Performance Characteristics Of Materials Flashcards
Tell me about conductivity when talking about materials
- either electrical or thermal conductivity
- electrical conductor - allows the flow of electricity through the material
- electrical insulator - does not allow the flow of electrical current
- thermal conductor - allows the transfer of heat energy through the material
- thermal insulator - prevents the transfer of heat energy through the material
What are the 5 different types of strength used to describe a material
Bending strength
Tensile strength
Compressive strength
Shear strength
Torsional strength
What is bending strength
When a material can withstand the bending forces being applied to it
What is tensile strength
When a material can withstand the stretching or pulling forces being applied to it
What is compressive strength
Being able to withstand the forces of being crushed by pushing forces
What is what is shear strength
When the a material can resist sliding forces on a parallel plane
What is torsional strength
When a material can withstand the twisting forces being applied to it
What does hardness mean
When a material can resist abrasive wear such as scratching, surface indentation or cutting
What does toughness mean
When a material can withstand impact force without being damaged
Performance characteristics of woods
. Wood fibres grow along the branched known as the grain
. Wood is felled and sawn into usable pieces and then seasoned either by air or kiln
. This helps remove any moisture from the material
. Seasoning the wood will remove around 80-90% of moisture
. Seasoning the wood also helps prevent any defects in the wood such as twisting, warping and cracks
. Wood is strong in the direction of the grain (along it) and weak across the grain
. Wood is natural and can therefore biodegrade
Performance characteristics of metal
. Metal is mined from the ground in the form of ores
. Bauxite is the most common ore and makes aluminium
. The raw material is extracted the ore through a combination of crushing, smelting or heating
. Chemicals will also be added as well as huge amounts of electricity
. Metals can be recycled
Performance characteristics of polymers
. Most polymers are made via fractional distillation of crude oil
. Polymers which are made from crude oil take hundreds of years to degrade
. Polymers are self finishing as they are pigmented during the manufacturing process which therefore means they do not need any additional finishing processes
Performance characteristics of smart and modern materials
. Their physical properties change when there is a change in their environment e.g. change in temperature, electricity, pressure or light
. They are developed through the invention of new processes and will continue to be developed as technology advances
Performance characteristics of papers and boards
.Can easily be scored or cut into templates like nets for packaging
. The source of paper and boards comes from wood pulp
. During manufacturing, bleaches can be added to the pulp to make the paper or board white in colour
. They will biodegrade and can be recycled or left in landfill due to them being natural
Performance characteristics of textiles
. Natural fibres can come from either plants (cotton or linen) or animals (silk and wool)
. Natural fibres are very breathable
. They are naturally reoccurring and can be recycled and are biodegradable
. Manmade fibres are synthetic, do not absorb liquid
. They are make in laboratory situations
. Textiles can be treated to become fire and stain resistant
Performance characteristics of composites
. Materials that have enhanced properties
. Most common types are glass fibre reinforced polymer and carbon fibre reinforced polymers
. They are lightweight, corrosion resistant, hard and tough
. Composite boards like MDF, hardwood, plywood and chipboard exist
. They have less defects such as splits or knots and can come in large sizes
