| Subcritical Crack Extension in 2S Aluminum and in Zinc Foils. |
JAN 1974 |
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| Authors:
H. L. Smith; W. J. Ferguson; E. McLean; T. W. George; J. A. Kies; NAVAL RESEARCH LAB WASHINGTON D C
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 | The nucleation of advance fracture elements in metal foils was studied under the direction of G.R. Irwin in the years 1947 to 1949 in the Ballistics Branch of the Mechanics Division of the Naval Research Laboratory. Some heretofore unpublished results obtained on 2S aluminum and on zinc are analyzed here. The observations aid in the interpretation of fracture surface markings in other materials wherein discontinuous fracturing occurs. The spacings between ... |
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| GRAPHICAL METHODS FOR PLASTICITY CORRECTIONS IN FRACTURE MECHANICS, |
18 SEP 1969 |
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| Authors:
J. A. Kies; H. L. Smith; F. R. Stonesifer; NAVAL RESEARCH LAB WASHINGTON D C; NAVAL RESEARCH LAB WASHINGTON D C
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| Fracture mechanics is an analytical procedure that relates the critical stress, critical crack dimensions, and toughness of a given material so that standards of inspection and tolerable defects may be set. Failure analysis is a relatively simple and useful application of fracture mechanics. The subject of failure prevention and reliability assurance is at least equally important, but it is complicated by present limitations on the ability of nondestructive ... |
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| FRACTURE MECHANICS AS RELATED TO THE NEUBER STRESS CONCENTRATION FACTOR AND PLASTIC PARTICLE. |
30 JUN 1969 |
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| Authors:
J. A. Kies; H. L. Smith; NAVAL RESEARCH LAB WASHINGTON D C; NAVAL RESEARCH LAB WASHINGTON D C
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| A proposed relation between the Irwin stress intensity factor K and the Neuber stress concentration factor was examined to show the degree of its realism and applicability. Realistic limits to the stress sigma max and the radius of curvature of the notch rho were stated for that relation. (Author) |
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| TENSILE STRESSES ON THE SURFACE OF AN ELLIPSOIDAL CAVITY IN COMPRESSIVE LOADING SITUATIONS, |
12 MAR 1965 |
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| Authors:
D. R. Mulville; J. A. Kies; NAVAL RESEARCH LAB WASHINGTON D C
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| The stresses on the walls of embedded cavities have been investigated, particularly for compressive loading situations corresponding to those for shells for deep submergence. The discrepancy between theoretical and measured compressive strength of brittle solids is one motivating factor for extending this investigation. The maximum tensile stress components are equal numerically to the applied compressive stress. The maximum tensile stresses depend on the shape of the cavity, Poisson's ratio, and ... |
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| Fracture Testing of Weldments |
DEC 1964 |
59 pages |
| Authors:
J. A. Kies; H. L. Smith; H. E. Romine; H. Bernstein; NAVAL RESEARCH LAB WASHINGTON DC
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 | A new and improved apparatus has been designed and built for three point loading of bend bars. A new formula for 'K(sub Ic)' independent of Young's modulus has been derived which fits experimental calibrations and calculations by B. Gross with satisfactory accuracy. A formula is provided by which the requirements for specimen size and notch depth can be calculated for measuring K(sub Ic) for a given yield strength of material. ... |
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| A navy analysis of glass reinforced plastics for hydrospace applications. |
NOV 64 |
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| Authors:
J. A. Kies
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| In this paper we shall emphasize shells for deep submergence, particularly manned vehicles. Other objects such as surface craft and incidental hardware items, although interesting and important, would widen the scope too much for this paper. Even more specifically we shall discuss the applicability of grp for the 6000 and 20,000 foot ocean depths because a Navy hardware program is in planning for rescue and salvage and for exploration at ... |
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| A NAVY ANALYSIS OF GLASS REINFORCED PLASTICS FOR HYDROSPACE APPLICATIONS, |
NOV 1964 |
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| Authors:
J. A. Kies; NAVAL RESEARCH LAB WASHINGTON D C
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| Recent advances and remaining problems in the study of filament-wound glass reinforcing plastics are reviewed. Areas considered are fatigue studies, shear and tensile cracking, equal tensioning of fibers, port reinforcement, lay-up patterns, moisture effects, fiber properties, mechanical damage, and effects of porosity or bubbles in the resin. Emphasis is given to application to shells for manned deep submergence vehicles. |
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| THE STRENGTH OF GLASS FIBERS AND THE FAILURE OF FILAMENT WOUND PRESSURE VESSELS, |
28 FEB 1964 |
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| Authors:
J. A. Kies; NAVAL RESEARCH LAB WASHINGTON D C
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| In glass-reinforced-plastic rockets such as Polaris A3 and third stage Minuteman, the current strength/weight advantage over metals has been achieved in a major degree by utilizing a new glass designated S or S-994. Examination of what is meant by the strength of glass filaments has led to a new method of characterizing the strength, especially for the purpose of exploring new glasses. Since the tensile strength is influenced by flaws ... |
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| Effects of Moisture on the Strength of Filament-Wound Vessels, |
04 FEB 64 |
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| Authors:
I. Wolock; H. O. Ewing; J. A. Kies
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| Tests were conducted to determine the effects of moisture on the strength of fiberglass epoxy resin filament wound vessels. The specimens used were 8-inch diameter ovaloid spheroids made with E glass and S-994 glass, using Epon 826 resin and meta-phenylenediamine curing agent. The test vessels were preloaded to 80% of the average short-time burst pressure. Some of the vessels were then coated with a water-resistant coating, while others were stored ... |
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| A Notched Ring Test for Measuring the Resistance to Splitting in Fiber Reinforced Plastics, |
06 JUN 62 |
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| Authors:
J. A. Kies; H. O. Ewing
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| Craze cracking under stress is a prevalent mode of deterioration in glass filament wound rocket cases and failure by splitting and unwinding of strips in the hoopwound layers of the composite is one important mode of failure. In both cases the cracks in the resin run parallel with the glass filaments and often tend to run along the glass-resin interface. In order to measure the resistance of materials to this ... |
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| Recent Advances in Glass Fiber Reinforced Plastics Rocket Motors, |
06 FEB 62 |
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| Authors:
J. A. Kies; H. Bernstein
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| A comparison of the currently expected strength-density ratios of different materials with those of fiberglass plastics is given. A few parts of the Polaris Materials Research Program are described; with special emphasis on new methods for studying the resistance of motor cases to fracture failure by debonding of joints or laminations, and by splitting fractures in the fiberglass hoop windings. Nondestructive techniques for flaw detection are well advanced but the ... |
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| Tensile Strength of Glass Fibers, |
04 FEB 58 |
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| Authors:
J. A. Kies; R. E. McVicker
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| The effect of gage length on the breaking strength of glass fibers of two lots was measured. The size effect was relatively great for the abraded fibers and although the strength was low in long specimens, the indicated difference in strengths when extrapolated back to sufficiently short lengths is probably negligible. The Weibull and Irwin statistical theories were found to apply satisfactorily. More work is necessary before the strength of ... |
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| Energy Release Rates during Fracturing of Perforated Plates, |
22 APR 1955 |
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| Authors:
M. W. Brossman; J. A. Kies; NAVAL RESEARCH LAB WASHINGTON DC
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Reports by Author
