*AMPLITUDE, NAME=EQ, TIME=TOTAL TIME, VALUE=RELATIVE 0, 0, 0.02, 0.1, ... (time, acceleration)
This is the most debated topic in Abaqus earthquake analysis. Real structures have damping (energy loss) that numerical models do not inherently possess. Without damping, the model will vibrate indefinitely. abaqus earthquake analysis
using *BOUNDARY with prescribed acceleration on base nodes. *AMPLITUDE, NAME=EQ, TIME=TOTAL TIME, VALUE=RELATIVE 0, 0, 0
| Pitfall | Solution | |---------|----------| | Using implicit solver for high-frequency motion | Use explicit for > 10 Hz content or strong nonlinearity. | | Incorrect Rayleigh damping causing energy growth | Check frequency range; use *ENERGY PRINT to verify. | | Boundary reflections in SSI model | Use infinite elements or absorbent boundaries (viscous or Lysmer–Kuhlemeyer). | | Mass scaling too aggressive | Keep mass scaling factor < 5; monitor ALLPM (percent mass increase). | | Ignoring P-Delta effects | Activate NLGEOM=YES even for small strains. | Without damping, the model will vibrate indefinitely
Abaqus, powered by the SIMULIA suite from Dassault Systèmes, is the gold standard for finite element analysis (FEA) in geotechnical and structural earthquake engineering. Unlike linear solvers, Abaqus allows engineers to model the harsh realities of seismic events: soil liquefaction, steel yielding, concrete cracking, base isolation, and soil-structure interaction (SSI).
*Damping, alpha=alpha_factor, beta=beta_factor
By following the guidelines in this article, you are now equipped to perform robust, defensible seismic simulations. For further study, consult the official Abaqus Benchmarks Manual – specifically the examples on "Seismic analysis of a concrete gravity dam" and "Soil-pile interaction."