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Getting Started with Composites Testing

Getting Started with Composites Testing. Audio Information U.S . or Canada: 866-692-3582 UK: 0808-238-6019 Malta: 800-986-993 Participant pass code: 2274496. Agenda. Brief introduction of Instron Testing challenges in composites Focus on:

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Getting Started with Composites Testing

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  1. Getting Started with Composites Testing Audio Information U.S. or Canada: 866-692-3582 UK: 0808-238-6019 Malta: 800-986-993 Participant pass code: 2274496

  2. Agenda • Brief introduction of Instron • Testing challenges in composites • Focus on: • Alignment (Lorenzo Majno) • Strain Gages (Dick McManuis) • Software for composites testing (Parasar Kodati) • Composites module • Soft keys to pause, reset, reverse • Live displays

  3. Products & Services Electro-mechanical IndustrialProducts Static Hydraulic Hardness Wilson Services Repair, Calibration CEAST Plastics Dynamic Servohydraulic Electrodynamic

  4. Destructive Testing Oct 2005 HyperG Nov 2008 April 2007 Sept 2007 Test and Measurement Oct 2006 Non-destructive Testing Sept 2008 Jan 2008* July 2008 Feb 2007 December 2010 QSA GloBAL May 2008 Mar 2008 Feb 2007 $10 million Nov 2006 Weighing Solutions Food Safety / Inspection Dec 2008

  5. Composites!

  6. Technologies For Testing Composites • Technologies: • Electromechanical • Servohydraulic • Electrodynamic • Drop Weight Impact • Pendulum Impact • Rheological • Hardness • …more! • Properties: • Tensile • Shear • Flexure • Fatigue • Fracture/Delamination • Impact • Rheological • …ply direction… • …temperature… • …humidity…

  7. The “Ideal Coupon Tester”

  8. Coupon Tester “Challenges” ALIGNMENT & NADCAP CHANGING LOAD STRINGS SHIELDS AUTOMATED SPECIMEN HANDLING GRIPS (Coupons) “MANUAL CONTROL” ENVIRONMENTAL CHAMBERS EXTENSOMETRYClip-ons, AVE, DIC SOFTWARE METHODS FOR COMPOSITES STRAIN GAGESConditioning, Integration With BH FIXTURES, All Kinds CHAMBER MTG & ADJUSTMENT DEBRIS MANAGEMENTSealed Base, Debris Removal

  9. Today’s focus Alignment and NADCAP Software Features for Composites Strain gage setup

  10. Alignment Why should I care and what should I do?

  11. Why is Alignment so Important for Composites Testing? Ductile Metal Test • Misalignment introduces uneven stress distribution • Metal yields in high stress region but continue to carry load • Stress redistributes reducing the effect of misalignment on test results

  12. Why is Alignment so Important for Composites Testing? FiberComposite Test Misalignment introduces uneven stress distribution Fibers in high stress region fail Stress in remaining fibres increases causing rapid failure.

  13. Results of poor alignment: • Lower results • Peak performance = uniform stress • Inconsistent results • Scatter, variability, etc. • Modulus, max stress, … • Less desirable material in the marketplace • Lower revenues/profits for your company • Competitive disadvantage • Possible lost business

  14. Therefore… • Careful attention to alignment is good practice • Certain industries mandate proper alignment • Aerospace – NADCAP • AC7101 (General): • 10% (ductile = >5% strain to failure), • 8% (non-ductile = <5% strain to failure), • 5% (cyclic) • AC7122 (Composites): • 8% (all)

  15. OK so what do I need to do? Achieving superior alignment (minimal bending) involves: • The ability to measure it. • The ability to do something about it.

  16. Measuring Misalignment MAKE YOUROWNGaged specimen • Strain gaged “cell” • Match specimen (shape/stiffness) • Appropriate # of gages BUY ONEInstron “cell” HIRE ONEInstronAlignment Service • Signal Conditioning &Data Collection • Multi-channel • Software/Analysis • Calculate Bending %

  17. Adjusting Alignment • The old way: • Measure • Shim • Repeat/Trial & error • Now: • Alignment fixture • Fits between the cell and the crosshead • Adjust while under load • Real time bending %

  18. Adjusting Alignment: “AlignPro” • Align-Pro fixtures: • small adjustments of loadcell position (no shims) • X-Y and angular • optimize alignment between upper and lower grip • Servohydraulic or Electromechanical load frames • …with the load string under load (in real time)

  19. AlignPRO - System • Consists of: • Align-Pro Fixture • Strain gauged “cell” • Strain gauge conditioning • Software Note both round and flat strain gauged alignment specimens are acceptable – flat types are generally used for composites as they have the same form as the test specimens.

  20. Rules of thumb for meeting NADCAP • AlignPro Not needed: • NEW EM Floor Model with Ambient Hydraulic Wedge Grips* • Round Button Head/threaded metal sample with swivel couplings • AlignPro Required: • Any other EM system • Any Servohydraulic system • Mechanical Grips • Caution…

  21. Also: The Specimen In The Grips • Ensure proper front-back position(stops) • Ensure proper vertical placement(visual) • Enough gripping pressure not to slip, but not excessive

  22. Strain Gages

  23. Strain Gages • Measure bending and calculate elastic modulus (required by industry standards) • Measure Poisson’s ratio • Local strains at key locations on a component

  24. Strain Gages - Standards ASTM D3039 - Tensile Properties of Polymer Matrix Composite Materials • Gages on opposite sides at center of gage length • Bending check at 2000 µє • Bending less than 3 – 5 % • Recommend 350 ohm, 6 mm gages

  25. Strain Gages - Standards ASTM D3410 - Compressive Properties of Polymer Matrix Composite Materials with Unsupported Gage Section by Shear Loading • Gages on opposite sides at center of GL • Bending check at 2000 µє • Bending less than 10 % • Recommend 350 ohm, 1.5 - 3 mm gages

  26. Strain Gages - Standards ISO 527-4 and 527-5- Compressive Properties of Polymer Matrix Composite Materials with Unsupported Gage Section by Shear Loading • Gages on opposite sides at center of GL • 2 spaced near edges,1 centered • Bending check at 1500 µє • Bending less than 3 % • Recommend 350 ohm, 1.5 - 3 mm gages

  27. Working Principle Alignment Marks Resistance Grid Solder Tabs

  28. Wheatstone Bridge Measured signal Excitation voltage

  29. Simple Bridge Completion • Strain gage connection terminals • Bridge completion resistors • Shunt Calibration resistor

  30. Advanced Signal Conditioners • Adjustable excitation • Shunt Calibration • Amplification

  31. Strain Gage setup in Bluehill3

  32. Bluehill Software Demo

  33. Thank you Getting Started with Composites Testing • lorenzo_majno@instron.com • richard_mcmanuis@instron.com • parasar_kodati@instron.com

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