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trends-of-materials-applications
Werkstofftrend1engl
Overdimensioned parts
- high safety factors
- low load levels
Ductile material with a high
yield strength ratio
Relatively resistant to
corrosion cracking forms
and notches
Steels are corrosion-sensitive
Failure
under designed loads:
- static: not possible
- dynamic:
unlikely if the loads are below the
yield strength.
- good fracture-mechanical properties
due to overstress:
- tough forced fracture with major
plastic deformation
It is possible to catch catastrophic damage
(imbalances, rubbing) or limit it (e.g. blades
being thrown free)
Life span-limited parts
- low safety factors
- high load levels
High-strength, low-ductility or
brittle material,
very sensitive to corrosion
cracking forms and notches
(e.g. material inhomogeneities
and finishing-induced weak
points)
Failure
under designed loads:
- static: unlikely if there are no
unexpected additional factors (such
as brittle coatings) and the relevant
material behavior is completely
understood.
- dynamic: increased risk, since
small damaging influences can
become dangerous through crack
growth. Notch-sensitive.
- unfavorable fracture-mechanical
properties (initial crack size, crack
growth, critical crack length)
due to overstress:
- spontaneous failure with a
predominantly brittle forced fracture.
very small critical crack length.
"catching" catastrophic damage is
unlikely.
Life span-limited parts
- medium safety factors
- medium load levels
Ductile material with a low
yield strength ratio
Increasing sensitivity to
corrosion cracking types
and notches
(e.g. material inhomogeneities
and finishing-induced weak
points)
Failure
under designed loads:
- static: unlikely
- dynamic: unlikely within the "safe"
life span
possible cracking and crack growth
- acceptable fracture-mechanical
properties
due to overstress:
- tough forced fracture with minor
plastic deformation
Catching damage is rather unlikely because
smaller plastic deformations and small
critical crack lengths are not apparent
from the outside.
Development tendency
Development tendency
Symbolic
part loads
Design and loads
Material properties
Failure behavior
Trends of the applications of materials: