Vibration Basics - Parameters

Vibration parameters have to be clearly determined before selecting a mounting system.

The behavior of a mounting system may be influenced by various parameters. These must be determined before a particular type of suspension is selected.

Mass, available space for the mounting system, position of the center of gravity of the system to be suspended

The mass of the system to be suspended defines the type of mountings that can be used. The number of mountings depends on the permitted load and the space available for each mounting. The configuration of the system determines the location and therefore the type of mounting. The position of the center of gravity of the system is very important. The characteristics of the suspension will depend on the relative position of the center of gravity and the mountings.

Environmental constraints

The environmental constraints to which the mounting is subjected must be known as accurately as possible before determining the type of suspension. The characteristics of an elastomeric mounting change significantly with temperature, contaminants, and humidity, ozone, atmospheric pressure, etc... It is also advisable to define the operating ranges of the suspension where specific characteristics are required (for example, between - 30°C and 70°C (-22°F to 158°F), the suspension should comply with specified transmissibility limits and from :

-50°C to 120°C (-58°F to 248°F) the suspension must not be irreversibly damaged). The type of mounting and choice of material depend directly on the environmental constraints. Hutchinson offers an extensive range of products and material to allow the optimum solution to be chosen.

Excitation

As most anti-vibration mountings are nonlinear, it is very important to specify the type of excitation : sinusoidal, random, shock, constant acceleration. A mounting system responds in different ways to each type of excitation.

Life time

The life time is a decisive factor when selecting the suspension. It depends on the load conditions of the suspension and the intrinsic characteristics of the elastomers.

The more clearly the parameters described above are known and controlled, the easier it is to select a suitable suspension. The questionnaire on the following pages is a guide to help selection.

Our technical services are available to help you to specify the requirements.

System response

It is normal practice either to specify the maximum level of transmitted acceleration that an equipment can accept or the maximum sway space available. The maximum transmitted acceleration may be frequency dependent.