Abstract: A torque transfer coupling includes a shaft and a first second set of hydraulic devices. Each hydraulic device of the first set of hydraulic devices has a first end operably connected to a first end of the shaft, wherein the hydraulic devices of the first set of hydraulic devices are disposed about an axis of the shaft. Each hydraulic device of the second set of hydraulic devices has a first end operably connected to a second end of the shaft, and wherein the hydraulic devices of the second set of hydraulic devices are disposed about the axis of the shaft. Each hydraulic device can include a piston and cylinder assembly wherein extension and retraction of each piston of each hydraulic device is generally tangential to a portion of a circle encircling the shaft.

Abstract: One aspect of the invention is a test assembly comprising a prime mover, an actuator assembly and a torque transfer coupling. The actuator assembly has an end configured to be attached to a shaft of a portion of a test specimen such as a wind turbine assembly. The actuator assembly has a shaft supported for rotation by hydraulic bearings. The torque transfer coupling connects the primer mover to the actuator assembly.

Abstract: A torque transfer coupling includes a shaft and a first second set of hydraulic devices. Each hydraulic device of the first set of hydraulic devices has a first end operably connected to a first end of the shaft, wherein the hydraulic devices of the first set of hydraulic devices are disposed about an axis of the shaft. Each hydraulic device of the second set of hydraulic devices has a first end operably connected to a second end of the shaft, and wherein the hydraulic devices of the second set of hydraulic devices are disposed about the axis of the shaft. Each hydraulic device can include a piston and cylinder assembly wherein extension and retraction of each piston of each hydraulic device is generally tangential to a portion of a circle encircling the shaft.

Abstract: One aspect of the invention is a test assembly comprising a prime mover, an actuator assembly and a torque transfer coupling. The actuator assembly has an end configured to be attached to a shaft of a portion of a test specimen such as a wind turbine assembly. The actuator assembly has a shaft supported for rotation by hydraulic bearings. The torque transfer coupling connects the primer mover to the actuator assembly.

Abstract: A high velocity actuator, which may be used as a blast simulator, is provided with an actuator cylinder tube having an opening at first and second cylinder ends, and an actuator piston rod slidably mounted within the actuator cylinder tube and extending through the opening in the first cylinder end. A control valve concentric to the actuator cylinder tube is configured to be coupled to a source of pressurized fluid and controls admittance of the fluid under pressure to the actuator cylinder at the second cylinder end to act on the actuator piston rod to extend the actuator piston rod towards the first cylinder end.

Abstract: A high velocity actuator, which may be used as a blast simulator, is provided with an actuator cylinder tube having an opening at first and second cylinder ends, and an actuator piston rod slidably mounted within the actuator cylinder tube and extending through the opening in the first cylinder end. A control valve concentric to the actuator cylinder tube is configured to be coupled to a source of pressurized fluid and controls admittance of the fluid under pressure to the actuator cylinder at the second cylinder end to act on the actuator piston rod to extend the actuator piston rod towards the first cylinder end.

Abstract: A device, preferably hydraulic, is connectable to a first body and a second body selectively forming a rigid connection therebetween or allowing relative motion. The device includes a cylinder having a chamber. The cylinder is connectable to one of the bodies. A piston rod is connectable to the other body. A tension rod has a piston slidable in the chamber and is coupled to the piston rod for slidable movement relative thereto. A second piston is slidable in the chamber and slidable relative to the tension rod.

Abstract: A test specimen holder for holding a test specimen in a material testing machine that applies force loads to the test specimen includes a base member having a first end coupleable to the material testing machine and a second end remote from the first end. A longitudinal axis extends from the first end to the second end. A body member extends from the second end to the first end and includes an aperture disposed on the longitudinal axis for receiving the test specimen. A displacement device displaces the body member relative to the base member substantially parallel to the longitudinal axis.

Abstract: An apparatus for oscillating a mass at a plurality of selective frequencies includes a source of compressible fluid and a cylinder having a bore filled with the compressible fluid. The cylinder includes a port opening to the bore, the port being connected to the source of compressible fluid. A piston slides in the bore to define a chamber. The piston is operably connected to the fluid mass to oscillate the mass. An average volume of the chamber is adjusted to change the frequency of the oscillating mass.

Abstract: A material test system capable of applying multiple force load components simultaneously includes a first actuator connected in parallel with a spring element. The first actuator and the spring element in turn are connected in series with the test specimen and a second actuator. The spring element is substantially rigid in order to transfer the force load from the second actuator to the test specimen yet substantially compliant in order to allow transfer of the force load from the first actuator to the test specimen.

Abstract: A pressure vessel fatigue test system has an adjustable mounting arrangement for a pressure vessel that can have open ends or closed ends, and which is to be subjected to a very high value, short duration pressure pulses, under controlled test conditions, to determine fatigue life of the vessel. In order to provide a pulse of high pressure that smiulates pulse pressures that may be present in the vessel, a cylinder having a bore filled with hydraulic oil is open to the interior of the vessel, and the vessel is also filled with hydraulic oil. A pressure generating piston is slidable in the bore or the cylinder and has a substantial mass that is attached to it. The mass is accelerated rapidly under control of an actuator in response to a control signal. When the piston first moves from a retracted position the oil in the cylinder bore is displaced into a low pressure accumulator.

Abstract: A mechanical screw drive loading test frame has a crosshead on the frame with a grip supported from the crosshead, and a second grip for gripping a second end of a specimen on which a second grip is connected to an axially movable shaft which is ragidly supported and guided for axial movement for loading the specimen. The support for the second grip is in a second rigid cross member positioned very close to the second grip to prevent lateral loads from loading the specimen transversly. The loading shaft is loaded from below the rigid cross member by a screw through a coupling and mounting arrangement which isolates load caused by misalignment in the drive screw or drive motor from the movable shaft and second grip.

Abstract: A tensile test grip for holding a specimen has a pullrod that is mounted in an annular bore, and carries a piston head that fits within a piston chamber, and both the pullrod and piston head are sealed on their outer surfaces with respect to the body forming the piston chamber, to form an enclosed chamber in which hydraulic fluid can be provided to permit swiveling alignment of the pullrod and the piston head relative to the housing that is a function of the direction of loading between the pullrod and the housing. The seal on the pullrod and the seal on the piston head with respect to the respective surfaces on which they seal is on a very short part spherical land to permit the pullrod and piston head to shift with respect to the housing and provide self alignment. The pullrod and piston can swivel freely for a limited amount to provide alignment during tensile loads.

Abstract: A clamp for use in testing machines to prestress a joint between a driving shaft and a driven shaft, both of which are externally threaded with each having a flat surface abutting the other in a plane substantially perpendicular to the driving axis. The clamp is internally threaded to cooperate with the external threads and has bolts which, when tightened, produce a force on the abutting surfaces to compressively preload the joint from forces on the flanks of the external threads.

Abstract: A material testing apparatus for testing physical properties of a test specimen includes an improved crosshead member adjustably supported on spaced vertical columns and adapted to support a grip for a test specimen to be loaded along a load axis. The improved crosshead member includes a load measuring (load cell) section defined by four spaced-apart openings located symmetrically with respect to the load axis. As shown there are two openings on each side of the load axis. The openings extend through the crosshead member. The crosshead is reduced in thickness or cross section between the openings to raise the stress levels in the crosshead so that strain gages are applied directly to the measuring section and can be used to measure the load applied to a test specimen.

Abstract: A press system that provides rapid advance of one platen on a movable crosshead through the use of programmed hydraulic controls and is specifically adapted for use with sheet molding compound (SMC) presses. Rapid locking or latching of the crosshead and the platen it carries is achieved through the use of hydraulically operated clamping and release cylinders. The lower platen is supported on hydrostatic bearings permitting the platen to move and at the same time parallelism of the mold halves is maintained by swiveling molding power cylinders. Separate push-back cylinders are used to separate the mold through a short load path so that when the mold "breaks away" there is very little springback to minimize any part breakage during mold stripping.The lower platen also includes a mounting arrangement that provides the advantages of a rolling bolster or lower platen with a minimum of mounting structure.

Abstract: A press system that provides rapid advance of one platen on a movable crosshead through the use of programmed hydraulic controls and is specifically adapted for use with sheet molding compound (SMC) presses. Rapid locking or latching of the crosshead and the platen it carries is achieved through the use of hydraulically operated clamping and release cylinders. The lower platen is supported on hydrostatic bearings permitting the platen to move and at the same time parallelism of the mold halves is maintained by swiveling molding power cylinders. Separate push-back cylinders are used to separate the mold through a short load path so that when the mold "breaks away" there is very little springback to minimize any part breakage during mold stripping.The lower platen also includes a mounting arrangement that provides the advantages of a rolling bolster or lower platen with a minimum of mounting structure.

Abstract: A swivel joint which has two mating part spherical reaction surfaces carried on two loading members. One of the surfaces is defined in part on a piston which is urged under pressure toward the mating part to take up backlash between the mating surfaces. A sealed area may be defined between the mating surfaces and which contains a quantity of fluid under pressure to carry the loads between the two surfaces on a hydrostatic bearing. The swivel joint permits high loads from hydraulic actuators to be supported without encountering high friction forces while permitting swiveling of the joint across a substantial range of angles.

Abstract: A high volume valve for controlling flow of fluid from a source of fluid under pressure, such as in an accumulator, to an actuator used for testing specimens under high rates of loading. The valve includes a poppet type valve piston that is normally held in a closed position by hydraulic pressure behind the poppet, and when the pressure holding the poppet closed is released, the main supply of fluid under pressure acts on the poppet to open it very quickly. A second accumulator open to the opposite side of the poppet from the main source of pressure is utilized for controlling speed of opening of the valve. The amount the poppet opens also can be adjusted for controlling the rate of flow of fluid from the main source of pressure to the actuator.

Abstract: A rapid opening valve assembly utilized in high rate specimen test systems which require that an actuator load a specimen at rates in the range up to one thousand inches per second and with deflections up to three inches. The high rate valve utilizes a poppet or valve piston member that rapidly opens once it is triggered. The ports may be very large and as shown the valve body is used in connection with a closely coupled accumulator pressure source that is ported directly to the actuator to provide adequate flow capacity. The specimen is generally for testing of metals, plastics, and elastomers under tension or compression.