Union College Mechanical Engineering Investigation of the State of Strain at the Nodal Intersections of Thermoplastic Isogrids using Speckle Image Photogrammetry R.B. Bucinell Union College Mechanical Engineering Schenectady, NY, USA Session 10: Applications of Optical Techniques 30 January 2003 Châlons en Champague CompTest 2003

Agenda Grids Isogrids Advantages of Thermoplastics Prototype Isogrid Project Manufacturing Experimental Evaluation Results and Conclusions 30 January 2003 Châlons en Champague CompTest 2003

Advantages of Grid Structures Highly Efficient Damage Tolerant Redistribution around damage Take Advantage of the Anisotropy of Composites Potential in Composites for Fabrication Automation 30 January 2003 Châlons en Champague CompTest 2003

Grid Types Quadri-Directional Tri-Directional Orthogrid Anglegrid 30 January 2003 Châlons en Champague CompTest 2003

History of Isogrids British Vickers Wellington Bomber McDonnell Douglas (1960) Payload Fairings, Edwards AFB (mid 80s) Aerospace Applications 30 January 2003 Châlons en Champague CompTest 2003

Thermoplastics Provide Significant Advantages In Situ Processing Effective Repair Recycling 30 January 2003 Châlons en Champague CompTest 2003

Prototype Study Manufacture Isogrid Test Analogs Optimization of Isogrid Configuration Manufacturing Automation 30 January 2003 Châlons en Champague CompTest 2003

Isogrid Mold 30 January 2003 Châlons en Champague CompTest 2003

Isogrid Lay-Up Pattern 30 January 2003 Châlons en Champague CompTest 2003

Experimental Evaluation Compare Composites to Aluminum and Steel Develop Understanding of Impact of Lay-Up Pattern Experimental Methods 3 Point Bend 30 January 2003 Châlons en Champague CompTest 2003

Prototype Isogrid 30 January 2003 Châlons en Champague CompTest 2003

Speckle Image Photogrammetry 30 January 2003 Châlons en Champague CompTest 2003

Analog Results 30 January 2003 Châlons en Champague CompTest 2003

Performance Summary Flexural Rigidity D=Et3/[12(1-2)] Gl/Ny isogrid ST Al solid St Mass (g) 2000 2391 6712 4336 12078 Slope (MN/m) 5.013 5.538 13.43 7.589 24.59 Mass Ratio 1 1.196 3.356 2.168 6.039 Stiffness Multiplication 1.71 37.5 10.2 220 Flexural Rigidity D=Et3/[12(1-2)] 30 January 2003 Châlons en Champague CompTest 2003

Full Field Results 30 January 2003 Châlons en Champague CompTest 2003

Grid Comparisons 30 January 2003 Châlons en Champague CompTest 2003

Next Steps 30 January 2003 Châlons en Champague CompTest 2003

Summary Thermoplastic Isogrids have Unique capabilities Composite Isogrid Outperforms Al and Steel Isogrid Speckle Image Photogrammetry verifies effectiveness of node strategy Future Work Includes Analysis and Manufacturing Automation 30 January 2003 Châlons en Champague CompTest 2003

Acknowledgements and QUESTIONS? Students Rebecca Terry, Matt Bamford, Paula Denemma, Jenny Moon, Matt Hilbert Orgaizations National Science Foundation Automated Dynamics Corp. NASA 30 January 2003 Châlons en Champague CompTest 2003