| Stress Gage Testing for Wet CARES |
JUN 88 |
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| Authors:
S. A. Miller; D. D. Keough; P. S. DeCarli; SRI INTERNATIONAL MENLO PARK CA
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 | Ground shock measurements are important for interpreting field experiments and validating computer codes. This report describes a material- independent approach to stress gage validation, and applies this approach in two experiments using the mutual inductance particle velocity (MIPV) gage and a stress gage using flat pack circuits in rained sand test beds. The two experiments are (1) MIPV gage validation experiment in rained sand test beds performed in SRI 2-foot-diameter ... |
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| Investigation of the Credibility of In-Situ Measurements of Radial and Tangential Stress in a Salt Test Bed |
31 MAY 86 |
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| Authors:
D. D. Keough; P. DeCarli; A. L. Florence; R. Mak; D. F. Walter; SRI INTERNATIONAL MENLO PARK CA
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| Eighteen ytterbium piezoresistant sensors in nine Teflon-steel flatpack stress gage-salt core assemblies were fielded in a spherical HE test in a salt medium. The objective was to examine the credibility of in-situ stress measurements by comparing measured stress with stress inferred from independent particle velocity measurements and with stress from computational simulations of the experiment. Criteria for gage emplacement were examined by finite element computational simulation of the emplacement configuration. ... |
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| Inclusion Effects on Stress Gage Measurements in Rock and Soil |
01 MAY 84 |
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| Authors:
A. L. Florence; L. E. Schwer; T. Cooper; J. T. Rosenberg; D. D. Keough; SRI INTERNATIONAL MENLO PARK CA
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| One of the main difficulties in measuring stress in rocks and soils is that the stress gage and installation disturb the stress field to be measured. Another difficulty is to relate the behavior of a sensing foil embedded within a stress gage package to the stress field surrounding the gage. The work reported is the first phase of a combined theoretical and experimental program to investigate problems of in-situ stress ... |
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| Simulation Development for Silo Test Program (STP). Volume 2. Detonation Characterization of NA/NP (Aqueous Nitric Acid/Nitropropane) and NPN (nitropropane Nitrate) |
31 MAR 84 |
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| Authors:
J. T. Rosenberg; D. C. Erlich; D. D. Keough; SRI INTERNATIONAL MENLO PARK CA
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| In support of the Defense Nuclear Agency (DNA) Silo Test Program, the planar steady detonation processes were characterized and initial JWL (Jones- Wilkins-Lee) equation of state (EOS) coefficients were developed for two chemical high explosives (HEs), NA/NP and NPN. NA/NP is a liquid explosive composed of weak (Baume 42) aqueous nitric acid (NA) and the solvent nitropropane (NP). The NA/NP studied here was 3.158 parts NA to 1 part NP, ... |
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| Calculational Evaluation of the Inclusion Effects on Stress Gage Measurements in Rock and Soil, |
MAY 1983 |
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| Authors:
A. L. Florence; D. D. Keough; P. Mak; SRI INTERNATIONAL MENLO PARK CA
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| Explosion-induced stress waves in rocks and soils are frequently measured by flatpack stress gages grouted in boreholes. The stress gage measurements differ from the free-field stresses if the grout forms on inclusion because of a mismatch of material properties or inadequate bonding with the medium. Calculational results are presented for a tuff medium to illustrate inclusion effects in elastic and elastic-plastic regimes. The main effect occurs if the inclusion-medium bonding ... |
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| High-Energy Air Shock Study in a Steel Pipe, |
JUL 1981 |
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| Authors:
H. D. Glenn; H. R. Kratz; D. D. Keough; R. P. Swift; LAWRENCE LIVERMORE NATIONAL LAB LIVERMORE CA
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| A modified Voitenko compressor was used to generate a 43 mm/microsec air shock in 20-mm-i.d. 6-m long steel pipe containing ambient atmospheric air. Fiber-optic ports provided diaphragm burst time, time-of-arrival data and velocity of the shock front along the pipe. Pressure profiles were obtained at higher enthalpy shock propagation than ever before and at many locations down the pipe. Between 0.10- and 5.0-m from the diaphragm the peak pressure being ... |
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| Analysis and Modeling of Piezoresistance Response |
30 SEP 1980 |
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| Authors:
Y. M. Gupta; D. D. Keough; G. E. Duvall; SRI INTERNATIONAL MENLO PARK CA
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| A phenomenological model of piezoresistance was formulated to calculate the resistance change of a gage element subjected to mechanical deformation. This model incorporates the tensor nature of piezoresistivity, elastic-plastic gage response to include mechanical and electrical hysteresis, and dimensional contributions. The phenomenological model was used to analyze past data on Manganin and ytterbium. The stresses and strains in the gage element, needed for this analysis, were approximated from geometrical considerations. ... |
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| Experimental Study of the Effects of Faults on Spherical Wave Propagation. |
OCT 1979 |
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| Authors:
J. C. Cizek; A. L. Florence; D. D. Keough; J. T. Rosenberg; SRI INTERNATIONAL MENLO PARK CA
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| A laboratory technique has been developed for investigating the effect on a spherical wave of a fault located close to a spherical explosive charge that is detonated to generate the wave. The medium is a grout that simulates tuff, the fault is idealized by Mylar sheets, and the sensor is a particle velocity gage. The gage principle is based on Faraday's law in that a voltage is induced in a ... |
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| Source Pressure and Flow Sample Measurements on DABS Tests S2 and S3. |
01 JAN 1979 |
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| Authors:
D. D. Keough; L. B. Hall; R. W. Gates; SRI INTERNATIONAL MENLO PARK CA
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| Air shock pressure-time histories were measured in the HE source region of the Air Force Weapons Laboratory (AFWL) DABS S2 test to determine source characteristics. Steel-ytterbium flatpack gages previously used for the measurement of soil stress were modified, and static, uniaxial strain calibration was performed at pressures to approximately 8 MPa. Results of static calibration at these low pressures and low strain rates agreed well with values extrapolated from high ... |
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| In Situ Constitutive Relations of Soils and Rocks. Spherical Field Tests and LASS Results for Pre-Dice Throw II Materials. LASS Error Propagation Analyses. |
APR 1977 |
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| Authors:
J. T. Rosenberg; P. S. De Carli; d. g. falconer; D. D. Keough; SRI INTERNATIONAL MENLO PARK CA
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| For several years, SRI has been measuring the dynamic mechanical response of in situ geologic materials near and above the elastic limit. A major achievement has been development of the LASS technique (Lagrange Analysis for Stresses and Strains), in which a mathematically complete Lagrange flow analysis is used to calculate dynamic stress-strain trajectories from field measurements of explosive-induced ground motion. Two fields shots were fired to provide data for proof ... |
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| PRESSURE TRANSDUCER FOR MEASURING SHOCK WAVE PROFILES. PHASE X: MEASUREMENT OF LOW-PRESSURE SHOCK WAVE PROFILES. |
08 MAR 1965 |
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| Authors:
D. D. Keough; STANFORD RESEARCH INST MENLO PARK CALIF
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| Summaries are given of tests on the radial tolerance of granite gages and the shelf life of calcium transducers. Equations-of-state data were obtained for Hi-D glass. |
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| PRESSURE TRANSDUCER FOR MEASURING SHOCK WAVE PROFILES: ADDITIONAL GAGE DEVELOPMENT. |
07 JUL 1964 |
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| Authors:
D. D. Keough; R. F. Williams ; STANFORD RESEARCH INST MENLO PARK CALIF
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