Energy absorption is a crucial element of vibration control as it is the
process that reduces the strength and magnitude of vibratory motions.
These repetitive vibrations, if left unabsorbed and allowed to reach
stationary mechanical components, can cause significant damage, slowed
production and even complete mechanical failure.
Automotive, manufacturing, transportation, heating, cooling, metallurgical, transportation, machine building and even recording industries utilize energy absorption properties to protect vital machines and electronic components. Many of these devices are subject to both internal and external vibrations, either of which can have a significant impact on their final results. Therefore the absorbing material is often located between the inner mechanisms and the exterior support frame. Shock mounts, shock absorbers and brushings are common elements that use variable techniques to absorb the kinetic energy produced by motion. Apparatuses such as these work by diffusing energy as heat before it reaches adjacent surfaces. Where additional energy absorption is needed, rubber pads are placed under oscillating machinery. Even a slight amount of vibration control has a significant impact on enhanced performance, fuel economy and engine lifespan. Noise reduction is another notable benefit of energy absorption leading to decreased vibration, especially in enclosed spaces or industrial settings where noise can infringe upon worker safety.
As aforementioned, energy absorption involves taking in kinetic energy and diffusing it as heat energy. While several techniques may achieve this, the use of hydraulic springs and specialized materials are most commonly used for this purpose in industrial settings. Hydraulic energy absorption utilizes various fluids and an enclosed spring or piston system. Motion is transferred to the spring or piston which compresses the fluids thereby transferring the kinetic energy. The fluids, often oil or water, then convert the received energy into heat which dissipates through the outer cylinder. While hydraulic systems are common in engine mounts, other absorbers such as rubber mounts and bumpers are a popular alternative as they can adhere directly to the oscillatory mechanism. Extruded rubber elements form a barrier between metallic components. When either side encounters a jolt or shock, the energy must pass through the rubber before it will affect the adjacent metal piece. Rubbers such as neoprene, silicone and EPDM possess the variable heat resistant, chemical resistant and hysteretic properties necessary to absorb kinetic energy and diffuse it as heat energy in order to reduce unwanted movement. In some instances several layers of rubber are used to optimize the effect. Additionally, some machines use both hydraulic and rubber energy absorption techniques. While these devices and materials do not always eliminate all vibration, they significantly slow down and reduce the intensity of movements through energy absorption.