Presentation on theme: "LANDING GEAR SHOCK ABSORBER DESIGN"— Presentation transcript:
1LANDING GEAR SHOCK ABSORBER DESIGN CONCORDIA UNIVERSITYMECH 7501, SUMMER 2009Presented to :Professor DR. S.V. HOAPresented by :Maruf Khondker (L) ID :A.K.M Lutful kabir ID :Amen Younes ID :Md Shelimuzzaman ID :Shafiul Islam ID :
2OUTLINES Introduction Configuration Design and Analysis Finite Element Analysis (FEA)Material Selection and ManufacturingWeight Estimation and Comparison.Conclusion.45 Second Video
3INTRODUCTIONLanding gear is a critical part & has significant effect on aircraft performance.The basic function is to support aircraft, absorb & dissipate impact kinetic energy.Early build airplanes conventionally used metal skids as landing gear .It is able to supports the airplane weight but is not able to absorb the landing shock.Oleo Pneumatic shock absorber is selected for high efficiency as they can absorb & remove vertical kinetic energy simultaneously.Composites are being increasingly used due to weight saving ,reduction in fabrication cost, specific stiffness & strength properties.
4Small size civilian air craft Aircraft ChoosingBeech craft Model 99.Small size civilian air craftCrewOneCapacity15 passengersLength44 ft 6¾ in (13.58 m)Wingspan45 ft 10½ in (13.98 m)Height14 ft 4⅓ in (4.37 m)Empty weight5,533 Ib (2,515 kg)Loaded weight10,400 IbMax takeoff weight11,300 Ib (4,727 kg)Power plantPratt & Whitney PT6A-20, -27
5Hawker 850 XP Luxurious & Mid-size airplane Aircraft ChoosingHawker 850 XP.Hawker 850 XP Luxurious & Mid-size airplaneCrewTwoCapacity8 to 15 passengersLength51 ft 2 in (15.60 m)Wingspan54 ft 4 in (16.56 m)Height18 ft 1 in (5.51 m)Empty weight15,670 Ib (7,108 kg)Max Landing weight23,350 Ib (10,591 kg)Max takeoff weight28,000 Ib (12,701 kg)Power plantHoneywell TFE731 – 5BR
6Shock Absorber dimension calculations Shock absorber choosing.Type: Oleo-pneumatic shock absorberReason:High efficiency.absorb and remove vertical kinetic energy simultaneously.
7Shock Absorber dimension calculations Landing gear Load distribution
15STRESS ANALYSIS AND LAMINATE DESIGN Summary of Analysis
16MATERIAL SELECTIONDifferent material has different properties. That are needed for various applications require the material should be chosen according to the choice of a given application.Depending on a selection of a material, the design, processing, cost, quality and performance of the product changeMaterial selection is important to redesign an existing product for better performance, lower cost, increased reliability, decreased weight, etc
17MATERIAL SELECTIONMaterial should be selected such that it can store the greatest elastic potential energy per unit volume without failure .Component SpecificationShock resistance of landingResist the vibrations during the flightThermal requirements: -60°C<T<60 °CWithstand water, humiditySurface has to resist the impact during the landingSmooth surface
18MATERIAL SELECTION Reinforcement system Carbon fibers (UHM) high strength and stiffness (E = 500 GPa)tolerance to high temperatures and corrosionlow weightexpensiveGlass fiber ( R glass)High strengthMedium stiffness (86 GPa)Corrosion resistanceFatigue resistanceLow cost w.r.t carbon fiberMatrix systemEpoxy:good mechanical properties (E = 4.5 GPa)humidity resistanceadhere very well to reinforcement fibers
19COMMON MATERIAL USED IN LANDING GEAR Aircraft materials are of high specific strength, and corrosion-resistant alloysSteel : provides low volume (as size is important) and high strength, can be made corrosion resistant. But the disadvantage is the weight of the steel. Most common landing gear steels are 4130, 4340, 4330V and 300M.Aluminum alloys are lighter weight in combination with high specific strength . But this alloy is very prone to stress concentration T736 are being used in the landing gear for its better strength and stress-corrosion immunity.titanium alloys , light weight and reduced corrosion susceptibility. Example Boeing’s 777 are using main gear structures that are mainly forged from the titanium alloy Ti-10V-2Fe-3Al from the mid-1990s.Magnesium was used previously for the landing gear wheels, but now it is discarded due to the fire hazard and susceptibility to corrosion.
20MATERIAL APPLICATIONS IN LANDING GEAR SteelBogies,pistons,braces,links,switch brakets, plug, axle, shaft, spring, plate, clamp, sleeve, arm(tube), pin, bushing,Aluminumarm, collar, shimm, wheel, adapter assemblyTitaniumMain landing gear structureMagnesiumNo use right now due to fire hazardAluminum BronzeExtremely used for upper and lower shock strut bearingsBerylliumBrake heat sink material and bushing materialComposite materialAircraft wheels, main landing gear parts including outer cylinder, pistons, side braces, torque arms, trailing arms, springs, wing panels, stabilizers and control surfaces
26Bonding Length Calculated 37 mm Considered in Design 40 mm BONDING LENGTH CALCULATIONConsider : 3000 N-mBonding Length Calculated 37 mmConsidered in Design 40 mm
27MANUFACTURING PROCESS We selected the Fiber placement technology for manufacture of the cylindrical part of the landing gear. The fiber placement technology allows the fiber placement at any angle in conformance with the local load conditions.Parts like drag brace, torque links are made by Resin Transfer moulding because it can be done at moderate pressure consequently reduces the cost.
32Max Hoop Stress 949 Mpa ≈ Rupture = FAIL FINITE ELEMENT ANALYSIS 3 ( METAL only – PISTON MADE OF FULL METAL )Pressure 7000 PSI (20.48 MPA)Max Hoop Stress 949 MPaMax Hoop Stress Mpa ≈ Rupture = FAILMax Displacement mm
33Max Hoop Stress 307 Mpa << Rupture = OK FINITE ELEMENT ANALYSIS 4 ( METAL only – PISTON MADE OF FULL METAL )Pressure 3000 PSI (20.64 MPA)Max Hoop Stress Mpa << Rupture = OKMax Displacement mm
34SUMMARY OF FINITE ELEMENT ANALYSIS MaterialWall Thickness (mm)Pressure (Psi)Max Hoop Stress (Mpa)Rupture (Mpa)Max Displacement (mm)Metal Liner13000108510002.25Composite + Metal598625000.247700023010.576Metal Only3070.104
35WEIGHT REDUCTION CYLINDER (Steel + Composite) 42.75 % MANUAL CALCULATIONCONSIDER FULLY METALKgMETAL LINERKgCOMPOSITE3.949 KgCOMPOSITEKg% of weight reduction = ( – )/ =42.75 %CALCULATION USING CATIABottom Torque Link (Steel + Composite)Upper Torque Link (Steel + Composite)40 %47 %57 %
36CONCLUSION ADVANTAGES: LESS WIGHT. CORROSIVE RESISTANCE. NO RUST . DISADVANTAGEHIGH COST.LOW PRODUCTION RATE.DEFLECTION HIGHER THAN METAL.