# Concepts of suspension Springs

1. Elasticity

If a force (load) is applied to an object made of a material such as rubber, it will create stress (deformation) in that object. When that force is released, the object will return to its original shape. We call this characteristic ÅgelasticityÅh. The springs of a vehicle use the principle of elasticity to cushion the body and occupants of a vehicle from road shock. The steel springs use bending or twisting elasticity.

REFERENCE: Even if an object has elasticity, if the force that is applied to it is excessively large, the elasticity limit will be exceeded, thus preventing the object from completely returning to its original shape. This is referred to as “plasticity”.

2. Spring rate (constant)

The deflection of a spring varies in proportion to the force (load) applied to it. That is, the value obtained by dividing the force (w) by the amount of deflection (a) is constant. This constant value (k) is called the “spring rate” or “spring constant”. A spring with a low spring constant is said to be “soft”, while a spring with a high spring constant is said to be “firm”.

3. Spring oscillation

When the wheels of a vehicle strike a bump, the vehicle’s springs will be rapidly compressed. Since each spring will immediately attempt to return to its original length, in order to release the compressed energy it will extend beyond its original length. Then the spring will respond to the rebound by attempting to return to its original length and will contract to less than its original length. This process, which is called spring oscillation, is repeated many times until the spring eventually returns to its original length. If spring oscillation was left uncontrolled, it would cause not only an uncomfortable ride, but would also lead to handling stability. To prevent this, shock absorbers are also provided.