23 results about "Pure bending" patented technology

The invention discloses a composite beam capable of enhancing the ultimate strength of an ultimate concrete structure. The span of the beam is measured, a bending moment graph of the beam is drawn, according to analysis of the bending moment graph, UHPC is selected for a pure bending section (the middle of the span) above a neutral axis of the beam, the upper half part of the beam is covered, and common concrete is used for the rest parts; half of the beam height is selected to use UHPC on the upper portion, and the structural ultimate strength of the composite beam can be improved; the FRP rib is used on the lower portion of the beam, the tensile property and ductility of the lower portion can be improved, a sleeve grouting anchorage device (the inner wall of a metal sleeve is provided with threads) and a wedge-shaped anchorage device (the clamping section is wrapped with a copper sleeve) are adopted, the anchoring reliability is ensured through the double effects of chemical bonding and mechanical meshing, and due to the fact that the FRP rib can be subjected to brittle failure and is preset to be in a super rib failure mode, the tensile strength and ductility of the lower portion can be improved. The problem of brittle failure of the FRP rib is solved. The beam is simple in design, convenient to construct, reasonable in stress, high in structural ultimate strength, high in reliability, wide in application range and material-saving.

The utility model belongs to the field of multi-field coupling tests, and particularly relates to a pure bending stress simulation-sound load-vibration combined loading test device. The device comprises a high-sound-intensity traveling wave tube, a static force loading module, a vibration table and a test piece, and the high-sound-intensity traveling wave tube is provided with an opening for accommodating the test piece; the static force loading module is mounted on the vibration table and is used for performing static force loading on the test piece; one end of the test piece extends into the high-sound-intensity traveling wave tube from the opening, and the other end of the test piece is connected with the static force loading module. According to the pure bending stress simulation-sound load-vibration combined loading test device disclosed by the invention, a set of new test device capable of simultaneously simulating pure bending stress, strong noise and strong vibration load is designed based on a four-point bending static loading mode on the basis of a traditional multi-field coupling test device; finally, the pure bending stress simulation-sound load-vibration combined test of the thermal protection structure test piece is realized.

The application relates to a support device for a pure bending mechanical test of an arc-shaped corrugated steel plate, which comprises a corrugated steel plate, a supporting table, and elastic wires, U-shaped channel steels and fixing components symmetrically arranged on both sides of the corrugated steel plate; the fixing components are fixed on the supporting table, the U-shaped channel steels are located on the supporting table, one end of the elastic wires is connected with the fixing components, the other end of the elastic wires is connected with the U-shaped channel steels, and the end of the corrugated steel plate is fixedly connected with the U-shaped channel steels. Compared with the prior art, the application has the advantages of ingenious structure, high test accuracy and the like.

This invention relates to the fields of computational mechanics and computer-aided engineering, specifically a mathematical model capable of predicting the forming shape of spherical bearings. The model takes the blank's geometric dimensions, mold parameters, and material elastic modulus as input. Based on the precise geometric relationships of the compression process, it establishes a system of equations, deriving the core relationship between the compression amount and the theoretical mean diameter, and solving for the theoretical shape without considering springback. By introducing the theory of compression-bending springback, it establishes springback geometric constraints and expressions for reverse stress. Based on the static equilibrium conditions under pure bending, it derives the explicit relationship between the radius after springback and the radius before springback, elastically correcting the theoretical shape to obtain a predicted shape closer to the actual forming result. The model's output can be compared and verified with finite element simulations and actual experimental data, exhibiting high prediction accuracy in the stable deformation stage with large compression amounts. This invention provides effective guidance for process parameter design and optimization, reducing the number of experiments and development cycles.

The present application relates to a pure bending moment load strength test device for a wing box segment, which is used to perform a pure bending moment load strength test for the wing box segment. The first actuator cylinder and the second actuator cylinder can apply load to the wing box segment through the first loading box segment, the first loading adapter plate, the first end adapter plate, the first end steel plate, and the second loading box segment, the second loading adapter plate, the second end adapter plate, and the second end steel plate. During this process, the first end pad connected to the bottom side of the first loading box segment and the first end convex hinge supported by the first end bracket can rotate and translate in the span direction, while the second end convex hinge connected to the second loading box segment and the second end concave hinge supported by the second end bracket can only rotate and cannot translate in the span direction, thereby ensuring that the pure bending moment load can be applied to the wing box segment stably. In addition, when the test load is large, the smooth completion of the test can be guaranteed.

This utility model discloses a bending moment locking device and a pure bending fatigue tester for a pure bending fatigue specimen, relating to the field of mechanical testing technology. It includes: multiple limiting rods, a first positioning baffle, a second positioning baffle, and multiple first limiting blocks, with each limiting rod arranged in parallel. The first positioning baffle is connected to one end of a limiting rod and can be positioned along the length of the limiting rod. The second positioning baffle is arranged parallel to the first positioning baffle and is slidably connected to the limiting rod, maintaining its slidable position. The first limiting block is fixedly connected to the end of the limiting member away from the first positioning baffle and is located on the side of the second limiting baffle away from the first limiting baffle. The distance between the two opposite sides of the first and second positioning baffles when the second positioning baffle and the first limiting block are pressed together is the standard lever arm length. The structure is simple, easy to use, and effectively ensures the accuracy of the test data.

The invention discloses a prediction method for oblique bending deformation of a Z-section profile. The prediction method for oblique bending deformation of the Z-section profile comprises the following steps: S1, determining attributes, section geometric features and an initial bending radius of a material; s2, determining an initial position of a neutral layer; s3, in the bending process of the section B, the offset of the neutral layer is determined; s4, solving a deformation deflection expression after unloading; wherein in the step S1, according to different cross section shapes, the two-cross-section profile can be divided into a hooked-edge two-cross-section profile and a hooked-edge-free Z-cross-section profile; in the step S4, for the hooked edge Z-section profile, the deformation deflection expression after unloading is shown in the specification; for the Z-section profile without the hooked edge, the deformation deflection expression after unloading is shown in the specification; e is the elasticity modulus of the material; mT is the moment of force which causes oblique bending deformation after roll bending unloading of the profile in the bending area of the profile; the length of the neutral layer is equal to the length of a pure bending area before roll bending of the hooked edge profile; the moment of inertia is the moment of inertia of the cross section of the middle hook edge Z profile in a coordinate system; t is the wall thickness of the material. By using the method for predicting the oblique bending deformation of the Z-section profile, accurate prediction of the oblique bending deformation of the Z-section profile can be realized.

The present invention provides a yield determination method for a soft rock tunnel confined concrete box steel arch frame. Under the limit state, the axial compressive ultimate bearing capacity N is obtained according to the stress distribution for the confined concrete box steel arch frame section. u and pure bending ultimate bearing capacity M u ; According to the stress state of the section, the expressions of the section axial force N and bending moment M are derived; through the axial compression ultimate bearing capacity N u , Pure bending ultimate bearing capacity M u , the cross-section axial force N and bending moment M are dimensionless, and the compression-bending yield criterion of the confined concrete box steel arch section is obtained; for the confined concrete box steel arch to be measured, the structural mechanics force method is used to decompose it and the current axial force F is obtained. Nφ and the current bending moment M φ The calculation formula is: the current axial force F Nφ and the current bending moment M φ Substitute the compression-bending yield criterion and, based on the generalized cross-sectional yield function, determine the yield condition of the confined concrete box-section steel arch to be measured. Clarify the yield condition of the support structure to avoid overly conservative or risky designs.

The application discloses an ultra-high performance concrete core column plate and an integrated design method thereof. According to the bending moment envelope, the plate span is divided into a pure bending section and a shear span section along the plate span direction, and the UHPC core column spacing, the plate thickness and the tensile reinforcement ratio are adjusted in different sections. In the bending moment peak value area, the core column spacing is reduced, the bottom plate thickness and the reinforcement ratio are appropriately increased, in the smaller bending moment area, the core column spacing is increased, and the reinforcement ratio is reduced, so as to control the dead weight and the cost. The relative density of the core column continuously or sectionally changes in the full span range. Based on the approximate linear relationship among the bearing capacity, the UHPC tensile strength, the tensile reinforcement ratio and the plate thickness, a bearing capacity expression is established, the material performance and the structural parameters of each section are reversely calculated by taking the bending moment and the deflection limit value as constraints, the cross-direction gradient configuration of the UHPC and the steel reinforcement is realized, and the economy and the structural performance are significantly improved.

This invention discloses a test apparatus for the ultimate strength of a ship hull beam section under cyclic loading, comprising a specimen, a gantry system, and an actuation device. The specimen includes a test section, an extension section, a lengthening section, supporting steel columns, and loading steel columns. Extension sections are welded to both ends of the test section, and the extension sections are fixedly connected to the lengthening sections. Loading steel columns are welded to both ends of the top and bottom surfaces of the test section. Supporting steel columns are welded to the ends of the lengthening sections. Support supports are fixedly installed at both ends of the gantry system, and the support supports have openings for the supporting steel columns to pass through at both ends, allowing the loading steel columns to slide freely along the ship's length. The actuation device includes an upper actuating head installed above the test section and a lower actuating head installed below the test section. This invention can simultaneously apply mid-sag / mid-camber loads to the test section of the ship hull beam while ensuring that the test section only bears pure bending moments and not shear stresses, thus obtaining the ultimate strength of the test section of the ship hull beam under cyclic loading of mid-sag / mid-camber.

The invention discloses a method for calculating the equivalent section modulus of a cold-formed thin-walled steel beam with a hole under a pure bend, the cold-formed thin-walled steel beam has a C-shaped section, and long round holes are continuously formed along a web plate; comprising the following steps that the width b of a web straight section of the cold-formed thin-walled steel beam, the height h of a flange straight section, the length d of a curled edge straight section, the plate thickness t, the total length e of an oblong hole, the appearance period S of the oblong hole, the semi-circle radius r of the two ends of the oblong hole and the steel yield strength fy are determined; based on an effective width method, considering local buckling and an oblong hole weakening effect, respectively calculating effective widths of a web, a flange and a curled edge, combining the effective widths to form an equivalent effective section, and calculating an effective area Aeff of the equivalent effective section and a distance eeff from an effective centroid to a center line of the web; and calculating an effective inertia moment Ieff and an equivalent section modulus Weff. According to the method, the section modulus after reduction can be quickly obtained by substituting the geometric dimension once, the method is simple and quick, and high-precision and zero-iteration preposed input can be provided for subsequent deformation checking calculation and flexural capacity design.

The invention discloses an insulator base and a box-type cross arm connecting method, and relates to the technical field of power system power transmission line engineering, and the insulator base and the box-type cross arm connecting method comprise a stress rod angle steel A. The stress rod angle steel A is provided with a first assembly, and the first assembly comprises a long bolt which is in threaded connection with the stress rod angle steel A; by comparing key data such as stress models and section characteristics of angle steel A of a stress rod and channel steel, the angle steel is preferably selected as a main stress component, lightweight design is achieved while the structural strength is guaranteed, 8 # channel steel and 757 angle steel are taken as examples, the bending section modulus of the angle steel to the limb outer edge is larger than the bending section modulus of the channel steel to a web outer edge shaft, and the strength of the steel is improved. The stress requirement of pure bending of the iron accessory can be more reliably met; according to different voltage grades, 755 angle steel and 75 * 7 angle steel are respectively selected, and all main stress section steel adopts Q355 marks, so that the overall weight of the iron accessory is reduced, the transportation and installation cost is reduced, and meanwhile, the bearing capacity of the structure is ensured to meet the use standard of a 110kV-220kV power system.

The invention relates to the technical field of ice mechanical tests, in particular to a simulated ice bending strength testing device and a testing method thereof. Comprising a rack, a fastening assembly and a loading assembly, the fastening assembly and the loading assembly are installed on the rack, and the fastening assembly is installed on the rack and used for clamping a model ice beam; the loading assembly is installed on the machine frame and used for applying load to the free end of the model ice beam, the loading assembly comprises a loading head, the loading head is arranged in the Y-axis direction, and the size of the loading head in the Y-axis direction is matched with the width size of the model ice beam, so that it is ensured that the load applied by the loading head perpendicularly passes through the center axis of the clamped model ice beam, and the loading efficiency is improved. Additional torque or axial force caused by eccentric loading is avoided, so that simulation of a pure bending stress state is realized. The testing device provided by the invention solves the technical problem of inaccurate measurement caused by difficulty in realizing accurate loading of brittle materials such as model ice in a bending strength test.

The application discloses a method for quickly predicting critical bending buckling load of a ribbed wallboard, and relates to the field of buckling analysis of a ribbed plate. The method comprises the following steps: establishing a simplified model of a blade ribbed wallboard under the action of pure bending moment; determining a stress distribution expression according to the simplified model of the blade ribbed wallboard; adopting finite element simulation to fit an effective width analytical expression of the blade ribbed wallboard; establishing a balance equation and boundary conditions of the simplified model of the blade ribbed wallboard based on the stress distribution expression; establishing a generalized characteristic equation by using the differential quadrature method based on the effective width analytical expression according to the balance equation and boundary conditions of the simplified model of the blade ribbed wallboard; and iteratively solving the generalized characteristic equation according to the geometric size, initial buckling stress value and initial half-wave number value of the blade ribbed wallboard to obtain a prediction result of the elastic critical bending buckling stress of the blade ribbed wallboard. The application can improve the prediction speed and accuracy of the buckling load.

This invention discloses a method for fixing and controlling tensile deformation in stretch bending forming, comprising: S1, prioritizing the shape and dimensions of key components during the stretch bending process; S2, simulating and calculating the stretch bending forming of the profile; S3, designing the stretch bending die based on the derived die curve; S4, manufacturing the die; S5, writing a stretch bending program using the simulated stretch bending curve calculated from the simulation; S6, marking lines on the bottom of the profile before stretch bending to measure the tensile deformation after stretch bending; S7, conducting a stretch bending test using the die; S8, inspecting the shape of the stretch bending part using a test template; and S9, reprocessing and correcting the die curve, and conducting a stretch bending test according to step S7. This stretch bending forming method effectively controls the tensile deformation of the stretch bending part by using a reasonable minimum fixed tensile deformation parameter, and adds springback compensation for the pure bending deformation component, which can reduce the shrinkage deformation and angular distortion of the cross-section, ensuring the stability and accuracy of the cross-sectional shape.

The present invention makes it possible to provide an optical fiber for a woven fabric that is less susceptible to defects such as occurrence of bright spots and breakage due to damage to the optical fiber during a manufacturing process for woven fabric using the optical fiber.　An optical fiber (10) for woven fabric, comprising at least one core (1) and a first sheath layer (11) surrounding an outer periphery of the core (1), wherein the bending stiffness of the optical fiber (10) as measured by the KES pure bending test is 0.500 gf·cm2 / yarn or less.

The invention relates to a pure bending moment testing device and a pure bending moment testing method based on double vertical sliding rails. According to the invention, a double-vertical sliding track scheme is adopted, and non-bending force is released by driving the sample to bend and allowing the two ends of the sample to freely move, so that a pure bending test with a large rotation angle is carried out, and the accuracy of a test result is ensured. Compared with existing three-point bending and four-point bending testing devices, the device is not only suitable for linear bending moment testing material structures such as sheets, spring steel and rulers which can be subjected to bending tests in a conventional universal material testing machine, but also can be used for carrying out large-angle-range nonlinear pure bending moment tests on different types of materials such as ultrathin flexible structures; the test requirements of various materials and structures on mechanical properties under the condition of large deformation are met, and the universality of bending moment test is remarkably improved.

The present application relates to box girder structure technical field, especially to a kind of heterogeneous corrugated sandwich composite variable cross-section box girder structure, including structure ontology, the structure ontology is the stereoscopic structure of two ends narrow middle wide, the transition area of two ends and middle part of the structure ontology is inclined plane, two ends of the structure ontology are support section, and middle part is pure bending section, the transition area between support section and the pure bending section is shear section, the structure ontology includes inner tube and outer tube that is sleeved in outer tube of inner tube, hollow cavity is equipped between the inner tube and the outer tube, variable cross-section rigid foam core is filled in the cavity.The structure is superior in bending resistance, shear resistance, high material utilization rate, and has the function design that can be used for laying line, ventilation etc..The present application also provides a kind of heterogeneous corrugated sandwich composite variable cross-section box girder structure forming process.

The present invention aims to provide a tissue reinforcement material having water absorbency and high stretchability. Provided is a tissue reinforcement material including a non-woven fabric containing polyglycolide, wherein the tissue reinforcement material has an average fiber diameter of 0.5 μm or more and 7.0 μm or less, an areal density of 1.0 g / m2 or more and 50 g / m2 or less, and a flexural rigidity (B value) measured with a pure bending tester of 0.001 gf·cm2 / cm or more and 0.01 gf·cm2 / cm or less.

The present invention provides a method for measuring tensile and compressive elastic moduli based on a four-point beam bending test, taking into account the dual-modulus properties of materials. Solution: A four-point bending beam specimen with a height-to-span ratio of less than 1 / 6 is used, with both ends simply supported. A symmetrical longitudinal concentrated load is applied, placing the middle section in a state of pure bending stress. Strain gauges are attached to the top and bottom surfaces of the middle section of the specimen, or strain is measured using DIC technology. The position of the neutral layer is determined from the strain on the top and bottom surfaces, and the horizontal stress distribution at the central cross section is then described. The maximum horizontal compressive stress and tensile stress on the top and bottom surfaces are calculated using force equilibrium and moment equilibrium equations. Finally, the compressive and tensile moduli of the material are inverted from the measured compressive and tensile strains. This method allows for simultaneous measurement of the tensile and compressive moduli, is simple to operate, and has high measurement accuracy.

The invention discloses an FRP rib limit bending radius measuring device and method, and the device comprises a loading system which comprises a smooth guide rail and two FRP rib fixing supports; the at least one FRP rib fixing support is arranged on the smooth guide rail and can slide along the smooth guide rail; the FRP rib fixing support is provided with an FRP rib fixing sleeve which can adaptively rotate in a vertical plane along the loading direction; the FRP rib to be measured is fixed in the FRP rib fixing sleeves of the two FRP rib fixing supports; and the driving system is connected with the FRP rib fixing support sliding along the smooth guide rail, so that the FRP rib fixing support slides along the smooth guide rail. According to the invention, the limit bending radius of the FRP rib in the nearly pure bending state can be accurately measured, and a quantitative evaluation method is provided for composite material manufacturers to determine the coiling radius which has no influence on the short-term and long-term mechanical properties of the FRP rib.

The invention discloses a concrete box girder non-linear deflection identification method considering a shear hysteresis effect, and the method comprises the steps: estimating the position of a neutral axis of a box girder through long gauge length strain and material performance, and then determining the curvature distribution and bending deflection; meanwhile, the shear hysteresis effect is considered, the additional deflection is calculated, and finally the corrected deflection after the pure bending deformation and the shear hysteresis effect are considered is obtained. By means of the method, the deformation state of the box girder structure can be accurately recognized in different load stages, and good adaptability is still achieved after concrete cracks. According to the method, the shearing force hysteresis effect and the material nonlinear characteristics are considered at the same time, limitation of traditional plane section assumption is avoided, and the deflection recognition accuracy is remarkably improved. Meanwhile, additional reference points do not need to be arranged, deflection identification can be achieved only by depending on strain monitoring data, and application and popularization in a bridge health monitoring system are facilitated.

The invention relates to an internal force calculation method for a circular homogeneous pipe-jacking tunnel under the action of ground unbalance loading, and the method comprises the steps: firstly converting ground single-side pile load and traffic load into equivalent horizontal unbalance pressure based on a space soil arching effect and a foundation pit single-side unbalance loading model; then, a combination model is established by superposing traditional uniformly distributed loads; then, according to a 120-degree soil arc bearing angle internal force coefficient method, the bending moment and the axial force are calculated, and two kinds of load combinations of strength and deformation checking calculation are completed; and finally, circumferential reinforcement is completed according to the pure bending section and the bending section. The method fills the design blank of the unbalance loading working condition, has simplicity and engineering precision, can guarantee long-term stability of the pipe jacking tunnel under the influence of unbalance loading, and is suitable for rapid and accurate design of engineering.