UNIVERSITI PUTRA MALAYSIA FINITE ELEMENT ANALYSIS AND OPTIMIZATION OF CLOSED DIE FORGING PROCESS FOR ALUMINIUM METAL MATRIX COMPOSITES - PDF

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UNIVERSITI PUTRA MALAYSIA FINITE ELEMENT ANALYSIS AND OPTIMIZATION OF CLOSED DIE FORGING PROCESS FOR ALUMINIUM METAL MATRIX COMPOSITES MOHAMED A. ABDULMAWLLA ITMA FINITE ELEMENT ANALYSIS AND OPTIMIZATION
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UNIVERSITI PUTRA MALAYSIA FINITE ELEMENT ANALYSIS AND OPTIMIZATION OF CLOSED DIE FORGING PROCESS FOR ALUMINIUM METAL MATRIX COMPOSITES MOHAMED A. ABDULMAWLLA ITMA FINITE ELEMENT ANALYSIS AND OPTIMIZATION OF CLOSED DIE FORGING PROCESS FOR ALUMINIUM METAL MATRIX COMPOSITES By MOHAMED A. ABDULMAWLLA Thesis Submitted to the School of Graduate Studies,, in Fulfilment of the Requirements for the Degree of Doctor of Philosophy October 2010 DEDICATION ii ABSTRACT Abstract of thesis presented to the Senate of in fulfilment of the requirement for the degree of Doctor of Philosophy FINITE ELEMENT ANALYSIS AND OPTIMIZATION OF CLOSED DIE FORGING PROCESS FOR ALUMINIUM METAL MATRIX COMPOSITES By MOHAMED A. ABDULMAWLLA October 2010 Chair: Faculty: Professor Shamsuddin bin Sulaiman, PhD Institute of Advanced Technology The demand for lighter and stiffer products has been increasing in the last few years especially in automobile and aerospace manufacturing. The closed die forging process of aluminium metal matrix composite (Al-MMC) material is presented as possible solution, because it produces parts with good mechanical properties and lighter weight. The computational modelling of closed die forging process, using finite element method and optimization techniques, makes the design optimization faster and more efficient, decreasing the use of conventional trial and error methods. In this work, a commercial finite element software, ANSYS has been used to model cold closed die forging process. The model is developed using ANSYS Parametric Design Language (APDL) to simulate a single stage axi-symmetry closed die forging process for H-cross sectional shape. Axisymmetric forgings with rib-web represent about 50% of the total forging output. So that the H-cross sectional shape used in this study has a wide applications. iii Simple compression test was carried out for aluminium alloy 6061 in order to determine its flow curve. Closed die forging experiment was conducted using aluminium alloy 6061 and then the experiment was simulated in order to verify the model for large deformation. The simulation results showed similar output with the experimental one. As a result, the model can be confidently used to simulate closed die forging for particulate reinforced Al-MMC. The Al-MMC material considered is AlMgSi matrix with 15%vol SiC particles, its flow curve and fractural strain are obtained from the literature. ANSYS Optimizer is used to obtain the maximum height that the material can flow in the rib by changing the design variables (DV) and the state variables (SV). Generally, design variables are geometrical parameters such as rib height to width ratio, web height to rib height ratio, fillet radii, draft angle and billet radius. State variables (SV) are some parameters that depend on the design variables such as the equivalent strain which must be below the fracture strain of the aluminium metal composite (AMC) material, and an acceptable contact gap (within the allowable tolerance range). The objective of this work is to achieve through simulation, the optimal die shape and billet diameter in consideration of complete die filling and the influence of metal flow deformation of Aluminium Metal Matrix Composite in a single stage closed die forging process. A commercially available finite element package (ANSYS) was used to investigate the effect of different die shapes and billet diameters on the closed die forging deformation. Optimization method called Sub-Problem Approximation Method was used to find out the optimal design set. iv The maximum rib height obtained in the single stage cold closed die forging of H- cross sectional shape disc made of AlMgSi matrix with 15%vol SiC particles is of the disc radius. Trying to get higher rib height lead to higher strain and cracks will occur in the fillet region. The rib width and the web height are and 0.3 of the disc radius simultaneously. Optimal billet height is 0.99 of the disc radius. The billet radius is a function of the die cavity volume and the billet height. The technique used in this work can be used for newly developed materials to investigate its forgeability for more complicated shapes in closed die forging process. v ABSTRAK Abstrak projek yang dikemukakan kepada Senat universiti Putra Malaysia sebagai memenuhi keperluan untuk ijazah Doktor Falsafah FINITE ELEMENT ANALYSIS AND OPTIMIZATION OF CLOSED DIE FORGING PROCESS FOR ALUMINIUM METAL MATRIX COMPOSITES By MOHAMED A. ABDULMAWLLA Oktober 2010 Penyelia: Professor Shamsuddin bin Sulaiman, PhD Fakulti: Institut Teknologi Maju Permintaan terhadap produk yang ringan dan kaku semakin meningkat dalam beberapa tahun terakhir terutama sekali dalam bidang pembuatan kereta dan aeroangkasa. Proses penempaan acuan tertutup bagi bahan logam aluminium matrik komposit (Al-MMC) dibentangkan sebagai penyelesaian mungkin, kerana menghasilkan bahagian dengan sifat mekanikal yang baik dan lebih ringan. Pemodelan pengkomputeran bagi proses penempaan acuan tertutup, dengan menggunakan kaedah unsur sehingga dan teknik pengoptimuman, membuat reka bentuk pengoptimuman yang lebih cepat dan cekap, mengurangkan penggunaan konvensional kaedah cuba dan jaya . Di dalam kajian ini, perisian unsur hingga komersil - ANSYS - telah digunakan untuk model penempaan sejuk acuan tertutup. Model ini telah dikembangkan dengan menggunakan Reka Bentuk Bahasa Parametrik ANSYS (APDL) untuk mensimulasikan tahap tunggal axi-simetri proses penempaan acuan tertutup untuk vi bentuk bahagian silang (H). Tempa axissymmetric dengan rusuk web mewakili sekitar 50% dari jumlah output keseluruhan penempaan. Jadi, bentuk H-bahagian silang yang digunakan di dalam kajian ini mempunyai penggunaan aplikasi yang meluas. Ujian mampatan yang ringkas telah dilakukan untuk aluminium aloi 6061 bagi mengetahui keluk alirannya. Eksperimen penempaan acuan tertutup telah dilakukan dengan menggunakan aluminium aloi 6061 dan eksperimen telah disimulasikan untuk mengesahkan model yang mempunyai kecacatan yang besar. Keputusan simulasi menunjukkan output yang sama dengan yang keputusan daripada eksperimen Sebagai hasilnya, model ini boleh digunakan untuk mensimulasikan penempaan acuan tertutup untuk Al-MMC bahan penguat. Bahan Al_MMC yang digunakan adalah AlMgSi matrik dengan 15% isi padu zarah SiC, keluk alirannya dan terikan patah yang diperolehi daripada bacaan. Pengoptimal ANSYS digunakan untuk mendapatkan ketinggian maksimum bagi bahan supaya dapat mengalir di rusuk dengan merubah pembolehubah rekabentuk (VD) dan pembolehubah tetap (SV). Umumnya, reka bentuk pembolehubah dan geometrik parameter seperti; nisbah ketinggian rusuk kepada lebar, nisbah tinggi web kepada tinggi rusuk, radius filet, sudut draf dan radius bilet. Pembolehubah tetap (SV) adalah sebahagian parameter yang bergantung kepada reka bentuk pembolehubah seperti; terikan yang seimbang yang harus di bawah terikan patah bahan AMC, dan jurang jarak yang boleh diterima (di dalam toleransi yang dibenarkan). vii Objektif daripada kajian ini adalah untuk mencapai bentuk acuan dan diameter bilet yang optimum di dalam pertimbangan penuh pengisian acuan dan juga pengaruh kecacatan aliran besi dari Besi Aluminium Matrik Komposit dalam proses penempaan acuan tertutup tunggal. Pakej unsur hingga komersial yang boleh didapati (ANSYS) digunakan untuk menyiasat kesan kecacatan penempaan acuan tertutup terhadap bentuk acuan dan diameter bilet. Kaedah optimasi yang disebut Kaedah Sub-Masalah Aproksimasi telah digunakan untuk mengetahui set reka bentuk yang optimum. Ketinggian rusuk maksimum diperolehi pada peringkat tunggal penempaan acuan tertutup cakera berbentuk keratan rentas-h yang diperbuat daripada matriks AlMgSi dengan 15% isipadu butiran SiC adalah dari bahagian radius terakhir ditempa. Percubaan untuk mendapat ketinggian rusuk yang lebih tinggi menyebabkan regangan yang lebih tinggi dan rekahan akan terjadi di kawasan-kawasan filet. Lebar rusuk dan tinggi web adalah dan 0.3 dari bahagian radius terakhir ditempa secara serentak. Ketinggian bilet secara optimum adalah 0.99 dari bahagian radius terakhir ditempa. Radius bilet adalah berkadaran kepada isi pada acuan berongga dan ketinggian bilet. Teknik -teknik yang digunakan dalam kajian ini boleh digunakan untuk bahan yang baru dibangunkan untuk menyiasat kemampuan menempa untuk bentuk yang lebih rumit dalam proses penempaan acuan tertutup viii ACKNOWLEDGEMENTS In the Name of Allah, Most Gracious, Most Merciful, all praise and thanks are due to Allah, and peace and blessings be upon His Messenger. I would like to express the most sincere appreciation to those who made this work possible: Advisory members, Family and Friends. I would like to thank Professor Shamsuddin Bin Sulaiman for providing me the opportunity to complete my PhD studies under his valuable guidance, for the many useful advice and discussions, for his constant encouragement and guidance, and for co-authoring and reviewing some of my publications, where his practical experience and technical knowledge made this research and those publications more interesting and relevant. In addition, special thanks extend to the supervisory committee member; Dr. M. K. A. Ariffin, Dr. Faieza Abdul Aziz and Dr. B.T. Hang Tuah Bin Baharudin. I am grateful for their willingness to serve on my supervisory committee, constant encouragement, helpful advice and many fruitful discussions. I am grateful to my beloved country Libya and the Engineering Academy, Tajoura for offering me the scholarship for pursuing the Ph. D. degree at Universiti Putra Malaysia. Thanks and acknowledgements are meaningless if not extended to my parents, wife and kids who deserve my deepest appreciation. I am grateful for the countless sacrifices they made to ensure that I could pursue my dreams and for always being ix there for me. Real and deepest thanks to them. All praise and words of thanks said to them will not be enough. Last but not least, very special thanks to my brothers, and sisters for their support and true love. Their love, support and encouragement are behind my success. x APPROVAL SHEETS I certify that an Examination Committee has met on 22/10/2010 to conduct the final examination of Mohamed A. Abdulmawlla on his PhD thesis entitled Finite Element Analysis and Optimization of Closed Die Forging Process of Al- MMC in accordance with Unversiti Pertanian Malaysia (HIGHER Degree) Act 1980 and Universiti Pertanian Malaysia (High Degree) Regulation The committee recommends that the candidate be awarded the relevant degree. Members of the Examination Committee are as follows: Mohd Sapuan Salit, PhD Professor Faculty of Engineering (Chairman) Datin Napsiah Ismail, PhD Associate Professor Faculty of Engineering (Internal Examiner) Tang Sai Hong, PhD Associate Professor Faculty of Engineering (Internal Examiner) Saleem Hashmi, PhD Professor Mechanical and Manufacturing Engineering Dublin City University (External Examiner) Bujang Kim Huat, PhD Professor/ Deputy Dean School of Graduate Studies Date: 22/10/2010 xi This thesis was submitted to the Senate of and has been accepted as fulfilment of the requirement for the degree of Doctor of Philosophy. The members of the supervisory committee were as follows: Shamsuddin bin Sulaiman, PhD Professor Faculty of Engineering (Chairman) Mohd Khairol Anuar Mohd Ariffin, PhD Lecturer Faculty of Engineering (Member) Faieza Abdul Aziz, PhD Lecturer Faculty of Engineering (Member) B.T. Hang Tuah bin Baharudin, PhD Lecturer Faculty of Engineering (Member) HASANAH MOHD GHAZALI, PhD Professor and Dean School of Graduate Studies Date: xii DECLARATION I declare that the thesis is my original work except for quotations and citations, which have been duly acknowledged. I also declare that it has not been previously, and is not concurrently, submitted for any other degree at or other institutions. MOHAMED A. ABDULMAWLLA Date: 22 October 2010 xiii TABLE OF CONTENTS DEDICATION ABSTRACT ABSTRAK ACKNOWLEDGEMENTS APPROVAL SHEETS DECLARATION LIST OF TABLES LIST OF FIGURES LIST OF ABBREVIATIONS & SYMBOLS Page ii iii vi ix xi xiii xvii xviii xxi CHAPTER 1 INTRODUCTION Importance of the Study Problem Definition and Scope of the Work Objective Thesis Layout 11 2 LITERATURE REVIEW Introduction Classification of Forging Operation Open Die Forging Closed Die Forging Material for Forging Forces and Energy Requirement Friction and Lubrication Selection of Die Material Die Design Factors Methods of Analysis Slab Method Slip Line Analysis 22 xiv 2.8.3 Upper Bound Technique Finite Element Method Finite Element Analysis of Metal Forming History of Finite Element Method Finite Element Method and Optimization Finite Element Method of Analysis Basics for Finite Element Formulation Finite Element Procedure Finite Element Package (ANSYS) Metal Matrix Composites Forming Discontinuous Reinforced Al-MMC Optimization Process Optimization Variables Optimization in Conjunction with FEM Optimization methods Summary 68 3 RESEARCH METHODOLOGY Introduction Assumptions used in simulation Billet and Die Cavity Shape selection Building the Model Using APDL Finite Element Software (ANSYS) ANSYS General Steps in Solving any Problem: ANSYS Optimization Module Experimental validation Compression Test Closed Die Experiment 87 4 FINITE ELEMENT FLOW SIMULATION AND OPTIMIZATION OF CLOSED DIE FORGING PROCESS Introduction Building ANSYS FE Model 93 xv 4.3 The Optimization Module ANSYS Optimization Module Summary RESULTS AND DISCUSSION Introduction Finite Element Results Load Displacement Curve Stress-Strain Distribution in the billet Optimization Results Problems encountered and solution attempts Volume Loss in FE Simulation Calculating the Billet Volume each Optimization Iteration Placing the Testing Samples Optimization Results Verification CONCLUSION Thesis Contribution Recommendations for Future Work 129 REFERENCES 131 APPENDICES 140 APPENDIX A: APDL File (Analysis file and optimization module) 140 APPENDIX B: Detail Drawings of Die inserts and Die Assembly 145 APPENDIX C: Paper A: Closed Die Forging Geometrical Optimization for Al- MMC 148 APPENDIX D: Paper B: Billet Shape Optimization For Minimum Forging Load154 APPENDIX E: Paper C: Optimization of Plate Forming Process Parameters 162 BIO DATA OF STUDENT 167 LIST OF PUBLICATIONS 168 xvi
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