resistanf materials-materials and compponents
- Created by: samiul15
- Created on: 28-04-16 14:16
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- Materials and components
- Materials
- There are two types of timber, called hardwood and softwood
- HARDWOODS-come from broad-leaved, deciduous trees,main hardwood timbers are ash, mahogany beech and oak.
- SOFTWOODS-come from coniferous trees,cone-bearing trees, such as cedar and pine
- Metals: ferrous and non-ferrous
- FERROUS METALS: contain iron. Examples are cast iron, mild steel, medium carbon steel, high carbon steel, stainless steel
- NON-FERROUS METALS:do not contain iron. Some common non-ferrous metals are aluminium, Duralumin, copper, zinc, brass and tin
- PLASTICS
- Natural sources of plastics include: plants, trees, animals, insects.
- Synthetic plastics are chemically manufactured from: Crude oil, Coal, natural gas
- THERMO-PLASTICS: can be heated and shaped many times
- EXAMPLES: Polyamide(nylon), acrylic, polypropylene, polystyrene, polythene
- THERMOSET PLASTICS: can only be heated and shaped once
- EXAMPLE: Epoxy resin, Melamine formaldehyde, polyester resin and Urea formaldehyde
- COMPOSITE MATERIALS:
- Formed by combining a reinforcing materials such as wood pulp and glue.
- ALLOYS ARE NOT COMPOSIITE MATERIALS
- SMART MATERIALS
- Are reactive materials. Their properties can be changed by exposure to stimuli, such as electric and magnetic fields, stress, moisture and temperature.
- Thermo-chromic pigments react to changes in temperature
- Photo-chromic pigments react to changes in light levels
- Nanomaterial: Improve the mechanical properties of a material, such as stiffness or elasticity. When incorporated into polymers, they can be used as lightweight replacements for metals
- Are reactive materials. Their properties can be changed by exposure to stimuli, such as electric and magnetic fields, stress, moisture and temperature.
- There are two types of timber, called hardwood and softwood
- WORKING PROPERTIES
- CONDUCTIVITY Is the ability of a material to conduct heat or electrical energy
- STRENGTH is the ability of a material to withstand a force without breaking or bending
- ELASTICITY: is the ability of a material to bend and then to return to its original shape and size
- PLASTICY Is the ability of a material to permanently change in shape
- MALLEABILITY Is the ability of a material to permanently deform in all directions without cracking
- DUCTILITY Is the ability of a material to deform, usually by stretching along its length
- HARDNESS Is the ability of a material to resist wear, scratching and indentation
- TOUGHNESS is the ability of a material to withstand blows or sudden shocks without breaking
- DURABILITY is the ability of a material to withstand wear, especially as a result of weathering
- FUSIBILITY is the ability of a material to change into a liquid or molten state when heated to its melting point
- COMPONENTS, JOINTS AND ADHESIVES
- COMPONENTS: Made from resistant materials are usually bought ready-made. The most common components are nails, screws, hinges and catches.
- Permanent and temporary joints: may be assembled using adhesives, nails, rivets, or one of the heat processes of brazing, soldering or welding
- Temporary fixings: usually involve components with a screw thread, such as screws, nuts and bolts, or one of the many knock-down
- Materials
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