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Engineering topics

Roy, P. A.

Publications and source records attributed to Roy, P. A..

Design and fabrication of a boron reinforced intertank skirt

Analytical and experimental studies were performed to evaluate the structural efficiency of a boron reinforced shell, where the medium of reinforcement consists of hollow aluminum extrusions infiltrated with boron epoxy. Studies were completed for the design of a one-half scale minimum weight shell using boron reinforced stringers and boron reinforced rings. Parametric and iterative studies were completed for the design of minimum weight stringers, rings, shells without rings and shells with rings. Computer studies were completed for the final evaluation of a minimum weight shell using highly buckled minimum gage skin. The detail design is described of a practical minimum weight test shell which demonstrates a weight savings of 30% as compared to an all aluminum longitudinal stiffened shell. Sub-element tests were conducted on representative segments of the compression surface at maximum stress and also on segments of the load transfer joint. A 10 foot long, 77 inch diameter shell was fabricated from the design and delivered for further testing.

Henshaw, J.↗

Development of lightweight aluminum compression panels reinforced by boron-epoxy infiltrated extrusions

Analytical and experimental studies were performed to evaluate the structural efficiencies afforded by the selective reinforcement of conventional aluminum compression panels with unidirectional boron epoxy composite materials. A unique approach for selective reinforcement was utilized called boron/epoxy infiltration. This technique uses extruded metal sections with preformed hollow voids into which unidirectional boron filaments are drawn and subsequently infiltrated with resin to form an integral part. Simplified analytical models were developed to investigate the behavior of stiffener webs with reinforced flanges. Theoretical results are presented demonstrating the effects of transverse shear, of the reinforcement, flange eccentricity and torsional stiffness in such construction. A series of 55 tests were conducted on boron-infiltrated rods and extruded structural sections.

Roy, P. A.↗

Boron epoxy reinforced structural sections.

A NASA Research program on the development of lightweight aluminum stiffening sections will be reviewed. The sections under investigation are hollowed extrusions which have been reinforced with boron epoxy by means of a fiber infiltration scheme being developed by Avco. Advantages of this type of construction are cost, environmental stability, manufacturing flexibility, and simplicity in joining. Present studies are focused on developing and verifying structural concepts for stiffener sections for compression panels. Results of analytical studies to size boron reinforcement will be discussed. Compression test results on stiffener sections will be presented and the design of a large compression panel will be reviewed. Results from compression panel efficiency studies indicate that panels with infiltrated stiffeners may be as much as 25% lighter than comparable all aluminum panels.-

Roy, P. A.↗