Structural bonding of the next generation large canadarm (NGLC) ground test bed

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Proceedings titleInternational SAMPE Technical Conference
ConferenceSAMPE Tech 2012 Conference and Exhibition: Navigating the Global Landscape for the New Composites, 22 October 2012 through 25 October 2012, North Charleston, SC
SubjectBondline thickness; Dimensional tolerance; Finite element models; Manipulator systems; Mechanical fastener; Progressive damage; Telescoping segments; Torsional stiffness; Adhesive joints; Aluminum; Cargo handling; Continuum mechanics; Equipment testing; Exhibitions; Finite element method; Optimization; Robotic arms; Stiffness; Translation (languages); Reduction
AbstractThe Next Generation Large Canadarm (NGLC) ground test bed is constrained by the physical stowage volume available on future exploration vehicles. NGLC demonstrates a reduction in the launch package of a large manipulator system while maintaining reach capability through deployment and retraction. NGLC is comprised of two telescoping segments, connected by three pitch joints. The segments consist of an inner and outer boom with a lock mechanism for either position. A rail network allows relative translation of the booms. NGLC bending and torsional stiffness requirements were met through the use of composite materials and adhesive bonding. Each boom features a centre composite section bonded to two aluminum sections using a stepped-lap joint. The elimination of mechanical fasteners maximized NGLC stiffness through a reduction of the clearance required between the telescoping assemblies and an increase of the inner segment diameter. Progressive damage finite element (FE) models optimized the lay-up and predicted positive margins of safety for combined bending and torsion load cases. Continuum mechanics analysis of the bonded joint was used to predict adhesive and adherend stresses due to the applied loads. A modular bonding apparatus with constrained relative adherend translation accommodated customized bonding processes for each operation. Steel rail segments were simultaneously bonded to the composite section inner surfaces, while the composite and aluminum sections were sequentially bonded. The joint and the bonding processes were optimized for bondline thickness control and minimum void entrapment. Key challenges included maintaining dimensional tolerances over the large structure, excess adhesive management and fouling of inaccessible critical surfaces.
Publication date
AffiliationNational Research Council Canada (NRC-CNRC); Aerospace (AERO-AERO)
Peer reviewedYes
NPARC number21269201
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Record identifier95c3a7c2-31f3-4ac3-bc6a-3147a3970a67
Record created2013-12-12
Record modified2016-05-09
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