- #1
Doc
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Hi all,
I need to bond the back surface of an elliptical mirror (75mm major diameter and 37.5mm minor diameter) onto a voice-coil actuated mirror mount that is going to be operating at 500 Hz and has an adjustment range of +-1.5 degrees. I need to determine the g-force likely to be acting on the mirror to determine the amount of adhesive that I need to use.
To do this calculation I am examining a point on the outermost 'edge' of the mirror as shown in Fig 01 attached. I am assuming curvilinear motion in that the point is rotating around a central point (essentially a see-saw action). I am only interested in the range of motion from the mount's total range of motion, so from the very bottom of its travel to the very top: 3 degrees, as shown in Fig 02. The time period for one total oscillation is 2ms, but I'm only interested in half of that as shown in the sketch, 1ms.
From here I simply calculate the angular acceleration, and then the tangential component of that, see Fig 03. I divide the tangential acceleration component by 9.81 to get the number of g's.
I'd just like some comments about whether this is the correct approach or not. It's been quite a while since I've had to do anything theoretical.
I thought a decent way to double-check might be to analyse this as a simple harmonic motion problem also, but I'm not too sure about that.
Thanks,
Doc
I need to bond the back surface of an elliptical mirror (75mm major diameter and 37.5mm minor diameter) onto a voice-coil actuated mirror mount that is going to be operating at 500 Hz and has an adjustment range of +-1.5 degrees. I need to determine the g-force likely to be acting on the mirror to determine the amount of adhesive that I need to use.
To do this calculation I am examining a point on the outermost 'edge' of the mirror as shown in Fig 01 attached. I am assuming curvilinear motion in that the point is rotating around a central point (essentially a see-saw action). I am only interested in the range of motion from the mount's total range of motion, so from the very bottom of its travel to the very top: 3 degrees, as shown in Fig 02. The time period for one total oscillation is 2ms, but I'm only interested in half of that as shown in the sketch, 1ms.
From here I simply calculate the angular acceleration, and then the tangential component of that, see Fig 03. I divide the tangential acceleration component by 9.81 to get the number of g's.
I'd just like some comments about whether this is the correct approach or not. It's been quite a while since I've had to do anything theoretical.
I thought a decent way to double-check might be to analyse this as a simple harmonic motion problem also, but I'm not too sure about that.
Thanks,
Doc
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