Abstract :
Structure repair is one of the aircraft maintenance activities specifically
dealing with damaged aircraft structures to maintain the strength of the structure,
so it is necessary to repair the damage in accordance with the procedures
established in SRM or manufacturing. Corrosion was found in the fuselage skin
structure of the Boeing 737-900ER aircraft and the repair method was carried out
a service request to the manufacturer because the repair process was not covered
by the SRM guide document and the value of the strength of the repair structure
was not known. The purpose of this study was to model, calculate the maximum
stress and calculate the Margin of Safety value for the fuselage skin repair doubler
on Boeing 737-900ER aircraft with station number 847-867 between stringers 23L-
25L on damaged structures and after repair of variations in simulation flight
altitude.
Modeling and analysis were carried out using CATIA V5R21 software
based on the finite element method with the modeling stages, input material
properties, load and restraint, meshing, computation, and results. Through the
simulation, it is known that the maximum stress value in the critical area when a
structure is given tension loading, so that the maximum stress can be used to
determine the Margin of Safety of the analyzed structure.
The highest Margin of Safety value for the damaged structure occurred at a
flight altitude of 5000 feet at 4.76 and the lowest value at a flying altitude of 40000
feet at 0.19. Meanwhile, the highest Margin of Safety value in the repair structure
occurs at a flight altitude of 5000 feet at 8.20 and the lowest value at a flying
altitude of 40000 feet at 1. The Margin of Safety value obtained in variations in
flight altitude tends to get smaller with increasing altitude.