Accession Number : ADB040136

Title :   Large Area Composite Structure Repair.

Descriptive Note : Final rept. Jan 76-Feb 79,

Corporate Author : NORTHROP CORP HAWTHORNE CA AIRCRAFT GROUP

Personal Author(s) : Labor, J. D. ; Myhre, S. H.

Report Date : MAR 1979

Pagination or Media Count : 125

Abstract : This final report summarizes activity for the period from 1 January 1976 to 22 Feb 1979 during a program aimed at developing and validating procedures for the repair of large-area damage to various graphite/epoxy and graphite-boron/epoxy primary and secondary structures. The effort was concerned with repair concepts that supply nearly complete structural restoration to the damaged part, including the effects of temperature, moisture, and fatigue, while at the same time being amenable to military depot implementation. Repairs were developed which were essentially flush on the outer surface to meet severe aerodynamic smoothness criteria, and which could be made to both monolithic and sandwich panels with access from either both sides or from one side only. Procedures were developed and evaluated using a low resin content (35%) AS/3501-6 unidirectional graphite/epoxy prepreg and FM 400 film adhesive as the primary repair materials with a no-bleed layup, cocured under vacuum pressure for two hours at 350F. Testing was conducted to evaluate the effects of several adverse environments, including hydraulic fluid, jet fuel, paint stripper and water. Tensile tests indicated that water caused the greatest strengthloss, and exposure to water was used during the program to evaluate repairs. (Author)

Descriptors :   *REPAIR, *EPOXY RESINS, *GRAPHITE, *BORON, COMPOSITE STRUCTURES, HYBRID SYSTEMS, DAMAGE, TEMPERATURE, MOISTURE, FATIGUE(MECHANICS), JOINTS, CONFIGURATIONS, TEST METHODS, DEMONSTRATIONS, COSTS, HONEYCOMB STRUCTURES, SANDWICH PANELS.

Subject Categories : Plastics
      Structural Engineering and Building Technology
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE