week 2 Flashcards
what are the 4 key info’s a stress/strain graph is able to provide
Elastic behaviour
Yielding
Strain hardening
Necking
what is poisson’s ratio
When a material is stressed in one direction, it will deform (strain) in the direction of the load
what is deformation also known as?
strain
what 2 ways are materials tested
tensile strength test and destruction test
what is devleoped on the elastic limit
strain is developed directly proportional to the applied stress
what happens beyond the stress limit
plastic deformation
what is yield stress
stress at which noticeable plastic deformation has occured
what test is used for a material that is unable to provide a clear yield point
proof stregnth
what is ductility
the extend of plastic deformtion
what does a ductile material go through prior to failure
large plastic deformation
what is fracture
this is the last stage of tensile test, when the material fails and breaks into 2 pieces
what is brittle fracture
this is when fracture occurs elastic deformation, but with no plastic strain
what is ductile fracture
occurs after plastic deformation
what is toughness
Toughness is the ability of a material to absorb energy prior to failure
what does toughness measure
• It is measures as energy to break a unit volume of material.
what 3 parameters affect toughness
strain rate
temperature
notch effect
what 2 things decrease temperature is lowered on a material
toughness and ductility decreases when temperaturre is lowered
what is the notch effect and how can it effect toughness
this is the flaws, cracks and defects in the material which are able to decrease the toughness of the material.
what is the strain rate
the rate of loading
how can the strain rate effect toughness and ductility
Toughness and ductility decrease as the rate of loading increases
what is hardness
this is the resistance of a material to surface indentation
