Soil Behavior from Unconventional Loading Conditions
Random and sinusoidal loading conditions were used in this study to determine the soil moduli and the damping ratios of cohesive soil samples. Test results showed some differences between...
Experimental Photoelastic Analysis of Tunnels Containing Cracks
Due to the presence of cracks the strength of the structure is decreased in the present paper an experimental two dimensional photoelastic technique has been developed to analyze the circular...
Dynamic Analysis of Sliding Seismic Isolators
The friction pendulum system (FPS) sliding seismic isolators are being used for the seismic isolation rehabilitation of the U.S. Court of Appeals Building, San Fransisco. This paper will...
Direct Tensile Test: Stability and Bifurcation
Unnotched specimens of quasibrittle materials that exhibit post-peak strain softening do not deform symmetrically in a direct tension test. The phenomenon (which is similar to the recently...
Determination of In-Situ Stresses From Acoustic Emissions
Acoustic emissions (AE) are microseismic activities that are generated in concrete by cracking and damage. The rate of Acoustic Emissions, called the 'Event Rate', can provide indication...
Evaluating Polymer Concrete Bridge Expansion Joints Using Acoustic Emission
This study is to simulate the acoustic emission (A/E) of polymer concrete bridge expansion joints subjected to controlled representative loads by a rotating test apparatus on a circular...
Micromechanical Simulation of Wave Propagation in Dense Granular Assemblies
Two-dimensional DEM with modified Mindlin's contact law has been used to study the load transfer mechanisms in 'consolidated' granular assemblies. Results of simulation are presented and...
Neural Network Modeling of the Mechanical Behavior of Sand
Given a set of triaxial test data, an artificial neural network (ANN) has been trained to model the mechanical behavior of a medium-to-fine sand. Once trained, the ANN was tested by simulating...
Computer Simulation of Direct Shear Test
This paper presents a pilot study of a computer simulation of direct shear test on sands using the Discrete Element Method. The numerical test setup is described first, which is followed...
Stochastic Modeling of Fatigue Crack Growth with Retardation
This paper develops a new methodology for modeling fatigue crack growth accounting for both material inhomogeneity and the random nature of the loading process by modeling the crack growth...
Vortex Suppression in Wet-Pit Pump Intakes
Two distinct examples to suppress both air-entraining and boundary-attached subsurface vortices in large vertical pump intakes are presented that were developed by means of hydraulic model...
Automated Identification of Compression-Induced Cracking in Cement Paste
The development of image analysis techniques to identify cracks using scanning electron microscope images of hydrated cement paste is described. Cracks are identified based on both the...
High-Resolution Interwell Seismic Experiments in Sedimentary Formations
High-frequency interwell seismic data were acquired to examine full waveforms recorded in the pulsed mode and in the swept mode as well as to perform traveltime inversion tomography for...
A Wax-Coupled Borehole Seismic Detector for High-Resolution Measurements
A triaxial borehole seismic detector was developed for high-resolution measurements at frequencies up to 2,000 Hz. Applications for this detector include three-component shallow reverse...
Ultrasonic Wave Scattering by a Crack in a Composite Plate
A hybrid method is presented for analyzing ultrasonic wave scattering of plane strain waves by a crack in a composite plate. The hybrid method combines a finite element formulation in...
Sensitivity of Lifeline Response to Models for the Spatial Incoherence of the Seismic Ground Motions
The sensitivity of the response of above-ground and buried lifelines to different models describing the spatial variability of the seismic ground motions is examined. It is shown that...
Evolution of Damage in Brazilian Test Using Holographic Interferometry
A common method for estimating the tensile strength of concrete is the Brazilian Test. The test is carried out by loading a cylinder on its side in diametral compression. Accodring to...
Updating Dynamic Models and Their Associated Uncertainties for Structural Systems
The problem of updating a structural model and its associated uncertainties using dynamic test data is addressed, considering uncertainties which arise from measurement noise, modeling...
Systolic Anterior Motion of the Mitral Valve: In Vitro Flow Studies
Using an in-vitro approach, the goal of this study was to determine and to characterize the mechanism of systolic anterior motion of the mitral valve in obstructive hypertrophic cardiomyopathy....
Intra Vena Cava Balloon Pumping
An innovative prototype intravenous hollow-fiber oxygenator was developed in 1984 by B.G. Hattler. The device consisted of a microporous, hollow-fiber membrane oxygenator inserted into...
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