14. Natural Frequencies
Natural frequency is crucial for understanding the structural response during dynamic events such as earthquakes. The interaction between a structure's natural frequency and external forces can lead to resonance, amplifying vibrations and potentially causing structural failure. This chapter explores the fundamental concepts of vibrations, natural frequency calculations, modal analysis, the impact of site conditions, and techniques for designing earthquake-resistant structures.
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14.12.1Structural Tuning Concept
The structural tuning concept involves adjusting a structure's mass and...
What we have learnt
- Natural frequencies are affected by the mass and stiffness of structures.
- Resonance occurs when external forces match a structure's natural frequency, increasing the risk of damage.
- Various techniques and codes exist for assessing and managing frequencies during structural design.
Key Concepts
- -- Natural Frequency
- The frequency at which a system naturally vibrates when not subjected to external forces or damping.
- -- Resonance
- A phenomenon that occurs when the frequency of an external force matches the natural frequency of a structure, leading to amplified vibrations.
- -- Modal Analysis
- A technique used in structural engineering to determine the natural frequencies and mode shapes of a structure.
- -- Tuned Mass Dampers (TMDs)
- Devices that are added to structures to absorb energy at specific frequencies to reduce vibrations.
- -- Base Isolation
- A seismic design strategy that decouples a building from ground motion by introducing flexibility at the base.
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