Search results
Results From The WOW.Com Content Network
The Tacoma Narrows Bridge, with a main span of 2,800 feet (850 m), was the third-longest suspension bridge in the world at that time, following the George Washington Bridge between New Jersey and New York City, and the Golden Gate Bridge, connecting San Francisco with Marin County to its north.
A physical object, such as a building, bridge, or molecule, has a set of normal modes and their natural frequencies that depend on its structure, materials and boundary conditions. The most general motion of a linear system is a superposition of its normal modes.
If a structure's natural frequency matches an earthquake's frequency [citation needed], the structure may continue to resonate and experience structural damage. Modal analysis is also important in structures such as bridges where the engineer should attempt to keep the natural frequencies away from the frequencies of people walking on the bridge.
The bridge collapse had lasting effects on science and engineering. In many undergraduate physics texts, the event is presented as an example of elementary forced resonance, with the wind providing an external periodic frequency that matched the natural structural frequency; [7] the cause is still debated by engineers today. A contributing ...
Mechanical resonance is the tendency of a mechanical system to respond at greater amplitude when the frequency of its oscillations matches the system's natural frequency of vibration (its resonance frequency or resonant frequency) closer than it does other frequencies. It may cause violent swaying motions and potentially catastrophic failure in ...
The first order or the principal parametric resonance is achieved when the driving/excitation frequency is twice the natural frequency of a given system. Higher orders of parametric resonance are observed either at or at submultiples of the natural frequency. For direct resonance, the response frequency always matches the excitation frequency.
Natural frequency, measured in terms of eigenfrequency, is the rate at which an oscillatory system tends to oscillate in the absence of disturbance. A foundational example pertains to simple harmonic oscillators, such as an idealized spring with no energy loss wherein the system exhibits constant-amplitude oscillations with a constant frequency.
The goal of modal analysis in structural mechanics is to determine the natural mode shapes and frequencies of an object or structure during free vibration.It is common to use the finite element method (FEM) to perform this analysis because, like other calculations using the FEM, the object being analyzed can have arbitrary shape and the results of the calculations are acceptable.