Composite skid landing gear design investigation

Composite Skid Landing Gear

Shrotri, Kshitij ; Aerospace Engineering

University:Georgia Institute of Technology

Department:Aerospace Engineering

关键词: Composite Skid Landing Gear;   

Others  :  https://smartech.gatech.edu/bitstream/1853/24763/1/Shrotri_Kshitij_N_200808_PhD.pdf

美国|英语

来源: SMARTech Repository

【 摘 要 】

A composite skid landing gear design investigation has been conducted. LimitDrop Test as per Federal Aviation Regulations (FAR) Part 27.725 and Crash testas per MIL STD 1290A (AV) were simulated using ABAQUS to evaluate performance ofmultiple composite fiber-matrix systems. Load factor developed during multiplelanding scenarios and energy dissipated during crash were computed. Strength andstiffness based constraints were imposed. Tsai-Wu and LaRC04 physics basedfailure criteria were used for limit loads. Hashin s damage initiation criteriawith Davila-Camanho s energy based damage evolution law were used for crash.Initial results indicate that an all single-composite skid landing gear maynot be feasible due to strength concerns in the cross member bends.Hybridization of multiple composites with elasto-plastic aluminum 7075 showedproof of strength under limit loads. Laminate tailoring for load factoroptimization under limit loads was done by parameterization of a single variablefiber orientation angle for multiple laminate families. Tsai-Wu failurecriterion was used to impose strength constraints. A quasi-isotropic N = 4(pi/4) 48 ply IM7/8552 laminate was shown to be the optimal solution with a loadfactor under level landing condition equaling 4.17g s. LaRC04 predicts thatfailures will be initiated as matrix cracking under compression and fiberkinking under in-plane shear and longitudinal compression.All failures under limit loads being reported in the metal-composite hybridjoint, the joint was simulated by adhesive bonding and filament winding,separately. Simply adhesive bonding the metal and composite regions does notmeet strength requirements. Filament wound bolted metal-composite joint showsproof of strength. Filament wound composite bolted to metal cross member radiiis the final joining methodology. Finally, crash analysis was conducted as per requirements from MIL STD 1290A(AV). Crash at 42 ft/sec with 1 design gross weight (DGW) lift was simulatedusing ABAQUS. Plastic and friction energy dissipation in the reference aluminumskid landing gear were compared with plastic, friction and damage energydissipation in the hybrid metal-composite design. Damage in composites wasmodeled as progressive damage with Hashin s damage initiation criteria andDavila-Camanho s energy based damage evolution law. The latter meetsrequirements of aircraft kinetic energy dissipation up to 20 ft/sec (67.6 kJ) asper MIL STD 1290A (AV). Weight saving possibility of up to 49% over conventionalmetal skid landing gear is reported. The final design recommended includes Ke49/PEEK skids, 48 ply IM7/8552 crossmember tapered beams and, Al 7075 cross member bend radii bolted to the filamentwound composite tapered beam. Concerns in composite skid landing gear designs,testing requirements and future opportunities are addressed.