimental Techniques

Chapter 4: Experimental Procedures and Set-up4.1. Introduction4.2. Excitation of the Test Structure4.3. Transducer Selection4.4. Accelerometer Selection4.5. Selection of Analysis4.6. Test Fixture Design4.7. Fibres for Reinforced-Plastic Composite Material4.8. Test Specimens - Composite held/hung by4.8.1 1C3F4.8.2 2C2F4.8.3 3C1F4.8.4 4C4.8.5 Bungee (417)4.9. Control of Test Specimen4.10. Arrangement of Instrumentation4.11. Nodal Layout4.12. Data transfer from Spectrum Analyser to MatLab

Chapter 5: Modelling5.1 Introduction5. 1.1 Finite Element Method (FEM)

5.2 The Underlying Method5.2.1 Model Definition5.2.2 Modal Analysis5.2.2 [a] Harmonic Response5.2.2 [b] Frequency Response

5.3 Analysis Considerations5.3.1 Modes5.3.2 Material Tests to Determine Input Parameters5.3.3 Density

5.4 Numerical Case Study5.4.1 The Effects of Different Mechanical Properties5.4.2 Boundary Condition Effects of Simulated Plate-i5.4.3 Mode Shapes

Chapter 6: Experimental Results6.1 Introduction6.2 Reciprocal Theorem6.2.1 Experiment Case Study6.2.2 The Effect of the Mass Density

6.3 Comparison between Three Panels of Plates6.3.1 Free Boundary Condition6.3.2 Effect of Boundary Conditions

Chapter 7: Discussion and Conclusion7.1 Introduction7.2 Comparison of Natural Frequencies7.2.1 Comparison of Natural Frequency— One Clamped7.2.2 Comparison of Natural Frequency - Two Clamped7.2.3 Comparison of Natural Frequency - Three Clamped7.2.4 Comparison of Natural Frequency - Four Clamped

7.3 Comparison of Mode Shapes7.4 Conclusion7.5 Suggestion for Future Study

8 REFERENCES9 APPENDICESAppendix AAppendix BAppendix C