Aere 423 Project Composite Kneepads

Aere 423 Project Composite KneepadsHabirah Mohd RosliGertude ProfioFall 08Iowa State UniversityIntroductionComposite protectors used as safety gear for motorcyclistFocus on the rider kneesBuild and test the protectors resistance impact

ManufacturingFiber orientation doesnt matter(0o and 90o)Impact testing The mold based on shape and size of manufactured child kneepadUsed 6 plies of carbon fiberDifferent materials to cover the moldRelease filmWaxRelease spray

ManufacturingHoles on the mold filled in by epoxyCured at room temperature as plastic mold might be damaged in autoclave

Intended TestingBased on national standard for cycle safety gear, the speed of impact test range between 13-23ft/sVertical impactImpact for 200lb personAdult kneepads expensive

Testing

Testing was done at CNDE using impact machine

Due to equipment limitationspeed desired cannot be achieved (max 23ft/s)

2 sets of testing Sample attached with epoxySample attached with tape

Both composite and plastic kneepad were tested

p/s: mention that we put aluminum as the base 6Testing

We created fixtures out of wood to secure the kneepads on the machine.We set an aluminum plate under the wood to keep the wood from being broken during the test.Impact tester-46.5 inch drop-Failure test: 32.5 lb load-Impact test: 8.4 lb load

Different types of kneepadSampleMaterialKneepad attached to the woodWood attached to aluminum plateLoad lb1Carbon fiberEpoxyTape32.52PlasticEpoxyTape32.53PlasticTapeTape8.44Carbon fiberTapeTape8.45PlasticTapeNo Tape8.4resultscarbon fiber, epoxy, 32.5lbPlastic, epoxy, 32.5lbPlastic, tape, 8.4lbCarbon fiber, tape, 8.4lbPlastic, no tape, 8.4lbKneepadPeak Load (lb)Deflection at peak load (in)Impact velocity (ft/s)13314.751.3115.2123877.931.3615.332135.91.2515.164557.040.6815.2652921.391.2915.21Results Overview

Note: 1 and 2 carbon fiber;tape;32lb 3 and 5 plastic; 8.4lb 4 carbon fiber; 8.4lb 5 no tape; 8.4lb

Force ComparisonPeak Contact Force (kN)Damage7.3Split fracture of patella8.9Split femoral condolytesKneepadPeak Contact Force (kN)39.5 kN42.5 kN513 kN

DiscussionsThe used of tape doesnt affect the impact testing results.Deflection is low for carbon fiber kneepad.Impact velocity is between the range of recommended testing (~15ft/s)

Future WORKTest the samples with different loadsIncrease the number of plies of carbon fiber for making an adult kneepad mold and test it.

Questions?