Accession Number : ADA258574
Title : Effects of Material Degradation on Large Space Structures Dynamic Response.
Descriptive Note : Master's thesis,
Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH
Personal Author(s) : Perdigao, Alan J
Report Date : Aug 1992
Pagination or Media Count : 245
Abstract : Composite Large Space Structures (LSS) including booms, planar surfaces, antennas, platforms, and space stations are proposed for use in NASA's Space Station 'Freedom' and the DOD's Global Protection Against Limited Strikes programs. Because of their low mass and high strength and stiffness, composite repetitive lattice structures are ideal for these space applications. LSS will be required to sustain severe environmental effects - radiation, thermal cycling, atomic oxygen bombardment, collision with micrometeoroids and space debris, and hostile actions - and transient operational loads - docking, slewing, manned activities, control system, and the mobile service center - while maintaining strict mission parameters. Platform pointing is one example of these requirements and necessitates tolerances of less than one thousandth of a degree. Over time, material and structural degradation will occur due to environmental effects causing a change in the structure's stiffness and dynamic response. Likely, this structural damage will require immediate repair to restore the LSS to full mission capability. This thesis investigates the dynamic response of one LSS - the NASA Dual-Keel Space Station with 5 meter graphite epoxy erectable truss under one operational load - shuttle docking - and Low Earth Orbit (LEO) environmental conditions, and predicts how the material, structural properties, and dynamic response change over the 20-30 year design life. Results show the effects of material degradation on the station's dynamic response and mission requirements and has applications for NASA and DOD logistics planning for future LSS.
Descriptors : *DEGRADATION , *MATERIALS , *COMPOSITE STRUCTURES , THERMAL PROPERTIES , CONTROL , REQUIREMENTS , STATIONS , TRANSIENTS , DEBRIS , DYNAMICS , STRUCTURAL PROPERTIES , SURFACES , TIME , STRENGTH(MECHANICS) , GRAPHITE , THESES , STRUCTURES , STIFFNESS , DYNAMIC RESPONSE , MASS , LOGISTICS PLANNING , SPACE STATIONS , SLEWING , TRUSSES , LOGISTICS , PROTECTION , TOLERANCE , ANTENNAS , MISSIONS , GRAPHITE EPOXY COMPOSITES , ATOMIC STRUCTURE , SPACE MAINTENANCE , COLLISIONS , MANNED , DOCKING , MOBILE , PLANNING , RESPONSE , HIGH STRENGTH , PLATFORMS , REPAIR , OXYGEN , ENVIRONMENTAL IMPACT , PARAMETERS , EARTH ORBITS , ORBITS , RADIATION , GLOBAL , CONTROL SYSTEMS , DAMAGE
Subject Categories : Laminates and Composite Materials
Logistics, Military Facilities and Supplies
Distribution Statement : APPROVED FOR PUBLIC RELEASE