NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Genetic Optimization of a Tensegrity StructureMarshall Space Flight Center (MSFC) is charged with developing advanced technologies for space telescopes. The next generation of space optics will be very large and lightweight. Tensegrity structures are built of compressive members (bars), and tensile members (strings). For most materials, the tensile strength of a longitudinal member is larger than its buckling strength; therefore a large stiffness to mass ratio can be achieved by increasing the use of tensile members. Tensegrities are the epitome of lightweight structures, since they take advantage of the larger tensile strength of materials.

The compressive members of tensegrity structures are disjoint allowing compact storage of the structure. The structure has the potential to eliminate the requirement for assembly by man in space; it can be deployed by adjustments in its cable tension. A tensegrity structure can be more reliably modeled since none of the individual members experience bending moments. (Members that experience deformation in more than one dimension are much harder to model.) Structures that can be more precisely modeled can be more precisely controlled.

Furthermore, an astoundingly wide variety of natural systems, including carbon atoms, water molecules, proteins, viruses, cells, tissues and even human and other living creatures are tensegrity structures. Through the process of evolution, nature continually improves the design of living creatures for the environment they live in. Since tensegrities are nature's structure of choice, it is conceivable that they have other benefits we are unaware of.

A. Keane and S. Brown designed a satellite boom truss system with an enhanced vibration performance. They started with a standard truss system, then used a genetic algorithm to alter the design, while optimizing the vibration performance. An improvement of over 20,000% in frequency-averaged energy levels was obtained using this approach.

In this report an introduction to tensegrity structures is given, along with a description of how to generate the nodal coordinates and connectivity of a multiple stage cylindrical tensegrity structure. A description of how finite elements can be used to develop a stiffness and mass matrix so that the modes of vibration can be determined from the eigenvalue problem is shown. A brief description of a micro genetic algorithm is then presented.
Document ID
20020068836
Acquisition Source
Marshall Space Flight Center
Document Type
Contribution to a larger work
Authors
Jaime R. Taylor
(Austin Peay State University Clarksville, United States)
Date Acquired
August 20, 2013
Publication Date
July 1, 2002
Publication Information
Publication: Research Reports-2001 NASA/ASEE Summer Faculty Fellowship Program
Publisher: Marshall Space Flight Center
Volume: NASA/CR-2002-211840
Issue Publication Date: July 1, 2002
Subject Category
Optics
Funding Number(s)
CONTRACT_GRANT: NAG8-1786
Distribution Limits
Public
Copyright
Public Use Permitted.
Document Inquiry

Available Downloads

There are no available downloads for this record.
No Preview Available