Section 10.3.2. Inspection Method Development
During the development of the critical parts list, it is
necessary to consider how each part will be inspected for flaws. This must be considered not only during the
manufacturing process but also during the periodic inspections to be performed
during the aircraft life. The results
of the fracture analysis can be significantly affected by the inspection method
and the selection of initial flaw sizes.
As improved inspection methods are incorporated into production
use, it is to be expected that improved design will result. The trade-off between inspection costs and
performance may also be considered.
Table 10.3.1. Examples Of NDE Capabilities [Ehert, 1979]
Inspection Method
|
Flaw Type
|
Standard NDE
|
Special NDE
|
Penetrant or magnetic particle
|
Surface flaw
(Depth x length)
|
0.19 x 0.38 cm
(0.075 x 0.150 in.) or equivalent area
|
0.083 x 0.127 cm
(0.025 x 0.050 in.) or equivalent area
|
Ultrasonics
|
Embedded flaw (diameter)
|
0.254 cm (0.100 in.)
|
0.12 cm (0.047 in.)
|
Radiographic
|
Surface or embedded (depth x length)
|
0.7t x 1.4t
Min length = 0.38 cm (0.150 in.)
|
0.6t x 1.2t
Min length = 0.127 cm (0.050 in.)
|
t = thickness