7 results about "Shear friction" patented technology

The present invention discloses a method for monitoring and evaluating the service performance of key-tooth adhesive joints in segmented box girders. The method comprises: distributing multiple first stress measuring points, multiple second stress measuring points, multiple third stress measuring points, and adjacent segment vertical displacement measuring points in the region of 1 / 4 to 1 / 8 of the beam span, as well as at joint locations where cracks, defects, or suspected defects are detected through nondestructive testing, with each stress measuring point distributed in the tensile and compressive zones of the joint section; distributing multiple first measuring points along the beam-height span joint, distributing multiple second measuring points on the key teeth along the beam height, and distributing multiple third measuring points simultaneously on the key teeth on both sides of the joint along the beam height, staggered from the placement of the multiple second measuring points; and evaluating the service status of the joint based on the monitoring results of each of the aforementioned measuring points and shear-friction theory. The present invention can address the problems of poor feasibility of current destructive testing methods for joint service status, the accuracy and lack of verification of nondestructive testing results, and the limitations of the application of load test results.

The invention provides a multifunctional geosynthetic material direct shear pull-out test device which comprises a test rack, the top of the test rack is fixedly provided with a shear box temperature control box used for placing an upper shear box and a lower shear box and controlling the internal temperature of a box body, and the shear box temperature control box is connected with a refrigeration control system; a workbench for mounting the upper and lower shear boxes is arranged at the bottom in the shear box temperature control box; a vertical loading device for providing vertical shearing force is arranged right above the shear box temperature control box, and a horizontal loading device for providing horizontal shearing force is arranged on one side of the shear box temperature control box; the horizontal loading device and the vertical loading device are fixedly connected through a reinforcing inclined rod; a conveying roller way is arranged on the opposite side of the horizontal loading device, and the tail end of the conveying roller way is in butt joint with the freezing and thawing cycle test box body. The device can be used for performing an interface friction test between a geosynthetic material and a soil body, a direct shear friction test and a drawing friction test are integrated into one device, and a shear box temperature control box and a cooling liquid temperature control box are arranged at the same time to jointly adjust the temperature of a sample.

The invention relates to a microcosmic test device and method for measuring shear friction and anti-torsion characteristics of a microcosmic contact interface. Independent test modules for torsion test and shear test can be realized. The microcosmic test device comprises a support platform, a test unit (a torsion unit and a shearing unit) and a rotating unit. Compared with the prior art, normal displacement, shear displacement, friction coefficient and torsion angle of a contact interface under the single or coupling action of normal force, tangential force, torque and the like at the micro-nano scale are realized, and the relationship between force-displacement and torque-rotation angle is established; the microcosmic contact mechanical properties of a particle aggregate, a particle-plane, a plane-plane, a cemented sample interface and the like can be accurately reflected.

The invention relates to the technical field of experimental equipment, in particular to a dynamic shear friction experimental device which comprises a thrust unit capable of pushing an impact rod in the extension direction of the impact rod; the loading rod and the impact rod are coaxially arranged, the first end of the loading rod is provided with a first waveform shaper, and the impact rod can impact the first waveform shaper; the loading rod can impact the second waveform shaper and push the incident rod group to rotate around the central axis of the incident rod group; a sample group can be fixed and clamped between the incident rod group and the transmission rod, and the axial pressure assembly can apply a pushing force for pushing the transmission rod to face the incident rod group. In this way, the problem that control over the pulse duration, amplitude, rotation speed and waveform profile of incident waves in an existing dynamic shear friction experiment is limited greatly is solved, and particularly, the problem that shear and friction behaviors of materials cannot be accurately obtained at the high strain rate is solved.

The present invention provides a method for determining the interface strength parameters of a reinforcement plate of a small-spacing reinforced soil structure, comprising: S1, performing direct shear friction tests and pull-out friction tests under different vertical stresses using a block panel and reinforcement as test materials, and fitting to obtain the direct shear strength τ ds Linear relationship curve with vertical stress σ and tensile shear strength τ po The linear relationship curve of the vertical stress σ is used to determine the direct shear parameter and the interface pull-out parameter at the reinforcement-panel interface; S2, determine the lower limit of the shear strength at each vertical stress; the shear strength envelope τ of the reinforcement-panel interface is formed by the lower limit of the shear strength at each vertical stress. in —σ; S3. Determine the interface strength parameters of the reinforcement-panel interface under different vertical stresses; the present invention determines the interface strength parameters between the reinforcement and the panel under different vertical stresses based on the shear strength envelope obtained from the direct shear friction test and the pull-out friction test, laying the foundation for the accurate verification of the connection strength between the reinforcement and the panel at different positions.

The invention discloses a fabricated wall-plate abutted seam shear connection system, and belongs to the technical field of fabricated concrete structures. According to the system, a local vertical hole channel penetrating through a wall-plate interface is formed near a horizontal abutted seam of a prefabricated shear wall and a prefabricated floor slab or a laminated slab, steel bearing plates are arranged at the upper end and the lower end of the hole channel, a high-strength prestress pull rod is arranged in a penetrating mode, the two ends of the hole channel are locked through anchorage devices and nuts, and the adjustable axial pressure device with the stroke compensation capacity is formed. The axial pressure device is arranged near the connecting box or the sleeve grouting connecting piece, and the shear friction bearing capacity and the energy dissipation capacity are improved. In the construction stage, target axial pressure is set by tightening a nut, and axial pressure attenuation caused by prestress loss and interface cracking is compensated. The axial compression ratio passively formed by the whole structure is converted into the local normal pressure capable of being designed in the node layer, and the method is suitable for different design of shear resistance of different wall section interfaces and is different from a traditional prestress system crossing the whole wall.

This invention relates to the field of medical and nursing device technology, and discloses a hammock-type assisted turning bed and a turning method, including a bed frame body. The bed frame body includes multiple functional segments arranged sequentially along its length. Each functional segment is equipped with a bed surface driving mechanism and a support adjustment mechanism. The bed surface driving mechanism includes a roller winding device and a bed surface. Two roller winding devices are symmetrically arranged on both sides of the bed frame body of the functional segment. The two ends of the bed surface are wound around the rollers of the corresponding roller winding devices. The support adjustment mechanism is located below the bed surface and includes multiple electric cylinders arranged along the width direction of the bed frame body. The hammock-type assisted turning bed and turning method provided by this invention solve the problems of high risk of shear friction injury, high risk of pressure sores, poor comfort, and insufficient safety and adaptability in the practical application of existing technologies.