How self-reinforcing aeroelastic flutter differs from simple resonance, showing coupled torsional and bending motion of a bridge deck growing without bound above a critical wind speed, and how deck cross-section shape and torsional stiffness shift that critical speed.
Choose a deck cross-section, either a thin solid plate, an open truss, or a streamlined box girder, then gradually increase wind speed using the slider while watching the torsional and bending displacement traces. Note the wind speed at which oscillations stop decaying and begin growing instead, then adjust torsional stiffness and damping ratio to see how each shifts that critical flutter speed.
Deck cross-section selector (solid plate, open truss, streamlined box girder), wind speed slider, torsional stiffness slider, bending stiffness slider, mechanical damping ratio slider, and a reset or perturb button to introduce an initial disturbance and observe whether it decays or grows.
The original Tacoma Narrows Bridge deck was only eight feet deep for a span of nearly a mile and a half, giving it very low torsional stiffness for its length. Its replacement, opened in 1950, used a deck box roughly three times deeper with an open, streamlined design, and has stood without incident ever since.
How self-reinforcing aeroelastic flutter differs from simple resonance, showing coupled torsional and bending motion of a bridge deck growing without bound above a critical wind speed, and how deck cross-section shape and torsional stiffness shift that critical speed.
How self-reinforcing aeroelastic flutter differs from simple resonance, showing coupled torsional and bending motion of a bridge deck growing without bound above a critical wind speed, and how deck cross-section shape and torsional stiffness shift that critical speed.
Choose a deck cross-section, either a thin solid plate, an open truss, or a streamlined box girder, then gradually increase wind speed using the slider while watching the torsional and bending displacement traces. Note the wind speed at which oscillations stop decaying and begin growing instead, then adjust torsional stiffness and damping ratio to see how each shifts that critical flutter speed.
The original Tacoma Narrows Bridge deck was only eight feet deep for a span of nearly a mile and a half, giving it very low torsional stiffness for its length. Its replacement, opened in 1950, used a deck box roughly three times deeper with an open, streamlined design, and has stood without incident ever since.