When honeycomb composite structures are fabricated for the aerospace industry, they are designed to be closed to their operating einvironment for the life of the composite structure. However, once in service, this design can break down. Damage can set in motion a chain reaction of events that will ultimately degrade the mechanical integrity of the composite structure. Through thermographic analysis, the tendency of honeycomb composite structures to absorb and retain water was investigated, and an attempt was made to quantify the extent of water ingression in the Boeing 767 aircraft. Through thermographic analysis, the exterior honeycomb composite structures were found to contain less than 50 kg of water per plane. On average, over 90 % of the water found on an aircraft was contained in five problematic parts, which included the outboard flap wedges, the nose landing gear doors, the main landing gear doors, the fixed upper wing panels, and the escape slide door. Problems with skin porosity were attributed to water ingression in the outboard flap wedge. The water found in the nose and main landing gear doors was due to cracks in the potting compound around the fasteners and hinge fittings. The Kevlar lamina in the upper wing panels caused microcracking in the facesheet of the panel, thereby compromising the honeycomb core. Lastly, water in the escape slide door was traced back to potting compound problems and Kevlar. Ultimately, this research will aid in the fundamental understanding and design of future honeycomb composite sandwich structures.
Evaluation of the in-service performance behavior of honeycomb composite sandwich structures
Bewertung des Betriebsverhaltens von Wabenverbund-Sandwichkonstruktionen
Journal of Materials Engineering and Performance ; 8 , 6 ; 661-668
1999
8 Seiten, 8 Bilder, 2 Tabellen, 14 Quellen
Aufsatz (Zeitschrift)
Englisch
Wabenstruktur , Sandwich-Bauweise , Verbundwerkstoff , Flugzeugbau , Flugzeugrumpf , Flugzeugzelle , Oberflächenschaden , Wasserangriff , Wasseraufnahme , Betriebsverhalten , Betriebssicherheit , Ausfallwahrscheinlichkeit , mechanisches Verhalten , Thermographie , Wasserrückhaltung , Flugzeugfahrwerk , Flügeloberseite , Fahrzeugtür , Außenhaut , Mikroriss , Risseinleitung , Vergussmasse , Wasserströmung , Schichtwerkstoff , faserverstärkter Kunststoff , Dauerfestigkeit , Dauerfestigkeitsprüfung , Lebensdauerprüfung , Wabenstrukturlaminat
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