Whip Antenna Analysis
Whip Antenna Analysis
(OP)
Hello all,
I am running across a problem trying to analyze reactions in antenna brackets used to support whip antennas. The primary concern is our random vibration analysis. Many of the antennas have a spring base that keeps the antenna fairly "rigid" most of the time. However, when the antenna deflects radially, the spring causes it to "snap" back. I'm not sure what you would call it, but it's as if the spring experiences coil bind at the center of oscillation when it's damping out the recoil.
There are some ways that I have come up with to model this non-linearly, but that doesn't help me for my linear random vibration study. Simply measuring the stiffness of the spring and adding that to the model won't take into account the "shock" effect.
If this is unclear, I can try to elaborate. If anyone has any suggestions or ideas, please let me know as I am having trouble overcoming this obstacle.
Thanks,
Bryson
I am running across a problem trying to analyze reactions in antenna brackets used to support whip antennas. The primary concern is our random vibration analysis. Many of the antennas have a spring base that keeps the antenna fairly "rigid" most of the time. However, when the antenna deflects radially, the spring causes it to "snap" back. I'm not sure what you would call it, but it's as if the spring experiences coil bind at the center of oscillation when it's damping out the recoil.
There are some ways that I have come up with to model this non-linearly, but that doesn't help me for my linear random vibration study. Simply measuring the stiffness of the spring and adding that to the model won't take into account the "shock" effect.
If this is unclear, I can try to elaborate. If anyone has any suggestions or ideas, please let me know as I am having trouble overcoming this obstacle.
Thanks,
Bryson





RE: Whip Antenna Analysis
RE: Whip Antenna Analysis
RE: Whip Antenna Analysis
Rob Stupplebeen
RE: Whip Antenna Analysis
RE: Whip Antenna Analysis
Failing that, real time dynamics with loadings derived from the psd. Yeuch! (but interesting). Sorry I can't help more - interesting question.
gwolf
RE: Whip Antenna Analysis
You could synthesize a time history with the same spectrum as the psd, but you have to make some assumptions that will have big effects on fatigue life.
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Whip Antenna Analysis
TOP
CSWP, BSSE
www.engtran.com www.niswug.org
"Node news is good news."