SHAPE MORPHING OF FLEXIBLE SURFACES AND ACTUATOR …
Transcript of SHAPE MORPHING OF FLEXIBLE SURFACES AND ACTUATOR …
Technische Universität München
Lehrstuhl für Leichtbau (LLB)Institute of Lightweight Structures
SHAPE MORPHING OF FLEXIBLE SURFACES AND ACTUATOR INTERACTION
Horst Baier, Leri Datashvili
Institute of Lightweight Structures (LLB)Technische Universität München, Germany
Technische Universität München
Lehrstuhl für Leichtbau (LLB)Institute of Lightweight Structures
Membrane and reflector structures
Advanced fiber composites / hybridmat. & structures
Smart Structures Multidisc. design optimization and procedures
Research areas at LLB / TU München
Technische Universität München
Lehrstuhl für Leichtbau (LLB)Institute of Lightweight Structures
„Classical“ adaptive structures: dyn. load alleviation
Technische Universität München
Lehrstuhl für Leichtbau (LLB)Institute of Lightweight Structures
Low speed
High speed
Human eye
Morphing biological systems
Flight systems Optical (RF) Systems
Technische Universität München
Lehrstuhl für Leichtbau (LLB)Institute of Lightweight Structures
high loads and stiffness… and morphing
high shape precision… and morphing
Morphing Aerospace StructuresMassive change in geometry
Technische Universität München
Lehrstuhl für Leichtbau (LLB)Institute of Lightweight Structures
Morphing wing: rereference mission
Technische Universität München
Lehrstuhl für Leichtbau (LLB)Institute of Lightweight Structures
Morph. param. influence on diff. criteria
Technische Universität München
Lehrstuhl für Leichtbau (LLB)Institute of Lightweight Structures
Spoke concept
Skin integrated actuators Pneumatic concept
Wing morphing machanisms
Technische Universität München
Lehrstuhl für Leichtbau (LLB)Institute of Lightweight Structures
Institute for Lightweight Structures LLB
Morphing wing
Morphing actuators Morphing surfaces
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Friswell, Swansea
Technische Universität München
Lehrstuhl für Leichtbau (LLB)Institute of Lightweight Structures
Massively morphing sat reflectors …
... to achieve non-isotropic RF beam radiationin (space) antennas
requires actuators and a morphing surface with• low in-plane and shear stiffness
• moderate bending stiffness
• very low CTE
• good thermal and electr. conductivity
Technische Universität München
Lehrstuhl für Leichtbau (LLB)Institute of Lightweight Structures
Micro-mech. FE model(stiffness, CTE, …)
Simul and test results
Triax C-fibre shell-membrane material (soft silicone matrix): CFRS
Structural and reflector material
• excellent thermo-mechanical properties• good RF properties• moderate - good morphing behavior
Technische Universität München
Lehrstuhl für Leichtbau (LLB)Institute of Lightweight Structures
Triax CFR-matrices with different Young‘s moduli
Mat. properties and level of anistropy depend on specimen size
Technische Universität München
Lehrstuhl für Leichtbau (LLB)Institute of Lightweight Structures
Possible actuator types
Stroke: 20mmForce: 15N
Low mass actuators with high strokes; space compatibility = ?
EAP „bubble“ actuator
Technische Universität München
Lehrstuhl für Leichtbau (LLB)Institute of Lightweight Structures
Actuator – structure interface
Technische Universität München
Lehrstuhl für Leichtbau (LLB)Institute of Lightweight Structures
Lab demonstration model
“Proper” concept also requires ..
…proper actuator length + alignment + smooth load introduction into morphing surface
Refl. membrane
Manually driven actuators in lab model
Actuator i/f toreflect. surface
Technische Universität München
Lehrstuhl für Leichtbau (LLB)Institute of Lightweight Structures
Determination of actuator strokes
… typically 50 – 100 actuators per m2 of reflecting surface
Discretized goal shape generated shape
(step-wise sol. incase of nonlin. behav.)
with uij
displacement at dof
i from unit stroke at actuator j
xj
actual strokes to be determined from optim. problem
i= 1, .. N, N: number of dofs
of FEM
J= 1, .. m , m: number of actuators
Technische Universität München
Lehrstuhl für Leichtbau (LLB)Institute of Lightweight Structures
Some typical results
•Surface rms deviation of actual shape vs. goal (required) shaperms < 0.15 mm (for 1 m diam. reflector)
•Surface rms deviation between simalation vs. test resultsrms < 0.1 mm
shape morphing amplitudes of 10-15 mmwith high spatial frequency possible
concurrent mechanical and RF simulation and optimization preferable / feasible? simultaneous determination of design (+mat.!) parameters preferable / feasible ? other / better mech. design options e.g. by higher integration level ?
Further open points:
Technische Universität München
Lehrstuhl für Leichtbau (LLB)Institute of Lightweight Structures
Morphing in biol. cells flexible cell walls with morphable reinf.
Morphing in biology
lense
Actuating muscles
Human eye
Technische Universität München
Lehrstuhl für Leichtbau (LLB)Institute of Lightweight Structures
Integrated Integrated displdispl. . fieldfield identification identification
Measurement of strain at
many positions
Reconstr. model using.
• modal data
• Krylov vectors
• other FEM data
• exp. data
[C]
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500-10
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y [mm]
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real displacement fieldestimated displacement field
Displacement field
Real and reconstructed displ. field
FOS in CFRS
Technische Universität München
Lehrstuhl für Leichtbau (LLB)Institute of Lightweight Structures
• high forces (many tons)
• high strokes
• moderate resolution
• low spatial frequency
• high reliability
• low mass / volume
• self locking
• moderate temp. range
•low frequency
• small forces
• small or high strokes
• high resolution (µm range)
• high spatial frequency
• good reliability
• low mass / volume
• self locking
• extreme temperature range
• quasi-static
Morphing requirements
Aero-elasticity RF-elasticity
Coupling Aeodyn. Coupling RF. structureModelling:
Struct.