Aluminium fatigue design (cyclic wind loading) to Eurocode EN 1999-1-3

[susurruspeanut]

I've determined the N - stress relationship (relating the maximum stress the aluminium can take for a number of load cycles), but I don't know how many load cycles the aluminium should be designed to. Can anyone help? The design life is 20 years, and it's a 100kg sign that will cantilever off a wall (about 5m in the air) in the UK.

Perhaps this is something you determine in EN 1991-1-4 (wind loading to Eurocode)?

Cheers

 

[rb1957]

what flavour of Aluminium ? 2024 ? 6061 ? ... ?? what temper ?

I don't know your code requirements, possibly the code specifies fatigue loads (similar to defining static loads as a 1/100 years gust). Your design life is 20 years or 7305 days or 175320 hours ... maybe designing for 1E6 cycles is adequate ? which (for 2024T3, with a healthy Kt = 3.4) would give you 10ksi (for a 1/hr load).

another day in paradise, or is paradise one day closer ?