?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.relation=http%3A%2F%2Fmiis.maths.ox.ac.uk%2Fmiis%2F108%2F&rft.title=Shimmy+in+aircraft+landing+gear&rft.creator=Barton%2C+David&rft.creator=Wood%2C+David&rft.subject=Aerospace+and+defence&rft.description=Shimmy+is+an+oscillation+in+aircraft+landing+gear+that+can+occur+both+on+landing+and+take-off%2C+typically+in+a+band+of+velocities.+It+causes+excessive+wear+on+components+and+can+cause+accidents.+The+nose+wheel+is+roughly+like+a+caster+on+a+shopping+trolley%3A+the+horizontal+axle+of+the+wheel+is+mounted+in+an+assembly+that+is+free+to+rotate+about+a+vertical+axis.+Shimmy+is+(or+at+least+includes)+oscillation+of+the+wheel+assembly+about+this+vertical+axis.+The+current+engineering+approach+has+little+understanding+of+the+physical+mechanisms+causing+shimmy%2C+but+relies+on+the+use+of+shimmy+dampers%2C+and+on+systematic+maintenance+and+replacement+of+landing+gear+components.+Simulations+are+carried+out+with+finite+element+models+and+multi-body+systems%2C+and+there+are+theoretical+models+due+to+St%C3%A9p%C3%A1n+and+Somieski.+In+fact+shimmy+can+also+involve+lateral+oscillation+of+the+landing+gear+(as+well+as+torsional)+and+can+be+coupled+to+and+caused+by+flutter+of+the+airframe.+The+phenomenon+is+multi-scale+in+nature%2C+as+it+can+be+linked+to+normal+mechanical+wear+of+key+components+at+one+scale%2C+and+gross+flexibility+effects+at+the+vehicle+scale.+Airbus+wish+to+identify+it+earlier+in+order+to+address+passenger+comfort%2C+pilot+comfort%2C+manage+mechanical+wear+and+avoid+overfatiguing+the+system+elements.+Specifically%2C+Airbus+wish+to+identify+key+system+elements+that+may+cause+shimmy%2C+when+given+a+particular+configuration+of+an+aircraft.+At+early+stages+of+development+the+configuration+may+involve+the+shape+and+size+of+the+fuselage+and+design+of+the+landing+gear%2C+whilst+at+the+other+end+of+the+development+process%2C+the+configuration+may+also+consist+of+detailed+system+elements+such+as+actuators%2C+etc.+Airbus+relies+on+systematic+maintenance+and+replacement+of+landing+gear+components%2C+thereby+avoiding+the+occurrences+of+the+abovementioned+phenomena.&rft.date=2007-04-17&rft.type=Study+Group+Report&rft.type=NonPeerReviewed&rft.format=application%2Fpdf&rft.language=en&rft.identifier=http%3A%2F%2Fmiis.maths.ox.ac.uk%2Fmiis%2F108%2F1%2FAirbus-ShimmyReport.pdf&rft.identifier=++Barton%2C+David+and+Wood%2C+David++(2007)+Shimmy+in+aircraft+landing+gear.++%5BStudy+Group+Report%5D+++++