4.1 Flashcards
physical properties
observable characteristics of a material
mechanical properties
indicate how a material behaves under various loads
list physical properties
- mass (amount of matter in a material)
- weight (relies on gravitational forces as well)
- volume
- density
- hardness (resistance material offers to scratching)
- electrical resistivity
- thermal conductivity
- thermal expansion (degree of increase in dimensions when object is heated)
list mechanical properties
- tensile strength (ability to withstand pulling forces)
- compressive strength (abilite to withstand being squashed)
- stiffness (resistance of elastic body to bending under force)
- toughness (ab. to resist breaking when receiving sudden shock)
- brittle (breaks into sharp shards)
- plasticity (avility to be formed into new shape permanently)
- elasticity (ab. to bend and return to original shape)
- ductility (ability to be extruded into wire etc)
stress
tensile force applied to given area (F/A)
strain
response of material due to stress (change in L/original L)
youngs modulus
measure of stiffness of an elastic material. used to select materials for design context
yield point
B on og graph. material will no longer return to initial shape
necking
netween c and d, going tosard breaking
point d on youngs modulus
failure point
point c on youngs modulus
ultimate tensile strength
material selection chart
charts used to identify appropriate materials based on desired properties
aesthetic properties
aspects of product that relate to tastem texture, smell, appearance
define smart materials
materials designed to react to external stimuli. adapt, change properties if needed
list smart materials
- piezoelectricity – give off small electrical discharge when deformed
- shape memory alloys – metals that go back to original shape after exposure to heat or electricity
- photochromicity – reversible change of color when exposed to light
- electro rheostatic – fluids undergo change in viscosity when exposed to electric field
- magneto rheostatic – fluids undergo changes in viscosity when exposed to magnetic field
- thermoeletricity – electricity produced from heat
