r4.02.05 Absorbing border elements

Summary

This document describes the layout of absorbent boundary elements in code_aster. These paraxial elements, whose theory is described here, are assigned to elastic or fluid domain boundaries to deal with 2D or 3D soil-structure or soil-fluid-structure interaction problems. They make it possible to satisfy the Sommerfeld condition verifying the hypothesis of anechoicity: the elimination of diffracted and non-physical elastic or acoustic plane waves coming from infinity.

• 1. Introduction
  • 1.1. Problem of a semi-infinite medium for ISS
  • 1.2. State of the art of digital approaches
• 2. Paraxial element theory
  • 2.1. Boundary spectral impedance
  • 2.2. Paraxial approximation of impedance
  • 2.3. Taking into account the incident seismic field
• 3. Transient anechoic fluid elements
  • 3.1. Standard formulation
  • 3.2. Impedance of vibro-acoustic elements in code_aster
  • 3.3. Usage in code_aster
• 4. Elastic absorbent elements in code_aster
  • 4.1. Adaptation of seismic loading to paraxial elements
  • 4.2. Implementation of transient and harmonic elements
  • 4.3. Plane wave seismic loading mode
  • 4.4. Inclined plane wave loading
  • 4.5. Usage in code_aster
• 5. Bibliography