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Damping materials in mechanics and construction: ideas, applications and advantages

Damping

Damping materials are essential in mechanics and construction. They are used to absorb shocks and vibrations and to improve the operation of machines and systems. Due to their unique properties, they can be used in various mechanical and technical applications. This article describes different types of damping and elastic materials, as well as their application in mechanics and construction. This article deals with different types of damping materials, how they are used in mechanical applications and what specific properties they have.

Why does it make sense to use damping materials in mechanics?

Damping materials can be used in mechanics as vibration dampers to reduce vibration, shock and/or noise generated by mechanical systems such as motors, transmissions and other components. By reducing vibration and noise emissions from mechanical systems, overall system performance, reliability and safety are improved. By effectively dampening your system, you optimize the properties of your application and reduce the risk of damage or failure. Since the use of damping materials minimizes the material stress caused by vibrations, they significantly increase the lifetime of a mechanical system.

Types of damping materials

There are different types of damping materials that can be used efficiently in mechanics and construction. These include polyurethanes, elastomers and foams. Each material has its own specific properties that must be considered for the respective application and the possible solutions. The choice of damping material depends on the specific requirements of the system, such as the frequency of the vibration or the intensity of the shock.

Polyurethane rubber

Polyurethane rubber has good vibration dampening properties. It has excellent mechanical strength and, in combination with its high abrasion resistance, it is particularly durable. Since polyurethane rubber has pronounced vibration-damping properties, it effectively cushions shocks and absorbs the resulting energy. It also has excellent oil resistance and is primarily suitable for use in dry and chemical-free environments. Depending on the application area, particularly heat-resistant, antistatic or abrasion-resistant forms of polyurethane rubber can be used.

Properties of polyurethane
Designation Unit Polyurethane rubber
Standard Vulkollan® Abrasion-resistant Ceramic polyurethane rubber Heat-resistant Rebound arm Very soft
Hardness Shore A 95 90 70 50 30 92 68 90 70 95 90 70 50 90 70 15
Specific gravity g/cm³ 1.13 1.13 1.20 1.20 1.20 1.26 1.20 1.13 1.13 1.2 1.15 1.13 1.03 1.02
Tensile strength MPa 44 27 56 47 27 45.5 60 44.6 31.3 42 26 53 45 44.6 11.8 0.6
Elongation % 380 470 720 520 600 690 650 530 650 360 440 680 490 530 250 445
Heat stability up to °C 70 80 (short-term 120) 70 70 120 70 80
Low temperature resistance up to °C -40 -20 -20 -20 -40 -20 -20 -20 -40
Note: The characteristic values for tensile strength and elongation are measured according to JIS standard K6251.

Elastomers

Elastomers are used in a wide range of mechanical applications. Elastomers commonly used in industrial applications include:

  • Nitrile Rubber (NBR)
  • Chloroprene Rubber (CR)
  • Ethylene Rubber (EPDM)
  • Butyl Rubber (IIR)
  • Fluororubber (FPM)
  • Silicone rubber (SI)
  • Hard rubber
  • Natural Rubber (NR)

Elastomers are very versatile and can be used in different designs for a wide variety of applications. Elastomers generally have a pronounced damping effect and can therefore withstand even strong vibrations and shocks. Depending on the type of caoutchouc used, the material has particularly chemical and temperature resistant properties and can be used in applications where a high level of shock absorption is required.

Properties of caoutchouc
Designation Unit Nitrile rubber (NBR) Chloroprene rubber (CR) Ethylene rubber (EPDM) Butyl rubber (IIR) Fluororubber (FPM) Silicone rubber (SI) Hard rubber (Hanenaito®) Natural Rubber (NR)
Standard High-strength version
Hardness Shore A 70 50 65 65 65 80 60 70 50 50 57 32 45
Specific gravity g/cm³ 1.60 1.30 1.60 1.20 1.50 1.80 1.90 1.20 1.20 1.30 1.20 0.90
Tensile strength MPa 12.7 4.4 13.3 12.8 7.5 12.5 10.8 7.4 8.8 7.8 8.3 10.3 16.1
Elongation % 370 400 460 490 380 330 270 300 330 400 810 840 730
Max. Operating temperature °C 90 99 100 120 120 230 200 200 60 70
Temperature for continuous use °C 80 80 80 80 210 150 150 30 70
Low temperature resistance up to °C -10 -35 -40 -30 -10 -70 -50 10 0
Note: The characteristic values for tensile strength and elongation are measured according to JIS standard K6251.

Foams

Foams are able to effectively dampen vibrations by absorbing the energy of the vibration through a multitude of individual pores. They are very flexible and can also be installed on uneven or curved surfaces. They have good elasticity and, due to their porosity and low weight, can be used in a variety of ways to minimize vibrations and dampen sound. Another advantage of foam is the wide frequency range in which it can absorb vibrations.

What are shock absorbers used for in mechanics?

Shock absorbers are used in mechanics to reduce or dampen the motion of an object or system. They can also prevent delays that can cause vibrations and oscillations in mechanical systems. Shock absorbers are often used in mechanical systems to absorb shocks and dampen the speed of moving objects, when they change direction or encounter an impact. Often used to dampen hydraulic systems (e.g. oil), which allows for a compact design and robust operating characteristics.

In this data sheet MISUMI shows an application example for “shock absorbers in mechanics”.

How the damping characteristics affect your application

The damping characteristics are an important factor in selecting the right shock absorber for an application. This characteristic describes the behavior of the damper depending on the speed and deflection of the moving object.

There are different types of damping characteristics which are determined by the size, number and alignment of the openings between the pressure chamber and the pressure accumulator inside the shock absorber.

Damper, classification according to the damping characteristics

Damper, classification according to the damping characteristics
Structure Execution by prefabricated force Description
One opening S-design
Type A
Type B
Type L		 Type A, B, L A single hole design has the same resistance properties as a slotted design with space between the piston and cylinder, a single pipe design with an opening in the piston, or a double pipe design and one single opening.
A piston with one opening runs in an oil-filled cylinder. Since the opening area is the same throughout the stroke, the resistance is greatest immediately after an impact and then decreases evenly throughout the rest of the stroke.		 Graph
Multiple irregular openings Medium speed Type A, B, L In this double pipe design, the piston runs in the inner pipe. This inner pipe has several openings in the direction of lift and not only constant energy, but also energy from different sources can be absorbed. Designed for the absorption of kinetic energy during the first half of the stroke and regulation of the speed during the second half. Therefore, it is well suited for the absorption of energy in connection with air cylinders. Graph
Multiple openings High speed
H-design		 H-design In this double pipe design, the piston runs in the inner pipe. It has several openings in the direction of lift. Since the openings slowly become smaller at a decreasing lifting speed, the resistance remains relatively constant, even if it is slightly wave-like. Graph

How do you choose the right shock absorber for your application?

When selecting the right shock absorber for an application, other factors must be considered in addition to the damping characteristics in order to achieve an optimal damping effect. To determine the correct shock absorber for your application, the following calculations and tests must be performed:

  • Calculation of inertial energy
  • Calculating the temporary damper stroke
  • Calculating excess energy
  • Calculation of total energy
  • Checking the Maximum Equivalent Mass
  • Selection of damping characteristics
  • Check the maximum energy consumed per minute

The choice of shock absorber depends on the type of application. For example, high-speed applications require shock absorbers with a higher damping capacity.

The temperature and ambient conditions must be considered to achieve optimal performance. Careful selection and installation of shock absorbers can help extend the lifetime of mechanical systems and minimize noise and vibration.

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Product overview in the MISUMI catalog