A5090986160- Seismic Performance and Analysis
- Structural Health Monitoring Techniques
- Structural Engineering and Vibration Analysis
- Seismology and Earthquake Studies
- Seismic Waves and Analysis
- Vibration and Dynamic Analysis
- Machine Learning in Materials Science
- Geotechnical Engineering and Underground Structures
- Electrocatalysts for Energy Conversion
- Structural Response to Dynamic Loads
- Geophysics and Sensor Technology
- earthquake and tectonic studies
- Computational Drug Discovery Methods
- Fluid Dynamics Simulations and Interactions
- Structural Analysis and Optimization
- Masonry and Concrete Structural Analysis
- Catalytic Processes in Materials Science
- Fuel Cells and Related Materials
- Formal Methods in Verification
- Seismic and Structural Analysis of Tall Buildings
- Software Reliability and Analysis Research
- Probabilistic and Robust Engineering Design
- Surface Chemistry and Catalysis
- Vibration Control and Rheological Fluids
- Meteorological Phenomena and Simulations
SLAC National Accelerator Laboratory
2019
Stanford University
2018-2019
Interface (United States)
2019
Stanford Synchrotron Radiation Lightsource
2019
Community Health and Emergency Services
2018
Technical University of Denmark
2016-2017
University of Birmingham
2012-2015
California Institute of Technology
1985-2013
The Edgbaston Hospital
2013
Iowa State University
2010-2012
The atomic simulation environment (ASE) is a software package written in the Python programming language with aim of setting up, steering, and analyzing atomistic simulations. In ASE, tasks are fully scripted Python. powerful syntax combined NumPy array library make it possible to perform very complex tasks. For example, sequence calculations may be performed use simple 'for-loop' construction. Calculations energy, forces, stresses other quantities through interfaces many external electronic...
abstract In this study of the dynamics building-soil interaction, soil is modeled by a linear elastic half-space, and building structure an n-degree-of-freedom oscillator. Both earthquake response steady-state to sinusoidal excitation are examined. By assuming that interaction system possesses n+2 significant resonant frequencies, reduced superposition responses damped oscillators subjected modified excitations. The results valid even though systems do not possess classical normal modes. For...
Abstract Materials discovery is increasingly being impelled by machine learning methods that rely on pre-existing datasets. Where datasets are lacking, unbiased data generation can be achieved with genetic algorithms. Here a model trained on-the-fly as computationally inexpensive energy predictor before analyzing how to augment convergence in algorithm-based approaches using the surrogate. This leads accelerated algorithm combining robust qualities of rapid learning. The approach used search...
We present the incorporation of a surrogate Gaussian process regression (GPR) atomistic model to greatly accelerate rate convergence classical nudged elastic band (NEB) calculations. In our approach, cost converging no longer scales with number moving images on path. This provides far more efficient and robust transition state search. contrast conventional NEB calculation, algorithm presented here eliminates any need for manipulating obtain converged result. is achieved by inventing new...
Abstract Strong shaking of structures during large earthquakes may result in some cases partial separation the base structure from foundation. A simplified problem this type, dynamic response a rocking rigid block allowed to uplift, is examined here. Two foundation models are considered: Winkler and much simpler ‘two‐spring’ It shown that an equivalence between these two can be established, so one work with two‐spring Simple solutions equations motion developed methods analysis proposed. In...
abstract A numerical method for computing response spectra from strong-motion earthquake records is developed, based on the exact solution to governing differential equation. The gives a three four-fold saving in time compared third order Runge-Kutta of comparable accuracy. An analysis also made errors introduced at various stages calculation so that allowable can be prescribed integration. Using proposed or other methods accuracy, example calculations show by procedures are much less than...
Abstract The problem of determining linear models structures from seismic response data is investigated using ideas the theory system identification. approach to determine optimal estimates model parameters by minimizing a selected measure‐of‐fit between responses structure and model. Because earthquake records are normally available only small number locations in structure, because noise records, it necessary practice estimate dominant modes rather than stiffness damping matrices A new...
A general nonlinear hysteretic force-deflection relation for a one degree-of-freedom structure is presented. The continuous, smooth function and describes yielding behavior varying between the limits of linear elasto-plastic cases. steady-state response to sinusoidal excitation having these properties investigated, resonant amplitude frequency curves are obtained. typical family verified by numerical integration equation motion. equivalent viscous damping factor determined. It concluded that...
The two-dimensional scattering and diffraction of SH waves arbitrary angle incidence from irregular, canyon-shaped topography is formulated in terms an integral equation. Taking advantage the simple boundary conditions SH-wave problems, method images applied to reduce equation one with a finite integral, which can readily be solved numerically by available methods. The first analytically case cylindrical canyon verify its accuracy, then two idealized cross sections based upon Pacoima...
A technique is presented for determination of local magnitude, M_L, from strong-motion accelerograms. The accelerograph records are used as an acceleration input to the equation motion Wood-Anderson torsion seismograph produce a synthetic seismogram which then read in standard manner. When applied 14 San Fernando earthquake, resulting M_L 6.35, with deviation 0.26. This good agreement previously reported value 6.3. also other earthquakes western United States available. An average = 7.2...
The paper treats the application of concept equivalent viscous damping to steady-state response simple yielding structures subjected sinusoidal excitation. Using elasto-plastic oscillator as an example, it is shown that results differing by several hundred per cent can be obtained, depending on way resonant frequency shift characteristic modeled. It concluded amplitude matching produce most useful for purposes, and this approach meaningful also earthquake response. When applied oscillator,...
The effect of gravity on the earthquake response one-degree freedom yielding structures is studied by subjecting them to simulated excitation. Interest centered time required for progressing point collapse. results show that increase significantly development permanent set, over occurring when ignored. Because increases as deflection grows, set rapidly just prior failure. statistics elasto plastic indicate average failure inversely proportional square ratio strength lateral yield level...
The dynamic response of a finite flexible pile, partially embedded in an elastic half‐space and under transverse loadings, is discussed. loadings are applied at the unembedded end pile may, general, be combination time‐harmonic lateral shear force moment. By treating as one‐dimensional structure three‐dimensional continuum, interaction problem formulated Fredholm integral equation second kind, which solved by appropriate numerical procedure. Selected results presented to illustrate basic...
Density functional theory calculations are performed on 38 and 79 metal atom truncated octahedron clusters to study oxygen dissociation as a model for the initial stage of reduction reaction. Pure platinum alloyed platinum-titanium core-shell systems investigated. It is found that barrierless occurs (111) facet pure clusters. A barrier ~0.3 eV observed (100) facet. For cluster, barriers both facets, typically ~0.6 eV. The differences between two attributed ability distort surface We show...
abstract The Millikan Library Building, a nine-story reinforced concrete shear-wall structure at the California Institute of Technology, was tested dynamically by means two eccentric mass vibration generators located on ninth floor. response levels ranged up to maximum acceleration 0:02 g. natural periods vibration, mode shapes and energy dissipation were measured for first second E-W translational modes, N-S fundamental torsional mode. Soil-structure interaction investigated measuring...
Abstract Horizontal ground motion generated by vibration tests of the nine-story Millikan Library Building on Caltech campus was recorded surface in Pasadena area at distances up to 3 miles from building. Later it learned that vertical component also seismograph Mt. Wilson, 6.7 and 4,800 ft higher elevation. The magnitude acceleration varied 2.04 × 10-2g excitation level ninth floor building 3.2 10-7g Wilson. Simple calculations show multistory buildings are particularly well-suited for...
A simple instrument was developed to estimate hail energy input per unit area. By using certain simplifying assumptions, the instruments have been calibrated in laboratory permit estimates of from measurements dent size and number dents Special effects noted during field use a large these are described. It is estimated that, although absolute error estimating hail- may exceed 300 cent, comparative by this equipment approximately 50 percent.
Abstract The rigid body motions of the bridge deck, along with impact between deck and abutments, were source extensive damage on skew highway bridges during 1971 San Fernando earthquake. In this paper, a model for is presented analysed. focus appropriate representation abutments explanation inducement in‐plane rotational vibrations as result impact. A simplified briefly described first, kinematic mechanism problem explained. Then, analysis more detailed realistic follows. This applied short...
Abstract A mathematical formulation is presented for modelling the dynamic process of failure a class ductile, moment‐resisting, reinforced concrete (R/C) frame buildings when subjected to intense earthquake motion. The includes geometrically non‐linear term that accounts destabilizing action gravity. In many cases practical interest, in which structures have strong columns and weak girders, employed method synthesizing restoring force properties can provide satisfactory description...