Highspeed Dynamics

MAXWELL DAMPING

Systems undergoing dynamic loading, such as an earthquake or explosive blast, naturally dissipate vibrational energy over time. For a dynamic numerical analysis, some form of artificial damping needs to applied so that the model should reproduces such energy losses.

FLAC3D 9 introduces Maxwell dynamic damping for time-domain seismic deformation analyses. FLAC3D models using Maxwell damping can be 10-200 times faster, and as accurate, than those models using Rayleigh damping. With Maxwell damping, large, 3D site response and soil-structure interaction are now practical to analyze.

SOIL STRUCTURE INTERACTION

For example, the FLAC3D 9 model shown below simulates a caisson foundation, using shell elements, which is much stiffer than the surrounding soils. This model consists of nearly 100,000 zones and over 15,000 structural shell elements.

An analysis of a 30-second earthquake input time history for this model, using a typical computer, requires approximately 10 hours using Maxwell damping, whereas it would require more than 50 days when Rayleigh damping was used. In other words, using Maxwell damping, the calculation is 120 times faster for this model. This is a substantial benefit for similar practical projects.

FLAC3D soil structure interaction model subjected to an earthquake. Displacements are exaggerated using a deformation factor of 20,000x.

RAMBERG-OSGOOD HYSTERETIC DAMPING

The Ramberg-Osgood model has also been added as one of several hysteretic damping calculations for dynamic modeling. The Ramberg-Osgood hysteretic model overcomes the shortcoming of overly large damping at large shear strains by other available hysteretic damping models in FLAC3D. Hysteretic damping may be preferred where: (1) designers and licensing authorities do not accept fully nonlinear simulations and (2) faster model run times are desired, as additional damping (e.g., Rayleigh) may not be necessary.


Latest News
  • 3DEC 9 Officially Released ITASCA announces the release of 3DEC v9, an advanced three-dimensional, hybrid discontinuum and continuum modeling...
    Read More
  • A Big Hand of Applause for Our 2023 Summer Interns ITASCA Minneapolis would like to extend our sincerest thanks to our 2023 summer interns for...
    Read More
  • Itasca has announced the release of FLAC2D v9 Itasca has announced the release of FLAC2D v9, revolutionizing the way we analyze and predict...
    Read More

Upcoming Events
22 Feb
MGS Geotechnical Engineering Conference
The MGS Geotechnical Engineering Conference provides a forum to interact with peers, meet specialty contractors, and hear researchers a... Read More
25 Feb
SME MINEXCHANGE Conference & Expo
SME's annual conference and expo, MINEEXCHANGE, brings together mining and mineral industry professionals to share best practices and i... Read More
13 Mar
Getting Started with 3DEC
Objectives of the training: Understand the 3DEC numerical approach and the types of problems it can solveKnow how to manipulate the 3DE... Read More