A finite model truncates an infinite domain. Seismic waves reflect from artificial boundaries, causing spurious amplifications. Solution: Use Infinite Elements (CIN3D8) or Dashpots / Low-Reflection Boundaries.
Step 1: Build the FE model
Step 2: Perform eigenvalue extraction
*STEP, NAME=Eigen, PERTURBATION
*FREQUENCY, EIGENSOLVER=LANCZOS, NORMALIZATION=MASS
20
*END STEP
Step 3: Apply gravity load (static step) abaqus earthquake analysis
*STEP, NAME=Gravity, NLGEOM=YES
*STATIC
0.01, 1.0
*DLOAD
ALL_ELEMS, GRAV, 9.81, 0., -1., 0.
*END STEP
Step 4: Seismic time history step
*STEP, NAME=Earthquake, NLGEOM=YES, INC=10000
*DYNAMIC, HHT-ALPHA=-0.05
0.01, 30.0, 1e-7, 0.01
*BOUNDARY, TYPE=ACCELERATION, LOAD CASE=1
BASE_NODE, 1, 1, 9.81
*AMPLITUDE, NAME=ACC_X, INPUT=eq_x.txt
*DAMPING, ALPHA=0.12, BETA=0.002
*END STEP
Earthquake engineering relies heavily on numerical simulation to predict how structures will respond to seismic activity. Abaqus, developed by Dassault Systèmes, is one of the industry-standard software packages for this purpose due to its robust non-linear capabilities and extensive material models. A finite model truncates an infinite domain
This guide provides an overview of the workflows, methods, and best practices for conducting earthquake analysis in Abaqus. Step 3: Apply gravity load (static step) *STEP,