Chapter 1 L03 Flashcards
What is destructive testing used for. Give test examples.
- Determination of material properties
- Quality assurance
- Validation of design phase parameters
- Ex: Creep and Fatigue test
Name 5 typical mechanical loads for material characterization
- Tension
- Compression
- Shear
- Torsion
-Bending
Why are test methods standarized ?
- Applicability to the material
- Comparability of results
What is an isotropic material?
A material that was identical properties in all directions and can be described with one E-modulus
What is an orthotropic material?
A material with different behaviors depending on the direction
Tensile testing. Basic elements
“Notes”
Difference between strain gauge and extensometer
Strain Gauge: Measures small strain
Extensometer: Measures medium strain
Tensile testing. Stress-Strain.Graph
“Notes”
Define Hardeness
It is the ability to resist penetrations by other substances
Name 3 Hardness Tests, form of the indenter and one +/-
- Brinell (HB) : Sphere
Not applicable to thin materials - Vickers (HV) : Pyramid
Applicabel to hard and soft materials - Rockwell : Cone
Quick and automable
What is the state of the specimen after the Hardness Testing
Not fractured and only with a small deformation
Define Creep
Slow deformations under constant stresses
When is the does creep become relevant?
It becomes important at elevated temperatures and long-term loading
How are the Creep Tests carried out?
The subject is under a constant load with different temperatures
Creep Testing charts
“Notes”
Which information do you get from the uniform plastique elongation zone?
The ultimate tensile strength and the moment before the neck formation
Explain material failure due to MATERIAL FATIGUE
Material fatigue appears when having a time-variant load, which can cause the material to fail even without reaching the yield strength
Fatigue Testing graphs
“Notes”
How are the results of Impact Bending Tests?
Qualitative (Ductile or Brittle), with no units
