Title
Statically determined structures: Tension between classical and modern design
Author
Kappelhof, J.P.
Nijenhuis, J.R.
Technisch Physische Dienst TNO - TH
Contributor
Hatheway, A.E. (editor)
Publication year
2003
Abstract
The two most important characteristics of opto-mechanical structures used in space or for astronomy are high accuracy and stability. Much time, money and energy is invested in achieving this. However, because resources are limited, it is important to realize that the cost of an instrument is mainly determined during the design process. Three factors can influence the design to a great extent. These are: creativity, design rules and analysis. The most important tool for analysis nowadays is the computer. This has become so powerful that even large structures are no problem to analyse in detail using finite elements. It is even tempting to spend much time and effort in optimising structures with the computer. However, basis for the best result is creativity during the design phase and the application of design rules. Although design rules are used extensively, it is surprising to see that one of the most important ones is so little used. This paper therefore deals specifically with the rule to make structures statically determined. The importance is invaluable because to apply this rule means much less need for computers. Furthermore its application often results in non-conventional structures and it helps to clearly define the basics of the structure. It also provides simple qualitative results that help to make decisions concerning alternatives. Results of computer models can be verified on their validity. Some interesting results of the application of this design rule are shown. Examples are the linear guiding system for an optical delay line and the design of a telescope. Also, existing structures, like the secondary mirror mount of the VLT, will be analysed and it will be shown what they would have looked like had they been statically determined.
Subject
Design rules
Iso-static design
Opto-mechanics
Statically determined structures
Astronomy
Decision making
Degrees of freedom (mechanics)
Finite element method
Interferometers
Large scale systems
Optical design
Optical telescopes
Thermal expansion
Space optics
To reference this document use:
http://resolver.tudelft.nl/uuid:59bbcfa4-8515-4b01-ace6-8a8af87370c8
TNO identifier
237490
ISSN
0277-786X
Source
Optomechanics 2003, 7-8 August 2003, San Diego, CA, USA, 5176, 114-125
Series
Proceedings of SPIE - The International Society for Optical Engineering
Document type
conference paper