48 results about "Fracture Toughness Testing" patented technology

The invention discloses a test-based crystal plasticity and cohesion model coupling hydrogen induced cracking simulation method, which comprises the following steps: carrying out a hydrogen filling mechanical property test on a metal material to obtain a true stress-true strain curve of the metal material in a hydrogen environment; carrying out a hydrogen-filled fracture toughness test on the metal material to obtain a stress intensity factor of the metal material in a hydrogen environment; constructing a cohesion constitutive model; a metal material electron back scattering diffraction microscopic characterization test is carried out, microstructure characteristics are obtained, and a polycrystalline model is constructed; constructing a crystal plastic constitutive model; coupling crystal plasticity constitutive and cohesion constitutive, and calibrating crystal plasticity to-be-determined parameters by adopting a trial-and-error method; and carrying out finite element simulation analysis on hydrogen-induced cracking behaviors with different microstructure characteristics in a hydrogen environment to obtain stress-strain data and crack data of the hydrogen-induced cracking behaviors. According to the invention, high-precision simulation of the hydrogen-induced cracking micromechanism of the metal material in the hydrogen environment is realized.

The invention relates to a composite material II-type interlayer fracture toughness measuring device for obtaining a complete R curve, which is suitable for a tensile load device to carry out fracture toughness test on a test piece made of a polymer matrix composite material, and comprises a base, a support plate arranged in a special-shaped I-shaped structure, a loading lug plug, a support table and an adjusting plate, the supporting plate is detachably installed on the top face of the base, the adjusting plate is installed on the top face of the supporting plate in a horizontal sliding mode, the supporting table is fixedly installed on the top face of the adjusting plate, the small end of the loading lug plug is connected with the output end of the tension load device, and the large end of the loading lug plug fixes one end of a test piece in a pin hole matching mode. And the other end of the test piece is mounted on the trapezoidal part of the supporting table, so that the test efficiency is improved, and a complete II-type interlayer fracture toughness curve of the composite material is obtained.

The invention discloses a metal material hydrogen compatibility simulation test method based on hydrogen content. The method comprises the following steps: S1, sample preparation; s2, charging hydrogen in a high-pressure hydrogen environment; s3, diffusible hydrogen is measured; s4, preparing an electrochemical hydrogen charging solution; s5, carrying out hydrogen charging by using an electrochemical hydrogen charging solution; s6, storing the sample; s7, drawing a hydrogen concentration change curve; s8, electrogalvanizing process parameters are set; s9, performing hydrogen charging in a simulated high-pressure hydrogen environment; s10, the sample is galvanized; s11, carrying out a slow tensile test and a fracture toughness test on the sample; and S12, evaluating the high-pressure hydrogen embrittlement of the sample based on the results of the slow tensile test and the fracture toughness test. According to the method, the hydrogen embrittlement performance of the material under different hydrogen pressure environments can be obtained, and the influence of the influence factors on the high-pressure hydrogen embrittlement performance of the steel can be analyzed in combination with the process, alloy components and stress states of the steel.

The invention discloses a hydrogen compatibility simulation test method in a high-pressure environment based on hydrogen diffusion. The method comprises the following steps: S1, preparing a sample; s2, performing a hydrogen permeation test in a high-pressure hydrogen environment; s3, preparing a hydrogen permeation cathode hydrogen filling solution; s4, performing a hydrogen permeation test in a simulated high-pressure hydrogen environment; s5, applying and adjusting cathode hydrogen charging current under simulated high-pressure hydrogen permeation; s6, determining a dynamic hydrogen charging current; s7, performing a smooth slow tensile simulation test in a high-pressure hydrogen environment; s8, carrying out a notch slow tensile simulation test in a high-pressure hydrogen environment; s9, carrying out a fracture toughness test; and S10, performing high-pressure hydrogen embrittlement evaluation based on the results of the smooth slow tensile simulation test and the fracture toughness test. According to the method, the hydrogen embrittlement performance of the material under different hydrogen pressure environments can be obtained, and the influence of the influence factors on the high-pressure hydrogen embrittlement performance of the steel can be analyzed in combination with the process, alloy components and stress states of the steel.

To improve versatility and simplicity of fracture toughness value perdition.SOLUTION: A fracture toughness value prediction method is provided, involving acquiring a fracture toughness parameter at the time when a locally generated stress on a test piece evaluation part in a fracture toughness test as obtained through a first numerical analysis reaches a local breaking stress at a fracture initiation point obtained based on a brittle fracture test as a fracture toughness value of a target material.SELECTED DRAWING: Figure 2

The invention relates to a fatigue life prediction method based on a physical failure mechanism in a liquid lead bismuth environment, and the method comprises the following steps: building a representative volume element model, and defining elements belonging to a slip band; defining a crystal plasticity constitutive equation; determining parameters in the crystal plasticity constitutive equation; calculating the average shear strain range of the slip band; carrying out a fracture toughness test to obtain specific fracture energy; establishing a fatigue life prediction model based on a physical failure mechanism; carrying out a symmetrically cyclic low-cycle fatigue test on the metal material in a predicted-temperature high-oxygen liquid lead bismuth environment to determine the thickness of an oxide film; and establishing a fatigue life prediction model in the high-oxygen-concentration liquid lead bismuth environment, and predicting the fatigue life of the metal material in the high-oxygen-concentration liquid lead bismuth environment. According to the method, the fatigue life in the liquid lead-bismuth environment can be predicted by carrying out a low-cycle fatigue test for calibrating crystal plasticity constitutive equation parameters in the air at the predicted temperature and a fracture toughness test in the air and liquid lead-bismuth environment.

The deep rock fracture toughness test system and method provided by the embodiment of the present application, wherein the system comprises a test sample, a vacuum pressure chamber and a host computer; the vacuum pressure chamber is provided with a confining pressure loading device, an axial pressure loading device, an electric resistance testing device and a camera device; the host computer is used to control the confining pressure loading device and the axial pressure loading device to load pressure on the test sample, so that the initial crack on the test sample is expanded; the host computer is also used to acquire the electric resistance change of the test sample and the expansion image of the initial crack when the initial crack on the test sample is expanded, and determine the fracture toughness of the test sample according to the electric resistance change of the test sample and the expansion image of the initial crack. The small change of the crack of the test sample is detected by monitoring the electric resistance change of the test sample, and the accurate crack change data is obtained by combining the image in the crack expansion process, so that the detection accuracy of the crack is improved, and the calculation accuracy of the rock fracture toughness is ensured.

This invention discloses a test method for evaluating the hydrogen embrittlement susceptibility index of welded joints using principal component analysis, belonging to the field of material performance evaluation technology. The method includes the following steps: S1, processing the pipe welded joint into a notched round bar slow strain rate tensile specimen and conducting a slow strain rate tensile test; S2, processing the pipe welded joint into a stepped-notch CT specimen for fracture toughness and conducting a fracture toughness test; S3, calculating the specific performance loss rate under hydrogen-doped conditions and performing standardization; S4, calculating the hydrogen embrittlement susceptibility evaluation index I. PC S5. Perform scanning electron microscopy analysis on the slow strain rate tensile fracture surface to determine the risk level of hydrogen-induced cracking in the sample; S6. Determine the I-value that distinguishes different risk levels of hydrogen-induced cracking. PC Scope. This invention employs the aforementioned test method for evaluating the hydrogen embrittlement sensitivity index of welded joints using principal component analysis, which improves the statistical significance of small sample data and yields a more objective and comprehensive evaluation system for hydrogen embrittlement sensitivity.

This invention discloses a testing device and method for fracture toughness testing of welded joints in pipeline steel under corrosive environments, belonging to the technical field of fracture toughness testing equipment. It includes a test vessel unit and a testing unit. The test vessel unit comprises a test vessel body and a test vessel lid, the lid of which can close onto the opening of the test vessel body. The test vessel lid has an air inlet and an air outlet; the air inlet is used to connect to an air inlet pipe, and the air outlet is used to connect to an air outlet pipe. The testing unit includes a bending clamp assembly and a loading linear displacement measuring assembly. The bending clamp assembly is connected to the shaft of the testing machine and can be used to clamp the test specimen. Driven by the shaft of the testing machine, the bending clamp assembly can press down on the test specimen. The loading linear displacement measuring assembly is connected to a measuring point on the test specimen and is used to measure the linear displacement of the measuring point. This invention enables fracture toughness testing of welded joints under corrosive environments, ensuring the accuracy and safety of the test.

The embodiment of the invention provides a material fracture toughness testing device and method, and relates to the technical field of material fracture toughness testing. The device comprises a supporting assembly which comprises a workpiece platform and two supporting rollers; two mark points P1 and P2 are arranged on the plane A of the workpiece platform along the parallel line of the axes of the two supporting rollers; the loading assembly comprises a liftable loading roller; two sides of the bottom of the loading roller are provided with two first light emitters, and projection points of the first light emitters on a plane A are O1 and O2; the image recognition system is used for acquiring images of P1, P2, O1 and O2; the control system is used for controlling the workpiece platform to translate and rotate, so that the line segment P1P2 and the line segment O1O2 are collinear; and the auxiliary positioning structure comprises a limiting element and a second illuminator, and can ensure that the prefabricated notch of the test workpiece is accurately positioned right below the axis of the loading roller. The method can ensure that the test workpiece meets the spatial geometric constraint condition of the fracture toughness test, and improves the accuracy and reliability of the test.

The application relates to the technical field of material performance testing, and particularly relates to a heterogeneous material fracture toughness testing method, a double cantilever beam sample and a manufacturing method. The heterogeneous material fracture toughness testing method comprises the following steps: a double cantilever beam sample is provided, the double cantilever beam sample comprises a base layer, a first substrate and a separation layer, the first substrate is provided with the base layer on both sides in a first direction, the separation layer is arranged between the first substrate and any base layer, a separation area and a to-be-tested area are formed between the first substrate and the base layer adjacent to the separation layer in a second direction, and the separation area has a prefabricated crack; a sample testing step is performed, the double cantilever beam sample is installed on a testing device, the double cantilever beam sample is loaded by the testing device to make the to-be-tested area delaminate, and target data is acquired; and a result calculation step is performed, and a type I interlaminar fracture toughness value is acquired according to the target data. The heterogeneous material fracture toughness testing method provided by the application can improve testing accuracy.

The invention discloses a part interlayer fracture toughness test method, device and equipment and a storage medium, and the method comprises the steps: applying different loading forces to a standard test part based on a mechanical test system, and obtaining test data of each test point at different test moments through a digital image correlation technology DIC; performing top-hat transformation processing on the test image of each test point to obtain a processed test image, and obtaining the size of the precrack according to the processed test image; and calculating according to the precrack size and the loading force of each test point at different test moments to obtain the interlayer fracture toughness of the standard test part. The method comprises the following steps: on the basis of acquiring crack opening displacement and angle of a fiber reinforced composite material I-type interlayer fracture toughness test piece through DIC, synchronizing the dynamic change process of the length of a prefabricated crack extending along with loading of a load at different moments with a real-time load, and meanwhile, optimizing an acquired test image by combining a Top-hat technology, so as to obtain a test result of the I-type interlayer fracture toughness of the fiber reinforced composite material I-type interlayer fracture toughness of the fiber reinforced composite material I-type interlayer fracture toughness test piece. And the measurement precision of the interlayer fracture toughness is improved.

The application discloses a kind of based on ENDB sample dynamic fracture toughness testing device, including test auxiliary device and Hopkinson bar experimental device, Hopkinson bar experimental device includes incident bar and transmission rod, test auxiliary device includes load transmission structure, dial, support seat component, sample fixing assembly and auxiliary fixing assembly, dial, sample fixing assembly and support seat are fixed by distance adjusting component of three through three connections.This application can accurately adjust the included angle α between loading rod and prefabricated crack, so that the dynamic fracture toughness test of a variety of different angles III and I, III mixed type can be realized, the dynamic fracture toughness test experiment of a variety of diameter sizes ENDB sample can be satisfied, and a certain fracture failure play space is reserved between dial and sample, to improve sample damage effect and the accuracy of experimental results.The whole device has no direct or indirect contact with the outside world, reduces the loss of energy, improves the accuracy of experimental results.

The application belongs to the technical field of fracture toughness evaluation, and specifically discloses a small-size fracture toughness testing method for metal materials based on fracture cross-section characteristics, which utilizes the fracture cross-section shape of a test sample, considers the elastic energy distribution of a normal fracture zone dominated by I-type fracture and a shear fracture zone dominated by II-type fracture, establishes a linear relationship between G and J, carries out a fracture test by using a multi-sample method with different thicknesses, determines different groups of data, obtains and estimates values by combining a least square method, forms a new method for evaluating the small-size fracture toughness of metal materials based on fracture cross-section characteristics, and avoids the difficulty of directly using standard pieces for evaluation for materials such as high-strength steel, and has significant engineering application value.

The present invention discloses a preparation method of a recombined compact tension specimen, comprising the following steps: 1) preparing a specimen for a target material and spraying speckles on the surface of the specimen; 2) conducting a fracture toughness test on the specimen, and during the fracture toughness test, measuring the specimen by using a full-field strain measurement system; 3) determining a plastic strain region on the surface of the specimen according to the measurement result of the full-field strain measurement system and excising the plastic strain region, and retaining the non-plastic strain regions on both sides of the specimen to obtain a recombined block; 4) welding the recombined block with auxiliary materials to obtain the recombined compact tension specimen. The preparation method of the recombined compact tension specimen of the present invention, through reasonable recombination means and verification means, enables the performance of the recombined specimen to be similar to that of the original specimen; and the non-plastic deformation regions (recombined blocks) after the fracture toughness test can be recombined into two or more specimens, increasing the material utilization rate by three times or more.

This application belongs to the field of fracture toughness testing under corrosive environments, and specifically discloses a method for calibrating the stress intensity factor loading rate in fracture toughness testing under corrosive environments. The method includes: preparing a specimen and creating a pre-crack; using a corrosive solution to create a pre-corrosive environment at the crack tip; establishing a corrosive environment on a testing machine and performing a three-point bending test on the specimen in the corrosive environment at a preset testing machine loading rate to obtain the specimen's yield strength; loading the specimen in the corrosive environment using multiple different testing machine loading rates to 60%-90% of the yield strength, and recording the force-time curves for each loading; calculating the corresponding stress intensity factor loading rate based on the force-time curves and performing linear fitting to obtain the corresponding functional relationship. This application solves the problem that when conducting fracture toughness testing under corrosive environments, it is impossible to directly set the stress intensity factor loading rate, and existing calibration methods cannot accurately reflect the coupling effect of the corrosive environment.

The utility model relates to the field of metal material fracture mechanical tests, and particularly discloses a fracture toughness test clamp suitable for various thicknesses, which comprises a clamp seat and two opposite loading arms, the loading arms are slidably connected onto the clamp seat, the two loading arms are simultaneously in threaded connection onto a two-way screw, the two-way screw is mounted on the clamp seat, and the two-way screw is in threaded connection with the clamp seat. The two loading arms are used for getting close to or getting away from each other along the two-way screw, and the two-way screw is in threaded connection to the center line of the loading arms. The scheme is used for solving the problem that a traditional integrated tool cannot adapt to samples with different thicknesses.

The utility model provides a sample preparation tool for an I-type fracture toughness test. The sample preparation tool comprises a platform, the upper surface of the platform is horizontal and is used for placing a lower-layer base material; a base material limiting mechanism; the limiting device is arranged on the upper surface of the platform and is used for limiting the end parts of the laminated lower-layer base material and the upper-layer base material and limiting the displacement of the lower-layer base material and the upper-layer base material in the horizontal direction; the film fixing mechanism comprises a first gasket, a second gasket and a gasket pressing part; the first gasket is arranged on the upper surface of the platform, and the thickness of the first gasket is the same as that of the lower-layer base material located at the bottom; the second gasket is arranged on the first gasket, and the thickness of the second gasket is the same as that of an adhesive layer between the lower-layer base material and the thin film; the gasket pressing part is used for pressing the second gasket and the first gasket to the upper surface of the platform. When the sample preparation tool for the I-type fracture toughness test is used for sample preparation, the accurate position of a film in a sample and the accurate and uniform thickness of an adhesive layer can be ensured, and the tool is simple to operate and high in sample preparation efficiency.

This invention belongs to the field of material and structural performance testing technology, specifically relating to a method for estimating the plane strain fracture toughness of materials based on small specimens and energy principles. The method includes the following steps: S1, designing small specimens for fracture toughness testing; S2, conducting fracture toughness testing; S3, analyzing the fracture morphology of the small specimens; S4, calculating the energy consumed per unit area in each region; and S5, calculating the plane strain fracture toughness of the material. The method described in this invention for estimating the plane strain fracture toughness of materials based on small specimens and energy principles can significantly improve the efficiency of obtaining plane strain fracture toughness and save on related experimental costs. Furthermore, the entire process is simple, convenient, and fast, with strong engineering practicality and applicability.

The application discloses a pipeline girth weld fracture toughness testing method, which comprises the following steps: processing a notch and a fatigue pre-crack on a test piece with a predetermined size, wherein the length direction of the test piece is consistent with the axial direction of the pipeline; expanding the fatigue pre-crack at the front end of the notch of the test piece and performing fatigue pre-cracking; after the fatigue pre-cracking reaches a target value, processing a side groove on the test piece; continuously loading the test piece at a constant rate, while monitoring the load and displacement during the loading process; stopping after the test piece reaches a preset degree of crack expansion; during the continuous loading, measuring the crack expansion by using a regularization method; measuring the initial crack length and the final crack length; and inversing the crack length in the crack expansion process according to the measured initial crack length and the final crack length. The application can accurately obtain the fracture toughness of the pipeline girth weld, make the safety evaluation of the pipeline girth weld more accurate, and thus guarantee the safe operation of the pipeline.

A fracture toughness testing machine evaluates fracture toughness of a specimen in pure mode. The testing machine includes: a testing-load applying device for applying a predetermined testing load to the specimen, in which the stresses are present; and a cancelling-load applying device for applying a cancelling load to the specimen to cancel the stresses therein. The cancelling-load applying device includes: a pressing-force applying portion that applies a pressing force to the specimen as the canceling load; and a pressing-force determining portion that determines magnitude of the force. The pressing-force determining portion calculates the magnitude of the force using pre-stored equations so that an energy release rate related to in-plane shear mode crack deformation becomes zero.

The invention belongs to the field of performance prediction of titanium alloy, and particularly relates to a TC11 titanium alloy fracture toughness prediction method considering heat treatment temperature. Comprising the following steps: (1) carrying out double annealing heat treatment on the TC11 titanium alloy at different temperatures, carrying out quasi-static stretching and fracture toughness tests on the TC11 titanium alloy subjected to heat treatment, and recording test data; (2) establishing a TC11 titanium alloy fracture toughness prediction model considering the heat treatment temperature by introducing a correction term of the heat treatment temperature; (3) fitting the prediction model in the step (2) according to test data in the step (1) to obtain values of a basic toughness coefficient m and a temperature sensitivity coefficient n; and (4) verifying the TC11 titanium alloy fracture toughness prediction model. By introducing the heat treatment temperature correction term, the quantitative relation between the heat treatment temperature and the fracture toughness is established, the fracture toughness is predicted, the test cost is reduced, and the material design is optimized.

The invention discloses a test method for evaluating a hydrogen embrittlement sensitivity index of a welded joint by using a principal component analysis method, and belongs to the technical field of material performance evaluation, and the test method comprises the following steps: S1, processing a pipeline welded joint into a notched round rod slow strain rate tensile sample, and carrying out a slow strain rate tensile test; s2, the pipeline welding joint is machined into a fracture toughness stepped notch CT sample, and a fracture toughness test is conducted; s3, calculating a specific performance loss rate in the hydrogen-doped environment, and carrying out standardization processing; s4, calculating to obtain a hydrogen embrittlement sensitivity evaluation index IPC; s5, performing scanning electron microscope analysis on the slow strain rate tensile fracture, and judging the risk level of hydrogen induced cracking of the sample; and S6, determining an IPC range for distinguishing different hydrogen induced cracking risk levels. According to the test method for evaluating the hydrogen embrittlement sensitivity index of the welded joint by using the principal component analysis method, the statistical significance of small sample data can be improved, and a more objective and comprehensive hydrogen embrittlement sensitivity evaluation system is obtained.

The invention relates to a method for simulating a uniaxial tensile behavior in a liquid lead bismuth environment. The method comprises the following steps: carrying out a uniaxial tensile test on a metal material sample in an air environment to obtain a stress-strain curve; establishing a double-scale finite element model of the metal material sample by utilizing ABAQUS finite element software, and simulating uniaxial stretching of the double-scale finite element model in an air environment; carrying out a fracture toughness test and a uniaxial tensile test on the metal material in a liquid lead bismuth environment to obtain a stress-strain curve; uniaxial stretching of the dual-scale finite element model in the liquid lead bismuth environment is simulated through ABAQUS finite element software. According to the method, the finite element model is established, ABAQUS finite element software is used for calculation, and the damage behavior of the metal material in the stretching process in the air and liquid lead bismuth environment can be visually observed; different structures and boundary conditions can be predicted through the established model and parameters, and the method has the advantages of being accurate in result, high in efficiency and low in cost; and the established dual-scale finite element model can effectively reduce the calculation cost.

The invention relates to the technical field of post-irradiation mechanical sample processing, and provides a post-irradiation mechanical fracture sample processing and recycling method which comprises the following steps: selecting a metal sample which is subjected to neutron irradiation and is fractured after finishing a Charpy impact test or a fracture toughness test; a linear cutting machining mode is adopted, a plastic deformation area at the fracture of the broken metal sample is removed, and a machining unit body in a regular geometrical shape is obtained; detecting the processing unit body by adopting a Vickers hardness detection method; according to the actual size of the machining unit body, machining positions and machining directions of the small-size samples are planned; machining the machining unit bodies into a plurality of small-size samples in a machining manner; after machining is completed, the size of the small-size sample is detected in a non-contact mode through an optical measuring device; and carrying out mechanical property test on the small-size sample by using load test equipment. According to the method, dozens of small-size samples are processed from one standard fracture sample, and the utilization rate of the samples is increased.

The invention discloses a hydrate sediment fracture toughness testing system, and belongs to the technical field of hydrate sediment fracture toughness testing, the system comprises a sample synthesis unit, a three-point bending test unit and a direct shear test unit, the three-point bending test unit is detachably connected to the sample synthesis unit, and the direct shear test unit is detachably connected to the sample synthesis unit. The method is used for measuring the I-type fracture toughness of the hydrate sediment; the direct shear test unit can be detached to replace the three-point bending test unit, is connected to the sample synthesis unit and is used for measuring the II-type fracture toughness of the hydrate sediment. In the testing process, a horizontal loading mode is adopted, so that the influence of gravity on fracture toughness is eliminated. In order to reduce the influence of friction force on fracture toughness, the system adopts a design scheme of a three-point bending bracket, a sliding base and a guide rail. In addition, the hydrate has the characteristic of being easy to decompose at normal temperature and normal pressure, the sample synthesis unit can realize synthesis of the hydrate, and it is ensured that the hydrate is not decomposed in the testing process.

The application relates to a fatigue life prediction method based on a physical failure mechanism under a liquid lead-bismuth environment, which comprises the following steps: establishing a representative volume element model and defining elements belonging to a slip band; defining a crystal plasticity constitutive equation; determining parameters in the crystal plasticity constitutive equation; calculating an average shear strain range of the slip band; carrying out a fracture toughness test to obtain a specific fracture energy; establishing a fatigue life prediction model based on the physical failure mechanism; carrying out a low-cycle fatigue test of a metal material under a high-temperature and high-oxygen liquid lead-bismuth environment to determine an oxide film thickness; and establishing a fatigue life prediction model under a high-oxygen-concentration liquid lead-bismuth environment to predict the fatigue life of the metal material under the high-oxygen-concentration liquid lead-bismuth environment. The low-cycle fatigue test for calibrating parameters of the crystal plasticity constitutive equation in the prediction temperature air and the fracture toughness test in the air and the liquid lead-bismuth environment can be carried out, so that the fatigue life under the liquid lead-bismuth environment can be predicted.

The utility model relates to the technical field of fracture toughness testing, in particular to a clamping tool suitable for I-II type fracture toughness testing of a composite material, which comprises a first clamping plate, the first clamping plate comprises a bottom plate, one side of the upper surface of the bottom plate is provided with a first placing step, and the other side of the upper surface of the bottom plate is movably provided with a second clamping plate; a guide column extending horizontally is arranged on one side of the first placing step, and the guide column and the second clamping plate are installed in a sliding and penetrating mode; the first clamping plate comprises a first placing step, a first baffle is arranged on the upper surface of the first placing step, the second clamping plate comprises a second placing step, a second baffle is arranged on the upper surface of the second placing step, and the first baffle and the second baffle are oppositely arranged; the side plate is detachably connected with the bottom plate; the side plate is connected with one side of the second clamping plate through a hydraulic cylinder; through the structural design of hydraulically controlling clamping force and spring ejection, the problems that in the prior art, the clamping force is difficult to control, and opening is difficult after a test is finished are solved.

The invention provides a crack type defect evaluation method and device for a hydrogen conveying pipeline and a management system. The method comprises the steps that basic information of the hydrogen conveying pipeline is obtained; determining test conditions according to the basic information and test equipment requirements; respectively carrying out tensile test and fracture toughness test on multiple groups of non-hydrogen absorption samples and multiple groups of hydrogen absorption samples under test conditions to obtain multiple tensile curves and multiple fracture toughness; a failure evaluation curve of the hydrogen conveying pipeline is established based on the tensile curve under the saturated hydrogen absorption time and the multiple fracture toughness; detecting a crack type defect of the hydrogen conveying pipeline by adopting a pipeline defect detection technology, and determining an evaluation point of the crack type defect; and under the condition that the ordinates of the evaluation points are larger than the ordinates of the corresponding failure evaluation points, the hydrogen conveying pipeline is controlled to stop running, and alarm information is sent out. The method solves the technical problem that in the prior art, the safety of the hydrogen conveying pipeline cannot be determined through safety evaluation of cracks caused by the hydrogen induced cracking mechanism of the hydrogen conveying pipeline.

The present invention discloses a hydrate sediment fracture toughness testing system, which belongs to the technical field of hydrate sediment fracture toughness testing. The system includes a sample synthesis unit, a three-point bending test unit and a direct shear test unit. The three-point bending test unit can be detachably connected to the sample synthesis unit and is used to measure the type I fracture toughness of the hydrate sediment; the direct shear test unit can be detachably replaced by the three-point bending test unit and connected to the sample synthesis unit to measure the type II fracture toughness of the hydrate sediment. During the test, horizontal loading is adopted to eliminate the influence of gravity on fracture toughness. In order to reduce the influence of friction on fracture toughness, the system adopts a design scheme of a three-point bending bracket, a sliding base and a guide rail. In addition, hydrates are easy to decompose at room temperature and pressure. The sample synthesis unit can realize the synthesis of hydrates and ensure that the hydrates do not decompose during the test.