Search Results

This document provides recommendations concerning the minimum knowledge and analytical skill guidelines for a composite and metal bond repair design engineer. Teaching levels have been assigned to this curriculum to define the knowledge, skills and abilities needed to design appropriate repairs.

This specification covers boron filaments and 6061-0 aluminum alloy foil laminated and bonded into a composite sheet.

The use of bonded composite doublers offers the airframe manufacturers and aircraft repair facilities an alternative repair process that alleviates the abovementioned concerns. ...Instead of riveting multiple steel or aluminum plates to facilitate an aircraft repair, it is now possible to bond a single Boron-Epoxy composite doubler to the damaged structure.

The use of bonded composite doublers offers the airframe manufacturers and aircraft repair facilities an alternative repair process that alleviates the above-mentioned concerns. ...Instead of riveting multiple steel or aluminum plates to facilitate an aircraft repair, it is now possible to bond a single Boron-Epoxy composite doubler to the damaged structure.

This specification and its supplementary detail specifications cover interleaf carrier materials in the form of polyethylene film or coated paper tape or sheeting.

In addition, it provides selected guidance on other technical topics related to this class of composites, including material selection, material specification, processing, characterization testing, data reduction, design, analysis, quality control, and repair of typical metal matrix composite materials. The Composite Materials Handbook, referred to by industry groups as CMH-17, is a six-volume engineering reference tool that contains over 1,000 records of the latest test data for polymer matrix, metal matrix, ceramic matrix, and structural sandwich composites. ...CMH-17 provides information and guidance necessary to design and fabricate end items from composite materials. It includes properties of composite materials that meet specific data requirements as well as guidelines for design, analysis, material selection, manufacturing, quality control, and repair. ...The fourth volume of this six-volume compendium includes properties on metal matrix composite material systems for which data meeting the specific requirements of the handbook are available.

The information provided is consistent with the guidance provided in Volume 1, and is an extensive compilation of the current knowledge and experiences of engineers and scientists from industry, government, and academia who are active in composites. The Composite Materials Handbook, referred to by industry groups as CMH-17, is a six-volume engineering reference tool that contains over 1,000 records of the latest test data for polymer matrix, metal matrix, ceramic matrix, and structural sandwich composites. ...CMH-17 provides information and guidance necessary to design and fabricate end items from composite materials. It includes properties of composite materials that meet specific data requirements as well as guidelines for design, analysis, material selection, manufacturing, quality control, and repair. ...The third volume of this six-volume compendium provides methodologies and lessons learned for the design, analysis, manufacture, and field support of fiber-reinforced, polymeric-matrix composite structures. It also provides guidance on material and process specifications and procedures for using the data that is presented in Volume 2.

CMH-17 provides information and guidance necessary to design and fabricate end items from composite materials. It includes properties of composite materials that meet specific data requirements as well as guidelines for design, analysis, material selection, manufacturing, quality control, and repair. ...The last volume of this six-volume compendium is an update to the cancelled Military Handbook 23, which was prepared for use in the design of structural sandwich polymer composites, primarily for flight vehicles. The information presented includes test methods, material properties, design and analysis techniques, fabrication methods, quality control and inspection procedures, and repair techniques for sandwich structures in military and commercial vehicles. ...The information presented includes test methods, material properties, design and analysis techniques, fabrication methods, quality control and inspection procedures, and repair techniques for sandwich structures in military and commercial vehicles. The Composite Materials Handbook, referred to by industry groups as CMH-17, is a six-volume engineering reference tool that contains over 1,000 records of the latest test data for polymer matrix, metal matrix, ceramic matrix, and structural sandwich composites.

The strength of glass fiber used in composite leaf springs was measured after and before the manufacturing process. From the experimental data, the Weibull distribution parameters were estimated by graphical regression, non-linear regression and maximum likelihood methods.

The use of bonded composites may offer the airframe manufacturers and aircraft maintenance facilities a cost effective method to extend the lives of their aircraft. ...The Federal Aviation Administration has sponsored a project at its Airworthiness Assurance NDI Validation Center (AANC) to validate the use of bonded composite doublers on commercial aircraft. A specific application was chosen - reinforcement of an L-1011 door frame - in order to provide the proof-of-concept driving force behind this test and analysis project. ...However, the data stemming from this study serves as a comprehensive evaluation of bonded composite doublers for general use. The associated documentation package provides guidance regarding the design, analysis, installation, damage tolerance, and nondestructive inspection of these doublers.

UAS structures need both the introduction of new advanced composites and the definition of light weight construction based on thin walled configuration. With this idea in mind, Stiffening concepts are frequently used to increase structural performance, i.e. buckling characteristics, of a thin plates. ...Manufacturing of composite stiffened structures can give rise to the presence specific damaged situations such as skin/stiffener de-bonding. ...The static structural behavior of a damaged stiffened composite panel is summarized from previous research investigation and presented. Uniaxial compression and biaxial test loading conditions are applied to the panel in order to point out the damage effects on static behavior.

The analysis results are validated by measurements on a fastened composite wingbox.

Presently, many manufacturers are replacing aluminium with fiberglass, Kevlar, and carbon fiber composites (CFC) to take advantage of the fuel savings allowed by weight reduction. It is well known that lightning strikes may cause severe damage to unprotected composites, so protective measures must usually be incorporated. ...It is well known that lightning strikes may cause severe damage to unprotected composites, so protective measures must usually be incorporated. Presently available methods involve application of a layer or ply of conductive material to the laminate, which compromises the original weight savings and sometimes imposes manufacturing and repair difficulties.

Airplane level lightning testing is used to verify lightning protection effectiveness of airplane systems. Time domain pulse and frequency domain swept-frequency transfer function tests are two acceptable airplane level ground test methods available to the aircraft manufacturer. Although both methods offer an acceptable verification means, both methods pose their own technical challenges. The intent of this paper is to present data collected from lightning pulse and swept-frequency transfer function tests conducted on a 777 airplane, and to compare these tests results. The data collected for this comparison includes several pulse and transfer function measurements made on flight control wiring routed along the rear spar of the 777 graphite vertical and horizontal stabilizers. The pulse measurement involved injecting 20 kA damped sinusoid pulse into the tip of the stabilizer while measuring the induced voltage on an individual wire within select shielded flight control bundles.

An exact approach to the aeroelastic spanwise lift distribution and divergence instability of swept (aft and back) uniform composite wing structures is developed in this paper. The approach based on the Laplace transform technique enables one to solve in a unified manner both aeroelastic problems. ...Numerical results are finally presented to demonstrate the effects played by the fiber-orientation, ply lay-up, warping restraint and wing geometry both on the subcritical static aeroelastic response and on the divergence instability of composite swept wings.

(CTAS) in the development of composite patch repair techniques through an internally funded research and development program (IRAD) prior to the award of the C141-B Drop-In-Repair (DIR) Contract and subsequently in supporting the various activities of fulfilling the contractual requirements after the contract award, for Warner-Robins Air Logistics Center (WRALC) during August 1993 through October 1994. ...WRALC had decided to repair most of the weep holes (limited to a maximum of fifteen holes per wing), using Boron/epoxy composite patch doublers, as a near-term remedial measure, in lieu of full wing plank replacement. ...Although the overall C141-B DIR Program involved other repair and maintenance work, CTAS was able to respond to the challenges of the program on short notice, due to the groundwork laid with the composite patch repair technology through the IRAD Program. Also, this paper describes the quality assessment of the manufactured and the installed Boron/epoxy patches through the non-destructive inspection (NDI) data acquired for the patches before and after installation on the aircraft.

A study of indirect lightning effects on carbon composite structures with internal tubing is performed using the ‘ab initio’ Maxwell equation codes MAFIA and Microwave Studio (MWS).

Persons who successfully complete the requirements of this certification standard are considered to be able to perform basic composite repairs to composite structures in compliance with the manufacturers’ repair documentation or other acceptable repair methods. ...It is recognized that the structural integrity of repaired composite structures depends upon the capabilities of the individuals who are responsible for performing the repairs. ...This document is intended to address repairs of composite structure regardless of the type of structure such as marine, wind turbine, automotive, aircraft, or other applications.