1. Characterization of Carbon Fiber and Glass Fiber Fabrics by Drape Fixture By: Aaron Holmberg

2. Scope of Project The following parameters must be determined through experimentation  Force needed to deform fabric in shear related to the fabric’s characteristics  Locking Angle: The angle at which the shear force increases rapidly and the fabric begins to wrinkle related to the fabric’s characteristics Determining these characteristics will help in predicting the drapability / formability of these fabrics which is useful knowledge when determining manufacturability of curved components with a particular fabric

3. Fixture Design A fixture was designed to help determine the lock angle and force vs. fiber angle of fabrics  Fabric is clamped between two ridged steel plates  A rubber gasket was used between the plates to distribute clamping force evenly along the fabrics edge  Universal ball transfer unit (not pictured) were attached to the side of the bottom clamp to reduce friction on the glass guides (shown in green) during shearing test.  Dowel pins were install on the bottom clamp for alignment and tensile fiber attachment point.

4. Fixture Design The back was cut out to allow for convective heat transfer during tested performed in the oven The simple design allowed most of the fixture to be build at Sicomp

5. Installation of Fabric Tip fixture on its side Lay spacers into place

6. Installation of Fabric Lay fabric blank and tensile fiber into place with a sheet of glass on top of fabric to eliminate fabric wrinkles Clamp jaws are set in place and tightened while holding the bottom clamp edge against the spacer

7. Installation of Fabric Flip fixture upright Remove spacers Set guide in place

8. Experiments Various fabrics were cut into 200mm x 210mm pieces After installing the fabric sample, an incremental increase of tension was applied by adding weights to a receptacle attached to the tensile fiber The lower jaw displacement was measured by hand after each incremental increase in tension

9. Fabrics Tested Five different fabrics were loaded into the fixture.  Devold AMT - glass fiber 90 o  Sigmatex - carbon fiber 90 o Light 0 o glass fiber weave  CS-Interglass 0 o -90 o small tight weave  Sparas till VAC - carbon fiber 0 o -90 o heavy weave  No Label - carbon fiber 0 o -90 o light loose weave Additional information on these fabrics can be found in the table at the end of this Power Point presentation

10. Results Devold AMT - glass fiber 90 o  Very stiff during loading  Instantaneous wrinkling  No load data taken because of wrinkling

11. Results Sigmatex - carbon fiber 90 o light 0 o glass fiber weave  Little resistance to shear  No locking angle found  No wrinkling experience at higher angles  Fiber compression at higher angles created fabric thickening without wrinkles of the fabric  Louver fiber formations were observed in the fabric near the clamps

12. Results Photo of Louvers observed during experiment Fibers would rotate out of plane only near the clamping surfaces

13. Results No Label - carbon fiber 0 o -90 o light loose weave  First fabric tested  Load was incrementally applied and displacement measured Tensile fiber was 317mm long at 0mm displacement which created large variations in tensile angle (angle of tensile fiber relative to horizontal) as displacement was increased due to a fixed pivot point Tensile angle was compensated for in calculations found in Excel file Future experiments were performed with a longer tensile fiber (1.920m) do decrease angle variation  Experimental results were inconclusive due to inaccuracy of measuring by hand and variation in tensile angle

14. Results CS-Interglass 0 o -90 o small tight weave  The only fabric tested with a significant historysis Historysis could be related to a combination of relatively greater friction between GF compared to CF and / or the tighter weave constricting sliding motion between fibers  Load incrementally applied and displacement measured  Locking angle determined to increase with greater tension on fabric as shear is applied It is assumed low angle wrinkles are related to the friction between fibers overcoming tension applied by the weight of the lower clamp jaw Additional downward force applied to the lower clamp jaw by hand allowed greater angles to be reached before fabric wrinkled

15. Results With 7.9 Newtons of downward force due to the weight of the lower clamp jaw a locking angle of 9 degrees was found When additional downward force was applied by hand to the lower clamp jaw a locking angle of 16 degrees was found  The locking angle is defined as the point just before wrinkles are observed

16. Results Sparas till VAC - carbon fiber 0 o -90 o heavy weave  Binder was removed from this fabric by placing it in an oven at 400 C for two hours  Shear force was incrementally increase and displacement measured  Wrinkles were observed at approximately 50 degrees

17. Results 0-90 Heavy Carbon Fiber – Tensile Force vs. Fabric Angle Note: Tensile angle is not compensated for in the graph below

18. Additional Equipment Desired More accurate data could be gathered using the following equipment in parallel with the drape fixture  Variable speed linear actuator with 200mm of travel and 20 N of force  20 N load cell  Linear displacement transducer Hand measurements proved to be extremely inaccurate

19. Conclusion Additional testing will be needed before good fabric characterization results can be gathered  Fixture was proven to have potential in testing 0-90 woven fabrics.  Variation of lock angle results relative to fabric tension may be a concern in future experiments  Compensation for tensile angle resulted in questionable calculation results hens why it was excluded from the graph  Uncertainty may be associated with louvers observed near clamp surfaces. Additional testing may be needed to determine its effects.

20. DescriptionsInformation 90 deg. Glass fiber Devold AMT Batch # 7523 Roll # 10 Width 127 cm 90 deg. Carbon Fibers (Sigmatex) Product DV3461270 Roll # 006731 / 001 280 GSM / PW-BUD / HTS 5631 12K (Aero) / 1270mm 0-90 tight weave glass fiber CS - interglas Style 7781 Finish FK (600) Piece # 6009998 SAP - no 554370 Code 6100457 0-90 Loose weave carbon fiber No label Width 42 cm Location - top shelf 0-90 Heavey carbon fiber Sparas till VAC for forms forsolr 070508 / AH Slangs Okt. - 07