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natural frequency bridge beam
has anyone any idea on how i could calculate the natural frequency of a concrete bridge beam?
sure.
best way, to be honest, is fea, but if it is a single span uniform beam supported at each end then the first mode is given by
f=1/2/pi*a*sqrt(e*i/mu/l^4) hz
for simply supported a=9.81, for fixed fixed a=22.4
mu=mass per unit length
all units are consistent.
the book you need is by robert d blevins
cheers
greg locock
normally the first nat freq would lie somewhere in between simpply supported and fully fixed conditions, both are well defined by the textbooks. should use them for sanity check after fea work.

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2009-09-10, 03:38 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	natural frequency bridge beam natural frequency bridge beam has anyone any idea on how i could calculate the natural frequency of a concrete bridge beam? sure. best way, to be honest, is fea, but if it is a single span uniform beam supported at each end then the first mode is given by f=1/2/piasqrt(e*i/mu/l^4) hz for simply supported a=9.81, for fixed fixed a=22.4 mu=mass per unit length all units are consistent. the book you need is by robert d blevins cheers greg locock normally the first nat freq would lie somewhere in between simpply supported and fully fixed conditions, both are well defined by the textbooks. should use them for sanity check after fea work. __________________ 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]