Finite element modeling and testing of a deformable carbon fiber reinforced polymer mirror

Wilcox, Christopher C.; Baker, Michael; Wick, David V.; Romeo, Robert C.; Martin, Robert N.; Clark, Brett W.; Breivik, Nicole L.; Boyce, Brad Lee

doi:10.1364/ao.51.002081

Cited by 2 publications

(7 citation statements)

References 6 publications

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“…8, so these are repeated below for completeness. Figure 1(a) shows the resulting deviation from a 1250 mm spherical surface using a point-load force pulling the mirror at its apex and Figure 1(b) the resulting deviation with a uniform radial force pushing inward along the circumferential edge [8]. Notice that the point-load and radial phase maps from Figure1(a) and (b), respectively, are somewhat complimentary in error.…”

Section: Overviewmentioning

confidence: 95%

“…The four different forces tested -point-load, radial, constant pressure, and tangential -were representative of four possible actuation techniques. The model simulated a 203.2 mm (8 in) diameter CFRP mirror being actuated from a relaxed radius of curvature (ROC) of 2000 mm to a stressed ROC of 1250 mm [8]. The ROC of a surface is the distance between the surface apex and its center of curvature.…”

Section: Overviewmentioning

confidence: 99%

“…The model was tested by simulating a point-force at the mirror apex and pushing with increasing force values to alter its shape. The simulation was experimentally verified with high accuracy (less than 10% RMS error) using a commercial wavefront sensor [8].…”

Section: Introductionmentioning

confidence: 97%

“…Both finite element modeling and interferometric optical testing indicate that thin-shelled, replicated CFRP mirrors can be used as large diameter deformable mirrors for both focus control and high-order correction [5,8]. CFRP has a high stiffness-toweight ratio and is significantly more robust than glass thinshelled mirrors [5].…”

Section: Introductionmentioning

confidence: 99%

“…Several different actuation methods were modeled, including point and constant pressure loads on the back of the mirror, and radial and tangential loads at the edge of the mirrors [8]. For the radius of curvature changes that we are interested in for phase diversity and adaptive zoom, the results of the modeling suggest that a blend of radial and point-load forces may balance aberrations, thereby reducing the resultant wavefront to acceptable optical performance.…”

Section: Introductionmentioning

confidence: 99%

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Actuation for carbon fiber reinforced polymer active optical mirrors

Jungwirth

Wick

Baker³

et al. 2012

2012 IEEE Aerospace Conference

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Adaptive or active elements can alter their shape to remove aberrations or shift focal points. Carbon fiber reinforced polymer (CFRP) material improves upon current active mirror materials, such as Zerodur, in several ways: low stiffness-to-weight ratio, very low hysteresis, and greater dynamic range of correction. In this paper, we present recent developments in CFRP mirror actuation, i.e., changing the mirror's shape in an accurate and repeatable fashion. Actuation methods are studied both theoretically, using finite element analysis, and experimentally, using interferometric testing. We present results using two annular rings to push against the mirror's back, producing a wavefront with less than 20 waves of total error. Applications for this work include active telescope secondaries, phase diversity, and adaptive zoom systems.

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Section: Overviewmentioning

confidence: 95%

Section: Overviewmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Actuation for carbon fiber reinforced polymer active optical mirrors

Jungwirth

Wick

Baker³

et al. 2012

2012 IEEE Aerospace Conference

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Optimal design of a Φ760 mm lightweight SiC mirror and the flexural mount for a space telescope

Xue

Wang

et al. 2017

Review of Scientific Instruments

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A flexural support technique for lightweighted Primary Mirror Assembly (PMA) of a space telescope is presented in this article. The proposed three-point flexural mount based on a cartwheel flexure can maintain the surface figure of the PMA in a horizontal optical testing layout. The on-orbit surface error of the PMA causes significant degradation in image quality. On-ground optical testing cannot determine the zero-gravity figure of the PMA due to surface distortion by gravity. We unveiled the crucial fact that through a delicate mounting structure design, the surface figure can remain constant precisely without inducing distinguishable astigmatism when PMA rotates with respect to the optical axis, and the figure can be considered as the zero-gravity surface figure on the orbit. A design case is described to show the lightweight design of a SiC mirror and the optimal flexural mounting. Topology optimization and integrated opto-mechanical analysis using the finite element method are utilized in the design process. The Primary Mirror and mounting structures were fabricated and assembled. After the PMA mirror surface was polished to λ/50 RMS, optical testing in different clocking configurations was performed, respectively, through rotating the PMA by multiple angles. Test results show that the surface figure remained invariant, indicating that gravity release on the orbit will not cause an additional surface error. Vibration tests including sweep sine and random vibration were also performed to validate the mechanical design. The requirements for the mounting technique in space were qualified.

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Finite element modeling and testing of a deformable carbon fiber reinforced polymer mirror

Cited by 2 publications

References 6 publications

Actuation for carbon fiber reinforced polymer active optical mirrors

Actuation for carbon fiber reinforced polymer active optical mirrors

Optimal design of a Φ760 mm lightweight SiC mirror and the flexural mount for a space telescope

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