Composite Panels & Adhesives. Composite Panels Panels are fiberglass on both sides with a core in...
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Transcript of Composite Panels & Adhesives. Composite Panels Panels are fiberglass on both sides with a core in...
Composite Panels& Adhesives
Composite Panels
• Panels are fiberglass on both sides with a core in the middle consisting of either foam or a honeycomb structure
Fiberglass Core: Foam or Aramid
Core Options
Material Density
Compresive Strength
Tensile strength
Shear Sength
Shear Modulus
Cost
units (lb/ft^3) psi psi psi psi ($/ft^3)
Cirrus - HT 61 4.1 145 261 131 2900 4.96
Evonik 51 A - PMI Foam 3.248 131 276 116 2760 -
Ultracor UCF-83-1/4-3.0 3 246 27 223 61000
Aramid Core .25 In. Thick 1.8 109 - 52/62 (L/W)1579/2882
(L/W)7.95
Aramid Core .125 In. Thick 1.8 109 - 52/62 (L/W)1579/2882
(L/W)4.95
Final Core Material
• HT Diab 61- Wing Skins
• Ability to lay up curves of Airfoils
• Cheapest that met criteria of foams
• Aramid Core- Spar, Aft Spar, Rib
• Light Weight
• Cheapest per Pound
Adhesive Options• DP 420
– 3M, Two Part Epoxy » From 3M Epoxy Comparison
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
Adhesive Options (Cont.)
• PTM & W: – ES6292 Lightweight Tough Epoxy Adhesive
• Two Part Epoxy
• Designed for use in the structural assemblies involving composites
• Already used by Cirrus Design Center
Adhesive Testing
• Objectives:– Test Max Adhesive Loads
• Need to make sure adhesives aren’t effected by surfaces
– Test surface preparation techniques
Adhesive Testing (Cont.)
• Materials Tested:– Adhesives:
• PTM & W ES6292
• 3M DP 420
– Composites:• Aramid Core with Fiberglass Skin
• HT Diab Foam Core with Tencate Fiberglass
Adhesive Testing (Cont.)
• Tensile Test:– Load Bonds in Tension– Measure Load at Fracture– Calculate Lbs/In. Bond Strength
• Test Equipment:– Constant Strain Load Cell– Measures Load and displacement
Adhesive Testing (Cont.)
Adhesive Testing (Cont.)
• Tensile Load Justification:– Jaws:
• 2° freedom on both directions– Top & Bottom
• All samples were applied within 1 degree of perpendicular
• Therefore: Tension loads were perpendicular to bond
Adhesive Testing (Cont.)
• Surface Preparation:– All surfaces were lightly sanded to rough up
surface
– All surfaces were cleaned with to remove
Adhesive Testing (Cont.)
• Results:– Bond Strength per Inch of Bond (Lbs/In)
• PTM & W ES6292= 81.7 ± 4.1 Lbs/In
• 3M DP 420=87.1 ± 4.4 Lbs/In
» Uncertainty Estimated at 5%
Adhesive Testing (Cont.)
• Conclusions:– Adhesives were comparable in
Strength per Inch
– Both Adhesives meet strength requirements for wing
– PTM & W ES6292 Adhesive is better because of lower cost
Adhesive Testing (Cont.)
• Errors:– Improper preparation:
• Issue: Samples broke at surface
• Resolution: Better Surface Preparation– Sanding (possibly Sand Blasting)
– Better Removal of oils from surface
• Effect:– Bonds Broke Prematurely– With Better Preparation Bonds could hold more Weight
Adhesive Testing (Cont.)
– Test Equipment:• Issue: Jaws Slipping• Resolution: Better Transition from Material to Jaw
– Adhere Aluminum Tab into Composite– External Clamp System with Aluminum Tab for Jaw
» Allow Material to be secured by clamp and Jaw to attach to Aluminum Tab
• Effect:– Load might be underestimated. – Result: Bond Strength could be higher than reported
Adhesive Testing (Cont.)
• Further Testing:– Shear Test Side View:
Composite A
Composite B
Adhesive Testing (Cont.)
– Shear Test Top View:(Load Pulling out from picture)
Composite A
Composite B
Bond
Adhesive Testing (Cont.)
• Shear Test:
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
Epoxy Safety Precautions
• Effects of Overexposure:– Eyes: Causes severe conjunctive irritation,
Corneal injury and Iritis– Skin: May cause irritation, burns, ulceration, or
skin sensitization– Inhalation: Vapors are irritating and cause tears,
burning of nose and throat, coughing, wheezing nausea and vomiting
Epoxy Safety Precautions (Cont)
– Ingestion: Moderately toxic, may cause mouth and throat burns, abdominal pain, weakness, thirst and coma.
– Chronic: Amine vapors may cause liver and kidney injury. Eye, skin or lung may develop or be irritated by Amine vapors.
[From MSDS of ES6292B with Beads]
Epoxy Handling Precautions
• Respiratory: – Not required unless process is creating dust,
mist or vapor.
• Ventilation: – Breathing of vapor must be avoided.
• Hand Protection:– Impervious gloves, neoprene or rubber, must be
worn
Epoxy Handling Precautions(Cont.)
• Eye Protection:– Splash proof Goggles or safety glasses
• Other:– Clean body covering clothing and shoes
[From MSDS of ES6292B with Beads]
Aramid Core Handling Requirements
• Ventilation required when machining produces dust, mist or vapor
• Light Hand Cotton gloves for General Protection
[From Aramid Core MSDS]