Rayleigh Damping Coefficient Calculation



As Rayleigh Damping Coefficient Calculation, there is an excel formulation for alpha and beta calculation. In Excel, we can obtain alpha and beta based on natural frequencies and the coefficient of amplification. 

Rayleigh damping is a method used in structural and mechanical engineering to model the damping in a system. It is a simplified approach that uses two parameters, typically denoted as alpha (α) and beta (β), to characterize the damping properties of a system. These parameters are used to create a damping matrix in finite element analysis, and they are calculated based on certain criteria.

To calculate the Rayleigh damping coefficients alpha and beta in Excel, you need to have the natural frequencies of the system and the coefficient of amplification. The general equation for Rayleigh damping is:

C = α * M + β * K


  • C is the damping matrix
  • M is the mass matrix
  • K is the stiffness matrix

The alpha (α) and beta (β) coefficients are scalar values that scale the contributions of the mass and stiffness matrices to the overall damping.

Here's how you can calculate alpha and beta in Excel:

  1. Obtain the natural frequencies of your system. These are the frequencies at which the system vibrates when there is no damping.

  2. Determine the coefficient of amplification. This is a value that characterizes the amplification of motion in the damped system compared to the undamped system at a specific frequency. It is often provided in the problem statement or can be calculated from experimental data.

  3. Set up a system of equations based on the Rayleigh damping equation:

    For the first natural frequency (ω1): α * ω1 + β * ω1^2 = ξ * ω1

    For the second natural frequency (ω2): α * ω2 + β * ω2^2 = ξ * ω2

    You'll have as many equations as you have natural frequencies.

  4. Solve this system of equations in Excel. You can use Excel's solver or other mathematical techniques to find values for alpha (α) and beta (β) that satisfy the equations.

  5. Once you've solved for α and β, you can use them to create your damping matrix for use in finite element analysis or structural analysis.

The damping coefficients α and β are essential for modeling the system's dynamic behavior, as they control the amount of energy dissipation in the system. By knowing the natural frequencies and the coefficient of amplification, you can use Excel to calculate these coefficients, which are crucial for accurate simulations and analysis of damped systems in engineering applications.

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07 Nov 2023
Last Modified
07 Nov 2023
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166.85 Kb
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File Author:
Alper Akis

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Comments: 1
JohnDoyle[Admin] 4 months ago
A useful debut calculation! Thanks for sharing! I have awarded a three month XLC Pro subscription by way of thanks.