experimental modal analysis in time domain

I have experimental modal data(acceleration and input force) in time domain and i need to find K,M, and c values in matlab , please provide proper steps for how to approach this problem.

Answer 1

[Dhruv]

To obtain K, M, and c values from experimental modal data in the time domain using MATLAB, follow the steps below:

1. Load the experimental data into MATLAB, which includes the acceleration response and the input force.
2. Calculate the frequency response function (FRF) using the measured input and output signals.
3. Estimate the modal parameters (natural frequency, damping ratio, and mode shape) by performing modal analysis on the FRF using either the peak-picking or curve-fitting method.
4. Use the estimated modal parameters to calculate the mass, stiffness, and damping coefficients.
5. Evaluate the accuracy of the estimated modal parameters and coefficients by comparing them to those obtained from theoretical models or other experimental methods.

Refer to the following documentations for further help:

Modal parameters from frequency-response functions - MATLAB modalfit (mathworks.com)

Frequency-response functions for modal analysis - MATLAB modalfrf (mathworks.com)

[Mahmoud Hassan]

@Dhruv

Hi,

Could you please provide any documenation on Point 4: Use the estimated modal parameters to calculate the mass, stiffness, and damping coefficients.

Thanks in advance