Rotating mirror is not only as an imaging element in optical path of ultra-high speed camera, where imaging quality is affected by surface quality and plane deformation of the rotating mirror, but also as an element to implement ultra-high speed, because performances of the ultra-high-speed camera system are mainly dependent on the static and dynamic mechanical properties of the rotating mirror. In this paper, the static and dynamic properties of magnesium alloy rotating mirror with equilateral-triangle cross-sections were investigated by theoretically and numerically method. At the speed of 2×105 rpm, the maximum lateral deformations of the mirror facet with width 17.32 mm and length 40 mm is 2.476 μm. The maximum von Mises stress is 35.1 MPa. The deformation and stress are less than that of aluminum alloy rotating mirror, which has been successfully applied in many types of RM for ultra-high speed cameras. The first three frequencies of magnesium alloy rotating mirror are 9,539.9 Hz, 9,540.9 Hz and 12,726.0 Hz, respectively. While the first three frequencies of aluminium alloy rotating-mirror are 9,683.9 Hz, 9,685.2 Hz and 11,016.0 Hz. From which it is preliminarily shown that a magnesium alloy rotating mirror can be used as replacement for an aluminium alloy rotating mirror in ultra-high-speed camera.
KEYWORDS: Mirrors, Numerical analysis, Cameras, Statistical analysis, Lithium, Analytical research, Monte Carlo methods, Modal analysis, Data modeling, Sun
The numerical analysis and experiment about dynamic sensitivity of rotating mirror were done to verify the
influence of the structural dimensions of rotating mirror on the natural frequency. Firstly, the model of dynamic
sensitivity of rotating mirror was established by the ANSYS Parameter Design Language, then the dynamic sensitivity
analysis of rotating mirror was done based on the Monte Carlo method and the Latin Hypercube Sampling Technique.
The result shows that the spearman rank correlation coefficient of basic variables is different from each other, which
reveals that the variables impact the natural frequency in different ways. The radius of rotating mirror body R5 and the
radius of shaft segment R2affect mostly the natural frequency among these variables, and the length of the shaft
segment L1 affects hardly the natural frequency of rotating mirror. R5 and R2 influence the same natural frequency in
opposite way. With the single variable principle, the experiments for dynamic sensitivity were done to examine the
results of numerical simulation. The results show that the R5 of rotating mirror increase by 4% which cause the first
natural frequency value decreasing from 466.3 to 426.6 Hz. However, when the length of L1 of rotating mirror reduces
about 10% the amplitude-frequency response curve of rotating mirror is almost unchanged. The results of experiment
are good agree with the numerical analysis show that the numerical analysis is a high accurate method to optimize the
structural size of rotating mirror for avoiding the influence of resonance.
It is the major failure mode of high-cycle fatigue for rotating mirror. Test methods for fatigue are commonly used
in researching the fatigue life of rotating mirror, but not practically. In this paper, numerical analysis and experimental
were used for researching the fatigue life of rotating mirror. With the finite element analysis software ANSYS, a static
strength about the rotating mirror was calculated at first and the results of stress from computing were imported into the
nSoft as the cyclic stress load spectrum for analyzing the fatigue life of rotating mirror. According to the S-N curve of
rotating mirror which defined by the material properties, the Miner linear cumulative damage law and the Goodman
Mean Stress Correction Model, the fatigue life of rotating mirror was calculated by nSoft. It shows that the fatigue
failure of rotating mirror does not occur under the speed of 3x104 rpm, because no node is damaged within the threshold
of infinite numerical cycles in that speed. Then a fatigue life experiment was done. 10 specimens of rotating mirrors
worked for 360 minutes respectively in the speed of 3x104 rpm on the bench of the rotating mirror test system. The
cycle index of stress was more than one million times, and no fatigue failure was occurred for every last sample. The
results from the numerical are in accord with that from experimental analysis. It is high accurate to analyze the fatigue
life of the rotating mirror by the method of numerical analysis.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.