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car shredder fdn
i am designing a pile foundation to support a car shredder mill. the manufacturer gave dynamic forces and frequencies on the drawings, so i have performed a time history/dynamic analysis in staad to get the foundation natural frequencies and vibration response.
the natural frequency of the foudation is 50% removed from the machine, so i am good there. but the vibration amplitudes are higher than i would expect. the nature of the mill is that it is constantly changing the dynamic load based on how big/dense/fast the scrap is coming in.
has anyone designed one of these, and what guidelines did you use for permissable vibrations?
thanks.
find a job or post a job opening
do you mean 50% higher than operating frequenci(ies)?
waht allowance have you made for damping from surrounding soil?
50% higher in the vertical and 50% lower in the horizontal than the operating frequency (10 hz). can't seem to get enough stiffness to get 50% higher in the horizontal. using 5% damping right now, that seems low though, 10 or 20% may be more appropriate i am looking into that.
i am not yet sure that having the vertical natural frequency above and the horizontal below is good practice- it seems like in some direction between the vertical and horizontal the frequncy would match the machine.

2009-09-07, 10:56 PM	#1
huangyhg 超级版主注册日期: 04-03 帖子: 18592 精华: 36 现金: 249466 标准币资产: 1080358888 标准币	car shredder fdn car shredder fdn i am designing a pile foundation to support a car shredder mill. the manufacturer gave dynamic forces and frequencies on the drawings, so i have performed a time history/dynamic analysis in staad to get the foundation natural frequencies and vibration response. the natural frequency of the foudation is 50% removed from the machine, so i am good there. but the vibration amplitudes are higher than i would expect. the nature of the mill is that it is constantly changing the dynamic load based on how big/dense/fast the scrap is coming in. has anyone designed one of these, and what guidelines did you use for permissable vibrations? thanks. find a job or post a job opening do you mean 50% higher than operating frequenci(ies)? waht allowance have you made for damping from surrounding soil? 50% higher in the vertical and 50% lower in the horizontal than the operating frequency (10 hz). can't seem to get enough stiffness to get 50% higher in the horizontal. using 5% damping right now, that seems low though, 10 or 20% may be more appropriate i am looking into that. i am not yet sure that having the vertical natural frequency above and the horizontal below is good practice- it seems like in some direction between the vertical and horizontal the frequncy would match the machine. __________________ 借用达朗贝尔的名言：前进吧，你会得到信心! [url="http://www.dimcax.com"]几何尺寸与公差标准[/url]