welcome to our second lesson in the ansys innovation course for material performance
today we'll be investigating material families and how we can compare them
to one another in a useful visual way materials is a constantly growing field
it can be daunting at first to have all these different options before you when designing a
product and yet as we saw in lesson one material selection is an integral part of product design
how do we begin to become familiar with this ever-changing field one way to do
this is by breaking down the larger field of materials into smaller more manageable sections
materials can be broken down into different classifications or families these families
have different sets of attributes allow us as engineers and designers to group them together
it can be helpful when first learning about materials to understand these classifications
now there isn't just one attribute that sets one material family apart from one another
it's the combination that gives us the guidelines to group these materials together
now often when i'm talking about material families i'm comparing a family to the mature
field of materials as a whole now i could do this through lots of tables with numbers but what if
there was a more visual approach in materials science we often use one of these an ashby chart
to compare individual materials or materials families with one another in a highly visual way
in these charts the individual circles or bubbles represent individual materials we use bubbles and
not dots because these different attributes have ranges no material is perfect after all
the larger bubbles or envelopes represent material families
and their general trends and it's these envelopes that we're using today
to compare the different attributes of our material families with one another
now what are we comparing when we're looking at these charts we're comparing material properties
material properties are traits that represent how material reacts or behaves
under specific situations or stimuli now this isn't a course dedicated to material
properties but we will be defining six here to help us compare these families with one another
we'll be defining density stiffness fracture toughness yield strength electrical resistivity
and thermal conductivity density is a property you may be familiar with from science class its
mass over volume so if i have a brick and a sponge of the same volume the brick will be much heavier
stiffness is the material's ability to resist deformation when a force is being applied
we can think about it this way if a weight was attached to the end of a beam
and the other end was anchored into the wall a material with high stiffness
would not bend under the force of the weight whereas the material with low stiffness would
fracture toughness is a material's ability to resist fracture if we want to think of an airplane
wing if its material had low fracture toughness it would snap not ideal for our application
yield strength is the strength of a material after a very specific amount of force has been applied
generally this amount of force equals the point at which the material starts to yield or change shape
think of a spring you can stretch it a little bit and it'll go back to its original shape
but if you pull or deform it far enough the shape changes permanent the strength needed to begin
this permanent deformation is the yield strength
electrical resistivity is a measurement of how much a material resists
the passage of electrical current resistivity is the inverse of conductivity
which can be helpful when thinking about this concept
think of an electric wire we want electricity to pass easily through these wires so they get
to our homes and workplaces therefore the wires have a low resistivity or a high conductivity
an incandescent light bulb on the other hand uses the high
electrical resistance of tungsten wire to create light and heat allowing us to light up our homes
finally we have thermal conductivity which is a measurement of how well a material can
conduct heat or how easily heat passes through a material think of trying to boil water a pot
with a high thermal conductivity will allow the heat to pass through more efficiently therefore
the water will boil more quickly a pot made with a low thermal conductivity material will not allow
the heat to pass quickly meaning i have to wait a long time for the water to boil when making pasta
now that we've defined our six properties we can start to compare our material families
today we have six families to compare with one another ceramics metals glasses elastomers
polymers and hybrid materials which encompasses composites foams and natural materials
we now will have four short videos that go over these different material families
some are more similar than others and have been grouped together accordingly
first we'll investigate ceramics and glasses then moving on to metals
then thirdly we'll look at polymers and elastomers and determine how they're different and finally
we'll end with hybrids so stick around and learn more about these material families
you