Ok, I’ve got the types of structures down but what about the forces that act on them?

Compression

This action is when a substance is put under force from each end, like standing on a block of foam, it is being compressed between your feet and the floor. If the material subject to compression reaches a point that it won’t return to it’s original state it is said to have buckled.

Tension

This is stretching a substance, like the steel cables that are used in suspension bridges. If the material is put under too much tension it can snap depending on it’s elasticity.

Torsion

Work shops are full of objects under torsion. Every time you use a screw or a clamp or a pillar drill you are witnessing torsion in action.

Shearing

Shearing force can be quite destructive, in scissors it just cuts the paper or fabric you’re working on but put it in the context of an earthquake and all of a sudden you’ve got huge sections of rock moving against one another. Rivits can also be put under shearing force if the metal plates it’sfixing together move towards or away from each other.

Bending

Bending is a mixture of compression and tension, the upper surface of the object being bent is under compression and the lower surface is under tension. A substance that is put under too much bending force can develop wrinkling and folds on the top surface and splits and cracks underneath, think of what happens when you bend up a cardboard box to put in the recycling.