摘要:
An in-situ specimen fixture particularly adapted for prestressing rod-type SNTT-type specimens comprising a tube and end cap wherein the specimen is secured at one end to the tube, and at the opposite end to the end cap. The end cap is rotatable relative to the tube, and may be fixedly secured for creating a torsional force prestressing the specimen enclosed within the tube.
摘要:
Provided are several examples of apparatuses and methods for applying loads to material specimens in pressurized fluid environments. The apparatuses use the fluid pressure as the force for applying the loads to the specimens.
摘要:
A stress-strain testing apparatus imposes a stress-strain on a specimen while disposed in a controlled environment. Each end of the specimen is fastened to an end cap and a strain gage is attached to the specimen. An adjusting mechanism and a compression element are disposed between the end caps forming a frame for applying forces to the end caps and thereby stress-straining the specimen. The adjusting mechanism may be extended or retracted to increase or decrease the imposed stress-strain on the specimen, and the stress-strain is measured by the strain gage on the specimen while the apparatus is exposed to an environment such as high pressure hydrogen. Strain gages may be placed on the frame to measure stress-strains in the frame that may be caused by the environment.
摘要:
An in-situ specimen fixture particularly adapted for prestressing rod-type SNTT-type specimens comprising a tube and end cap wherein the specimen is secured at one end to the tube, and at the opposite end to the end cap. The end cap is rotatable relative to the tube, and may be fixedly secured for creating a torsional force prestressing the specimen enclosed within the tube.
摘要:
Disclosed are several examples of an apparatus for connecting the free ends of two electrical power transmission lines having conductor strands disposed around a central, reinforcing core. The examples include an inner sleeve having a body defining an inner bore passing through an axially-extending, central axis, an outer rim surface disposed radially outward from the central bore, and one or more axially-extending grooves penetrating the body at the outer rim surface. Also included is an outer splice having a tubular shaped body with a bore passing coaxially through the central axis, the bore defining an inner rim surface for accepting the inner sleeve. The inner bore of the inner sleeve accepts the reinforcement cores of the two conductors, and the grooves accept the conductor strands in an overlapping configuration so that a majority of the electrical current flows between the overlapped conductor strands when the conductors are transmitting electrical current.
摘要:
Disclosed are several examples of an apparatus for connecting the free ends of two electrical power transmission lines having conductor strands disposed around a central, reinforcing core. The examples include an inner sleeve having a body defining an inner bore passing through an axially-extending, central axis, an outer rim surface disposed radially outward from the central bore, and one or more axially-extending grooves penetrating the body at the outer rim surface. Also included is an outer splice having a tubular shaped body with a bore passing coaxially through the central axis, the bore defining an inner rim surface for accepting the inner sleeve. The inner bore of the inner sleeve accepts the reinforcement cores of the two conductors, and the grooves accept the conductor strands in an overlapping configuration so that a majority of the electrical current flows between the overlapped conductor strands when the conductors are transmitting electrical current.
摘要:
The invention provides fatigue testing of a material specimen while the specimen is disposed in a high pressure fluid environment. A specimen is placed between receivers in an end cap of a vessel and a piston that is moveable within the vessel. Pressurized fluid is provided to compression and tension chambers defined between the piston and the vessel. When the pressure in the compression chamber is greater than the pressure in the tension chamber, the specimen is subjected to a compression force. When the pressure in the tension chamber is greater than the pressure in the compression chamber, the specimen is subjected to a tension force. While the specimen is subjected to either force, it is also surrounded by the pressurized fluid in the tension chamber. In some examples, the specimen is surrounded by hydrogen.
摘要:
A stress-strain testing apparatus imposes a stress-strain on a specimen while disposed in a controlled environment. Each end of the specimen is fastened to an end cap and a strain gage is attached to the specimen. An adjusting mechanism and a compression element are disposed between the end caps forming a frame for applying forces to the end caps and thereby stress-straining the specimen. The adjusting mechanism may be extended or retracted to increase or decrease the imposed stress-strain on the specimen, and the stress-strain is measured by the strain gage on the specimen while the apparatus is exposed to an environment such as high pressure hydrogen. Strain gages may be placed on the frame to measure stress-strains in the frame that may be caused by the environment.
摘要:
A method for determining fracture toughness KIC of materials ranging from metallic alloys, brittle ceramics and their composites, and weldments. A cylindrical specimen having a helical V-groove with a 45° pitch is subjected to pure torsion. This loading configuration creates a uniform tensile-stress crack-opening mode, and a transverse plane-strain state along the helical groove. The full length of the spiral groove is equivalent to the thickness of a conventional compact-type specimen. KIC values are determined from the fracture torque and crack length measured from the test specimen using a 3-D finite element program (TOR3D-KIC) developed for the purpose. In addition, a mixed mode (combined tensile and shear stress mode) fracture toughness value can be determined by varying the pitch of the helical groove. Since the key information needed for determining the KIC value is condensed in the vicinity of the crack tip, the specimen can be significantly miniaturized without the loss of generality.
摘要:
An apparatus for inducing cavitation at a surface of a specimen includes a cavitation chamber, a window extending through the wall of the chamber to an area outside the chamber, a test specimen positioned within the chamber, and a cavitation media inside the chamber and in contact with the surface of the specimen. A laser light source is disposed outside the chamber, and is operable to provide a laser beam through the window and into the cavitation media. The laser light source generates a shock wave in the cavitation media, the shock wave causing cavitation at the surface of the specimen.