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ZONAIR Analysis for JSF Flight Loads
P. C. ChenD. H. LeeD. D. Liu
7430 E. Stetson Drive, Suite 205, Scottsdale, AZ 85251-3540, Tel (480) 945-9988, Fax (480) 945-6588, E-mail: [email protected]
ZPC19/Lockheed/ZONAIR
ZONAIR Analysis for JSF Flight Loads
• A ZONAIR JSF panel model has been generated from the CFD surface mesh provided by LMCO
• JSF NASTRAN model solution was provided by LMCO to give– Generalized mass and stiffness matrices for flexible loads– Grid points for spline
• Two sets of trim analysis were performed– Rigid loads computed by ZONAIR– Rigid loads interpolated from CFD solutions to ZONAIR panels
• NASTRAN static analysis was performed using the NASTRAN FORCE/MOMENT bulk data cards generated by ZONAIR trim analysis
• Sectional loads (shear, bending moment, and torsion) and elastic-to-rigid ratio of CL, CM, etc. were generated.
ZPC19/Lockheed/ZONAIR
ZONAIR Panel Model• ZONAIR panel model is generated as follow
– Creating surface geometry from the JSF CFD surface mesh using PATRAN– Generating CQUAD4 and CTRIA3 applying mapped mesh on the surface geometry
• Panel edge alignment with hinge lines of control surface is modeled• Flow-through boundary condition is specified on the inlet panels
CFD GRID ZONAIR (4314 PANELS)
ZPC19/Lockheed/ZONAIR
Comparison of Cp between ZONAIR and CFD solutions at M=0.9, AoA=0.0 deg.
CFD ZONAIR
ZPC19/Lockheed/ZONAIR
Interpolated Cp on ZONAIR Panels from CFD Solutions at M=0.9, AoA= 0.0 deg.
• The interpolated CFD Cp is used as the rigid loads for flexible load analysis
T
R IK q G AIC G x q F F
Stiffness matrix from NASTRAN
Spline matrix
AIC matrix computed by ZONAIR
Rigid loads
Inertia loads
ZONAIR+CFDCFD
ZPC19/Lockheed/ZONAIR
Generation of SPLINE Matrix• The thin plate spline method (3D spline) is used to generate the spline matrix
• ZONAIR outputs graphical files to allow visual inspection of the accuracy of the spline matrix
Mode 4
Mode 5
Mode 6
NASTRAN Modes Deformed ZONAIR Modes14.254 Hz
15.009 Hz
16.582 Hz
ZPC19/Lockheed/ZONAIR
Flexible-to-Rigid Ratio v.s. Dynamic Pressure at =0.90
CL CM
CLh CMh
ZPC19/Lockheed/ZONAIR
Trim Analysis at M=0.90 and Sea Level
• 9.0 g pull-up is specified as the trim conditions– Two trim equations: Lift=9.0g and moment=0.0– Two trim variables: angle of attack and horizontal tail deflection angle
• Two sets of trim analysis are performed: rigid loads computed by ZONAIR and interpolated from CFD solutions
Rigid load by ZONAIR
=12.673o
=24.988o
=13.771o
=26.182o
Rigid load by CFD
ZPC19/Lockheed/ZONAIR
Sectional Loads of 9g Pull-Up at M=0.90, Sea Level
ZONAIR
ZONAIR + CFD
ZONAIR
ZONAIR + CFD
ZONAIR
ZONAIR + CFD
Sectional Shear Force
Sectional Bending Moment
Sectional Torsional Moment about ¼ Chord
ZPC19/Lockheed/ZONAIR
NASTRAN Static Analysis using ZONAIR Generated Loads
• ZONAIR trim analysis generates loads in terms of NASTRAN FORCE/MOMENT bulk data cards at structural grid points– User can insert the file into the NASTRAN input deck for
subsequent detailed stress analysis
ZPC19/Lockheed/ZONAIR
Ease of Adding Underwing Stores
• Two macroelements can be specified:– CAERO7: thin wing modeling with thickness effects simulated by source
sheet– BODY7: automated panel/grid generation of body of revolution
• Pylons and store fins can be modeled by CAERO7 and store body can be modeled by BODY7
Front View
