MASTODON Newsletter (Fall 2018)
R&D100 Awards
MASTODON was selected as a finalist for the 2018 R&D100 awards.
Beam Elements in MASTODON
Geometrically nonlinear beam and lumped mass/inertia elements have been recently added to MASTODON. These elements can now be used to model structures using stick-mass models. As a test scenario, a stick-mass model of a nuclear power plant from the SASSI manual (Ostadan, 2006) (Figure 1) was modeled using MASTODON and LS-DYNA. The first 15 natural frequencies of the MASTODON model agree well with the SASSI and the corresponding LS-DYNA models, and the spectral acceleration at a location on the structure matches well with the LS-DYNA results as shown in Figure 2.
Figure 1: Illustration of a representative nuclear power plant structure and the corresponding stick mass models from SASSI manual.
Figure 2: Comparison between spectral acceleration at a location on this structure obtained using MASTODON and LS-DYNA for ground motion applied at the base of the stick-mass models.
Structural Dynamics Laboratory
The Facility Risk Group is setting up the Structural Dynamics Laboratory (SDL) at INL to collect data by conducting a series of experiments. The first set of experiments focus on the interface behavior of soil and structures. For this purpose, a reaction frame has been designed to house a soil box and two high capacity actuators. The data is collected by state-of-the-art equipment including slip sensors, string potentiometers, load cells and high-resolution cameras. The collected data, along with the existing literature, will be the basis for the soil-structure interface models that will be integrated to MASTODON.
Figure 3: Photograph of the soil box and the reaction frame in the structural dynamics laboratory.
Facility Risk Group Presents at the NPH Workshop
The DOE Natural Phenomena Hazards (NPH) meeting was held on the 23rd and 24th of October and was attended by various professionals working on the safety of nuclear structures from seismic and other natural hazards. There were four talks from the Facility Risk Group:
"Idaho National Laboratory Nuclear Safety Research Program", Justin Coleman
"Towards a Risk-Based, Cost-Optimized Design of Safety-Related Nuclear Structures and Facilities", Chandu Bolisetti
"Impact of Topographic Effects on Site Response at Nuclear Facility Sites", Swetha Veeraraghavan
"Preliminary Investigation of Effects of Sliding and Gapping Phenomena in Soil-Structure Interaction Modeling", Efe Kurt
Figure 4: Illustration of risk-informed and risk-based design methodologies.
References
- Farhang Ostadan.
SASSI - A System for Analysis of Soil Structure Interaction - User's Manual.
University of California, Berkeley, California, 2006.[BibTeX]