Realistic simulation using FEA tools to design and optimize plastics
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The document discusses using finite element analysis (FEA) tools to realistically simulate plastics to design and optimize plastic parts. It covers modeling challenges with plastics, simulating thermo-mechanical response, durability, design optimization, and case studies applying FEA to problems like impact analysis, fatigue life prediction, blow molding, and thickness optimization. The goal is to use realistic simulation to increase design robustness, decrease costs, and provide the best starting point for advanced plastic designs.
Realistic simulation using FEA tools to design and optimize plastics
- 1. REALISTIC SIMULATION USING FEA TOOLS TO DESIGN AND OPTIMIZE PLASTICS Arindam Chakraborty, PhD, PE Partner, Virtual Integrated Analytics Solutions (VIAS) Houston, TX www.viascorp.com May 10, 2017
- 2. Agenda © 2017 Virtual Integrated Analytics Solutions Inc. • VIAS Overview • Realistic Simulation • FEA of Plastics • Durability of Plastics • Design Optimization • Simulation for Additive Manufacturing • Case Studies • Concluding Remarks 2
- 3. WHO WE ARE
- 4. VIAS Overview Engineering Consultancy Training Hardware Software © 2017 Virtual Integrated Analytics Solutions Inc. • Multiple Industry Experience • Presence in Houston (Main Office), Chicago, Cincinnati, Detroit, San Francisco, • Team consists of Ph.D. and Masters in Solid Mechanics, Fluid Mechanics, Materials and Corrosion, Numerical Analysis, Statistics; Optimization and Reliability • Solution partner of Dassault Systèmes SIMULIA products – Abaqus, Isight, fe-safe, Tosca • Provide Virtual Design Experience through Collaboration and Data Analytics – Provides Automation and Customization • Provide 3D Printing and AM Simulation Services 4
- 5. Our Technical Capabilities © 2017 Virtual Integrated Analytics Solutions Inc. Design by Analysis and Validation using Simulation FEA based Fracture / Damage Mechanics Optimization and Reliability Multi-physics Simulations (CFD, Thermal Analysis) Composites and Elastomer Modelling Delamination, De- bonding and Crack Propagation S-N and e-N based Fatigue Analysis Simulation Automation / Plugin In Environment Testing and Test Program Support Additive Manufacturing Simulation 5
- 7. What is Realistic Simulation? © 2017 Virtual Integrated Analytics Solutions Inc. 7 • “Realistic Simulation” is a simulation that is physically realistic and “life like” in every way • Enables engineers to create life like models that will behave similarly to the real part / product. • Typically, start with simple models and increase the complexity, model size and the physics as confidence in simulation results increase their • Enables building up expertise and most importantly find value in the simulation
- 8. Why Realistic Simulation? © 2017 Virtual Integrated Analytics Solutions Inc. 8 • Designers often create innovative concepts, but retreat to conventional shapes due to limited time and resources for physical prototyping and testing • Simulation enables designers to virtually test new innovative concepts ▪ Reduces design time and the expensive cost of physical testing ▪ Lowers material cost and improves sustainability by light-weighting ▪ Reduces damage cost during production and transport by eliminating bad designs quickly Courtesy Mechanical Design and Analysis Corporation, 2010 SCC
- 10. Challenges in Modelling Plastics and Polymers © 2017 Virtual Integrated Analytics Solutions Inc. 10 • Polymeric materials are complex in their mechanical behavior • Exhibit large strain, anisotropic and irreversible response which is often accompanied by stable localized necking behavior • Modelling failure and fracture a challenge • Simulation software/ models must deal with severe non-linearities Blow Molding (Plastic Bottle) Necking (ASTM D638 Hyperelastic) Viscoelastic Rubber Seal Insertion Fracture/ Delamination Viscous Paste
- 11. FEA for Thermo-Mechanical Response of Plastics © 2017 Virtual Integrated Analytics Solutions Inc. 11 • Initial FEA simulation codes were largely developed for heavy duty components and were concerned predominantly with metals • Plastics/ Polymers have much higher strains and large displacements in comparison to metallic materials • Modern FE codes accommodate large strain formulations, including hyperelasticity, viscoelasticity • Non-linear codes (Abaqus) perform better since they are designed to accommodate large deformations • Physically Motivated Models - material response from a viewpoint of the microstructure • Phenomenological Models - material response from the viewpoint of continuum mechanics
- 12. Necking in Polymer – Strain Rate Effect © 2017 Virtual Integrated Analytics Solutions Inc. 12 Necking: Testing vs Simulation (ASTM D638 Specimen) Necking: Strain Rate Dependence
- 13. FEA of Plastic Fabrication © 2017 Virtual Integrated Analytics Solutions Inc. 13 • Plastic part fabrication generally entails the process of injection molding • The main aim for the injection molding process is to maintain uniform wall thickness of the component • A non-uniform thickness during the process causes ▪ Sink marks within the component ▪ Residual stresses due to uneven shrinkage ▪ Warping of component ▪ Voids within components • FEA gives us an opportunity to preemptively predict, visualize and minimize these effects
- 15. © 2017 Virtual Integrated Analytics Solutions Inc. Solution Paradigm 11 22 12 033 11 22 12 033 Fatigue Life Prediction Given the material properties and strain history of a rubber component, compute the number of cycle repeats that will be endured before the fatigue process produces cracks of a given size Crack Driving Force Crackgrowth rate StrainHistory NominalStrain Time 11 22 12 Material Properties Nonrelaxing Option Quantify Strain Crystallization, Min and Mean Strain Effects Thermal Option Quantify dissipative properties, thermal properties, temperature dependence Hyperelastic Option Simple, Planar, and Equibiaxial tension, Mullins Effect
- 16. OPTIMIZATION
- 17. Design Optimization © 2017 Virtual Integrated Analytics Solutions Inc. 19 • Process Integration and Design Optimization • Integrate Disparate Simulation Tools without programming • Automate Simulation Process Flows
- 18. POLYMER AM
- 19. Simulation for Evolving Technologies: Polymer AM © 2017 Virtual Integrated Analytics Solutions Inc. 22 Part level simulation with support structures Tool Path information from slicer (GrabCad) Warping Effects – Mobius Arm Material Orientations during layup Abaqus Thermal Model vs Thermal Imaging Data
- 20. Multi-scale Infill Homogenization: Polymer Extrusion Methods © 2017 Virtual Integrated Analytics Solutions Inc. 23 Geometric Infill's Multi-scale material homogenization using RVE Method Representative Volume Elements (RVEs)
- 21. CASE STUDIES
- 22. Case Study: Impact Analysis (Handgun Slider) © 2017 Virtual Integrated Analytics Solutions Inc. 26 Preliminary Prototype Test Prototype Simulation 0 5000 10000 0 10 20 30 Stress(psi) Strain (%) Material Stress-Strain Data (Test) Polycarbonate (Higher Strain Rate) Polycarbonate (Lower Strain Rate) Softer Polymer (Low Strain Rate) Polymer Metal Cage (For Stiffness)
- 23. Case Study: Plastic Bottle Drop © 2017 Virtual Integrated Analytics Solutions Inc. 28
- 24. Case Study: Residual Stress © 2017 Virtual Integrated Analytics Solutions Inc. 29 • Residual stresses may be introduced into plastic parts produced by the injection molding process ▪ As a result, the part may warp or experience a reduction in strength ▪ The design of an injection molded product can be improved if the effect of residual stresses on the final shape and performance of the product are predicted accurately • Abaqus and Moldflow can be used for this purpose
- 25. Case Study: Fatigue Life of Polyurethane © 2017 Virtual Integrated Analytics Solutions Inc. 30 Fixed Step 1: Fit piston and rubber seal inside liner Step 2: Apply Pressure Translation of piston and urethane seal inside liner using reference point of rigid body Rigid body with center point at the axis as reference Pressure = 5000 psi Number of cycles for Pressure Load = 120 cycles /min Temperature: 170 F
- 26. Case Study: Fatigue Life of Polyurethane © 2017 Virtual Integrated Analytics Solutions Inc. 31 Determine the stress field from FEA model in the rubber seal within the mud pump piston under application of cyclic operating pressure
- 27. Case Study: Fatigue Life of Polyurethane © 2017 Virtual Integrated Analytics Solutions Inc. 32 • The lowest fatigue cycles in the seal is 2.7E+06 cycles. • Region with lowest fatigue cycles matches with the failure location of the actual sample
- 28. Case Study: Collapse under Pressure © 2017 Virtual Integrated Analytics Solutions Inc. 33 Optimize device wall thickness for specified collapsing pressures 0 200 400 600 800 1000 1200 1400 1600 1800 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8 8.5 9 9.5 10 10.5 11 11.5 Stress(psi) Strain(in/in) Stress-Strain Curve for Floelle Device and Silicone PenroseTube MED-4810 MED-4815 MED-4050 (Silicone Penrose Tube) Hyperelastic material using Marlow strain energy potential model
- 29. Case Study: Blow Moulding - Plastic Bottle © 2017 Virtual Integrated Analytics Solutions Inc. 34 • Challenge ▪ Check if a new bottle design can be manufactured ▪ Expensive prototype cost to validate a new bottle design • Simulation ▪ Incorporate the geometry of new bottle design and physical phenomena involved in the Blow Molding process • Value ▪ Quickly eliminate bad designs and drastically reduce cost of prototyping and testing ▪ Capture realistic thickness distribution of package after blow molding ▪ Optimize preform shape to produce a desired final thickness distribution
- 30. Case Study: Thickness Optimization © 2017 Virtual Integrated Analytics Solutions Inc. 35 • Top Load (TL) thickness optimization • Vary thickness smoothly along bottle height ▪ Use 5 thickness values as optimization parameters • Constraints – minimum TL force > 100 N • Optimization target – minimize mass 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 0 50 100 150 200 250 Target Thickness STH • Mass: 43% reduction • Meets target Top Loading Force
- 32. Highlights for Simulating Plastics © 2017 Virtual Integrated Analytics Solutions Inc. 37 • Simulation can – Capture complex material response (hyperelastic, elastic-viscoplastic, …) – Include large deformation, dynamic response – Provide tools to optimize design, perform reliability study – Automate the analysis workflow – Perform fatigue and fracture assessment for rubbers
- 33. Plugins, Plugins, Plugins © 2017 Virtual Integrated Analytics Solutions Inc. 38
- 34. Summary © 2017 Virtual Integrated Analytics Solutions Inc. 39 • In summary, simulation that mimics realistic scenarios helps by – Increasing design robustness and confidence in product quality – Decrease in development costs and improvement in product performances – Providing a best possible starting point for futuristic and more advanced designs – Functional design and optimization
- 35. © 2017 Virtual Integrated Analytics Solutions Inc. Thank you 40