Calculation of the elastic properties of a triangular cell core for lightweight composite mirrors

F E Penado, James H. Clark, Joshua P. Walton, Robert C. Romeo, Robert N. Martin

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)

Abstract

The use of composite materials in the fabrication of optical telescope mirrors offers many advantages over conventional methods, including lightweight, portability and the potential for lower manufacturing costs. In the construction of the substrate for these mirrors, sandwich construction offers the advantage of even lower weight and higher stiffness. Generally, an aluminum or Nomex honeycomb core is used in composite applications requiring sandwich construction. However, the use of a composite core offers the potential for increased stiffness and strength, low thermal distortion compatible with that of the facesheets, the absence of galvanic corrosion and the ability to readily modify the core properties. In order to design, analyze and optimize these mirrors, knowledge of the mechanical properties of the core is essential. In this paper, the mechanical properties of a composite triangular cell core (often referred to as isogrid) are determined using finite element analysis of a representative unit cell. The core studied offers many advantages over conventional cores including increased thermal and dimensional stability, as well as low weight. Results are provided for the engineering elastic moduli of cores made of high stiffness composite material as a function of the ply layup and cell size. Finally, in order to illustrate the use of these properties in a typical application, a 1.4-m diameter composite mirror is analyzed using the finite element method, and the resulting stiffness and natural frequencies are presented.

Original languageEnglish (US)
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
Volume6665
DOIs
StatePublished - 2007
EventNew Developments in Optomechanics - San Diego, CA, United States
Duration: Aug 28 2007Aug 30 2007

Other

OtherNew Developments in Optomechanics
CountryUnited States
CitySan Diego, CA
Period8/28/078/30/07

Fingerprint

elastic properties
mirrors
composite materials
Composite materials
cells
Stiffness
stiffness
low weight
sandwich structures
Optical telescopes
Finite element method
honeycomb cores
Mechanical properties
mechanical properties
Dimensional stability
dimensional stability
Natural frequencies
Mirrors
Thermodynamic stability
Elastic moduli

Keywords

  • Composite mirrors
  • Isogrid core
  • Lightweight mirrors
  • Lightweight telescope
  • Sandwich construction

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Condensed Matter Physics

Cite this

Penado, F. E., Clark, J. H., Walton, J. P., Romeo, R. C., & Martin, R. N. (2007). Calculation of the elastic properties of a triangular cell core for lightweight composite mirrors. In Proceedings of SPIE - The International Society for Optical Engineering (Vol. 6665). [66650B] https://doi.org/10.1117/12.732689

Calculation of the elastic properties of a triangular cell core for lightweight composite mirrors. / Penado, F E; Clark, James H.; Walton, Joshua P.; Romeo, Robert C.; Martin, Robert N.

Proceedings of SPIE - The International Society for Optical Engineering. Vol. 6665 2007. 66650B.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Penado, FE, Clark, JH, Walton, JP, Romeo, RC & Martin, RN 2007, Calculation of the elastic properties of a triangular cell core for lightweight composite mirrors. in Proceedings of SPIE - The International Society for Optical Engineering. vol. 6665, 66650B, New Developments in Optomechanics, San Diego, CA, United States, 8/28/07. https://doi.org/10.1117/12.732689
Penado FE, Clark JH, Walton JP, Romeo RC, Martin RN. Calculation of the elastic properties of a triangular cell core for lightweight composite mirrors. In Proceedings of SPIE - The International Society for Optical Engineering. Vol. 6665. 2007. 66650B https://doi.org/10.1117/12.732689
Penado, F E ; Clark, James H. ; Walton, Joshua P. ; Romeo, Robert C. ; Martin, Robert N. / Calculation of the elastic properties of a triangular cell core for lightweight composite mirrors. Proceedings of SPIE - The International Society for Optical Engineering. Vol. 6665 2007.
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