13400 results about "Pre stress" patented technology

The present invention relates to the mounting of pre-stressed electroactive material in such a manner that large displacement actuators or sensors result. The invention comprises mounting the pre-stressed electroactive material to a support layer. This combination of a pre-stressed electroactive material and support layer may in turn be attached to a mounting surface. The pre-stressed electroactive material may be a ferroelectric, pyroelectric, piezoelectric, or magnetostrictive material. The size, stiffness, mass, and material of the support layer is selected to result in the electroactive device having dynamic response properties, environmental capability characteristics, and the required resilience optimized for a given application. The capacity to connect the support layer to a surface expands the arenas in which the pre-stressed electroactive device may be used. Application for which the invention may be used include actuators, sensors, or as a component in a pumps, switches, relays, pressure transducers and acoustic devices.

A hearing-aid device and a method for transmitting sound through bone conduction are disclosed. The hearing-aid device comprises a piezoelectric-type actuator, housing and connector. The piezoelectric actuator is preferably a circular flextensional-type actuator mounted along its peripheral edge in a specifically designed circular structure of the housing. During operation, the bone-conduction transducer is placed against the mastoid area behind the ear of the patient. When the device is energized with an alternating electrical voltage, it flexes back and forth like a circular membrane sustained along its periphery and thus, vibrates as a consequence of the inverse piezoelectric effect. Due to the specific and unique designs proposed, these vibrations are directly transferred trough the human skin to the bone structure (the skull) and provide a means for the sound to be transmitted for patients with hearing malfunctions. The housing acts as a holder for the actuators, as a pre-stress application platform, and as a mass which tailors the frequency spectrum of the device. The apparatus exhibits a performance with a very flat response in the frequency spectrum 200 Hz to 10 kHz, which is a greater spectrum range than any other prior art devices disclosed for bone-conduction transduction which are typically limited to less than 4 kHz.

A pipette device has a coupling stud on which a pipette tip can be stuck in a slipping-on direction for coupling. The coupling stud has an adjustable pre-stress member that can be adjusted into a prestress state and a release state via an actuation device which is provided in the coupling stud. The pipette tip has an axial stop which interacts with a counter-stop of the coupling stud in an axial coupling position of the pipette tip. The prestress member in its prestress state acts upon a working surface of the stuck-on pipette tip having a surface component of the pipette tip, which extends radially inward, turned away from the stuck on direction, in such a way that it abuts sealingly on the working surface, and prestresses the pipette tip on the pipette unit into the axial coupling position. The prestress member, in its releasing state, substantially releases the working surface of the pipette tip (101).

A modular precast construction block system (10) with a wall subsystem (12) and a foundation subsystem (14). The wall subsystem (12) has a number of wall units (16) having cavities (40) and prestressed tension cables (58) cast therein. The wall units (16) are vertically stacked with alignment channels (42) in the top surface (28) of one wall unit (16) receiving the key portion in the bottom surface (30) of the wall unit (16) above, to form walls (26) with vertically aligned cavities (40). Threaded wall bars (24) and extension bars (74) are threaded through the cavities with a wall tensioning assembly (22) applying downward force on the wall units (16) and providing structural strength to the wall. The foundation subsystem (14) includes a variety of precast foundation members including T footing members (126), pier members (128), grade beam members (130), and column members (132). The T footing members (126) and grade beam members (130) include complementary angled pairs for creating angled and "T" joint foundation designs.

The invention belongs to the architecture field, which relates to an improvement with the foundation pile shape and the structure and the manufacturing method of the foundation pile and the foundation pile shaper in the architecture field, in particular the invention is a prestressing force high strength concrete square pile and the manufacturing method thereof and the shaping device. In the invention a square terminal plate is disposed on the two ends of the square pile, and the four sides of the terminal plate is provided with a groove, while the center is equipped with a circular hole, and between the circular hole and the four sides, a strain hole and a threading hole are arranged symmetrically; a stirrp of a reinforcement cage in a twist is welded on the principal reinforcement continuously, wherein the principal reinforcement is the steel strand or the steel bar; the concrete square pile and the four-side corners of the terminal plate are in a stress elimination arc, and the pile core is a columnar mid level outlet having the same diameter with the terminal plate central circular hole. The manufacturing method is characterized in that, the principal reinforcement has the fix ed length and blanking, and the stirrp of the reinforcement cage is welded in the seam welder with the high degree of mechanisation; the principal reinforcement is stretched in a group of a whole pile fixed value, wherein the stretching performance is good and the balance is consistent; the disposable high pressure has short shaping time, low energy consumption, high product grade; the die design meets with the shaping requirement of the shape, which is convenient to use.

The invention relates to a node connection device for a self-centering prestressed concrete frame. The node connection device is a device used for the connection between the beam and the column of a prefabricated reinforced concrete frame, and aims at improving energy consumption of a frame structure under seismic action and eliminating or reducing the residual deformation and damage of the frame structure. The connection device is characterized in that combined steel parts form an energy consuming device, two external friction steel plates (3) are arranged in the energy consuming device, are respectively and symmetrically arranged on the two sides of a column end reinforcing steel plate (4) and are connected with the column end reinforcing steel plate (4) into a whole body, two internal friction steel plates (8) are arranged between the two external friction steel plates (3), the upper end and the lower end of each internal friction steel plate (8) are respectively provided with a bean end reinforcing steel plate (5), friction discs (15) are respectively arranged between the two internal friction steel plates (8) and the two external friction steel plates (3), and friction-type high-strength bolts (12) penetrate through the external friction steel plates (3), the friction discs (15), the internal friction steel plates (8) and a prefabricated concrete beam (2) and connect all parts together.

A lift-type turbine comprising at least three blades at circumferentially spaced positions is supported for rotation about a vertical axis. Each blade has an airfoil shape to generate a torque about the axis responsive to wind across the blades. A support comprising cables under tension is connected between adjacent ones of the blades to extend generally circumferentially about the turbine. Accordingly a minimum number of parts form the structure of the blades while minimizing the drag produced during rotation thereof due to the support members lying in a common circumferential path. The tension of the support members can support the blades in a pre-stressed condition to optimize the shape and performance thereof.

The invention discloses a preformed material for post-tensioned prestressing pipeline vacuum grouting or mudjacking and a preparation method thereof. The preformed material includes the following components by weight percent: 65 to 95 percent of silicate cement, 0.01 to 3 percent of high-range water-reducing agent, 0 to 1 percent of stabilizing agent, 0.05 to 5 percent of retarding agent, 1 to 20 percent of expanding agent, 0.2 to 2 percent of corrosion inhibitor, 0.01 to 1 percent of air entraining agent and 0 to 30 percent of mineral materials, wherein by uniformly and proportionally mixing the silicate cement, the high-range water-reducing agent, the stabilizing agent, the retarding agent, the expanding agent, the corrosion inhibitor, the air entraining agent and the mineral materials, the post-tensioned prestressing pipeline vacuum grouting or mudjacking preformed material can be obtained. After being uniformly mixed and stirred with water with neutral pH value according to the water cement ratio ranging from 0.24 to 0.32, the preformed material can be used, the obtained grouting material has the advantages of low water cement ratio, favorable flowability, no water bleeding and delamination, and favorable pumpability; meanwhile, the preparation method of the preformed material is simple and the raw material sources of the preformed material are wide.

Methods are disclosed for nondestructive testing and measuring the structural health of prestressed concrete structures, such as slabs, columns, girders, bridges, towers, elevated storage tanks, silos, cooling towers, wind power generation towers, liquefied gas storage tanks, nuclear power containment buildings, and the like. Measurements are made as the structure undergoes tensioning and detensioning operations. By measuring actual movements of cardinal points on the structure, in an absolute three-dimensional coordinate system, and comparing the measurements to a model—as tension on a tendon is changed—a margin of safety is assured. High accuracy measurements are made by electronic distance measurement (EDM) instruments over hundreds of meters, which yield coordinates of cardinal points with an uncertainty of the order of one part per million. The methods are proposed as possible alternatives to prior failures of post-tensioned concrete, including the Las Lomas Bridge, the Kapiolani Interchange On-Ramp, Turkey Point Unit 3 Nuclear Power Plant, and Crystal River Unit 3 Nuclear Power Plant. An extensive review of the most closely related prior arts is included.

A method for detecting breaks in a prestressed wire, rod or bar embedded in concrete surrounding a metal pipe is described. A remote field eddy current probe is traversed axially internally through the pipe so as to create an energy flow path externally of the pipe and a transformer coupling through the pipe, and generate a signal in a detector coil axially spaced from an exciter coil. As the exciter coil traverses the wire, rod or bar containing the break a signal change is generated, regardless of the radial position of the detector coil relative to the break.

The invention relates to an oscillatory drive having an output shaft that can be driven to perform a rotationally oscillating movement about its longitudinal axis and that comprises a free end, a holding fixture at the free end of the output shaft comprising a contact surface for attachment of a tool, a mounting section on the holding fixture, raised relative to the contact surface, that projects to the outside in the direction of the longitudinal axis and that is designed for form-locking connection with a mounting opening of a tool placed in contact with the contact surface, and having a securement for fixing the tool with its mounting opening on the holding fixture, the securement permitting the tool to yield in axial direction under the action of a torque, against a pre-stress, and the mounting section permitting the tool to rotate by a certain angle of rotation when the tool gives way axially.

The invention discloses a self-resetting pier column structural system with a built-in energy dissipation assembly and an implementing method for the self-resetting pier column structural system, and belongs to the field of bridge engineering. The self-resetting pier column structural system consists of a pier column, a bridge abutment, energy dissipation steel bars, non-adhesion prestressed steel bars with an elastic resetting function and an embedded part; in the novel pier column structural system capable of effectively reducing residual deformation and ensuring sufficient energy dissipation, a pier is connected with the bridge abutment through the energy dissipation steel bars and the non-adhesion prestressed steel bars. Compared with the conventional pier column node, the self-resetting pier column structural system has the advantages that: the non-adhesion prestressed steel bars are positioned in the axle center of the pier column, a self-resetting restoring force can be generated, and the problem that the conventional pier has large residual deformation under the action of an earthquake load and cannot serve people any longer can be solved well; the self-resetting pier column structural system is flexible in design and definite in structural stress; the pier is ensured to have sufficient strength and rigidity; and the self-resetting pier column structural system can be implemented by a prefabricating or on-site pouring method, is easy and convenient to construct, and is an advanced and practical novel pier column system.

Various high-strength microwave antenna assemblies are described herein. The microwave antenna has a radiating portion connected by a feedline to a power generating source, e.g., a generator. The antenna is a dipole antenna with the distal end of the radiating portion being tapered and terminating at a tip to allow for direct insertion into tissue. Antenna rigidity comes from placing distal and proximal radiating portions in a pre-stressed state, assembling them via threaded or overlapping joints, or fixedly attaching an inner conductor to the distal portion. The inner conductor is affixed to the distal portion by, e.g., welding, brazing, soldering, or by adhesives. A junction member made from a hard dielectric material, e.g., ceramic, can be placed between the two portions and can have uniform or non-uniform shapes to accommodate varying antenna designs. Electrical chokes may also be used to contain returning currents to the distal end of the antenna.

A treatment for bioprosthetic tissue used in implants or for assembled bioprosthetic heart valves to reduce in vivo calcification is disclosed. The method includes preconditioning, pre-stressing, or pre-damaging fixed bioprosthetic tissue in a manner that mimics the damage associated with post-implant use, while, and/or subsequently applying a calcification mitigant such as a capping agent or a linking agent to the damaged tissue. The capping agent suppresses the formation of binding sites in the tissue that are exposed or generated by the damage process (service stress) and otherwise would, upon implant, attract calcium, phosphate, immunogenic factors, or other precursors to calcification. The linking agent will act as an elastic reinforcement or shock-absorbing spring element in the tissue structure at the site of damage from the pre-stressing. In one method, tissue leaflets in assembled bioprosthetic heart valves are preconditioned by simulating actual flow conditions for a predetermined number of cycles, during or after which the valve is exposed to the capping agent.

A prestressed concrete frame includes prefabricated beam and pile and integrated by prestressed reinforce. The pile is of a length over 2-3 floors. The beam is of a length for one room. Reinforce inside the beam is of a length at least equal to the short beam line. Binding reinforce concentrated in the beam center zone is of a length at least equal to the short beam line. Structure reinforce is also applied into the beam. Joint reinforce is applied to the beam ends. A distance of 30-40mm left between the beam and pile. This frame is of good stability for earthquake.

A dynamic radial seal includes a rigid casing. The seal also includes an elastomeric casing positioned interior of and bonded to the rigid casing. The elastomeric casing has an axial spring member which extends radially inwardly from and axially along the rigid casing. The axial spring member includes a neck portion which extends from the elastomeric casing and a seal attachment portion that is attached to the neck portion and has a bonding surface. The seal also includes a pre-stressed fluoropolymer seal which has a bonding surface and a sealing surface. A bond joins the bonding surface of the pre-stressed fluoropolymer seal to the bonding surface of the seal attachment portion. The seal attachment portion of the spring member is operative to provide sealing contact of the fluoropolymer seal along the entirety of its sealing surface when engaged with a mating surface of a shaft. The fluoropolymer seal may be formed from PTFE and may include a groove or grooves formed in the sealing surface to enhance the sealing performance of the seal. The elastomeric casing may also incorporate a static seal or temporary dynamic seal to facilitate in-process testing or dirt exclusion, as well as one or more additional dirt exclusion features to protect the fluoropolymer seal from damage caused by environmental contaminants during the use of the seal.

The invention provides a finite element analysis method for the temperature action on a prestressed reinforced concrete continuous rigid frame bridge. The finite element analysis method is used for analyzing and calculating the stress and displacement distribution in the construction and finished bridge stage under different temperature gradient models, and provides references for designing and optimizing the prestressed reinforced concrete continuous rigid frame bridge. Through calculational analysis based on finite elements and the structural mechanics, the forward-calculation method is adopted for structural distortion and stress analysis according to the actual construction loading sequence of the bridge structure, so that the complex mechanics problem of box girder temperature self-stress, temperature secondary internal force in a prestressed reinforced concrete statically indeterminate structure and secondary stress of the temperature secondary internal force is solved easily, conveniently and efficiently, and the finite element analysis method has important practical value.

The invention belongs to the building support component technology field including the stress automatic control and monitoring as well as the structural safety, and relates to a steel tube supporting internal force automatic compensating and displacement controlling system. The system comprises an upper system, a PLC control system module and a field executive system. A steel support is arranged on a reinforced concrete diaphragm wall, a hydraulic jack is arranged on the steel support, and real time pressure monitoring values are fed back through a pressure sensor. The steel support and the hydraulic jack form a pre-stressed steel support structure, the hydraulic jack is connected with a hydraulic pump station through an oil circuit, and is connected with the PLC control system module through the pressure sensor, the hydraulic pump station is connected with the PLC control system module, and a PLC controlling device is connected with the upper system. Through auto-control software and a PLC control system, the automatic control to the axial force of the steel support is realized, thereby controlling the displacement and the settlement of the deep excavation supporting structure and the adjacent basic facilities.