How do you select a structural damping material?

1 Types of damping materials

There are three main categories of damping materials: passive, active, and hybrid. Passive damping materials are those that absorb and dissipate energy without requiring external power or control. Examples of passive damping materials are viscoelastic polymers, rubber, metal foams, and concrete. Active damping materials are those that use sensors, actuators, and controllers to apply counteracting forces or displacements to the structure. Examples of active damping materials are piezoelectric ceramics, magnetostrictive alloys, and shape memory alloys. Hybrid damping materials are those that combine passive and active elements to achieve enhanced performance. Examples of hybrid damping materials are tuned mass dampers, base isolation systems, and semi-active dampers.

2 Properties of damping materials

The properties of damping materials depend on their composition, structure, and interaction with the dynamic system. When measuring and comparing these materials, it is important to consider the damping ratio, which indicates how effectively the material reduces vibrations; the damping capacity, which reflects the material's ability to absorb and convert energy; the damping frequency, which depends on the material's stiffness and mass; and the damping temperature, which affects its durability and reliability.

4 Criteria for selecting a damping material

When selecting a damping material, several factors need to be taken into account, such as the type, size, shape, and function of the structure, the nature, intensity, and frequency of the dynamic loads, the desired level of damping performance, the available budget and resources, and the environmental and operational conditions. The criteria for choosing a damping material include compatibility with the structural material, loading conditions, and design objectives; effectiveness in providing sufficient damping ratio, capacity, frequency, and temperature; efficiency in optimizing material usage; durability to maintain properties over time; and sustainability to minimize environmental impact.

5 Examples of damping materials

To demonstrate how different damping materials can be applied to different structures and scenarios, here are several examples. Viscoelastic polymers are passive damping materials composed of long-chain molecules that deform and relax under stress, dissipating energy as heat. These polymers are often used as coatings, adhesives, or inserts in composite structures like wind turbine blades, aircraft wings, and bridges to reduce vibrations and noise. Piezoelectric ceramics are active damping materials that generate electric charges when subjected to mechanical strain, and vice versa. These ceramics are usually implemented as sensors and actuators in smart structures such as buildings, dams, and satellites to monitor and control vibrations and displacements. Tuned mass dampers are hybrid damping materials that consist of a secondary mass attached to a spring and a damper, tuned to resonate with the primary structure. They are typically used as counterweights in tall structures like skyscrapers, towers, and chimneys to balance and dampen the sway and oscillation.

6 Here’s what else to consider

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