32 results about "Tension stress" patented technology

This invention discloses a ribbed prestressed concrete composite floor slab and its design method, relating to the field of prefabricated building structure design technology. The method includes calculating the total bearing capacity of prestressed steel bars required in the primary load-bearing direction and the total bearing capacity of ordinary steel bars required in the secondary load-bearing direction, based on the span and load parameters of the target floor slab. The reserved extension lengths of the two types of steel bars are determined according to the precast portion and the total thickness of the composite. The types, spacing, tensile stresses, and precise curve trajectory coordinates of the prestressed steel bars within the precast concrete are designed in detail, and the types, spacing, and arrangement coordinates of the ordinary steel bars are also designed. An internal reinforcement space model of the precast portion is generated based on the coordinate parameters of all steel bars, and a three-dimensional structural model of the ribbed precast template is generated by combining the geometric boundaries. This method achieves refined reinforcement design and digital expression of manufacturing information.

The application relates to a kind of high strain rate under fiber concrete material dynamic axial tensile performance test method, comprising: setting Hopkinson tensile rod device, using the verified Hopkinson tensile rod device to pulse wave is applied to test piece, and the deformation of resistance strain gauge is collected;The deformation is converted into voltage signal, for calculating the strain of resistance strain gauge and the average compressive stress of test piece;Based on strain and average compressive stress, determine the dynamic tensile stress-strain relationship of test piece, according to the dynamic tensile stress-strain relationship of test piece, the dynamic tensile stress time history and dynamic axial strain time history are point by point corresponding pairing on time axis, and the dynamic tensile stress-strain curve of test piece under high strain rate is obtained.The application can make the performance test of fiber concrete and other materials under high strain rate more easily realized, provide the basis for the dynamic performance characterization of material, help the application and popularization of high-performance materials under extreme working conditions such as explosion impact.

This invention discloses a method for strength calculation of a detachable support device. The method includes: obtaining the supporting force and radial force per unit length of the detachable support device; calculating the bending moment and horizontal tensile force at the connecting section based on the supporting force and the radial force per unit length; establishing the static moment equilibrium equation of the connecting section and determining the neutral axis position of the connecting section through iterative calculation; calculating the moment of inertia of the connecting section based on the neutral axis position; and calculating the maximum tensile stress borne by the fastener based on the moment of inertia, the bending moment, and the horizontal tensile force, so as to perform strength verification of the connecting section. This invention derives the strength verification formula and judgment criteria for key stress sections in detachable support structures, which is convenient for engineering technicians and ensures operational safety.

The present application relates to a kind of spot I type nugget fracture failure constitutive model construction method, belong to the fracture mechanics and numerical simulation method technical field of spot welding joint.The technical scheme of the present application is: the parameter construction of constitutive model is carried out, parameter is directly used for spot welding joint related finite element simulation;Spot welding joint is bonded with uniaxial tensile fixture, and the tensile experiment of nugget fracture form is completed under tensile testing machine and the load-displacement curve and maximum load are recorded;Finite element model is constructed and tensile displacement is calculated;Convert and correct stress-displacement curve in combination with measured nugget area, solve maximum tensile stress and fracture energy, parameter is substituted into model and the precision of replacement connection mode is verified.The beneficial effects of the present application are: the accurate construction of spot I type nugget fracture failure constitutive model is realized, which provides standardized mechanical parameter support for spot welding joint structure reliability design and welding process optimization, and significantly improves the accuracy and engineering application value of finite element simulation.

This invention provides a method for improving joint cracking in inner liner layers, comprising: measuring at least one shrinkage rate value during the production process of the inner liner layer; and adjusting the conveying control parameters of the inner liner layer production line based on the measured shrinkage rate value. In this embodiment, the method for improving joint cracking in inner liner layers quantifies the shrinkage state during the production process of the inner liner layer and adjusts conveying control parameters such as the tension of the floating roller and the speed of the cooling roller based on the shrinkage rate measurement results. This ensures that the inner liner layer completes sufficient stress release and achieves stable conveying on the production line, fundamentally eliminating the cause of joint cracking due to continued shrinkage of the inner liner layer material. By controlling the tension and speed parameters of the conveying process, it ensures that the inner liner layer reaches a dimensionally stable state before entering the molding process, thereby avoiding tensile stress at the joint caused by subsequent material shrinkage. This solves the technical problem of frequent joint cracking of the inner liner layer during the molding of the tire blank in related technologies.

This invention discloses a stability analysis method for the bearing arch of a large-span tunnel based on compressive and tensile safety factors, belonging to the field of tunnel and underground engineering construction data analysis technology. The method includes the following steps: obtaining the tunnel geometry, surrounding rock mechanical strength, ground stress, and support parameters; simplifying the bearing arch formed by anchor spraying reinforcement into an arched beam elastically fixed to the sidewalls at both ends; determining the plastic loosening zone of the roof slab through numerical simulation, and using its self-weight as the main vertical load; calculating the internal forces and edge normal stresses of key sections of the bearing arch using structural mechanics, and classifying them into compressive and tensile stresses accordingly; calculating the compressive and tensile safety factors of each section based on the natural strength parameters of the surrounding rock, and using the minimum value as a quantitative index for evaluating the overall stability of the bearing arch. This invention establishes a quantitative mechanical model of the bearing arch, realizing accurate and convenient assessment of the safety of the anchor spraying support structure of the roof slab of ultra-large span tunnels.

The invention provides a method for determining the detonation speed of an explosive used for tunnel caving blasting by considering the influence of ground stress, and belongs to the technical field of blasting engineering and rock mass mechanics. Comprising the steps of obtaining rock mass mechanical parameters, blasting parameters and crustal stress data; establishing a stress analysis model based on ground stress and a blasting design drawing; establishing a crustal stress redistribution model caused by a cut cavity in the model, calculating radial pressure stress generated by crustal stress redistribution among the caving holes, and drawing a polar coordinate graph; establishing a collapse inter-hole explosion stress superposition model, and calculating circumferential tensile stress generated by explosion at the central points of the two holes; and based on the dynamic tensile strength and stress state of the rock, establishing a strength criterion for forming the inter-hole through crack, and deducing and solving the minimum explosive detonation speed required by the criterion. The blasting joint forming quality is effectively improved, back break is controlled, surrounding rock damage is reduced, and the safety, economical efficiency and reliability of blasting engineering are improved.

The application discloses a physical simulation device of superposition of extrusion and tensile stress field, comprising a power device, a sand box bin and an automatic sand distribution device, wherein the automatic sand distribution device is located above the sand box bin, and the power device is arranged at the bottom side of the sand box bin, and further discloses an experimental method of the physical simulation device of superposition of extrusion and tensile stress field. The application is suitable for the technical field of structural geology and can simulate the structural development of strata under the background of extrusion or tensile stress by adopting the power device to control the sand box to perform extrusion and tensile movement. The problem of frictional resistance of sand layer is solved by using the synchronously active side plate of the sand box. Through forward modeling and reproduction, the data collection of the development process of deep structure and the influence on shallow structure under the action of multi-period extrusion and tensile stress field is realized, and the application has universal applicability and operability.

The present application relates to the technical field of rock slope engineering, and provides a rock slope anchoring system and a construction method, the system comprising a plurality of adaptive deformation connecting structures and a plurality of anchoring structures corresponding one by one, the plurality of adaptive deformation connecting structures being arranged at intervals on the slope surface; two adjacent adaptive deformation connecting structures being connected through a connecting beam, the anchoring structure being arranged in an anchoring hole; one end of the anchoring structure being anchored at the bottom of the anchoring hole, and the other end being exposed and connected with the corresponding adaptive deformation connecting structure; the part of the anchoring structure in the anchoring hole having a pressure-relief section, which can absorb rock mass displacement through axial deformation, so as to avoid the anchoring structure from being broken due to tensile stress exceeding the limit; the adaptive deformation connecting structure and the connecting beam being connected in sliding fit, so that the adaptive deformation connecting structure can displace along the slope surface relative to the connecting beam, and the local pressure-relief capacity in a single anchoring hole is transmitted to the entire slope surface, thereby improving the long-term stability of the rock slope in complex environments such as heat and humidity.

The application discloses a kind of building material quality defect detection method and system, the method comprises: obtaining the steel member material image under the tension stress of each time point collection, the steel member material image of each steel member material image is preprocessed, the steel member body data of the material image to be measured of each time point and steel member is obtained;The crack region of the material image to be measured of each time point is identified, and the edge point of crack region is screened starting edge point and end edge point;According to starting edge point and end edge point, the turning point of crack is screened, the crack sawtooth degree between each time point is calculated by the turning point of crack, the crack propagation change amount is calculated by the crack sawtooth degree between each time point crack;Through crack propagation change amount, judge the fatigue detection result of the steel member material image under the tension stress.

This invention discloses a computational method for vibration and stress fatigue analysis of hydraulic pipelines under nonlinear boundary conditions. The method first establishes the dynamic control equations of the hydraulic pipeline under nonlinear boundary conditions, then solves and verifies the system using the harmonic balance method and the Runge-Kutta method to obtain the response and stress distribution of the entire pipeline. Based on the calculation results, the tensile and bending stresses at arbitrary locations in the pipeline are further solved. This identifies the location with the highest stress, and fatigue life is predicted based on the maximum stress. This method more closely approximates the actual working conditions of hydraulic pipelines, improves the accuracy of stress analysis, and contributes to in-depth research on the fatigue failure mechanisms of hydraulic pipelines, providing theoretical support for engineering design and fault early warning.

The present application belongs to the technical field of geotechnical engineering anchoring and supporting, and provides a prestressed expanding-shell type anchor rod and a construction method thereof, which comprises a rod body including a locking section and a pulling section, the front end of the locking section is an expanding-shell head, the expanding-shell head is expanded outward by abutting the head end of the rod body against the bottom of an anchor hole and rotating it, the locking section and the pulling section are integrally connected in sequence, and the connecting end of the locking section and the pulling section is provided with a first conical frame and a second conical frame in correspondence; the first conical frame and the second conical frame each comprise a pull ring, a shaped ring and a tensile reinforcement. The anchor rod structure has excellent axial tensile capacity, and the anchoring capacity with the surrounding rock and soil layer is stronger than that of the conventional anchor rod, so that the axial tensile stress generated by the large deformation of the surrounding rock and soil can be well coped with, the normal supporting capacity can still be maintained in this case, thereby reducing the deformation degree of the rock and soil layer and facilitating the subsequent maintenance by the staff.

This invention relates to the field of bridge reinforcement design technology, and in particular to a method for flexural design of prestressed CFRP-reinforced reinforced concrete (RC) simply supported beams. The method includes the following steps: determining whether the bridge can achieve improved flexural bearing capacity through prestressed CFRP reinforcement of the RC simply supported beams; if the conditions are met, then performing a load-bearing capacity calculation for the prestressed CFRP-reinforced RC simply supported beams, including: firstly, obtaining the initial tension strain limit range of the prestressed CFRP according to the principle of adequate reinforcement failure, and then calculating the load-bearing capacity requirement M of the reinforced RC simply supported beams. s The control tension strain and the number of CFRP reinforcement layers for prestressed CFRP-strengthened simply supported RC beams were determined. Finally, based on the initial tension strain limit range of prestressed CFRP, the initial control tension strain and the design reinforcement amount of CFRP were obtained. A method for determining the initial control tension stress of prestressed CFRP was proposed, and the relationship between the number of CFRP layers and the initial tension stress was established. Based on this, a bending design method for prestressed CFRP-strengthened RC beams was proposed.

The application provides a superhigh-pressure acidizing fracturing pump fluid end assembly and a manufacturing method thereof, which comprises a valve seat base body, a valve body configured to be engaged and disengaged in the inner cavity of the valve seat base body through reciprocating movement, and a sealing rubber ring clamped on the valve body, the application opens an annular groove with a half-dove-tail inclined side wall and a sinusoidal wave-shaped groove bottom on a non-carburized hardening tough steel base body conical sealing surface, constructs a ceramic reinforced layer containing nanoscale and microscale carbides in the groove by in-situ self-reaction, the inclined configuration of the half-dove-tail side wall forms self-clamping locking by the thermal shrinkage effect of the cladding layer during cooling, converts the interface residual tensile stress into extrusion prestress, and the sinusoidal wave-shaped groove bottom disperses the axial high-frequency impact stress into shear stresses which offset each other, so that the macro fatigue collapse and micro coating cracking failure are solved, and the valve seat sealing surface has high erosion resistance, high fatigue resistance and high reliability.

The application discloses a super-large volume blank and a method for reducing the upsetting force of free forging, wherein the blank is designed as a drum shape with a large diameter at the upper and lower ends and a small diameter at the middle part, the three-way stress state of the metal during the upsetting is changed by using the drum shape structure, the axial compressive stress is converted into the radial tensile stress, the metal is guided to flow along the short axis direction under the minimum resistance law, and it is ensured that the deformation of the middle part of the blank after the outward drumming does not exceed the size of the two ends of the blank, so that the required upsetting force changes with the cross-sectional area of the middle part of the blank, and thus the upsetting of the super-large volume blank is performed with a smaller upsetting force. The blank is designed as the drum shape, so that the upsetting force of the free forging is not only reduced, but also the forming quality is improved.

This invention relates to a test method for determining the direct tensile strength of concrete based on a tension-compression bar model. The method includes the following steps: preparing a concrete beam specimen, wherein the concrete beam specimen is constructed with a stepped opening at mid-span, and tension and compression bars are sequentially arranged from bottom to top within the stepped opening; applying pressure to the stepped opening of the concrete beam specimen until the specimen fails, and recording the pressure load; determining the mid-span bending moment of the concrete beam specimen based on the pressure load; and determining the direct tensile strength of the concrete based on the elastic modulus, neutral axis height, moment of inertia of the concrete beam specimen, and a predetermined tension-compression bar model. This invention has the advantages of enabling the specimen to operate under approximately uniform tensile stress, producing test results close to the direct tensile strength, and being simple to operate.

The application provides a kind of underground interchange main body side wall structure concrete crack resistance waterproof construction method, it is related to underground engineering concrete construction technical field, the application is by dividing side wall into multiple sub-regions, obtains the geometric curvature of each sub-region, structural constraint, cross section variation, temperature action, shrinkage strain, load tensile stress, joint adjacent and waterproof weak parameter;Based on the first six parameters, calculate the crack resistance risk value, combined with the last two parameters to calculate the waterproof failure risk value, and determine the comprehensive protection requirement value accordingly;According to the comprehensive protection requirement value, the sub-regions are classified, and the target areas that need to be strengthened are identified;Different regions are respectively used C40 concrete with conventional or hybrid fiber optimal ratio, and the pouring segment length is dynamically determined according to the maximum crack resistance risk value, to realize differentiated crack resistance waterproof construction.

This structure comprises a first elastic member that extends linearly along a prescribed direction, and a second elastic member that extends in a curved shape along the prescribed direction and has a plurality of joining parts joined to the first elastic member at intervals along the prescribed direction. The structure further comprises a reinforcing member that is formed of a material having a lower mass density than the second elastic member and that is joined to a first surface or a second surface of the second elastic member. In the structure, when a pressing force in a direction toward the first elastic member is applied to a non-joining part, which is a portion between two adjacent joining parts of the second elastic member, and a non-joining corresponding part, which is a portion corresponding to the non-joining part of the reinforcing member, compressive stress in the prescribed direction is generated in the second elastic member and the reinforcing member and tensile stress in the prescribed direction is generated in the first elastic member along with bending deformation of the non-joining part and the non-joining corresponding part.

This invention relates to the field of metal pressure processing, specifically to a precision drawing method for reducing residual stress in wire. It includes surface pretreatment, initial drawing, intermediate anti-tension drawing, and final precision drawing steps. The process is carried out in series using a continuous wire drawing machine. The key is that the reduction rate of each pass decreases progressively, and the final pass uses a small reduction rate of 3%–5% combined with a large working cone angle of 14°–18°. Its core is to confine plastic deformation to the surface layer of the wire by utilizing the large cone angle and small reduction rate, while leveraging the elastic restraint of the deep core metal to introduce microscopic residual compressive stress into the surface layer. This invention effectively solves the problems of warping and stress corrosion cracking in downstream wire processing by transforming the residual tensile stress accumulated in traditional processes into compressive stress, significantly improving forming quality while maintaining high tensile strength.

This application relates to a support device and method for a mining roadway. First, a first support member and a second support member are placed on both sides of the mining roadway, with the first side conforming to one side of the surrounding rock and the second side conforming to the other side. The first and second straight sections extend to below the top of the surrounding rock. A fixing assembly initially fixes the first and second support members to the surrounding rock. A connecting assembly connects the first and second straight sections and applies a horizontal preload to the connecting assembly, causing the first and second support members to tend to move towards the middle of the mining roadway. The preload is transmitted to the top of the surrounding rock through the structure of the first and second support members, transforming into horizontal compressive stress on the top of the surrounding rock. This improves the stress state of the top of the surrounding rock, transforming the tensile stress area originally caused by roadway excavation into a compressive stress area, inhibiting the subsidence of the top of the surrounding rock, thereby improving the support effect of the support structure, reducing the maintenance of the mining roadway, and lowering the support cost.

This application discloses a two-dimensional material island with warped edges and its preparation method. A first material film with tensile stress is deposited on the upper surface of a two-dimensional material (such as graphite), and a smaller second material film is deposited on top of the first material film in a partially covering manner. By covering the two material films in this way, during the transfer of the two-dimensional material island to the substrate, the first material film can release stress, causing the lower two-dimensional material layer to warp at the edges. Furthermore, since the upper second material film can hinder deformation of the central region of the lower material, a two-dimensional material island with warped edges but a flat central region can be formed. This reduces the frictional effect of the edges on the two-dimensional material island and improves its super-lubricating properties.

This invention relates to the field of building structure demolition technology, specifically to a method and system for the layered cracking of concrete beams using a two-way prestressed transient differential method. Axial and eccentric prestresses are applied to both ends of the reinforced concrete beam, creating a stress gradient where the prestress in the tension zone is greater than that in the compression zone. N independent circumferential constraints are arranged at intervals along the beam's length, each equipped with an independent electromagnetic unlocking device. First, an unlocking signal is synchronously sent to the electromagnetic unlocking device in the tension zone to expose the longitudinal reinforcement. After a delay, an unlocking signal is synchronously sent to the electromagnetic unlocking device in the compression zone to cause the remaining concrete to fragment. This invention can completely preserve the reinforcing steel skeleton and control the size of the fragments.

This invention discloses a method for constructing prestressed wet joints in beams, addressing the problems of cracking at the interface between new and old concrete, as well as within the wet joint itself. A specialized construction device is placed at the starting point of the wet joint construction, spanning the beam on both sides of the joint. The hydraulic puller within the device inserts its pin into the socket formed by two U-shaped reinforcing bars, pulling the bars out. After welding, the hydraulic puller releases, removing the pin from the socket. The device is then moved along the beam's length to perform cold pulling and welding on the next pair of U-shaped reinforcing bars; this process is repeated until the remaining U-shaped reinforcing bars are cold pulled out and welded. During this process, the hydraulic loading force of the hydraulic jacks is gradually increased to maintain the tensile stress between each pair of U-shaped reinforcing bars at a value of N. This invention achieves mechanized construction through the combined use of the puller and welding robotic arm, making the construction of wet joints more standardized.

This invention relates to a spinning composite treatment method for stress relief and strengthening of conical forgings, belonging to the field of hot working and surface strengthening treatment of metallic materials. The method includes the following steps: S1 quenching treatment; S2 cold spinning treatment, which sequentially includes selecting forward or reverse spinning, installing arc-shaped or conical spinning wheels, setting the spindle speed and feed ratio, performing spinning with the first pass deformation ≤2%, and subsequent passes increasing to 3%–5% of the wall thickness, while simultaneously controlling the temperature rise to ≤50℃ through forced cooling, controlling the roundness error to ≤0.3 mm, and the wall thickness uniformity error to ≤±0.2 mm; S3 aging treatment. The advantages of this invention are: through uniform overall deformation by cold spinning, residual tensile stress is eliminated, work hardening is triggered, brittle phases are broken, and grains are refined, achieving synergistic stress relief and strengthening. The stress relief rate is ≥85%, the yield strength is increased by 8%–12%, and the elongation is maintained well. No special molds are required, and it is suitable for conical forgings made of aluminum alloys, titanium alloys, and ultra-high strength steel.

The utility model relates to underground pipe gallery construction technical field, and disclose a kind of prestressed locking mechanism of block type U-shaped pipe gallery core mould, the connecting assembly is composed of fixed cylinder, slider, limit rod, pull rod, spring, the fixed cylinder is fixedly installed in the top of mounting plate, the slider is slidably installed in the inside of fixed cylinder.The prestressed locking mechanism of block type U-shaped pipe gallery core mould is set up steel cable and accurate control tensioning stress in the key stress position of U-shaped module, more effective prestress can be applied to it, which can not only significantly improve the anti-deformation ability of U-shaped module as a whole, when the non-uniform settlement of local gene, load fluctuation produces upward reaction, the compressive stress previously established in the interior of U-shaped module can also be efficiently offset, greatly reduce the possibility of U-shaped module cracking due to tension, thereby avoiding the structural durability decline, leakage and other problems caused by crack, ensure that U-shaped module maintains stable and reliable working condition in long-term use.

The utility model discloses a press type case nail elastic lock piece for server slide rail, including inner frame, the tail end of inner frame is provided with elastic lock piece mechanism, is provided with the lock hole on elastic lock piece mechanism, the front end of elastic lock piece mechanism is provided with the guide block, and the inside of elastic lock piece mechanism is provided with the deformation groove, and the front end height of deformation groove inner wall is installed with the protruding portion, and the tail end fixed mounting of protruding portion has the press portion. The press type case nail elastic lock piece for server slide rail, when the case nail is inserted into the lock hole, and elastic lock piece mechanism produces deformation through the deformation groove, at this moment, the elastic recovery force of elastic lock piece mechanism is converted into radial locking force, when there is external force trying to pull apart elastic lock piece mechanism and case nail, the lock hole will be subjected to the tensile effect, make the original locking force convert into the tensile stress of resistance to stretch, thereby reduce the stress concentration degree of local, improve the bearing capacity and the anti -damage ability of elastic lock piece whole, avoid producing the problem that elastic lock piece can not normally lock.

This application discloses a method, apparatus, equipment, and readable storage medium for predicting the tensile fracture location, relating to the field of geological disaster prevention technology. To address the current problems of inaccurate prediction of the tensile fracture location in steeply sloping, tensile-cracked reservoirs and the inability to provide timely and accurate disaster warnings, the tensile fracture location prediction method includes: selecting a target rock layer from a layered rock mass wading slope; calculating the total tensile stress of the target rock layer based on its self-weight, the force exerted by the upper rock layers, and the pore water pressure; selecting the minimum value between the equivalent tensile strength of the target rock layer due to fracture expansion and the tensile strength due to water-rock softening as the critical stress for tensile fracture; constructing a stress balance equation by making the total tensile stress of the target rock layer equal to the critical stress for tensile fracture; and solving the stress balance equation using the length parameter of the target rock layer to obtain the tensile fracture location of the target rock layer. This application enables a more accurate determination of the tensile fracture location of layered rock mass wading slopes.

This invention relates to a protective layer combination formwork with damping structure and a building frame structure, belonging to the field of building structure technology. It solves the problem of brittleness and failure in concrete frame structures caused by the discontinuity between the high-ductility protective layer and ordinary concrete in the peak tensile stress region. The protective layer combination formwork with damping structure of this invention includes an upper protective layer occupant and a lower protective layer occupant; the upper and lower protective layer occupants are located on the upper and lower parts of the concrete floor slab, respectively, and are arranged in a three-dimensional cross pattern along the direction of the frame beams and frame columns; both the upper and lower protective layer occupants are equipped with damping occupants and stirrup keyways. Using the protective layer combination formwork of this invention during construction can significantly reduce the generation of cracks and brittle fracture transmission in the concrete frame, thereby improving the service life of the building frame structure.

This invention relates to a construction method for a building frame structure with a damping protective layer, belonging to the field of building structure technology. It solves the problem in existing technologies where the tensile stress peak zone at the interface between high-ductility materials and ordinary concrete is discontinuous, leading to fatigue cracks or brittle failure in the building. The preparatory work of this method includes fabricating components of the high-ductility composite formwork, fabricating concrete pouring molds, and fabricating mold panel assemblies. The concrete construction of this method includes the orderly installation of the mold panel assemblies and the upper protective layer occupants on the reinforcing steel frame, and the orderly removal of each mold panel and each high-ductility composite formwork component and its protective layer occupant component. The construction of the protective layer includes the laying of high-ductility material in the protective layer's occupant area with a damping structure. This invention significantly reduces the generation of cracks and brittle fracture transmission in concrete frames, lowers construction costs, and increases the service life of building frame structures.