** JOB: Building on soft soil – M7.0 earthquake
*HEADING
*PREPRINT, MODEL=YES
*PART, NAME=SOIL
... nodes and elements ...
*ELSET, ELSET=INF (for infinite elements)
*SOLID SECTION, ELSET=SOIL, MATERIAL=SOILMAT
*PART, NAME=BUILDING
... beams/columns using B31 elements ...
*MATERIAL, NAME=SOILMAT
*ELASTIC
50e6, 0.3 (E, nu for soft clay)
*DAMPING, BETA=0.01 (Rayleigh beta only)
*STEP, NAME=Geostress
*GEOSTATIC
*DLOAD
SOIL, GRAV, 9.81
*STEP, NAME=Earthquake, NLGEOM=YES
*DYNAMIC, EXPLICIT
, 20.0 (20 sec duration)
*BOUNDARY, TYPE=VELOCITY
BASE, 1, 1, v_x(t) (velocity history)
*CONTACT
*END STEP
Earthquake-induced pounding is a high-nonlinearity, short-duration event best solved in Explicit. Use:
After analysis, run *FREQUENCY extraction on deformed configuration to monitor period elongation – a key indicator of structural softening. abaqus earthquake analysis