According to the technical parameters of your application and the requested budget or natural frequency requirement, several types of vibration isolators can be selected.

Industrial machines can be installed on platforms where several elastic steps are present. Wheels or frames depending on their construction have their own elasticity. This elasticity will affect the natural frequencies of the system. In theory, in order to have precise vibration isolation calculations we should take all the elastic steps in consideration.

Since this level of input data is very hard to achieve, simplified mathematical models can be used to provide us with a good guidance value. Calculations that take into consideration the suspended element as a solid (rigid body) and take into account the fail-safesupports (integrated security) and analyze the stability that we obtain with the different solutions. The hardness of the rubber and the 6 degrees of freedom are AMC-MECANOCAUCHO®'s preference. This kind of vibration isolation calculation will be able to provide us the 6 natural frequencies of the system, knowing the input vibration we can then understand the expected vibration isolation performance of the suspended system.

In the image below we show an example of this type of calculation.

Our technical team will review this information to make the most appropriate product selection, taking into consideration the following key points:

1. Load capacity

Depending on the geometry of the support, and the hardness of the rubber we can have different load capacities for each vibration isolator. Therefore, the first stage of the selection would be to narrow the options to the products with the required load capacities. For this, we must know the weight per support.

As a standard default range, and to ensure a good durability throughout the product life, AMC Mecanocaucho® does not recommend loading the anti-vibration mounts over 85% of their load capacity.

2. Type of application

Industrial machinery has different utilities and therefore a different type of work.

Generally, the different applications can be divided into two large families, static applications, and dynamic applications. It is advisable to keep this in mind when reviewing the different families of anti-vibration mounts.

• Static applications: these are cases in which the equipment/object to be suspended does not move. For this reason, stability and safety against failure is an issue that is not as important as in dynamic applications when selecting the appropriate support. In these cases, we could go with soft rubber harnesses, and load the mounts to 70-85% of their load capacity.

  The frequency of the input vibration can differ and be variable for each type of machine. Therefore, the natural frequency of the suspended element is studied and tuned in order to achieve good stability and also optimum vibration isolation levels. For this purpose, AMC-MECANOCAUCHO applications engineers will be able to help and give you recommendations.

• Dynamic applications: these are applications that present movements, dynamic loads, shocks, etc. In these cases, we need to select fail-safe supports (integrated security) and analyze the stability that we obtain with the different solutions. The hardness of the rubber and the damping coefficient offered by each type of support is of great importance. As we can have dynamic loads, it is necessary not to load the supports excessively, in order to have a load margin for the most demanding moments.

These are the load ranges recommended by AMC for each type of application:

Some machines are exposed to transient shocks, such as inputs from the terrain they are driving on (speedbumps, potholes etc.) In these kinds of cases the frequency is generally low, therefore low stiffness vibration isolators are preferred. This property allows the mount to reach low natural frequencies of the system and reduce the accelerations reaching the machine.

Low natural frequency is achieved through low stiffness vibration isolators, this is good for vibration isolation however soft vibration isolators can lead to unstable suspended elements. In order to add stability to the system vibration isolators with damping systems can be introduced, this allows the suspended element to stabilize faster as shown in the graphic below.

Vibration isolatorings such as AMC-MECANOCAUCHO® Hydraulic mounts and hydraulic cone mounts have this damping feature.

The image below shows the section of the hydraulic mount and the speed of the liquid transfer from chamber to chamber in colors. The energy dissipation is done through the liquid transfer. These products can be tuned to meet the required stiffness and damping for each application. AMC-MECANOCAUCHO® applications engineers can calculate and select the optimum properties of the vibration isolator for your application.

3. Natural frequencies of the system

Another point to analyze are the natural frequencies obtained. Depending on the excitation frequency that is produced in the application, the natural frequencies that are obtained during the calculation will indicate the level of expected vibration isolation.

The further away the natural frequencies are from the excitation frequency, the greater the isolation level will be.

If we take the highest natural frequency mode obtained and multiply it by √2 we will obtain the frequency at which we will start to have vibration isolation.

If a low natural frequency is needed, we will need to select softer solutions (lower stiffness ‘’k’’), maintaining the necessary load capacity.

Therefore, depending on the target frequency, one type of support will be more appropriate than the other.

• Rubber-metal and Sylomer® solutions:

With these solutions the lowest natural frequencies obtained are around 8-10Hz. For this it is recommended to use the softest rubber compounds (40-50Sh) and lower Sylomer® densities.

If the application needs to have lower frequencies than 8Hz, we will need surely the use of supports that allow larger displacements (Spring mounts).

• Vibrabsorber+Sylomer® Spring mounts



These supports allow a greater displacement than metal-rubber solutions, allowing to obtain lower natural frequencies of between 3-6Hz. Being solutions with low stiffness, their use is recommended for static applications. If stability is also needed, it is recommended to use anti-seismic spring solutions.

4. Position of the mounts

The position of the anti vibration mountings determines the vibration modes of the suspended element. An even load distribution of all the anti vibration mountings is advisable. One easy way of obtaining this is by installing the vibration isolators equidistant to the COG (center of gravity).

Vibration isolators at the COG level provide more stable solutions and avoid excessive movement of the suspended elements, particularly on machines with high eccentricity. Since this is not possible in most of the cases, vibration isolators at different height levels crossing the center of gravity can be of great help for stability and longevity purposes.




Nevertheless even if this feature cannot be achieved, AMC-MECANOCAUCHO® applications engineers will be able to study the limitations of the application and propose positions where the best vibration isolation and stability can be achieved. Contact form AMC-MECANOCAUCHO® Applications engineers.

5. Temperature

In cases where the surrounding temperature is high, the limitations of the elastic element must be considered. The dynamic forces can also produce internal heat within the mount due to the friction. For an application which exceeds 60ºC a correct selection on the rubber compound must be done. AMC-MECANOCAUCHO® applications engineers can calculate and test in the laboratory different vibration isolators in order to reproduce such conditions and verify if the resistance of the vibration isolator is acceptable.

6. Structural limitations of frame

The issue of vehicle interior noise is becoming increasingly important as secondary characteristics such as vibration and sound levels are replacing primary ones such as reliability in vehicle purchasing decisions. Interior noise can come from many different sources, but a common one is booming noise. This phenomena can be generally described as a low frequency (less than 200 Hz) acoustic resonance that is driven by the structure. Structural inputs usually come from either the power train or structural response from road inputs.

In these cases, vibration isolators can mask the problem but they will not be able to resolve the problem as the origin of it is structural. A correctly selected vibration isolator will be able to attenuate the vibration arriving to the vehicle cabin, reducing the boom effect. Rubber compound with low dynamic stiffening properties are especially interesting for these cases. For this purpose AMC-MECANOCAUCHO applications engineers will be able to help and give you advice.

7. Vibration measurements

The previous considerations have taken into account theoretical aspects of the cabin. Empirical results on vibration isolation on cabs can be only understood by making physical vibration measurements. Understanding this data and contrasting it against the theoretical calculations can allow us to progress and find better solutions for our customers.

AMC-MECANOCAUCHO® provides a full service of engineering and vibration measurements for all types of applications. Should you be interested on this topic do not hesitate to contact our applications engineers.

For cases in which we have a lack of information to perform a 6 DOF calculation, a more simplified selection of supports can be achieved.

For cases in which the input data described at the beginning of this article is not available, and you want to make a pre-selection of the supports, please be noted that AMC Mecanocaucho® has developed a new online calculation tool to assist with this selection. This calculation tool is called VIBRATION ISOLATOR PRO WEB.

As the input data is limited, it is recommended to use this tool to get a general idea of what type of support could be used in a certain application. It is always advisable to ask AMC-MECANOCAUCHO applications engineers and get their approval according to the pre-selection carried out.

The Vibration Isolator Pro has been developed to perform anti-vibration calculations in a simple and effective way using basic input data such as the equipment mass and number of mounts. It is accessible as a web version on Mecanocaucho.com and also via our mobile app ‘Vibration Isolator Pro’ which is available for Android and IOS environments.

From our homepage https://www.mecanocaucho.com/en/ you can navigate to the Vibration Isolator Pro Web application. This selection tool will require the input of basic information about the application, while the resultant output will be the most suitable choice of anti-vibration supports from the AMC product range.

In case you have any questions or need clarifications, do not hesitate to contact the AMC MECANOCAUCHO® technical team.