Optimum division of multi-span beams to minimize vibration
Mohammad Amin Lak
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Mohammad Amin Lak
Structural engineer expert in steel structures | offshore wind foundation inventor | outside-the-box thinker
A multi-span beam is subject to a harmonic vertical load of 10 kN applied on the middle of its leftmost span. The harmonic load has a certain frequency.
The beam is an IPE 200 profile with an overall length of 20 m divided into four spans. It is subject to a permanent dead load of 10 kN/m. The first natural frequency of the beam in case of four equal spans of 5 m each, is about 4.0 Hz.
What would be the best distribution of the supports to minimize vibration of the loaded as well as the other spans? How does the optimum distribution of the spans depend on the excitation frequency?
What is the target? Minimum stress in Beam? what is the excitation frequency? What is the excitation source? Base excitation or a a machine placed at one of the spans?