Page 10 - Automotive Aerospace

Clarifying the Fatigue Fracture Mechanism

The aging of today's commercial transport aircraft has caused the transmission, to stop crack propagation or reduce propagation speed
relationship between design life and safety to be reviewed, resulting in until the crack is discovered during maintenance.
the introduction of the concept of damage-tolerant design. Fatigue, endurance, and reliability testing must be performed on
20 Hz General fatigue tester
Damage-tolerant design involves the investigation of fatigue crack materials subjected to pressure fluctuations due to repeated take-offs
1 kHz Non-resonant fatigue testerɹ
propagation speed, initiation sites, and method of inspection. In and landings and high-altitude flight.
practice, it is a method to design adequate residual strength, with
respect to both single load transmission and multiple load 300 Hz High-cycle fatigue tester

Observations of Fatigue Fracture Behavior Using an SEM Servo 20 kHz USF-2000
Repeated loads applied during fatigue testing result in deformation of the test sample.
Even small movements that can be ignored on a macro scale appear extremely large
when magnified by a scanning electron microscope (SEM). SEM images synchronized
with the sample deformation can be obtained by electrically moving the SEM
field-of-view in synchronization with these movements. The jigs holding the sample are
compact enough to be installed inside the SEM sample chamber. The compact heating
unit permits programmed heating of samples up to 800ºC to support a variety of tests.

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Compact Test Jigs are Easily Installed in the SEM Sample Chamber
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Test Jigs are Easily Installed in the SEM Sample Chamber
Composite Material at 823 K (550ºC)
ASTM E339 / E1820E1820
ASTM E339 /
Fracture Toughness Testing
It is extremely important to design aircraft against fatigue. The pressure in the passenger status.
cabin applies loads to the airframe during high-altitude flight. These become fatigue loads Special grips for compact test samples complying with ASTM standards, a COD bending
that are applied cyclically during each take-off and landing cycle. test jig, and a crack opening displacement gauge support the evaluation of a material's
Fracture toughness testing involves applying static or dynamic loads to a notched sample fracture toughness and crack propagation.
to investigate the brittle crack initiation and propagation and the fracture conditions and

OD Test
Jig
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CT Sample Grips and Clip Gauge
Fatigue Toughness Testing with a Resistance Heating Testerr
CT Sample Grips and Clip Gauge Fat igu e T oug hne e ss Tes tin g w it h a Res ist anc e e Heat ing Teste COD Test Jig
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