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Forces act on materials all the time - even if a material appears stationary it still has a force acting on it. There are five terms used to describe what type of force can act on a material:

• tension - a pulling force
• compression - a pushing force
• bending - forces at an angle to the material
• torsion - a twisting force
• shear - forces acting across the material

Electronic and mechanical products are often developed to be lighter and smaller. The strength of the product can be improved by adding extra materials to improve its shape and reinforce thinner areas to help stop compression and bending forces damaging the item.

Products like laptops and mobile phones need to be able to withstand heavy use. New materials are continually being developed to try to combat the problems of torsion, for example to protect the case, screen or internal parts of mobile phones when in a pocket.

Mixing materials together to create a composite can make a stronger material than when used alone, eg carbon fibre and fibreglass are composites that are used to make strong housings for electronic and mechanical systems. These fibres are layered together with a polymer resin - the fibres can be a variety of thicknesses and protect against compression, torsion, bending and tension. Casings for electronic products can also be strengthened by adding ribs of thicker material around the case to make the plastic shells stronger while cutting down on materials used - therefore, costing less.