4.1 Flashcards
What are physical properties of materials?
Materials that can be measured using non-destructive testing
What are the physical properties of materials? (8)
Mass
Weight
Volume
Density
Electrical Resistivity
Thermal Conductivity
Thermal Expansion
Hardness
What is mass?
The amount of matter contained in a space, it is constant (same regardless where it is measured) and measured in kg
What is volume?
The amount of 3-dimensional space a solid, liquid or gas occupies
What is weight and its design context?
A force that is measured in Newtons (N) which changes depending on the gravity / Weight must be considered to optimize the ideal performance through the perspective of ergonomics
What is density and its design context?
The relationship between mass and volume, measured in mass/volume (eg. 40kg/m2) / it is an important property where mass and volume are important
What is electrical resistivity and its design context?
A material’s ability to conduct or resist electricity / important property for an electrical component or safety equipment being used around electricity. The material will either need to insulate (high resistance, poorly conduct electricity) or conduct (low resistance, easily conduct electricity)
What is thermal conductivity and its design context?
Measures how fast heat moves through a material / important property for objects that are intended to be heated or used around heat (eg. metal cooking utensils easily conduct heat which would be a safety hazard)
What is hardness?
The resistance of a material to scratching or penetration
What is thermal expansion and its design context?
The degree to which a material increases its dimensions when heated / important property to consider when joining two different metals together
What are mechanical properties of materials?
Materials that are usually measured through destructive testing
What are the mechanical properties of materials?
Tensile strength
Compressive strength
Stiffness
Toughness
Ductility
Elasticity
Plasticity
What is tensile strength and its design context?
The ability of a material to resist pulling forces / important performance consideration for designs that need to resist pulling (eg. elevator cables/ cables in suspension bridges need high tensile strength to function safely)
What is compressive strength and its design context?
The ability of a material to resist pushing forces / important when selecting materials that need to support heavy loads (eg. glass, concrete)
What is stiffness and its design context?
The ability to resist deflection (bending) by a force and maintain its shape when force is applied to it / important when the shape of an object needs to be maintained under high forces (eg. airplane wings, bicycle frames)
What is toughness and its design context?
The ability to deform (change shape) but resist cracking and not fracture under impact / important where abrasion or cutting takes place (eg. car bumpers)
What is ductility and its design context?
The ability to be drawn or extruded into a wire-like form / considered when manufacturing a material
What is elasticity and its design context?
The ability of a material to bend and then return to its original shape / important to consider when the design needs to flex or bend when force is applied
What is plasticity and its design context?
The ability of a material to be formed into a new shape and not return to its original shape / important consideration for plastics and metals
What is Young’s Modulus used for?
Used to select appropriate materials for the design context. It indicates when a material will bend and then break.
What is Young’s Modulus measuring?
It is a measure of the stiffness of an elastic material (using the ratio of stress to strain)
How is Stress and Strain represented?
Plotted on a graph to represent the relationship between the amount of force applied and the materials’ changes in lengths
What are the basic concepts of a stress-strain graph?
As more force is applied to the material it will go through different zones affecting its performance characteristics, until it ultimately breaks
What is a Material Selection Chart and what is it used for?
It compares two material properties which are plotted on the chart and displayed in groups
What are the aesthetic properties of materials? (5)
Form and shape
Sound (that a material makes when touched impacts user experience)
Smell (connection to memory/ unhealthy materials)
Texture (smooth/ textured)
Appearance (color/ pattern)
What are aesthetic properties of materials?
Properties related to beauty and pleasure derived from a material
What are smart materials?
They are reactive materials, meaning they change their properties when exposed to certain stimuli
What are the properties of smart materials? (6)
Piezoelectricity
Shape memory
Photochromacity
Magneto-rheostatic
Electro-rheostatic
Thermoelectricity
What is piezoelectricity?
The ability to release an electric charge when deformed / when an electric current is passed through, its volume will increase or vibrate (eg. airbags)
What is shape memory?
Having a pseudo-elastic property that allows them to return to its original shape after deforming (stimulated by a change in temperature/ electrical current)
What is photochromicity?
The ability to change color when exposed to light
What is electro-rheostatic?
Fluids that experience a change in viscosity (thickness) when an electric force is applied
What is magneto-rheostatic?
Fluids that experience a change in viscosity (thickness) when an magnetic force is applied
What is thermoelectricity?
When two different conductors are joined to generate electricity when heat is applied
Scratch tests
Mohs scale (minerals), Bierbaum (ceramics), Pencil test(plastics)
