FEM Model of Biot’s Equation Free from Volume Locking and Hourglass Instability

Abstract eng:
A finite element modeling for liquefaction analysis that is free from volume locking and hourglass instability is proposed. Volume locking occurs when no or very small volume change is expected, which occurs under undrained condition or similar in liquefaction analysis, because bulk modulus of water is much larger than that of soil skeleton and volume of porewater hardly changes. On the other hand, hourglass instability occurs under excess reduced integration which is used to avoid volume locking. Proposed finite element formulation is based on so called u-U formulation, and different numerical integration schemes are employed for porewater and soil skeleton: ordinary integration for soil skeleton and reduced integration for all other element matrices. Numerical examples are made to evaluate effectiveness and accuracy of the proposed method by comparing other existing methods. The proposed method is shown to be accurate and also it is free from both volume locking and hourglass instability.

• Export as: BibTeX | MARC | MARCXML | DC | EndNote | NLM | RefWorks
• Add to your basket