The stress distribution in an aluminum interconnect for VLSI was calculated analytically by applying Eshelby’s method in micromechanics. The stresses were obtained as a function of the aspect ratio (r=thickness/width...
The stress distribution in an aluminum interconnect for VLSI was calculated analytically by applying Eshelby’s method in micromechanics. The stresses were obtained as a function of the aspect ratio (r=thickness/width) of the Al line cross section. The yielding criteria in plasticity were applied to determine whether the calculated stresses can induce relaxation due to plastic deformation. The stress after plastic deformation were maximum at r=1. Direct X‐ray stress measurements for Al lines with various aspect ratios were carried out to verify our analytical model. The aspect ratios were varied by changing the line width while maintaining the line thickness constant, and vice versa. In either case, no maximum was found at r=1, in contrast with the results of the analytical calculation. This disagreement was attributed to the fact that the yield stress of Al line was assumed to be independent of the aspect ratio in our calculation. Using a diffusional growth model of grain boundary voids, the time to failure of the Al line was estimated analytically. Life tests of Al interconnects were carried out to examine the model with respect to life test temperatures, the Al line aspect ratios, and passivation structures. Most of the experimental results were in good agreement with the predictions of the model, except for the lifetime differences for different passivation materials. It was suggested that mechanical properties of the passivation films affect the void nucleation density.
Characteristics of both thermoplastic and thermoset composite materials as they pertain to marine vehicle applications are discussed. Comparison of various material selection factors such as strength, damage and moist...
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Characteristics of both thermoplastic and thermoset composite materials as they pertain to marine vehicle applications are discussed. Comparison of various material selection factors such as strength, damage and moisture resistance, and flammability and toxicity as well as cost and availability of thermoset and thermoplastic composite materials are presented. Methods for testing and reducing the flammability and toxicity are discussed. Many commercially available composite systems are reported to provide favorable characteristics for marine applications. Although there seems to be a need for improved production technology for thermoplastics, they present potential advantages in physical properties over thermoset composites.
作者：
LAUGHLIN, TJFERRELL, TMThomas J. Laughlin
Ph.D. head controlled-release devices section and Teresa M. Ferrell research chemist Southern Research Institute 2000 Ninth Avenue South P.O. Box 55305 Birmingham AL 35255-5305REFERENCES Estrin N.F.1984. The Cosmetic Industry Scientific and Regulatory Foundations. Marcel Dekker Inc. New York.Donohue J.1987. Fighting the claims battle. Soap/Cosmetics/Chemical Specialties63(6):10.Carson H.C.1986. Cosmetics of Fragrance Review and Forecast. HAPPI23(12):40-52 102-104.Carson H.C.1984. Cosmetics of Fragrance Review and Forecast. HAPPI21(12):32-40. New Chemicals for Specialties. 1985. Soaps/Cosmetics/Chemical Specialties62(6):96.Lewis H.W.1984. Biotechnology in Japan. NTIS PB85-16946.Lion Corp. assignee. Enzyme-containing bleaching agent compositions. Japanese kokai 60023498. 1985 February 6. 4p. Int. Cl. C11D3/50 Appl. 82/130
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A proposed cost effective alternative to current U.S. Navy structurally configured hulls is presented in this paper. This proposed design for producibility concept involves the elimination of structural stanchions and...
A proposed cost effective alternative to current U.S. Navy structurally configured hulls is presented in this paper. This proposed design for producibility concept involves the elimination of structural stanchions and transverse web frames. The potential impact of this “no frame” concept on structural design, weight and construction and material costs for naval surface frigates and destroyers is reflected in 1) reduced costs for the installation of distributive systems and 2) a reduced number and complexity of structural details providing a more reliable and less costly structure. This study was performed in three parts: 1) Determine the most feasible length between bulkheads without frames; 2) Using this length perform detail weight studies and construction and material costs analysis comparison on a 72-foot long hull module, with and without frames, for a FFG-7, and 3) Estimate the saving in man hours of labor on the installation of distributive systems and shipfitting for an FFG-7. For the feasible length studies on the “no frame” structural configuration, thirty-seven strength, weight and vertical center of gravity studies were performed on two ship classes; twenty-two on the FFG-7 class and fifteen on the DD-963 class. The detailed weight studies and construction and material cost analyses were conducted for FFG-7 “no frame” and “as built” modules. Results indicating the “no frame” concept module was 6.8% heavier and 14.8% less costly than the “as built” module. For the impact of an FFG-7 “no frame” structurally configured hull on the cost of labor required for the installation of distributive systems and for other functional work such as ship fitting, welding, and electrical, this study indicated a reduction of 169,206 labor hours per ship, representing 7.12% of the total required man hours to fabricate an FFG-7 class ship. With the employment of the “no frame” concept, certain areas of significant concern and potential risk were addressed. These include: 1) t
The structural design of a ship's section is a complicated, repetitive and time consuming task. With the advent of new technology, high speed computers have enabled the ship designer to accomplish in a matter of s...
The structural design of a ship's section is a complicated, repetitive and time consuming task. With the advent of new technology, high speed computers have enabled the ship designer to accomplish in a matter of seconds what would formerly take days to accomplish by hand. The Structural Synthesis Design Program (SSDP) is a N avy developed computer-aided design tool which is used to design (or to analyze) the longitudinal scantlings for a variety of ship cross sections, consisting of any practical combinations of decks, platforms, bulkheads and materials, i.e., various steel and aluminum alloys. The final hull section design will have the lowest practical weight for the chosen geometric configuration, structural arrangements, and imposed loadings. The scantling developed by the program will satisfy all U.S. N avy ship structural design criteria. An explanation of the objective and design elements of N avy ship structures is included. The rationale behind the SSDP design philosophy is developed along with the significant program capabilities. In an attempt to highlight the influence of automated design procedures on the current naval ship design process, the effect of the SSDP on the DDG 51 destroyer structural development is addressed.
Destructive and non-destructive tests were carried out on three-fibre-reinforced plastic composites-glass, carbon and Kevlar reinforced epoxy-under hygrothermal exposure. In all cases good correlation was found betwee...
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Destructive and non-destructive tests were carried out on three-fibre-reinforced plastic composites-glass, carbon and Kevlar reinforced epoxy-under hygrothermal exposure. In all cases good correlation was found between the dispersion of ultrasonic attenuation data (measured by its coefficient of variation) and corresponding average values of strength and attenuation. Accordingly, dispersion may serve as a reliable parameter in non-destructive evaluation for detection and follow-up of hygrothermal degradation in fibre-reinforced laminates.
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