Modeling and Simulation for Aircraft Structural Repair Using Modern FEA Tools

Transcription

1 Modeling and Simulation for Aircraft Structural Repair Using Modern FEA Tools December 19-22, 2011 and January 9-12, 2012 Kuang-Hua Chang, Ph.D. Williams Presidential Professor School of Aerospace and Mechanical Engineering The University of Oklahoma Norman, OK, USA Course Outline Slide 1

2 Course Outline Introduction to finite element analysis (FEA) and SolidWorks Simulation Focus on the basics in FEA and SolidWorks Simulation Special topics relevant to practice and aircraft repair Bolts (rivets), welding, laminated composite, fatigue (and fracture), and model translation Course format Four days, 8 hours per day 16 lessons, 4 lessons per day, roughly 2 hours per lesson At least one hour hands-on per lesson Course Outline Slide 2

3 Important Focus Learn not only how to use the FEA tool, but how to use the tool correctly Learn how to check and verify results Avoid pitfalls a few typical examples Check and double check before presenting results to others Course pace will be adjusted in accordance with the technical background of the participants Objective: be able to use SolidWorks Simulation to model and solve general structural problems with confidence Course Outline Slide 3

4 Course Plan Day 1 Day 1 Lesson Contents Examples Morning 1. Introduction Course introduction and Overview SolidWorks Simulation Overview of SolidWorks Review of an existing model Simulation SolidWorks Simulation Help and tutorial models Units systems 2. A Quick Tutorial Cantilever Beam Example 3. Introduction to FEA 4. Mesh Refinement and Solutions Convergence Stress calculations Model generation, material definition, load and boundary conditions Analysis Result display and animation, report generation, graphs Comparison with analytical solution Introduction to finite element analysis Basic concept and formulation Using FEA tools Applications: reverse engineering, design and manufacturing, Biomechanics Study Mesh refinement: global and local refinement h-refinement vs. p-refinement Mesh refinement and solution convergence h-adaptive mesh Course Outline Slide 4

5 Course Plan Day 2 Day 2 Lesson Contents Examples Morning 5. Finite Hinge and symmetric boundary Element conditions Modeling Small vs. large deformation Sharp angle: singular problem (pitfall) 6. Model Idealization for Frame Structures 7. Model Idealization for Thin Shells 8. Assembly and Mixed Mesh Converting frame structures to beam or truss models Beam orientation and stress calculations Fixtures and loads Stress results Beam vs. truss Converting solid to shell model (for applications, such as aircraft skin panels) Thickness and offset Stress calculation for shell Fixtures and loads Stress results Simplifying assemblies for FEA Global vs. local contact Interface Mix solid with shell elements (pitfall) Rigid link Stress jump Course Outline Slide 5

6 Course Plan Day 3 Day 3 Lesson Contents Examples Morning 9. Model Importing parts Translation and IGES and STEP Feature FeatureWorks, automatic and interactive Recognition Importing assemblies 10. Connectors: Pin and Bolts 11. Connectors: Welding 12. Composite Materials Defining connectors between initially contacting faces, including rigid, pin, and bolt Listing forces encountered in the connectors Checking FOS Checking FEA results using analytical solutions Defining welding between initially contacting faces, including edge weld and spot weld Listing forces encountered in the welding Checking FOS Checking FEA results using analytical solutions General concept of composite materials Finite element modeling for composite structures Stress analysis for composite shells Verification examples Course Outline Slide 6

7 Course Plan Day 4 Day 4 Lesson Contents Examples Morning 13. Failure Analysis of a Composite Joint Defining hollow cylinders as composite shells, and adjusting composite orientation option Checking laminate stacking direction and viewing stress Using composite failure criterion to view factor of safety plot Altering composite layup to improve factor of safety 14. Fatigue Fatigue failure theories for crack initiation High cycle fatigue and low cycle fatigue S-N curve, cyclic load and endurance limits Mean and alternating stresses Cumulative damage Low cycle fatigue: strain-life approach Plastic strain correction Cycle counting and fatigue damage 15. Crack Propagation and Fracture 16. Wrap up and Advanced Courses Fracture mechanics Stress intensity factor and crack propagation Fracture toughness Crack propagation FEA and XFEA Bridging scale analysis Review and wrap up lessons Advanced FEA FEA for crack propagation FEA for metal forming Reverse engineering CNC programming and machining Y Z X Course Outline Slide 7