Analysis
Earthquake analysis
Transient analysis under ground motion, with Rayleigh damping.
Run Earthquake Analysis is a Newmark transient analysis (average acceleration, γ = 0.5, β = 0.25) under UniformExcitation patterns. Results are relative to the moving ground.
Workflow
- Import a record into a Path time series.
- Add a UniformExcitation load pattern that uses it, with a direction.
- Assign masses.
- Add the recorder with velocity and acceleration enabled if you want those results.
- Add the earthquake block and run.
Options
| Option | Default | Meaning |
|---|---|---|
| Patterns | — | The ground-motion patterns |
| dt | 0.01 | Time step |
| Steps | 1000 | Number of steps |
| Damping | — | See below |
| Convergence | — | See Convergence settings |
Rayleigh damping
| Mode | Inputs |
|---|---|
| Modal periods | Two named modes (such as T1 and T3) and a damping percentage |
| Anchor periods | Two periods and a damping percentage |
| Coefficients | alphaM and betaK, with C = αM·M + βK·K on the current stiffness |
The form shows the solved periods, or an error if they cannot be found. Modal damping needs mass and enough modes.