Numerical evaluation of the damping-solvent extraction method in the frequency domain by Ushnish Basu and Anil K. Chopra, Earthquake Engng Struct. Dyn. 2002; 31(6):1231–1250

✍ Scribed by Chongmin Song; John P. Wolf

• Publisher: John Wiley and Sons
• Year: 2003
• Tongue: English
• Weight: 81 KB
• Volume: 32
• Category: Article
• ISSN: 0098-8847
• DOI: 10.1002/eqe.280

✦ Synopsis

The Discussers appreciate the interest of the Authors in the damping-solvent extraction method, which permits modelling of unbounded domains by introducing artiÿcial damping and extracting its e ect. An independent evaluation based even on simple examples will lead to an increase in conÿdence and experience which is essential for this appealing mechanically-based method to be used by engineers in practice.

In this discussion three statements of the Authors, shown in italics in the following, are analysed. This permits the rules to choose the computational parameters (domain size, artiÿcial damping ratio, mesh density) to be stated which are also based on more general and realistic cases (besides a half-plane also a layer with cut-o frequencies and an embedded foundation) described in Ref. 8 of the Authors paper, in particular for the examples of [12][13][14][12][13][14][15][16] In addition, insight into the nature of the approximation in the damping-solvent extraction method is provided.

• There does not seem to be any systematic way of choosing the domain size necessary to achieve a speciÿed accuracy (page 1238). Choosing the domain size to ensure that the static sti ness is computed accurately leads to an unnecessarily large domain for analysis at higher frequencies (page 1231, Summary; page 1245 Conclusions).