TEST CASE 8.5 HARMONIC EXCITATION
Reference:
Analytical solution.
Problem description:
The accelerogram is considered in the form of a sinusoid, that is, the acceleration at time t is equal to sin(t). The response spectrum calculated by the program and obtained analytically is analyzed. The case is considered when the oscillation damping coefficient is equal to 15% of the critical value (the logarithmic damping decrement is equal to 0.953263).
Initial data:
Damping: β = 0.15;
Amplitude value of accelerogram acceleration: a_{0} = 1 m/sec^{2};
Seismic exposure time: t_{d}_{ }= 19.9 sec;
Circular frequency: θ = 30 rad/sec.
Files with initial data:
8_5.ar1 — input accelerogram;
8_5.txt — obtained response spectrum;
8_5_result.txt — comparison of spectra.
Analytical solution:
Calculation results:
Target value |
Analytical solution |
LIRA 10 |
Deviation, % |
Maximum acceleration on the spectrum |
3.175 |
3.157 |
0.57 |
Frequency corresponding to maximum acceleration, Hz |
0.166 |
0.17 |
2.4 |
Graphical comparison of the response spectra of accelerations obtained in the SP LIRA 10 and analytically: