229 results about "Bending fatigue" patented technology

A method for improving the fatigue performance of a titanium alloy seamless tube. The method comprises: S1, mixing raw materials, pressing same into a plurality of electrode blocks, and welding the plurality of the electrode blocks to obtain a consumable electrode; S2, smelting the consumable electrode 2-3 times by using a vacuum consumable electrode arc furnace, so as to obtain a titanium alloy cast ingot; S3, upsetting and drawing the cast ingot multiple times and rolling same into a titanium alloy bar; S4, subjecting the bar to precision forging, with the amount of times of heating being no more than twice; S5, annealing and straightening same, followed by turning and drilling treatments, so as to obtain a rough blank of a titanium alloy seamless tube; S6, subjecting same to multi-pass cold rolling, so as to obtain a semi-finished titanium alloy seamless tube product; S7, performing vacuum annealing and acid pickling; S8, performing electrolytic-magnetic composite polishing; and S9, performing a shot blasting treatment. The method can effectively improve the rotating bending fatigue performance, and the titanium alloy seamless tube can endure 20 million test cycles.

The invention relates to the technical field of ultra-high performance concrete, particularly discloses a fatigue performance evaluation method for a steel-UHPC combined bridge deck slab, and is used for solving the problem that the fatigue damage evolution process of the steel-UHPC combined bridge deck slab in the life cycle is difficult to accurately predict due to the fact that an existing evaluation method does not consider the influence of structural fatigue performance degradation. And the evaluation result is likely to be unsafe. According to structural parameters and material attributes of a reinforced UHPC layer, fatigue performance evaluation of a reinforced UHPC component under the action of an axial tension fatigue load is carried out, fatigue performance analysis of a stud connecting piece in ultra-thin UHPC under the action of a shear fatigue load is carried out, bending fatigue performance analysis of a steel-UHPC-pavement composition board is carried out based on a five-point bending test, and the bending fatigue performance of the steel-UHPC-pavement composition board is analyzed. And a time-varying fatigue analysis framework of the steel-concrete composite effect degraded steel-UHPC composite bridge deck is established, so that the evaluation result is more reliable, and the risk of unsafety is reduced.

The invention relates to the field of gears. A residual stress intensity factor is introduced into a Walker model, the influence of residual stress on the crack propagation residual life is analyzed, then a crack closing coefficient is introduced to correct the Walker model, and the bending fatigue life of the gear is obtained. The roughness and the dynamic meshing force are added into the model, the dynamic abrasion loss of the gear is calculated according to the improved Archard model, and the contact fatigue life of the gear is obtained; and finally, combining the gear bending fatigue reliability distribution function with the contact fatigue reliability distribution function by adopting a Copula function, and analyzing a competitive failure relationship among different failure forms by utilizing the combined distribution function to obtain a competitive failure reliability model so as to analyze the service life of the gear. According to the technical scheme, the technical problem of comprehensively describing the reliability of the gear is solved, accurate prediction of the reliability of the gear is achieved, and research, development and design of the gear are facilitated.

The invention provides a cable bending fatigue life prediction method and system based on reinforcement learning, and relates to the technical field of cable life prediction, and the method comprises the steps: collecting cable test sample data, calculating a stress distribution field and a strain distribution field, constructing a stress intensity factor calculation module, and calculating a crack propagation track and rate. A damage evolution tensor is constructed as a state feature, a network is trained based on a deep Q learning algorithm, uncertainty is quantified by adopting a Markov chain Monte Carlo method, and a credible interval and an early warning threshold are established.

The invention belongs to the technical field of metal part surface modification, and relates to a composite strengthening method for a carburized surface of a high-bearing gear of an aero-engine. According to the method, high-hardness and high-density ceramic shots are adopted as media for high-energy mechanical shot peening strengthening, the advantage that the subsurface strain hardening effect of the contact strengthening technology is good and the barb-shaped distribution characteristic of mechanical shot peening residual compressive stress are utilized, extremely high residual compressive stress is introduced to the subsurface position, and the contact fatigue performance of the tooth surface of the gear is improved. High-frequency laser shot peening strengthening is used for secondary treatment, so that the surface layer of the material is subjected to plastic deformation, high-amplitude residual compressive stress is introduced into the surface layer of the material within the depth range of more than 500 microns by utilizing the advantage of large influence depth of laser-induced shock waves, and the residual compressive stress can inhibit fatigue crack initiation, has a certain depth and inhibits fatigue crack propagation; and the bending fatigue resistance of the root of the gear can be effectively improved. And an abrasive flow process is adopted, so that the roughness is reduced to be more than 0.4 mu m.

Disclosed is a blended rope having an outer sheath (8) enclosing at least a strength member (7), the strength member (7) having high-strength synthetic fibers, the strength member (7) being a blended strength member (7) formed with a combination of ARAMID fibers and HMPE fibers, the blended strength member comprising a non-homogeneous distribution of the ARAMID and HMPE fibers, wherein the weight ratio of ARAMID to HMPE in the strength member (7) is preferably a minimum of 80:20.

The invention relates to the field of mechanical engineering, in particular to a multilevel screening speed reducer tooth matching method based on a standardized box body, which comprises the following steps of: acquiring basic parameters of an input gear speed reducer and parameters of each transmission stage, and acquiring derived parameter limit ranges of the basic parameters and the parameters; screening out a tooth matching scheme meeting user input constraint conditions, marking the tooth matching scheme as a candidate set # imgabs0 #, screening a serializable scheme based on general requirements of a serialized speed reducer on a final-stage gear pair, marking the serializable scheme as a candidate set # imgabs1 # on an existing standardized box body, designing a transmission system, and checking through tooth root bending fatigue strength to obtain a final-stage gear pair final-stage gear pair; and marking the tooth matching schemes meeting the strength requirement as a candidate set # imgabs2, performing serialized screening again based on the general requirement of the serialized speed reducer on the final-stage gear pair, and marking the schemes meeting the serialization as a final candidate set C1. According to the multi-layer screening mechanism, the tooth matching scheme meeting the strength requirement is rapidly matched for the serialized speed reducer.

The invention relates to the technical field of electronic engineering, in particular to a method and system for predicting the dynamic bending fatigue life of a circuit board and a medium. The method comprises the following steps: obtaining dynamic bending condition data of the circuit board, and carrying out a dynamic bending test on the circuit board according to the dynamic bending condition data of the circuit board, so as to obtain dynamic bending test data of the circuit board; performing circuit board test material feature extraction according to the circuit board dynamic bending test data so as to obtain circuit board test material data; performing circuit board dynamic bending analysis according to the circuit board test material data so as to obtain circuit board material dynamic bending data; and circuit board thickness feature extraction and circuit board layer number feature extraction are carried out according to the circuit board dynamic bending test data, so that circuit board thickness data and circuit board layer number data are obtained. Based on the electronic engineering technology, the accuracy of predicting the dynamic bending fatigue life of the circuit board is improved.

The invention discloses a gear pair life prediction method based on dynamic stress, belongs to the technical field of reliability design of mechanical transmission systems, and aims to solve the problem of inaccurate life prediction caused by neglecting a dynamic effect and a real surface topography in an existing gear design method. The method comprises the following steps: firstly, acquiring gear pair interface mechanical property parameters considering shafting vibration, dynamic load and surface roughness, wherein the parameters comprise transient oil film pressure, friction coefficient, oil film thickness and shear stress; solving a three-dimensional subsurface stress field by adopting an algorithm and calculating von Mises equivalent stress distribution; stress volume integration is conducted on different rough surfaces, the honed surface is used as the reference, the relative fatigue life of other surfaces is calculated based on the Zaretsky life prediction theory, and accurate prediction and process optimization of the contact fatigue life are achieved; meanwhile, the dynamic bending stress of the tooth root is calculated based on the dynamic normal load, and the bending fatigue safety coefficient is checked.

To provide a component that enables suppression of strength degradation in an excess carburized portion, including degradation of impact resistance and bending fatigue characteristics.SOLUTION: A vacuum carburizing steel containing, in mass%, C: 0.15-0.30%, Si: 0.70-1.20%, Mn: 0.90-3.00%, Cr: 0.50-1.50%, Mo: 0.10-1.00%, Al: 0.020-0.050%, Nb: 0.020-0.100%, and N: 0.0100-0.0300%, the balance being Fe and unavoidable impurities, wherein P and S among the unavoidable impurities satisfy P: 0.030% or less and S: 0.030% or less, and formulas A, B, C, and D: A: 0.12≤3[Al]+4[Nb]≤0.50, B: 0.20≤[N] / [Al]≤0.80, C: 5.0≤3[Si] / 0.5[Cr], D: 1.95≤-2[Si]+3[Mn]+[Cr]+2[Mo], are all satisfied.SELECTED DRAWING: Figure 1

The present invention relates to the field of electronic engineering technology, and particularly to a method, system and medium for predicting the dynamic bending fatigue life of a circuit board. The method includes the following steps: obtaining circuit board dynamic bending condition data, and performing a circuit board dynamic bending test according to the circuit board dynamic bending condition data, so as to obtain circuit board dynamic bending test data; extracting circuit board test material characteristics according to the circuit board dynamic bending test data, so as to obtain circuit board test material data; performing circuit board dynamic bending analysis according to the circuit board test material data, so as to obtain circuit board material dynamic bending data; extracting circuit board thickness characteristics and circuit board layer number characteristics according to the circuit board dynamic bending test data, so as to obtain circuit board thickness data and circuit board layer number data. The present invention improves the accuracy of predicting the dynamic bending fatigue life of a circuit board based on electronic engineering technology.

The invention relates to the technical field of flexible connecting pipelines, and discloses an asymmetric net sleeve metal hose and a forming method thereof.The asymmetric net sleeve metal hose comprises a corrugated pipe, the two ends of the corrugated pipe are fixedly connected with connecting pipes correspondingly, the outer side of the corrugated pipe is wrapped with a woven net sleeve, and the two ends of the woven net sleeve are fixedly connected with connecting rings correspondingly; the connecting ring is fixedly connected with the connecting pipe, and the woven mesh sleeve is of an unbalanced woven structure. The bending fatigue life of the metal hose is prolonged, the minimum bending radius is reduced, the self-supporting capacity of the metal hose in the specific direction is improved, and the application range of the metal hose is expanded.

The invention relates to the technical field of cylindrical gear bending fatigue strength tests, in particular to a metal material cylindrical gear bending fatigue limit test design method which comprises the steps of determining a metal material gear bending fatigue limit test method and test equipment; acquiring test cylindrical gear parameters, and designing a test fixture according to the test equipment and the cylindrical gear parameters; and performing a bending fatigue limit test on the test gear by using the test method and the test fixture to obtain test data, and analyzing the test data to obtain a test result. The method provided by the invention is good in operability, can obtain the bending fatigue limit of the metal material cylindrical gear with relatively high confidence and reliability, and participates in guiding gear design.

The invention discloses a tooth root rolling and finishing composite strengthening process method, which mainly considers that a gear is easy to generate tooth root bending fatigue failure under heavy load, obtains a modified tooth root through tooth root micro modification, and then adopts ultrasonic rolling to carry out tooth root local strengthening on the gear tooth root so as to improve the residual stress of the tooth root. And then the gear surface roughness after barreling and finishing is calculated according to the radius of the finishing abrasive particles, and the gear tooth root is subjected to finishing treatment based on a theoretical calculation result. And finally, the gear is processed to obtain the high-performance gear, so that the bending fatigue resistance of the gear tooth root is improved. And according to the gear material performance, the ultrasonic rolling strengthening tooth root performance parameters are determined. According to the stress relation, the tooth root residual stress after ultrasonic rolling strengthening is calculated, then the gear is subjected to barreling finishing machining analysis, the theoretical minimum roughness after barreling finishing is calculated according to the barreling finishing abrasive particle radius and tangential force, and finally actual machining is conducted. According to the method, grinding micro-modification, ultrasonic rolling strengthening and barreling finishing can be combined, the tooth surface of the gear is strengthened by correcting all technological parameters, the performance of the tooth root after machining is improved, and meanwhile the machining precision of the gear is improved.

The utility model relates to the technical field of cable processing, and belongs to a cable fatigue detection device. Comprising a workbench, the workbench is provided with a first mounting base and a second mounting base, the first mounting base is provided with a first clamping assembly, the second mounting base is provided with a torsion mechanism, the torsion mechanism comprises a torsion disc, and the torsion disc is provided with a reciprocating bending mechanism; the reciprocating bending mechanism comprises a reciprocating driving assembly and a second clamping assembly. The torsion of the to-be-tested cable can be realized through the torsion mechanism, the torsion fatigue strength of the cable can be detected, the reciprocating bending of the to-be-tested cable can be realized through the reciprocating driving assembly, the bending fatigue of the cable can be detected, multiple detections can be realized through a single device, and the detection efficiency is improved. The functionality of the device is improved, and the detection efficiency is improved.

The invention discloses a method for improving the rotating bending fatigue strength of an AlCoCrFeNi 2.1 eutectic high-entropy alloy, and belongs to the technical field of alloys. According to the method, the AlCoCrFeNi 2.1 eutectic high-entropy alloy is treated by utilizing an ultrasonic surface rolling process (USRP), so that the density of surface defects and holes of the AlCoCrFeNi 2.1 eutectic high-entropy alloy is effectively reduced, and the rotating bending fatigue strength of the AlCoCrFeNi 2.1 eutectic high-entropy alloy is improved. And meanwhile, the surface roughness is reduced, the surface structure morphology is changed, the crack propagation path is prolonged, and finally the purpose of improving the fatigue performance of the AlCoCrFeNi 2.1 eutectic high-entropy alloy is achieved. According to the method, the surface structure of the AlCoCrFeNi 2.1 eutectic high-entropy alloy can generate residual compressive stress under the action of high-frequency vibration and static-load rolling of the USRP, so that the initiation time of fatigue cracks is effectively prolonged, and the fatigue performance of the AlCoCrFeNi 2.1 eutectic high-entropy alloy is enhanced.

The high-strength steel sheet has a chemical composition with MSC value in the range of 2.7% to 3.8% by mass defined by a specific formula, wherein the high-strength steel sheet has a microstructure including specific microstructures in a surface layer region extending from the surface of the steel sheet to a depth of 100 μm and in an inner region other than the surface layer region. The high-strength steel sheet has the maximum height of the surface roughness of 30 μm or less, a tensile strength of 980 MPa or more, a uniform elongation of 6% or more, and a ratio of 107-cycle plane bending fatigue strength to tensile strength (fatigue limit ratio) of 0.45 or more.

The system comprises a hydraulic station, a servo electric cylinder, a programmable controller, an industrial control touch screen, a sensor detection technology and other technologies. The hydraulic station provides tension for the test bench and dynamically adjusts according to feedback of the tension sensor. The servo electric cylinder inputs height through the laser displacement sensor to control lifting, and therefore the purpose of controlling the steel wire rope to be horizontal is achieved. The PLC is used for sending instructions and collecting data. And the touch screen is used for writing instructions, monitoring equipment states and processing data. All the modules of the bending fatigue testing machine are matched to detect whether the hub can not generate cracks under the action of the specified bending moment and within the number of rotation turns or not. The bending fatigue test device provided by the invention integrates the functions of stepless speed regulation, automatic loading, automatic detection, recording and the like, and has relatively high competitiveness in the aspects of intelligent degree, manufacturing cost, accuracy and the like.

The invention discloses a hydraulic conduit composite working condition bending fatigue life evaluation test system and method, and relates to the technical field of hydraulic conduit reliability test, and the system comprises a vibration test system, a conduit installation clamp, an oil pressure pump source, and a stress acquisition and monitoring system. The method comprises the following steps of: directly simulating a temperature, pressure and vibration coupling action environment of a hydraulic conduit in actual work to obtain a relational expression between a fatigue strength limit of a conduit test piece and temperature, pressure and vibration stress; and finally, the bending fatigue life of the aircraft hydraulic conduit can be evaluated by measuring the temperature, pressure and vibration stress environment of the aircraft hydraulic conduit in actual work in combination with a relational expression curve obtained by a test.

The utility model relates to the technical field of elevator steel belt testing, in particular to a testing device for an elevator steel belt, which comprises a testboard, the upper end inside the testboard is rotatably connected with a turntable, the lower end face of the turntable is fixedly connected with an inner and outer gear ring, the inner and outer gear ring is of an open structure, and the outer wall of a rotating shaft is fixedly connected with a gear meshed with the inner and outer gear ring; as the inner and outer gear rings are of an opening structure, when the opening of the inner and outer gear rings rotates to the gear, the gear rotates to the interior of the inner and outer gear rings along with the inner and outer gear rings, then the gear is matched with the inner and outer gear rings to drive the rotating disc to rotate anticlockwise, and the rotating disc drives the connecting rod to rotate in the sliding hole in the reverse direction; through continuous rotation of the gear, the gear cooperates with the inner and outer gear rings to drive the rotating disc to rotate in a reciprocating manner, and then the steel belt is driven to repeatedly surround the outer walls of the two rotating wheels, so that the bending fatigue of the steel belt is tested.

The invention discloses an intelligent vehicle roller steel wire rope bending fatigue test method and device, the device comprises a packaging plate, a steel wire rope clamping assembly arranged on the packaging plate, and a shooting assembly arranged on the opposite surface of the packaging plate, and the steel wire rope clamping assembly is used for abutting against the center point of the steel wire rope so as to keep the center point of the steel wire rope unchanged; steel wire rope bending driving assemblies are arranged above and below the steel wire rope clamping assemblies on a back plate of the container plate and used for fixing the upper end and the lower end of a steel wire rope and driving the upper end and the lower end of the steel wire rope to swing with the center point of the steel wire rope as the circle center. The shooting assembly is used for shooting images of the central point of the steel wire rope when the upper and lower ends of the steel wire rope swing around the central point of the steel wire rope; the shooting assembly is connected with a processing system; the processing system tests the bending fatigue of the steel wire rope based on the image change of the central point of the steel wire rope; according to the invention, the image change of the central point of the steel wire rope can be quickly and accurately identified.

The invention discloses a preparation method of a hydrogen permeation resistant protective layer capable of prolonging the service life of titanium alloy, which specifically comprises the following steps: step 1, accurately mixing oxygen and argon through a mixing device according to a set proportion; 2, a titanium alloy matrix containing the aluminum element is selected; 3, the titanium alloy selected in the step 2 is subjected to ultrasonic cleaning and then loaded into a vacuum furnace, argon is introduced, a vacuum pump vacuumizes to 8 Pa, then the temperature of the vacuum furnace is increased to the oxygen permeation temperature, the vacuum pump is closed after 1.5 h, finally, the gas mixed in the step 1 is introduced into the vacuum furnace, the oxygen permeation process is conducted, and the hydrogen permeation resisting protective layer is prepared on the surface of the titanium alloy; the outer layer of the prepared hydrogen permeation preventing protective layer is Al2O3, the inner layer of the prepared hydrogen permeation preventing protective layer is TiO2, the hydrogen permeation preventing protective layer can prevent hydrogen atoms from permeating into the titanium alloy, and the bending fatigue life of the titanium alloy is prolonged.

This invention relates to a 1900MPa grade ultra-high strength and toughness stainless gear steel and its preparation method. The chemical composition of the 1900MPa grade ultra-high strength and toughness stainless gear steel, by mass percentage, is: C 0.08-0.11%, Cr 10-12%, Ni 2-4%, Mo 2-5%, Co 10-13%, V 0.2-0.6%, Nb 0.02-0.05%, Al 0.5-1.0%, with the balance being Fe and unavoidable impurities. Its composition design must meet the following requirements: Chromium equivalent Cr... eq It is 17~18, with a nickel equivalent (Ni). eq The martensitic transformation point is 14-15. s The temperature range is 240~280℃. Its beneficial effects are: strengthening through the composite precipitation of intermetallic compounds NiAl and M₂C carbides, combined with Cr... eq Ni eq M s A synergistic design incorporating 5%–10% metastable austenite achieves an excellent balance between strength and toughness. The resulting steel exhibits tensile strength ≥1900 MPa, yield strength ≥1550 MPa, elongation ≥13%, fracture toughness ≥80 MPa·m¹ / ², and bending fatigue limit reaching 920 MPa. It is particularly suitable for manufacturing critical structural components requiring high load-bearing capacity and high reliability, such as aircraft engines, and has broad application prospects.

The application provides a low-torque steel wire rope with a twist pitch, which improves the bending fatigue performance of the manufactured steel wire rope by setting a composite core, and effectively improves the radial support stiffness and the anti-torsion performance of the composite core by the radial constraint and the shaping support of the fiber core formed by the thermosetting resin layer. Meanwhile, the inner layer strand and the outer layer strand with opposite twist pitches are sequentially arranged outside the composite core, and the filling strand and the filling steel wire are arranged in the gap between the inner layer strand and the outer layer strand, which significantly improves the tensile strength and the anti-torsion performance of the steel wire rope, improves the structural compactness and the support of the whole steel wire rope, makes the stress of the steel wire rope more balanced during use, and avoids the structural damage caused by local stress concentration. Finally, by setting the twist pitches of the first steel wire, the inner layer strand and the outer layer strand, the manufactured steel wire rope has good low-torsion performance and bending fatigue performance, and has structural stability and a long service life, which can meet the long-term use requirements in multiple scenes such as hoisting and traction.

The application discloses a prediction method for the relationship between welding repair defects and fatigue life of TC17 titanium alloy blades, and comprises the following steps: step one, establishing a fatigue life prediction model related to repair defects; step two, preparing a rotary bending fatigue sample; step three, heat treating a surfacing sample; step four, processing the rotary bending fatigue sample; step five, testing the rotary bending fatigue; step six, analyzing a fracture and counting defects; and step seven, establishing a rotary bending fatigue life prediction model. The application selects an electric arc welding wire repair test block, tests the rotary bending fatigue performance of the test block, observes and counts the defect morphology, size and position of the fracture, analyzes the corresponding relationship between the defects and the fatigue life, establishes a fatigue life prediction model related to the repair defects, and determines the influence of the pore defects on the fatigue life of the repaired blade through the model.

The invention discloses a method for evaluating the low-temperature fatigue performance of an asphalt mixture, belongs to the technical field of road engineering, and aims to solve the technical problem of how to more accurately and comprehensively evaluate the fatigue performance of the asphalt mixture in a low-temperature environment. According to the technical scheme, the method comprises the following steps: preparing a prismoid test piece and a beam test piece made of the same asphalt mixture as the prismoid test piece; acquiring a temperature change sequence of the pavement structure in the target test environment for a plurality of continuous hours through temperature acquisition equipment; taking the collected temperature change sequence as an environment control condition, carrying out a constraint test piece temperature stress test on the prismoid test piece, and synchronously recording the axial force per hour in the test process; calculating the average temperature stress value in the test period according to the axial force per hour and the size of the prism test piece; the average temperature stress value serves as the initial stress level of the four-point bending fatigue life test and is pre-loaded on the beam test piece, and a plurality of different load stress levels are selected for testing.

The utility model relates to the technical field of hoist gates, in particular to a hoist gate rod piece linkage device which comprises a gate, two vertical plates are fixedly installed at the upper end of the gate, movable grooves are formed in the vertical plates, pin shafts are arranged in the movable grooves in a sliding mode, a plurality of blocking covers are fixedly arranged on the pin shafts, and the blocking covers are fixedly connected with the gate. The blocking covers are distributed on the two sides of the movable groove, a lead screw is rotationally arranged on the pin shaft, and the lead screw is arranged between the two vertical plates. The gate is rotationally connected with the bottom end of the lead screw through the vertical plate and the pin shaft, when the gate is sealed, the gate can radially move by the compression distance of the sealing ring, in the radial movement process of the gate, the lead screw can radially move in the movable groove in a small range through the pin shaft, the problem that the lead screw cannot radially move and is bent is solved, and the service life of the gate is prolonged. Therefore, bending fatigue of the lead screw can be effectively avoided, and the service life of the lead screw is greatly prolonged.

A blended rope is provided having an outer sheath (8) enclosing at least a strength member (7), the strength member (7) having high-strength synthetic fibers, the strength member (7) being a blended strength member (7) formed with a combination of ARAMID fibers and HMPE fibers, the blended strength member comprising a non-homogeneous distribution of the ARAMID and HMPE fibers, wherein the weight ratio of ARAMID to HMPE in the strength member (7) is preferably a minimum of 80:20.

The invention relates to the technical field of metal conduit fatigue testing, and provides a bending fatigue testing device for a metal pipe and a testing method using the bending fatigue testing device. Comprising a headstock and a tailstock, and a test piece is connected between the headstock and the tailstock through a fixing assembly; a bending degree adjusting assembly is arranged in the headstock, one side of the bending degree adjusting assembly is connected with a rotation driving assembly, and the other side of the bending degree adjusting assembly is connected with a test piece fixing assembly; the top of the linear sliding table module is sequentially connected with an upper adjustable clamp and a lower adjustable clamp, and the upper adjustable clamp and the lower adjustable clamp are used for clamping a test piece; the joints of the upper adjustable clamp and the lower adjustable clamp with the test piece are far away from the joint of the test piece and the tailstock, and two groups of strain gauges are adhered to one sides of the joints of the upper adjustable clamp and the lower adjustable clamp with the test piece. The beneficial effects are that: aiming at the bending fatigue performance test of the pipe, joint determination of bending fatigue failure of the pipe and the pipe joint is avoided, and the test efficiency is improved.