Damping

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Damping is defined as energy dissipation property of materials and structures that are subjected to time-variable loading. Damping is associated with irreversible transition of mechanical energy into thermal energy. Energy radiation into a surrounding medium is called radiation or geometric damping (Benaroya 2004).

Damping classification

  • material damping - energy dissipation by deformation in a medium.
  • structural damping - damping in assembled structures at their contact surfaces and interfaces (such as frictional losses, losses at contact surfaces, etc.).
  • radiation damping - energy radiation into the surrounding medium.
  • geometric damping - same as radiation damping.
  • active damping - damping with external energy and control.
  • passive damping - damping without external energy and control.
  • internal damping - damping inside defined system boundary.
  • external damping - damping outside defined system boundary.

Computational models for damping

  • modal damping ratios - applicable for linear elastic analysis of structures with classical damping that can be solved by classical modal analysis
  • damping matrix - damping matrix must be used when classical modal analysis is not applicable. This is the case of structures with nonclassical damping (for both linear and nonlinear analyses) and nonlinear systems with the damping of classical form. To account for all energy dissipating mechanism, the damping matrix should be determined from the damping ratios of the structure and not from member sizes and material damping (Chopra 2002).
    • classical damping matrix - applicable for systems with similar damping mechanism distributed throughout the structure
    • nonclassical damping matrix - applicable for systems that consist of two or more parts with different level of damping, such as a soil-structure system

References

 

Home > Topics > Traditional Analysis Methods e
Fundamentals Traditional analysis methods  · Section properties  · Mohr's Circle  · Interaction diagram
Theory Elasticity equations
Forces and Stresses Torsion  · Flexure  · Shear  · Principal stress
Basic Statics Beam equations  · Moment area method  · Vereschagin's rule  · Stiffness matrix  · Fixed end moments  · Determinate statics  · Indeterminate statics  · Maxwell's theorem of reciprocal displacements  · Betti's law
Influence lines  · Muller-Breslau principle
Basic Dynamics Damping  · Mass matrix  · Damping matrix
Energy Methods External work and strain energy  · Principle of work and energy  · Virtual work method  · Unit load method  · Castigliano's Theorem
Approximate Methods Moment distribution method
Graphical Cremona Diagram

See Also Computational analysis methods
Related Categories Traditional Analysis Methods
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