Anyone know what natural frequency of 7m tall cantilever sculpture ? 1

[tngv752]

I am doing the design check of a special stainless steel of a sculpture structure which include 4 square box sections. They are tied up all together (the tallest one is 7m, others are 4m, 5m and 6m high).
Anyone know what the natural frequency is or similar ?

Thanks

 

[ishvaaag]

Make a model with plates-shells or solid brick elements and find it by doing in a dynamic analysis in RISA 3-D or SAP-2000.

 

[JStephen]

Some of the equations (for seismic loading, for example) that use natural frequency also have a maximum value regardless of frequency. It may be cheaper to use that value than to calculate the actual frequency.

It sounds like you have sort of a pan-pipe arrangement? You might also consider that the natural frequency should be somewhere in between that of the longest and shortest member in the group, and natural frequency of a cantilever should be in reference books.

 

[Bagman2524]

There are several threads on this website on calculating natural frequency. Sqrt (Deflection/g) gives a good estimate.