Flanged Acrylic Plastic Hemispherical Shells for Undersea Systems - Static and Cyclic Fatigue Life under Hydrostatic Loading

1977 ◽  
Author(s):  
J. D. Stachiw ◽  
R. Sletten
Keyword(s):  
Fatigue Life ◽  
Cyclic Fatigue ◽  
Acrylic Plastic ◽  
Hydrostatic Loading ◽  
Hemispherical Shells

Polycarbonate Plastic Inserts for Spherical Acrylic Plastic Shells Under Hydrostatic Loading

1981 ◽  
Vol 103 (1) ◽  
pp. 90-98 ◽  
Author(s):  
J. D. Stachiw ◽  
R. B. Dolan ◽  
D. L. Clayton
Keyword(s):  
Fatigue Life ◽  
Structural Integrity ◽  
Structural Parameters ◽  
Cyclic Fatigue ◽  
Pressure Vessels ◽  
Plastic Shell ◽  
Acrylic Plastic ◽  
Hydrostatic Loading ◽  
Spherical Pressure

An acrylic plastic spherical pressure hull incorporating polycarbonate inserts for mounting of penetrators has been built and pressure tested. The transparent hull will serve as one atmosphere cockpit in Johnson-Sea-Link #3 submersible for 2500 ft. service. Tests have been conducted with model scale polycarbonate inserts in acrylic plastic spherical pressure hulls and windows to evaluate the structural integrity and cyclic fatigue life of polycarbonate plastic inserts and acrylic shells in which they are mounted under repeated hydrostatic pressurizations. Test results indicate that the short term, long term and cyclic fatigue life of a polycarbonate insert, serving as a bulkhead for electric or hydraulic penetrators in spherical acrylic plastic pressure hulls or windows, exceeds that of the acrylic plastic shell in which it is mounted. Structural parameters of polycarbonate inserts are discussed and design criteria formulated for their utilization in manned submersibles and pressure vessels for human occupancy. Particular emphasis is placed on selection of material, seal configuration, and retainment design.

Flanged Acrylic Plastic Hemispherical Shells for Undersea Systems—Part 2: Static and Cyclic Fatigue Life Under Hydrostatic Loading

1978 ◽  
Vol 100 (2) ◽  
pp. 249-260
Author(s):  
J. D. Stachiw ◽  
R. Sletten
Keyword(s):  
Fatigue Life ◽  
Fatigue Cracks ◽  
Cyclic Fatigue ◽  
Bearing Surface ◽  
Short Term ◽  
Ring Groove ◽  
Working Pressure ◽  
Temperature Range ◽  
Acrylic Plastic ◽  
Hydrostatic Loading

Over 25 acrylic plastic windows with t/Ri = 0.364 in the shape of hemispherical domes with equatorial flanges have been thermoformed from flat sheets and tested under short term, long term, and cyclic pressure loading at 65–75°F ambient temperature. Two kinds of flanges with O-ring grooves on the bearing surfaces were experimented with: Type 1, a flat lip with a rounded heel and instep, and Type II, a conical lip with a rounded heel. The 14,500 psi short term critical pressure of hemispherical windows with t/Ri = 0.364 was found to be independent of the equatorial flange configuration. Both the static and cyclic fatigue lives of the windows were also found to be independent of equatorial flange configuration. In either case, the maximum acceptable working pressure for 65–75°F temperature range was found to be 1000 psi. Only by elimination of the O-ring groove in the bearing surface of the window flange and the use of a thin neoprene bearing gasket between the arylic flange and the steel is it possible to extend the working pressure to 2000 psi for 65–75°F temperature range. Operating the flanged windows at pressures in excess of the safe working pressures shown above will generate fatigue cracks in the bearing surface of the flange in less than 1000 pressure cycles; at 5000 psi pressure the cyclic fatigue life decreases to less than 100 cycles.

NEMO Type Acrylic Plastic Spherical Hull for Manned Operation to 3000 ft Depth

1976 ◽  
Vol 98 (2) ◽  
pp. 537-549 ◽  
Author(s):  
J. D. Stachiw
Keyword(s):  
Fatigue Life ◽  
Stress Wave ◽  
Cyclic Fatigue ◽  
Short Term ◽  
Destructive Testing ◽  
Pressure Cycling ◽  
Acrylic Plastic ◽  
Scale Models ◽  
Spherical Pressure

NEMO Mod 2000 acrylic plastic pressure hull assembly represents the latest addition to the NEMO hull series represented by NEMO Mod 600 and 1000 hull assemblies. The 66 in. OD × 58 in. ID spherical acrylic hull with aluminum hatches has successfully withstood 24 hr long external hydrostatic pressurizations to 450, 900, 1350, and 1800 psi. Pressure cycling and short term destructive testing of 15 in. OD × 13 in. ID scale models has shown that the crackfree fatigue life is in excess of 1000 pressure cycles to 1500 psi and the short term implosion pressure is in the range of 4750–5000 psi. Stress wave emissions have been found to be a good indicator of incipient failure. NEMO Mod 2000 spherical pressure hulls with panoramic visibility are considered to be acceptable for manned submersibles with 3000 ft operational depth capability. The cyclic fatigue life of such hulls is conservatively predicted to be at least 12 × 106 ft hr.

Cyclic fatigue life characteristics of ceramic balls under variable thermal shock loadings

2021 ◽  
pp. 107924
Author(s):  
Shinya Matsuda ◽  
Jinya Takenaka ◽  
Kimito Arii ◽  
Keiji Ogi
Keyword(s):  
Fatigue Life ◽  
Thermal Shock ◽  
Cyclic Fatigue

scholarly journals Prediction of Cyclic Fatigue Life of Nickel-Titanium Rotary Files by Virtual Modeling and Finite Elements Analysis

2015 ◽  
Vol 41 (11) ◽  
pp. 1867-1870 ◽  
Author(s):  
Alessandro Scattina ◽  
Mario Alovisi ◽  
Davide Salvatore Paolino ◽  
Damiano Pasqualini ◽  
Nicola Scotti ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Finite Elements ◽  
Cyclic Fatigue ◽  
Nickel Titanium ◽  
Finite Elements Analysis ◽  
Virtual Modeling

Effect of the blooming of chemical curatives on the cyclic fatigue life of natural rubber filled with a silanized silica nanofiller

2010 ◽  
Vol 120 (5) ◽  
pp. 2497-2507 ◽  
Author(s):  
F. Saeed ◽  
A. Ansarifar ◽  
R. J. Ellis ◽  
Y. Haile-Meskel ◽  
A. S. Farid
Keyword(s):  
Fatigue Life ◽  
Natural Rubber ◽  
Cyclic Fatigue ◽  
Silanized Silica

Flanged Acrylic Plastic Hemispherical Shells for Undersea Application

1975 ◽  
Vol 97 (1) ◽  
pp. 1-9 ◽  
Author(s):  
J. D. Stachiw ◽  
J. R. Maison
Keyword(s):  
Finite Element ◽  
Hydrostatic Pressure ◽  
Stress Distribution ◽  
Boundary Conditions ◽  
Critical Pressure ◽  
Convex Surface ◽  
Elastic Analysis ◽  
Short Term ◽  
Acrylic Plastic ◽  
Hemispherical Shells

The effects of an equatorial flange and a nonuniform wall thickness upon the critical pressure and stress distribution in acrylic plastic hemispheres have been investigated by experimental and analytical methods. Forty acrylic hemispheres were fabricated and tested to destruction under short term hydrostatic pressure applied on the convex surface. Dome apex displacements were obtained from each specimen and strains were obtained from a selected few. A finite element elastic analysis was performed on one window configuration for two different boundary conditions and the experimentally derived stresses were used to determine which boundary conditions was the best for analytical analysis.

Multiaxial Low Cycle Fatigue Life Prediction at 300 °C Using Equivalent Strain Appoach

2011 ◽  
Vol 361-363 ◽  
pp. 1669-1672
Author(s):  
Wen Xiao Zhang ◽  
Guo Dong Gao ◽  
Guang Yu Mu
Keyword(s):  
Fatigue Life ◽  
Life Prediction ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Strain Range ◽  
Cyclic Fatigue ◽  
Equivalent Strain ◽  
Multiaxial Fatigue ◽  
Fatigue Life Prediction ◽  
Cycle Fatigue

The low cycle fatigue behavior was experimentally studied with the 3-dimension notched LD8 aluminum alloy specimens at 300°C. The 3- dimension stress-strain responses of specimens were calculated by means of the program ADINA. The multiaxial fatigue life prediction was carried out according to von Mises’s equivalent theory. The results from the prediction showed that the equivalent strain range can be served as the valid mechanics for predicting multiaxial high temperature and low cyclic fatigue life.

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