LAPPEENRANTA UNIVERSITY OF TECHNOLOGY LUT School of Energy Systems LUT Mechanical Engineering Yang Gao RESEARCH ON PROPERTIES AND DESIGN METHODS OF CUSHION PACKAGING MATERIALS FOR CONSUMER ELECTRONICS Examiners: Professor Kaj Backfolk D.Sc. Katriina Mielonen ABSTRACT Lappeenranta University of Technology LUT School of Energy Systems LUT Mechanical Engineering Yang Gao Research on Properties and Design Methods of Cushion Packaging Materials for Consumer Electronics Master’s thesis 2018 126 pages, 81 figures, 14 table Examiners: Professor Kaj Backfolk Ph.D. Katriina Mielonen Keywords: Packaging Material, Cushion Structure, Nonlinear, Simulation, Transport package is very important in the logistic. The main tasks of transport package are to select proper cushioning material and obtaining reasonable structure. For the consumer electronics packaging, EPS is the cushioning material used widely nowadays. But it cannot degrade and recycle, so lots of new cushioning materials appear. To use these new types of materials widely, it needs to do a lot of researches. This paper mainly discussed the property of the new cushioning materials and its design methods by simulation analysis and experimentation. Thus the cushion design methods of transport package are suggested. The paper, firstly, studied the property of new cushioning materials through dynamic test, discussed the novel way to determine the cushioning curves. Then, the paper studied the dynamic response of the nonlinear materials to judge performance of nonlinear packaging and utilized the software of finite element analysis to simulate packaging drop response. Finally, the design methods of the cushion packaging are suggested. ACKNOWLEDGEMENTS This master thesis was carried out in Lappeenranta University of Technology, Finland. This work was lasting for long time due to my working reason, but finally I finished it. Firstly, I want to express my highest respect to my supervisor, Professor Kaj Backfolk and Ph.D. Katriina Mielonen for giving me suggestions and encouragement to do my own research. They gave me valuable advice by rich experience. These suggestions opened my mind and helped me a lot. I appreciate Professor Haiyan Song from Tianjin University of Science & Technology for providing the equipment for the dropping experiments and her assistants who help me to finish the experiments. I also appreciate the help from Professor Huapeng Wu, Dr. Xinxin Yu, Mr. Changyang Li, Mr. Xin Wang, Miss Xinwa Wang and Miss Dan Fu as well. They gave me strong power to face all the difficulties. Fully love and many thanks to my parents and friends, without their supports, the thesis cannot be completed. Yang Gao Lappeenranta 22.05.2018 4 TABLE OF CONTENTS ABSTRACT ACKNOWLEDGEMENTS TABLE OF CONTENTS LIST OF SYMBOLS AND ABBREVIATIONS 1. Instruction...........................................................................................................................9 1.1. Overview of consumer electronics..........................................................................9 1.2. Overview of consumer electronics packaging.......................................................10 1.3. Distribution environment...................................................................................... 13 1.4. Cushioning materials for consumer electronics packaging...................................14 1.4.1. Common cushioning materials...................................................................15 1.4.2. Comparison of cushion materials in properties..........................................19 1.5. Valuable theory..................................................................................................... 20 1.5.1. Fragility theory...........................................................................................20 1.5.2. Damage boundary theory........................................................................... 23 1.6. Main work and research content........................................................................... 25 2. Study on properties of cushioning packaging materials...................................................28 2.1. Cushioning properties of materials........................................................................28 2.2. Study on Cushioning Properties............................................................................29 2.2.1. Testing principle of dynamic cushioning property of materials.................31 2.2.2. Performance comparisons of common cushioning materials.....................33 2.3. Research on determination method of cushion characteristic curve..................... 37 2.3.1. Relationship between material cushioning characteristic curve.................37 2.3.2. Determination method of material cushioning characteristic curve...........38 2.4. Conclusion.............................................................................................................42 3. Study on impact theory of nonlinear cushioning packaging............................................ 43 3.1. Basic mechanical properties of cushion materials................................................ 43 5 3.1.1. Elasticity.....................................................................................................43 3.1.2. Plasticity..................................................................................................... 48 3.1.3. Viscosity.....................................................................................................49 3.1.4. Creep.......................................................................................................... 51 3.2. Drop impact response analysis of nonlinear package........................................... 52 3.2.1. Dynamic model of package........................................................................52 3.2.2. Mathematical model of liner pressure deformation................................... 53 3.2.3. Integral solution of product response acceleration time equation..............55 3.3. Design rationality evaluation of nonlinear cushioning package........................... 63 3.4. Conclusions........................................................................................................... 64 4. Study on simulation method of cushioning packaging.................................................... 65 4.1. Scheme design of simulation for buffer packaging...............................................66 4.1.1. Standard introduction of dropping test.......................................................66 4.1.2. Program development of numerical simulation of cushioning packaging.67 4.2. Establishment of LCD (liquid crystal display) package model.............................69 4.2.1. LCD package prototype..............................................................................70 4.2.2. Establishment of geometry model..............................................................71 4.3. Material parameter setting.....................................................................................74 4.4. Model checking and editing.................................................................................. 78 4.5. Contact setting of each part of package.................................................................78 4.5.1. Main contact theory and contact type.........................................................78 4.5.2. Contact setting of package drop simulation............................................... 80 Package mesh partition.................................................................................................83 4.5.3. Mesh partition type.....................................................................................83 4.5.4. Mesh partition of LCD package model...................................................... 85 4.6. Boundary condition settings and solving.............................................................. 87 4.6.1. Drop simulation result and analysis of LCD package................................88 4.6.2. Bottom drop simulation results.................................................................. 90 6 4.6.3. Simulation results of short side drop..........................................................91 4.6.4. Simulation results of long side drop...........................................................92 4.6.5. Simulation results of edge drop..................................................................95 5. Experimental Study.......................................................................................................... 98 5.1. Test on dynamic cushioning performance of materials.........................................98 5.1.1. Dynamic buffer performance testing system..............................................98 5.1.2. Test objects and steps...............................................................................100 5.1.3. Test results and analysis...........................................................................102 5.2. Drop test of transport package.............................................................................104 5.2.1. Summary of drop impact test................................................................... 104 5.2.2. Test equipment......................................................................................... 105 5.2.3. Steps of the test.........................................................................................106 5.2.4. Analysis of test results..............................................................................107