Machining simulation of composite materials using engineering simulation software.

UNIVERSITI TEKNIKAL MALAYSIA MELAKA

MACHINING SIMULATION OF COMPOSITE MATERIALS

USING ENGINEERING SIMULATION SOFTWARE

This report submitted in accordance with requirement of the Universiti Teknikal Malaysia Melaka (UTeM) for the Bachelor Degree of Manufacturing Engineering

(Manufacturing Design) (Hons.)

by

ZAMMERI BIN ABD RAHMAN B051010253

801205-11-5021

FACULTY OF MANUFACTURING ENGINEERING 2014

MACHINING SIMULATION OF COMPOSITE

MATERIALS USING ENGINEERING SIMULATION

SOFTWARE

ZAMMERI BIN ABD RAHMAN

B051010253

UNIVERSITI TEKNIKAL MALAYSIA MELAKA 2014

UNIVERSITI TEKNIKAL MALAYSIA MELAKA

BORANG PENGESAHAN STATUS LAPORAN PROJEK SARJANA MUDA

TAJUK: Machining Simulation of Composite Materials Using Engineering Simulation Software

SESI PENGAJIAN: 2013/14 Semester 2 Saya ZAMMERI BIN ABD RAHMAN

mengaku membenarkan Laporan PSM ini disimpan di Perpustakaan Universiti Teknikal Malaysia Melaka (UTeM) dengan syarat-syarat kegunaan seperti berikut: 1. Laporan PSM adalah hak milik Universiti Teknikal Malaysia Melaka dan penulis. 2. Perpustakaan Universiti Teknikal Malaysia Melaka dibenarkan membuat salinan

untuk tujuan pengajian sahaja dengan izin penulis.

3. Perpustakaan dibenarkan membuat salinan laporan PSM ini sebagai bahan pertukaran antara institusi pengajian tinggi.

4. **Sila tandakan ( )

SULIT

TERHAD

TIDAK TERHAD

(Mengandungi maklumat yang berdarjah keselamatan atau kepentingan Malaysia sebagaimana yang termaktub dalam AKTA RAHSIA RASMI 1972)

(Mengandungi maklumat TERHAD yang telah ditentukan oleh organisasi/badan di mana penyelidikan dijalankan)

Alamat Tetap:

2539 - A KAMPUNG PAYA RESAK, BUKIT PAYONG, 21400 KUALA TERENGGANU, TERENGGANU. Tarikh: 23th June 2014

Disahkan oleh:

Cop Rasmi:

Tarikh: 23th June 2014

** Jika Laporan PSM ini SULIT at au TERHAD, sil a lampirkan surat daripada pihak berkuasa/ organisasi berkenaan dengan menyat akan sekal i sebab dan t empoh l aporan PSM ini perl u dikelaskan sebagai SULIT at au TERHAD.

DECLARATION

I hereby, declared this report entitled “Machining Simulation of Composite Materials Using Engineering Simulation Software” is the results of my own

research except as cited in references.

Signature :

Author’s Name : Zammeri Bin Abd Rahman Date : 23th June 2014

APPROVAL

This report is submitted to the Faculty of Manufacturing Engineering of UTeM as a partial fulfillment of the requirements for the degree of Bachelor of Manufacturing Engineering (Manufacturing Design) (Hons.). The member of the supervisory is as follow:

……… (Project Supervisor)

Proses pengisaran merupakan salah satu alat yang paling penting dalam proses memotong bahan komposit dengan alat geometri operasi pengisaran yang kompleks. Bahan komposit digunakan secara meluas dalam pelbagai sektor pembuatan termasuk aeroangkasa, marin dan automotif. Terdapat kekurangan penyelidikan tentang simulasi logam matriks komposit yang menggunakan Kaedah Unsur Terhingga 3D (FEM) dalam proses pengisaran dan kaedah unsur terhingga 2D tidak boleh mensimulasikan proses pengisaran yang kompleks. Oleh itu, kajian simulasi bermaklumat dengan lebih realistik 3D Model Unsur Terhingga (FEMs) dan juga model pemotongan ortogon untuk proses pengisaran yang kompleks CFRP/AL2024 telah dibangunkan untuk meramalkan mata alat dan bahan kerja menggunakan 3D Analisis Unsur Terhingga (FEA) dengan menggunakan ABAQUS/EXPLICIT. Akhirnya keputusan agihan tegasan, suhu pengisaran, daya pemotongan dan pembentukan cip diperolehi. Model ini mengambil kira kesan yang dinamik, undang-undang kerosakan bahan dan kriteria kenalan. Projek ini juga membangunkan Model 3D dalam pemesinan Realiti Maya (VR) yang memberikan satu penyelesaian yang optimum penjanaan laluan mata alat dengan bantuan simulasi menggunakan VERICUT. Simulasi dan pemodelan proses pemotongan mempunyai potensi untuk mengoptimumkan parameter pemesinan dan meningkatkan reka bentuk alat pemotong, terutamanya dalam pengisaran termaju yang berkelajuan tinggi.

ABSTRACT

The milling process is one of the most important tool for cutting process in milling operation of composite material with the complex tool geometry. Composite materials are widely used in a variety of manufacturing sectors including the aerospace, marine and automotive industries. There is a lack of research on simulating the metal matrix composites using 3D Finite Element Methods (FEM) in the milling process and the 2D finite element methods cannot simulate the complex milling process. Therefore, an informative simulation study with more realistic 3D Finite Element Models (FEMs) as well as an orthogonal cutting model for the complex milling process of CFRP/AL2024 was developed to predict tool and workpiece using 3D Finite Element Analysis (FEA) with ABAQUS/EXPLICIT. Finally the results of stress distribution, milling temperatures, cutting force and chip formation are obtained. This model takes into account the dynamic effect, material damage law and contact criteria. This project also develops the 3D Model in Virtual Reality (VR) machining that to give an optimal solution of the tool path generation with the help of simulation using the VERICUT. Simulation and modelling of cutting processes have the potential for optimizing machining parameters and improving the cutting tool design, especially in advanced high-speed milling.

ABSTRACT

Special Dedication to my beloved parents and family, My fellow colleague, My friends,

and all faculty members,

Who have support and guidance me.

Who is always there for me and always prays for me,

DEDICATION

First and foremost, I would like to express my biggest appreciation to my respected final year project supervisor, Engr. Dr. Mohamad Bin Minhat for all his precious supports and advices during completing this project report. With his kindness, he gives his best guidance and assistance throughout my final year project and preparation of this report writing. I would like to lovely appreciate his willingness to spend some time with me while doing this project.

My sincere appreciation also extends to all my fellow colleagues and people who have involved directly and indirectly to give contribution and provided assistance at various occasions. Their views and tips are useful indeed to complete my project reports. Great appreciation also gives to my lectures who have taught me throughout my study in Universiti Teknikal Malaysia Melaka. Also not forget, my special thanks go to all staff in Faculty of Manufacturing Engineering UTeM. Last but not least, I also would like to thanks to all my family members that give fully guidance and moral support in completing this project.

Thank you.

ACKNOWLEDGEMENT

Abstrak i

Abstract ii

Dedication iii

Acknowledgement iv

Table of Content v

List of Tables viii

List of Figures ix

List Abbreviations, Symbols and Nomenclature xi

CHAPTER 1 : INTRODUCTION 1

1.1 Overview 1

1.2 Problem Statement 3

1.3 Objectives 4

1.4 Scope of Work 4

1.5 Chapters Organization 5

CHAPTER 2 : LITERATURE REVIEW 6

2.1 Background 6

2.2 Previous Research Work on Composite Machining 8

2.3 Composite Materials 10

2.3.1 Carbon Fiber Reinforced Plastic (CFRP) 11 2.3.2 Manufacture Process of CFRP 12

2.3.3 Aluminum Alloy (AL2024) 12

2.4 Machining Simulation Using Engineering Simulation Software 13

2.4.1 Machining Simulation 16

2.4.2 Engineering Simulation Software 16 2.4.3 Finite Element Simulation of Machining Process 17 2.4.4 Process Simulation Approach 18

2.4.5 Mesh Adaptivity 19

TABLE OF CONTENT

2.4.6 ABAQUS/CAE software 20

2.4.7 ABAQUS/EXPLICIT 21

2.4.8 VERICUT Simulation software 21

2.5 Chapter Summary 22

CHAPTER 3 : METHODOLOGY 23

3.1 Project Planning 23

3.2 Process Planning Using ABAQUS 26

3.3 Stages in ABAQUS/CAE Analysis 28

3.3.1 Pre-processing (ABAQUS/CAE) 28

3.3.2 Simulation (ABAQUS /EXPLICIT) 29 3.3.3 Post processing (ABAQUS /CAE) 29 3.4 Composites Modeler for ABAQUS Using SIMULAYT Add-On 30 3.4.1 Composite Modeler with SIMULAYT Composite Modeler 31 3.4.2 Methods to Create Composite Modeler with SIMULAYT 33 3.5 Finite Element Modelling (FEM) for CFRP/AL2024 34 3.5.1 3D Finite Element Modelling (FEM) 34 3.5.2 Orthogonal Finite Element Modelling (FEM) 35 3.5.3 Material Properties and Material Constitutive 36

3.5.4 Material Damage Criteria 38

3.5.5 Contact Model Analysis 38

3.6 Process Planning Using VERICUT 39

3.6.1 Development of the Simulation Environment in VERICUT 41 3.6.2 3D Model in SOLIDWORKS (Static Models) 41 3.6.3 Simulation of Tool Path Using VERICUT 42

3.7 Chapter Summary 43

CHAPTER 4 : RESULT & DISCUSSION 44

4.1 Data Grouping 44

4.2 Design and Modelling of Parts 45

4.3 Defining the Material’s Properties in ABAQUS 49 4.4 Composites Modeler Draping Simulations and Solid Extrusion 50

4.5 Assembly Meshing in ABAQUS 54

4.6 Process of Simulation in 3D Finite Element Modelling (FEMs) 55

4.7 XY Data Graph 62

4.8 Construction Of The Virtual Machine in VERICUT 63

4.9 Design and Modeling The Machine 64

4.10 Process Simulation of Tool Path in VERICUT 66

4.11 Chapter Summary 68

CHAPTER 5 : CONCLUSION & FUTURE WORK 69

5.1 Conclusions 69

5.2 Recommendations for Future Work. 71

3.3 Chapter Summary 72

REFERENCES 73

APPENDICES

A Gantt Chart of PSM

B Analysis Input File Reported

C Field Output Reported At Integration Points

D Processing Part, Instance, And Assembly Information Ouput

3.1 Arrangement of the laminates 36

3.2 Physical Properties of CFRP 37

3.3 Constant parameters for the Johnson–Cook material model of CFRP 37 3.4 Fracture parameter for CFRP, Al2024 and PCD 38 3.5 End mill cutting condition under the milling process 42

LIST OF TABLES

1.0 Scope of works (SOW) 4

2.1 Auto-clave molding (CFRP) 12

2.2 Optional simulation software tools 17 2.3 Lagrangian process model with damage/element deletion 18 2.4 Eulerian (ALE) process model/example results 19 2.5 Meshing 3D model for the simulation of machining 20 2.6 Schematic diagram of tool path and machining operation 22

3.1 Project plan flow chart 25

3.2 Process plan flow chart using ABAQUS 27

3.3 Stages in ABAQUS/CAE analysis 28

3.4 The solid model of CFRP/AL2024 layup using SIMULAYT Composites Modeler for ABAQUS/CAE (CMA) V2013

30

3.5 The procedure to create composite modeler with SIMULAYT Plug-in Version 2013

31

3.6 Methods to create composite modeler with SIMULAYT 33 3.7 3D Finite Element Model (FEM) for milling of CFRP/AL2024 34

3.8 Meshing elements of workpiece material for CFRP/AL2024 and tool geometry

36

3.9 Process plan flow chart using VERICUT 40 3.10 Framework of simulation for virtual milling process 41

3.11 Virtual environment designed for milling process of the 3- Axis FANUC CNC vertical milling machine

43

4.1 Flat bottom end mill model designed using CATIA V5.21 45 4.2 Flat bottom end mill model import from CATIA V5.21 to

ABAQUS/CAE V6.13

46

LIST OF FIGURES

4.3 Flat bottom end mill solid model with element type in ABAQUS/CAE V6.13

46

4.4 Associative import to export a model from CATIA V5 to ABAQUS/CAE

47

4.5 Assembly modelling of 3D FEM using ABAQUS V6.13 48 4.6 Assembly modelling of orthogonal cutting using ABAQUS V6.13 48 4.7 Material defining for the composite layup of CFRP/AL2024 49 4.8 Solid mesh of CFRP/AL2024 layup using SIMULAYT composites

modeler for ABAQUS/CAE (CMA) V2013

50

4.9 Condition of layup laminate materials in materials dialog box. 51 4.10 CSYS coordinate system direction with Strain Plies of

CFRP/AL2024

52

4.11 The layup of seven plies using CFRP and AL2024 material with different number of ply and angle offset

53

4.12 The cloning a ply with layup model of CFRP/AL2024 53 4.13 Assembly meshing of the workpiece and cutting tool in 3D FEM

process

54

4.14 Assembly meshing of the workpiece and cutting tool in orthogonal cutting process

55

4.15 The stress distribution of 3D FEM at different cutting times (A, B, C, D, E and F)

57

4.16 The stress distribution of orthogonal cutting chip formation at different cutting times (A, B, C, D, E and F)

59

4.17 The temperature distribution of orthogonal cutting chip formation at different cutting times (A, B, C, and D)

60

4.18 Discontinuous and Continuous Chip for Orthogonal Cutting 61 4.19 XY graph between the milling Forces (N) versus Time (s) 63 4.20 3D wire frame model from SOLIDWORKS Premium 2012 64 4.21 3D model of 3-Axis FANUC vertical milling machine in VERICUT

V7.1.6

65

4.22 The result of simulation tool paths in VERICUT 66 4.23 Optimized G & M Codes in CNC program as a text format 67

AL2024 - Aluminum Al2O3 - Alumina

Ti6A14V - Titanium alloy

ALE - Arbitrary Lagrangian Eulerian

ASTM - American Society for Testing and Materials Standards BC's - Boundary Conditions

CAD - Computer Aided Drafting CAE - Computer Aided Engineering CAM - Computer Aided Machining CBN - Cubic Boron Nitride

CDM - Continuum Damage Modelling CFRP - Carbon Fiber Reinforcement Polymer CM - Composite Modeler

CMA - Composite Modeler for ABAQUS CNC - Computer Numerical Control DoE - Design of Experiments DoF - Degree of Freedom

FE - Finite Element

FEA - Finite Element Analysis FEM - Finite Element Method FEMs - Finite Element Models FRP - Fibre Reinforced Plastics FYP - Final Year Project

GFRP - Glass Fibre Reinforced Plastics HSM - High Speed Machining

NC - Numerical Control

PCD - Polycrystalline Coated Diamond PSM - Projek Sarjana Muda

LIST OF ABBREVIATION, SYMBOLS AND

NOMENCLATURE

R&D - Research And Development RSM - Response Surface Model

SFTC - Scientific Forming Technologies Company SOW - Scope of Works

SHPB - Split Hopkinson Pressure Bar VR - Virtual Reality

exp - Exponential

D - Diameter

F - Feed Rate

Gpa - Giga Pascal

Kg - Kilogram

L - Length

m - Melting

min - Minute

mm - Millimetre

Mpa - Mega Pascal

N - Value of cutter

P - Parameters

Q - Misses Stress

Ra - Surface roughness rpm - Revolution per minute

s - Second

T - Temperature

Tm - Melting Temperature

Tr - Room Temperature

V - Cutting Speed

W - Weight

Z - Number of teeth

This chapter contains the introduction and project background. This project is carried out based on the simulation and analysis of the milling process of carbon fibre composites CFRP/Al2024. Problem statements, objectives and scopes of this project are also discussed. There is also a chapter organization that explains about the overall subject in this report.

1.1 Overview

Composite is a superior material that is preferred in aerospace, marine and automotive industries. It is made up of a matrix material completely surrounding the reinforcement material to form unique properties and characteristics which do not exist in the matrix material naturally (R. Rusinek, et al., 2011). When the two phases unite to form a composite, it has properties or features that are not available in the original constituents of the composite materials formed (Alwarsamy et al., 2012). Recently, composite became the most preferred material in the aerospace industry due to the many benefits it provides, such as superior strength to weight ratio, stiffness, good fatigue as well as corrosion resistance and low manufacturing cost (NorKhairusshima M.K et al., 2011). Despite its excellent characteristics, machining of composite is difficult to conduct due to its high abrasiveness, non-homogenous and anisotropic structure (Klinkova et al., 2011). Research of composite machining mostly concentrates on drilling and turning. Rahman et al., (1999) developed feasible techniques for turning on Carbon Fibre Reinforced Plastics (CFRP).

INTRODUCTION

CHAPTER 1

According to Ferreira et al., (1999) focused on tool wear and illustrated the performance of different tool materials and supports that only Polycrystalline Coated Diamond (PCD) tool are suitable for used in finish turning. Palanikumar et al., (2004) presented an investigation on optimization of machining parameters for surface roughness using Design of Experiments (DoE) on different types of Glass Fibre Reinforced Plastics (GFRP). Hariharan et al., (2012) the influence of tool wear in a drilling process of CFRP composites is very high. Phadnis et al., (2012) developed 3D Finite Element Model (FEM) of drilling CFRP/A2024. However, there are few researchers dealing with machining of composite material using a CNC milling machine (NorKhairusshima M.K et al., 2011, Alwarsamy et al., 2012). To improve the manufacturing quality, performance of the tool, optimum cutting conditions and cost reduction are the key area need to be considered. On the other hand, the academicians are continually looking for alternatives that help of a better understanding of the metal cutting process.

Generally, there are two most common methods of conducting experiments associated with the machining process. First is by preparing some sample, set-up on the machine with predefined machining parameters and finally some data will be collected depending on the purpose of the experiments. However, this method has proved to be more expensive, especially dealing with composite materials. The second method is called simulation. Simulation models are very important in the machining process as comprehension and for the reduction of experimental tests. Results obtained from the simulation provides better understanding of system behaviour and in turn help in the process of optimization of tool geometries, cutting conditions and other parameters like the choice of the tool material and coating. Simulation eventually enables good predictions in the cutting force, stress and strain distribution. This will contribute to cost reductions for the machining process optimization that are still experimentally done and thus expensive (Madalina C. et al., 2008). Therefore, there are few researchers are focusing on modelling and simulation techniques to predict and optimize certain machining parameters such as the cutting force, surface roughness, stress–strain analysis etcetera. These techniques do not need to perform many experimental tests that will cost a lot of money and are time consuming (Hamed S. et al., 2007).

1.2 Problem Statement

CFRPs are an expensive material that fast gaining ground as the preferred material to replace the traditional material used for construction of aircraft and spacecraft (W. N. F. Mohamad et al., 2013). In recent years, the combinations of CFRP/metals to form a composite material have also gained popularity (Klinkova et al., 2011; R. Rusinek, et al., 2011). Literature reviews relevant to the field of composite material machining most often focus on analysis of cutting tools wear and methods of optimization for surface roughness. Most of the research conducted by performing actual machining operation which actually very expensive and time consuming. Another method of experiment which is less costly as described previously is simulation. Generally, most of the machining simulation only provides limited information such as tool path generations and errors/collision detection, Output like surface roughness, tool wear, cutting forces etcetera are not readily available on request.

Therefore, in this project, the simulation of the machining process of CFRP/AL2024 is conducted using the engineering simulation software. However, complex milling process cannot be simulated by 2D finite element methods (H. B. Wu. S. J. Zhang, 2013). Therefore, an informative simulation study with more realistic 3D Finite Element Model (FEM) and orthogonal cutting model for the complex milling process of CFRP/AL2024 is developed. This model takes into account the dynamic effect, material damage law and contact criteria. Also the 3D Model developed in virtual machining would give an optimal solution of the tool path generation with the help of simulation. Simulation and modelling of cutting processes have the potential for optimizing machining parameters and improving the cutting tool designs, especially in advanced high-speed milling.

1.3 Objectives

The overall aim of the Final Year Project (FYP) is to study and develop a methodology for simulating the machining process of CFRP/Al 2024 using a milling machine. The aim can be resolved into the following specific objectives:-

• To develop 3D Finite Element Model (FEM) for milling process using 3D Finite Element Analysis (FEA) with ABAQUS/EXPLICIT software.

• To simulate machining tool path, under the selected cutting conditions (speed, feed rate and depth of cut) using the VERICUT software.

1.4 Scope of Work

3D Finite Element Models (FEMs) Orthogonal Cutting Milling Process Simulation Tool Path Actual Machining Simulation/Analysis Using Engineering Simulation Software N o t Me an t CFRP/AL2024 Materials

Figure 1.0: Scope of works (SOW)

Figure 1.0 shows the Scope of Works (SOW) in this Final Year Project (FYP). The scopes of the project are mainly focused on studying about analysis and simulation in the milling process of CFRP/Al2024. In this project, an informative simulation study with a more realistic 3D Finite Element Models (FEMs) as well as an orthogonal cutting model has been developed to simulate the complex milling process of CFRP/AL2024 using the engineering simulation software.

This project also develops the 3D Model in virtual reality machining that to give an optimal solution of the tool path generation with considering speed, feed rates, and depth of cut with the help of simulation. The data from the observation and compilation will be used in simulation, applications of machining for verification. It will then help to analyze more conditions affecting the machinability of CFRP/AL2024. These studies are not meant for actual machining.

1.5 Chapters Organization

This dissertation consists of five chapters which is covered on PSM 1 and PSM 2. The report includes of introduction, literature review, methodology, result and conclusion. The first chapter introduces the background of the project, problem statement, objectives, scopes of the project and the report structure for overview the whole chapters in the report. Then follow by literature review on Chapter 2 which more on the research about the related project and review on the previous research work in composite machining, machining simulation and analysis using engineering simulation software. Chapter 3 focuses on the project planning as well as the methodology used during completing this project to ensure this project is successfully completed on the specified time period. This chapter explains about the flow of process planning, equipment and software application will be conducted. Chapter 4 describes the result and discussion of this project from the simulation and analysis process that has traversed. This project report ends with the conclusion of Chapter 5. Conclusions are made based on the result of simulation and analysis that have been conducted. Finally, suggestion and recommendation for the future work also included in this final chapter to improve this project.

The purpose of this chapter is to provide a general overview of past and current research work and placing the FYP project in wider context of simulation. All relevant information related to this project is refined and structurally present in this chapter. This literature review is vital to help in generating ideas to complete the tasks and project. The section of this report will review on previous research work on composite machining, composite materials, and machining simulation using engineering simulation software. Towards the end of this chapter, a summary of the literature is presented.

2.1 Background

Machining operations of composite materials which especially carbon fibre is extensively used in the aerospace industry in order to create smoothness on the desired surface and make a prototype part from a big blank or set of materials. Machining of the materials is very common and easily performed (Klinkova et al., 2011; R. Rusinek et al., 2011). However, the machining of the composite has proved to be more challenging. Machining of the composite material parts generates discontinuity in the fibre and thus affect the performance of the part, the temperature during the cutting process must be considered where it should not exceed the cure temperature or close to the melting temperature of the resin to avoid material disintegration. During machining process the smaller values of feed rate are much better as far as the tool life is concerned (W. N. F. Mohamad et al., 2013; Alwarsamy et al., 2012).

LITERATURE REVIEW

CHAPTER2

Adversely, this causes the process consuming more time and are very expensive. Machining also exposed the fibre to chemical and moisture and the effect of coolant materials on composites. The machining of composite materials required for dry machining process without using any coolant, or cutting fluid (W. N. F. Mohamad et al., 2013). This is due to the composite materials will expand if using the coolant or any cutting fluid during machining. The mechanical damage will occur faster when the workpiece that manufactured with composites are exposed to moisture and elevated temperature. The presence of water modifies the properties of the matrix and affected the mechanical properties such as strength, stiffness and creep (Rahman et al., 1999). Furthermore, there are several advantages by using dry cutting it will reduce the cost of machining (Premnath et al., 2012).

In the field of cutting process research, the Finite Element Method (FEM) is regarded as a ve1y useful tool to study the cutting process of materials. Many finite element models have been developed, including orthogonal cutting model, oblique cutting model, and 3D FEM. The orthogonal FEM has been more used to investigate the cutting mechanism. Simoneau et al., (2006) studied chip formation of medium carbon steel using 1hc orthogonal cutting model. Jin and Altintas, (2012) predicted micro-milling forces with the orthogonal model.

According to Mohammadpour et al., (2010) investigated the effect of machining parameters on residual stresses in orthogonal cutting. Molinari et al., (2011) studied the link between local variables and global contact characteristics in orthogonal cutting using the finite element method. Shams and Mashayekhi, (2012) established a nonlocal damage model to improve the orthogonal cutting simulation. Deng et al., (2009) used an orthogonal FEM to investigate burr formation. Zhang et al., (2012) investigated the cutting process of Ti6A14V based on crystal plasticity theory and discrete cohesive elements. Afazov et al., (2010) predicted micro-milling, cutting forces through the orthogonal cutting FEM.

According to Ferreira et al., (1999) focused on tool wear and illustrated the performance of different tool materials and supports that only Polycrystalline Coated Diamond (PCD) tool are suitable for used in finish turning. Palanikumar et al., (2004) presented an investigation on optimization of machining parameters for surface roughness using Design of Experiments (DoE) on different types of Glass Fibre Reinforced Plastics (GFRP). Hariharan et al., (2012) the influence of tool wear in a drilling process of CFRP composites is very high. Phadnis et al., (2012) developed 3D Finite Element Model (FEM) of drilling CFRP/A2024. However, there are few researchers dealing with machining of composite material using a CNC milling machine (NorKhairusshima M.K et al., 2011, Alwarsamy et al., 2012). To improve the manufacturing quality, performance of the tool, optimum cutting conditions and cost reduction are the key area need to be considered. On the other hand, the academicians are continually looking for alternatives that help of a better understanding of the metal cutting process.

Generally, there are two most common methods of conducting experiments associated with the machining process. First is by preparing some sample, set-up on the machine with predefined machining parameters and finally some data will be collected depending on the purpose of the experiments. However, this method has proved to be more expensive, especially dealing with composite materials. The second method is called simulation. Simulation models are very important in the machining process as comprehension and for the reduction of experimental tests. Results obtained from the simulation provides better understanding of system behaviour and in turn help in the process of optimization of tool geometries, cutting conditions and other parameters like the choice of the tool material and coating. Simulation eventually enables good predictions in the cutting force, stress and strain distribution. This will contribute to cost reductions for the machining process optimization that are still experimentally done and thus expensive (Madalina C. et al., 2008). Therefore, there are few researchers are focusing on modelling and simulation techniques to predict and optimize certain machining parameters such as the cutting force, surface roughness, stress–strain analysis etcetera. These techniques do not need to perform many experimental tests that will cost a lot of money and are time consuming (Hamed S. et al., 2007).

1.2 Problem Statement

CFRPs are an expensive material that fast gaining ground as the preferred material to replace the traditional material used for construction of aircraft and spacecraft (W. N. F. Mohamad et al., 2013). In recent years, the combinations of CFRP/metals to form a composite material have also gained popularity (Klinkova et al., 2011; R. Rusinek, et al., 2011). Literature reviews relevant to the field of composite material machining most often focus on analysis of cutting tools wear and methods of optimization for surface roughness. Most of the research conducted by performing actual machining operation which actually very expensive and time consuming. Another method of experiment which is less costly as described previously is simulation. Generally, most of the machining simulation only provides limited information such as tool path generations and errors/collision detection, Output like surface roughness, tool wear, cutting forces etcetera are not readily available on request.

Therefore, in this project, the simulation of the machining process of CFRP/AL2024 is conducted using the engineering simulation software. However, complex milling process cannot be simulated by 2D finite element methods (H. B. Wu. S. J. Zhang, 2013). Therefore, an informative simulation study with more realistic 3D Finite Element Model (FEM) and orthogonal cutting model for the complex milling process of CFRP/AL2024 is developed. This model takes into account the dynamic effect, material damage law and contact criteria. Also the 3D Model developed in virtual machining would give an optimal solution of the tool path generation with the help of simulation. Simulation and modelling of cutting processes have the potential for optimizing machining parameters and improving the cutting tool designs, especially in advanced high-speed milling.

1.3 Objectives

The overall aim of the Final Year Project (FYP) is to study and develop a methodology for simulating the machining process of CFRP/Al 2024 using a milling machine. The aim can be resolved into the following specific objectives:-

• To develop 3D Finite Element Model (FEM) for milling process using 3D Finite Element Analysis (FEA) with ABAQUS/EXPLICIT software.

• To simulate machining tool path, under the selected cutting conditions (speed, feed rate and depth of cut) using the VERICUT software.

1.4 Scope of Work

3D Finite Element Models

(FEMs)

Orthogonal Cutting

Milling Process Simulation

Tool Path

Actual Machining

Simulation/Analysis Using Engineering Simulation Software

N

o

t Me

an

t

CFRP/AL2024 Materials

Figure 1.0: Scope of works (SOW)

Figure 1.0 shows the Scope of Works (SOW) in this Final Year Project (FYP). The scopes of the project are mainly focused on studying about analysis and simulation in the milling process of CFRP/Al2024. In this project, an informative simulation study with a more realistic 3D Finite Element Models (FEMs) as well as an orthogonal cutting model has been developed to simulate the complex milling process of CFRP/AL2024 using the engineering simulation software.

This project also develops the 3D Model in virtual reality machining that to give an optimal solution of the tool path generation with considering speed, feed rates, and depth of cut with the help of simulation. The data from the observation and compilation will be used in simulation, applications of machining for verification. It will then help to analyze more conditions affecting the machinability of CFRP/AL2024. These studies are not meant for actual machining.

1.5 Chapters Organization

This dissertation consists of five chapters which is covered on PSM 1 and PSM 2. The report includes of introduction, literature review, methodology, result and conclusion. The first chapter introduces the background of the project, problem statement, objectives, scopes of the project and the report structure for overview the whole chapters in the report. Then follow by literature review on Chapter 2 which more on the research about the related project and review on the previous research work in composite machining, machining simulation and analysis using engineering simulation software. Chapter 3 focuses on the project planning as well as the methodology used during completing this project to ensure this project is successfully completed on the specified time period. This chapter explains about the flow of process planning, equipment and software application will be conducted. Chapter 4 describes the result and discussion of this project from the simulation and analysis process that has traversed. This project report ends with the conclusion of Chapter 5. Conclusions are made based on the result of simulation and analysis that have been conducted. Finally, suggestion and recommendation for the future work also included in this final chapter to improve this project.

The purpose of this chapter is to provide a general overview of past and current research work and placing the FYP project in wider context of simulation. All relevant information related to this project is refined and structurally present in this chapter. This literature review is vital to help in generating ideas to complete the tasks and project. The section of this report will review on previous research work on composite machining, composite materials, and machining simulation using engineering simulation software. Towards the end of this chapter, a summary of the literature is presented.

2.1 Background

Machining operations of composite materials which especially carbon fibre is extensively used in the aerospace industry in order to create smoothness on the desired surface and make a prototype part from a big blank or set of materials. Machining of the materials is very common and easily performed (Klinkova et al., 2011; R. Rusinek et al., 2011). However, the machining of the composite has proved to be more challenging. Machining of the composite material parts generates discontinuity in the fibre and thus affect the performance of the part, the temperature during the cutting process must be considered where it should not exceed the cure temperature or close to the melting temperature of the resin to avoid material disintegration. During machining process the smaller values of feed rate are much better as far as the tool life is concerned (W. N. F. Mohamad et al., 2013; Alwarsamy et al., 2012).

LITERATURE REVIEW

CHAPTER2

Adversely, this causes the process consuming more time and are very expensive. Machining also exposed the fibre to chemical and moisture and the effect of coolant materials on composites. The machining of composite materials required for dry machining process without using any coolant, or cutting fluid (W. N. F. Mohamad et al., 2013). This is due to the composite materials will expand if using the coolant or any cutting fluid during machining. The mechanical damage will occur faster when the workpiece that manufactured with composites are exposed to moisture and elevated temperature. The presence of water modifies the properties of the matrix and affected the mechanical properties such as strength, stiffness and creep (Rahman et al., 1999). Furthermore, there are several advantages by using dry cutting it will reduce the cost of machining (Premnath et al., 2012).

In the field of cutting process research, the Finite Element Method (FEM) is regarded as a ve1y useful tool to study the cutting process of materials. Many finite element models have been developed, including orthogonal cutting model, oblique cutting model, and 3D FEM. The orthogonal FEM has been more used to investigate the cutting mechanism. Simoneau et al., (2006) studied chip formation of medium carbon steel using 1hc orthogonal cutting model. Jin and Altintas, (2012) predicted micro-milling forces with the orthogonal model.

According to Mohammadpour et al., (2010) investigated the effect of machining parameters on residual stresses in orthogonal cutting. Molinari et al., (2011) studied the link between local variables and global contact characteristics in orthogonal cutting using the finite element method. Shams and Mashayekhi, (2012) established a nonlocal damage model to improve the orthogonal cutting simulation. Deng et al., (2009) used an orthogonal FEM to investigate burr formation. Zhang et al., (2012) investigated the cutting process of Ti6A14V based on crystal plasticity theory and discrete cohesive elements. Afazov et al., (2010) predicted micro-milling, cutting forces through the orthogonal cutting FEM.