Superposition method for analysis of free-edge stresses

Superposition techniques were used to transform the edge stress problem for composite laminates into a more lucid form. By eliminating loads and stresses not contributing to interlaminar stresses, the essential aspects of the edge stress problem are easily recognized. Transformed problem statements were developed for both mechanical and thermal loads. Also, a technique for approximate analysis using a two dimensional plane strain analysis was developed. Conventional quasi-three dimensional analysis was used to evaluate the accuracy of the transformed problems and the approximate two dimensional analysis. The transformed problems were shown to be exactly equivalent to the original problems. The approximate two dimensional analysis was found to predict the interlaminar normal and shear stresses reasonably well

Plans for the LIGO–TAMA joint search for gravitational wave bursts

We describe the plans for a joint search for unmodelled gravitational wave bursts being carried out by the LIGO and TAMA Collaborations using data collected during February–April 2003. We take a conservative approach to detection, requiring candidate gravitational wave bursts to be seen in coincidence by all four interferometers. We focus on some of the complications of performing this coincidence analysis, in particular the effects of the different alignments and noise spectra of the interferometers

A new look at numerical analyses of free-edge stresses in composite laminates

The edge stress problem for a + or - 45 deg graphite/epoxy laminate was examined. The reliability of the displacement formulated finite element method in analyzing the edge stress problem was investigated. Analyses of two well known elasticity problems, one involving a stress discontinuity and one a singularity, showed that the finite element analysis yields accurate stress distributions everywhere except in two elements closest to the stress discontinuity of singularity. Stress distributions for a + or - 45 deg laminate showed the same behavior near the singularity found in the well known problems with exact solutions. The displacement formulated finite element method appears to be a highly accurate technique for calculating interlaminar stress in composite laminates. The disagreement among the numerical methods was attributed to the unsymmetric stress tensor at the singularity

Arm cavity resonant sideband control for laser interferometric gravitational wave detectors

We present a new optical control scheme for a laser interferometric gravitational wave detector that has a high degree of tolerance to interferometer spatial distortions and noise on the input light. The scheme involves resonating the rf sidebands in an interferometer arm cavity

Oyster Spatfall in Virginia Rivers: 1982 Annual Summary

The Virginia Institute of Marine Science (VIMS) conducts weekly surveys from June through early October to obtain oyster spatfall information. Spat counts are made from oyster shells strung on wire and suspended from stakes on public and private beds. The number of spat on shells are counted each week of the spawning season to determine the potential of a particular area for receiving a strike and to predict the most likely period the strikes will occur

Treatment of shell with Polystream to increase survival of oysters (Crassostrea virginica) in Virginia

Survival of oysters set on shells treated with Polystream* was investigated during 1963 and 1964. Treated and control shells were held in wire bags in the high-salinity intertidal seaside area of the Eastern Shore and in the moderate-salinity subtidal areas of the lower James River. Significantly more spat survived on treated shells than on controls. Differences in survival could not be attributed to absence of drill predation on treated shell

The density of oysters and shell upriver from the Campostella bridge in the Elizabeth River

This study estimates the density of oysters and oyster shells on that portion of the J. H. Miles Co. lease which lies within 450 feet of the upriver edge of the Campostella Bridge. The Campostella Bridge is located on Route 460 on the Eastern Branch of the Elizabeth River (Figure 1). The area is restricted for shellfish culture by the Virginia State Health Department and salinities are high enough to favor the development of the oyster diseases Haplosporidium costalis (MSX) and Perkinsus marinum (Dermo). Because a combination of the effects of pollution and disease, the area has not produced commercial volumes of oysters for many years; probably since 1960

The physiography and extent of public oyster grounds in Pocomoke Sound, Virginia.

Public oyster grounds in Pocomoke Sound, Virginia, were charted in 1978 using an electronic positioning system to locate areas ~f oysters, shell, sand or mud. Over five thousand stations were occupied and 1,267 samples of the substrate were taken with hydraulically operated patent tongs. The information was used to draw large scale charts showing shorelines, depths, bottom types and out lines of public grounds. Substrates, elevations, slopes, oyster densities and spatfall levels were analyzed