46 results about "Type fracture" patented technology

The invention discloses a test device and method for blocking rock fractures by a soybean urease induced calcium carbonate deposition technology, the test device comprises a sample, a fracture simulation assembly and a slurry sealing assembly, the sample is composed of an upper rock test block and a lower rock test block; the fracture simulation assembly can simulate two kinds of rock fracture surfaces with different opening degrees. The test sample adopts an upper rock test block made of a transparent material to realize visualization in a test process; the upper shear box and the lower shear box are used for simulating a tension type fracture and a shear fracture surface of a rock, so that the condition that soybean urease induces calcium carbonate to deposit in different rock fracture generation mechanisms to block and reduce permeability of the rock fracture is better tested; when the lower shear box horizontally moves, the lower shear box is sealed through the slurry sealing assembly, and the sealing state can be kept in the shear dislocation of the crack; the device can test the relationship between the soybean urease induced calcium carbonate deposition plugging and permeation reducing effect and the rock fracture type and fracture parameters.

The utility model discloses a test device for blocking rock fractures by soybean urease induced calcium carbonate deposition, which comprises a sample, a fracture simulation component and a slurry sealing component, and the sample consists of an upper rock test block and a lower rock test block; the fracture simulation assembly can simulate two kinds of rock fracture surfaces with different opening degrees. The test sample adopts an upper rock test block made of a transparent material to realize visualization in a test process; the upper shear box and the lower shear box are used for simulating a tension type fracture and a shear fracture surface of a rock, so that the condition that soybean urease induces calcium carbonate to deposit in different rock fracture generation mechanisms to block and reduce permeability of the rock fracture is better tested; when the lower shear box horizontally moves, the lower shear box is sealed through the slurry sealing assembly, and the sealing state can be kept in the shear dislocation of the crack; the device can test the relationship between the soybean urease induced calcium carbonate deposition plugging and permeation reducing effect and the rock fracture type and fracture parameters.

The invention discloses a method for evaluating rock mass fracture freeze-thaw fracture damage risk based on surface temperature, which comprises the following steps: S1, carrying out data acquisition on a target area based on a multi-source sensor carried by an unmanned aerial vehicle platform, and obtaining fracture geometric parameters, daily surface minimum temperature, daily surface maximum temperature, daily temperature difference and fracture moisture conditions; s2, on the basis of the geometric parameters of the crack, constructing a crack frost heaving force analytical model; obtaining a quantitative relation between the stress intensity factor and the environment temperature; s3, the I-type fracture toughness of the target rock mass is measured, and the critical crack initiation temperature of the rock mass is determined; determining the number of critical freezing and thawing cycles; s4, on the basis of the daily earth surface minimum temperature, the daily temperature difference, the fracture moisture condition and the critical crack initiation temperature, the annual accumulated effective freezing and thawing cycle number is obtained; and calculating a freeze-thaw damage ratio, and carrying out risk quantification and grading. According to the invention, the problem of inaccurate evaluation caused by limitation to local monitoring and lack of an environment factor and material parameter integrated evaluation framework in the prior art is solved.

The invention relates to a pore permeability evaluation method for tight sandstone reservoirs containing cracks with different mechanical properties. The method mainly solves the problem that mechanical properties and shape parameters of different types of cracks are not considered in the existing tight sandstone permeability research. The method is characterized by comprising the following steps: S1, dividing mechanical cause types of deep compact sandstone reservoir fractures; s2, respectively preparing tight sandstone samples containing cracks with different mechanical properties; s3, performing overburden pressure pore permeability test on each sandstone sample to obtain the relationship between the confining pressure and the fracture permeability; s4, overburden gravity and pore pressure are calculated through logging, and effective confining pressure is calculated; and S5, evaluating the pore permeability of the cracks by utilizing a fitting formula of confining pressure and permeability of the cracks with different mechanical properties. The evaluation method solves the problem that the pore permeability parameters of multi-scale and multi-type fractures are difficult to quantitatively predict, so that the influence of the fractures with different scales and geometric properties on the permeability of the sandstone reservoir is determined.

The invention provides a femoral trochanter fracture type classification method. The method comprises the following steps: preprocessing an image data set; performing feature extraction on the image data by using an SIFT algorithm; performing feature extraction on the image data by using a DenseNet model; fusing the key point features and the deep features; and classifying the fused features. The method has the beneficial effects that the SIFT algorithm is combined with the DenseNet deep learning model, SIFT focuses on extracting local features in the image and has strong rotation and zoom invariance, and DenseNet captures more complex global features through dense connection characteristics, so that the overall structure and context information of the image are understood; according to the weighted fusion strategy, the model can dynamically adjust the weights of different features according to data characteristics and training stages, the adaptability of the model to different types of fracture features is enhanced, the model can make more accurate classification judgment through reasonable combination of local and global features no matter simple fracture or complex fracture, and the classification accuracy is improved. And the generalization ability of the model is improved.

The invention discloses a composite material / metal cementing structure II-type fracture performance evaluation method based on correction of end load splitting, and belongs to the field of cementing structure fracture mechanics. Comprising the following steps: 1) designing the thickness of a composite material and a metal cementing piece to obtain a cementing sample; 2) carrying out a clamp correction test on the glued sample to obtain clamp correction parameters; 3) calculating the equivalent bending modulus of the glued sample; (4) carrying out a cementing sample calibration end load splitting test to obtain II-type fracture data; and 5) based on the clamp correction parameters, the equivalent bending modulus, the II-type fracture data and the like, introducing an equivalent crack length, establishing a composite material / metal cementing structure II-type fracture toughness calculation model corrected by the coupling clamp, and solving the cementing sample II-type fracture toughness. According to the method, the thickness size design of the composite material / metal bonding sample, the difference between the material performance and the geometric size and the influence of a test fixture on the II-type fracture toughness calculation result are considered, and the accuracy of the test result is improved.

The application discloses a test method for studying the connection mechanism of hydraulic fractures and high-angle shear type fractures, and belongs to the technical field of indoor test of rock mass hydraulic fracturing. The test method for studying the connection mechanism of hydraulic fractures and high-angle shear type fractures preforms a through fracture at the side of a sample close to the top, performs high-temperature thermal shock treatment on the inner side of the through fracture, thereby forming a gradient damage zone, and processes a perforation upward in the middle of the bottom surface of the sample; the treated sample is placed in an experimental device, and a plurality of acoustic emission probes are pasted on the surface of the sample; a surrounding pressure and an axial pressure are sequentially applied by using a staged loading mode, then high-pressure water fracturing is continuously carried out in the perforation at a constant rate, and the fracture pressure and the corresponding flow rate are recorded when the sample is broken; the hydraulic fracturing process is analyzed according to the flow-pressure curve obtained by the test and the information collected by the acoustic emission probes, and the connection law of the hydraulic fracturing fractures and the through fractures is obtained by combining the CT three-dimensional reconstruction technology after the test.

The utility model relates to a material dynamic III-type fracture property testing device, and relates to the technical field of material dynamic property testing. Comprising a mounting platform, a baffle plate, a transmission rod, an incident rod, a torsion rod, a clamping-releasing device, a hydraulic loading device and a pressure-torque applying device, the pressure-torque applying device is installed on the baffle and connected with the torsion bar, the torsion bar is connected with the incident bar, the transmission bar abuts against the baffle, a sample is clamped between the transmission bar and the incident bar, the sample is in a thin plate shape, and a prefabricated gap is formed in the sample; the pressure-torque applying device is used for applying axial pressure to the torsion bar and applying torque to the torsion bar; the torsion bar penetrates through the clamping-releasing device, the clamping-releasing device is used for limiting rotation displacement of the torsion bar, and the hydraulic loading device is used for driving the clamping-releasing device to relieve rotation limitation on the torsion bar. According to the utility model, the dynamic loading of the material can be realized, and the material is subjected to III-type fracture damage, so that the dynamic III-type fracture property test of the material is completed.

The present invention relates to a combined reconstruction bone plate comprising a reconstruction plate, a connecting plate, and connecting screws. The reconstruction plate is provided with screw holes, and at least one end of the connecting plate is provided with a connecting head, which is provided with a connecting hole. The connecting screw can be assembled into the connecting hole and connected to any screw hole in the reconstruction plate. The present invention can be used in any combination according to the fracture type to achieve fixation of different fracture types, ensuring surgical effectiveness and excellent versatility.

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 invention provides a method for determining the fracture toughness of a hard alloy. Comprising the following steps: acquiring an elastic modulus, a Poisson ratio and a stress-strain curve of a hard alloy test piece; calculating the maximum cohesion according to a fracture calculation formula; constructing a Mooney Rivlin model and a cohesion model in finite element simulation software to compositely describe the characteristics of the hard alloy test piece; a plurality of models of the hard alloy test pieces with different fracture modes are constructed in finite element simulation software, and I-type fracture energy and II-type fracture energy are obtained through J integral analysis according to the models of the hard alloy test pieces with the different fracture modes; carrying out nanoindentation one-way compression finite element numerical simulation to obtain a simulation value of a stress-strain result, carrying out a nanoindentation experiment on the hard alloy test piece to obtain an experiment value of the stress-strain result, and adjusting parameters in finite element simulation analysis according to a difference value between the simulation value and the experiment value to obtain the stress-strain result. And re-calculating to obtain the I-type fracture energy and the II-type fracture energy.

The invention discloses a multi-angle rotating ultra-high core wall dam gravel-doped clay tensile-fracture test device which comprises a mold assembly, two groups of adjusting assemblies and two groups of loading assemblies, a dumbbell-shaped cavity is formed in the mold assembly body and is used for preparing and bearing a test soil test piece; the two sets of adjusting assembly bodies are distributed on the two sides of the mold assembly body in a central symmetry mode, each adjusting assembly body comprises a rotatable semicircular disc and a semicircular disc track, the rotatable semicircular discs are coaxially embedded in the inner sides of the semicircular disc tracks, and the semicircular disc tracks are movably connected with the rotatable semicircular discs; and the end part of the mold assembly body is embedded into the inner side of the semicircular disc track and is detachably connected through a mold fixing bolt. The front loading assembly, the front assembly body, the rear loading assembly, the rear assembly body and the mold assembly body are used in cooperation, the operation process is convenient and rapid, the device can be suitable for a uniaxial tensile test, a tensile fracture test, a shear fracture test, a tension-shear fracture test and a compression-shear fracture test at the same time, and the application range is remarkably widened.

The invention discloses a testing device and method for a rock dynamic I-type fracture test, and belongs to the technical field of detection of rocks and rock materials under dynamic loading in rock engineering, the testing device comprises a shell, and the inner wall of the shell is provided with a plurality of wire grooves; the sample is arranged in the shell; the end part of the incident rod penetrates through the shell and extends into the shell; the end part of the transmission rod penetrates through the shell and is matched with the incident rod to clamp a sample, and stress waves are transmitted to the sample; the telescopic assembly is arranged in the shell and corresponds to the sample so as to adjust the position of the sample; the plurality of acoustic emission sensor assemblies are arranged in the shell and are connected with the test sample so as to detect the test sample; the plurality of acoustic emission sensor assemblies are arranged in one-to-one correspondence with the plurality of wire slots; the acoustic emission sensor assembly is connected with the data acquisition line; and the data acquisition wire is arranged in the wire slot.

The present invention discloses a damage evolution characterization method for coupled failure behavior of heterogeneous adhesive joints, and constructs an extended power exponential fracture model for coupled failure of adhesive joints; a sample preparation device is used to prepare adhesive specimens with a cracked type I fracture mode and conduct a DCB experiment, and adhesive specimens with cracked type II and type III fracture modes are prepared and conduct an ENF experiment to obtain fracture toughness parameters; a sample preparation device is used to prepare adhesive specimens with type I and type II fracture modes of three different slopes of a base material A and a base material B of equal thickness, and DCB and ENF experiments are conducted respectively to obtain power exponent parameters; the extended power exponential fracture model into which the fracture toughness parameters and the power exponent parameters are substituted is used as a fracture model in a constitutive model of glue in a simulation of heterogeneous adhesive joints, and a simulation of coupled failure behavior of heterogeneous adhesive joints is realized. The present invention can efficiently characterize the coupled failure behavior of adhesive joints of multi-material hybrid structures.

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.

The invention discloses a device and a method for testing the high-temperature III-type fracture toughness of rocks, and the device comprises a cuboid sample with circumferential cracks, torsion clamps clamped at the two ends of the cuboid sample, a high-temperature furnace sleeved outside the circumferential cracks on the cuboid sample, and two synchronous rotating wheels sleeved on the cuboid sample, the two synchronous rotating wheels are symmetrically arranged on the two sides of the high-temperature furnace, angle sensors are arranged on the synchronous rotating wheels in a synchronous rotating mode, the torsion clamp is driven by a torsion testing machine, and the angle sensors and the torsion testing machine are connected to a computer through wires. The testing method comprises the following steps of: 1, acquiring data through the testing device; and 2, deducing a high-temperature III-type fracture toughness calculation formula by adopting a displacement method of a finite element method. The invention provides a new method for obtaining the III-type fracture toughness of the rock by using the pure torsional load and a suggested size of the sample, provides a new research method for a rock multi-field coupling fracture mechanical test, and fills the technical blank in the field.

The invention provides a slice type fracture water seepage pressure testing device which comprises a detection module, the detection module comprises an elastic substrate, a strain gauge and a waterproof layer, the strain gauge is arranged on the elastic substrate, the waterproof layer at least covers the strain gauge, and the strain gauge is used for detecting the water seepage pressure of the fracture when the detection module is arranged in the fracture. Different deformation quantities are generated according to different water pressures in the fractures; the signal input end of the processing module is connected with the signal output end of the strain gauge, and the processing module is used for collecting the deformation quantity of the strain gauge according to a preset sampling frequency range, obtaining the water pressure of the crack according to the deformation quantity of the strain gauge and recording the obtained water pressure along a timeline. According to the slice-type crack water seepage pressure testing device, the slice-type detection module can be easily inserted into a crack with a narrow space and can be matched with the processing module to accurately test the crack water seepage pressure, the overall structural design of the device is simple, and the manufacturing cost is effectively reduced.

The utility model relates to a material III-type fracture toughness testing device based on a Hopkinson torsion bar, and relates to the technical field of material dynamic performance testing. Comprising a base, a baffle, an emergent rod, an incident rod, a torsion rod, a torsion limiting device, a hydraulic loading device, a torque loading device and an axial pressure loading device, the axial pressure loading device is mounted on the baffle and connected with the torsion bar, the torsion bar is connected with the incident bar, the emergent bar is mounted on the baffle, and a sample is clamped between the emergent bar and the incident bar; the sample is of a cylindrical structure, and a gap vertically extending towards the outer surface is formed in the center in the sample; the torsion bar penetrates through the torsion limiting device to limit rotation displacement of the torsion bar, and the hydraulic loading device drives the torsion limiting device to relieve rotation limitation on the torsion bar; the torque loading device is in transmission connection with the torsion bar and applies torque to the torsion bar. According to the utility model, the Hopkinson torsion bar loading technology is used, so that the sample is in a pure shear stress state and is subjected to III-type fracture damage, and the accurate test of the III-type fracture toughness of the material can be realized.

The utility model provides a novel screw for fracture fixation, and relates to the field of medical instruments, the novel screw comprises a screw main body and a screw nested in the main body, and the tail part of the screw is provided with a folding blocking unit so as to improve the overall stability of the screw. A first thread part is arranged in the middle of the screw, and second thread parts extend out of the two ends of the screw and used for being connected with the supporting ring, the anti-disengaging backing ring and the nut to form a stable double-thread structure. The structure can be gradually screwed in the fracture fixing process, so that the device can adapt to different bone parts, and postoperative displacement is prevented through the anti-falling part. The folding blocking unit is composed of an installation ring, an annular piece and a plurality of sets of folding plates which can be movably connected, the small fracture blocks can be pressed tightly in the installation process, and the small fracture blocks are prevented from slipping in the healing process. The device is simple in structure, convenient to disassemble and assemble, high in applicability, capable of remarkably improving the fixing effect of a fracture part, especially suitable for fixing small free fracture blocks in orthopedic surgery and capable of promoting healing.

The application discloses a novel straight-shear type concrete fracture performance test specimen and a test method. The test specimen is in the shape of an ectopic notch. During the test, the test specimen is placed between two loading plates, and the length direction of the concrete part is perpendicular to the two loading plates. The two loading plates are loaded towards each other. Relative to the concrete part, the compression deformation of the steel block is almost zero, thus causing the relative deformation difference between the concrete part and the steel block. The two loading plates are continuously loaded towards each other, and the concrete part is fractured along the predetermined position. The method forms the deformation difference in the stress redistribution process through the different material stiffness on both sides of the crack, realizes the opposite displacement within the range of the test specimen, and causes the dislocation cracking. Since the crack is caused by the deformation difference inside the concrete part, there is no bending tensile stress influence. The application is used for solving the index test of the II type fracture performance of brittle materials such as ordinary concrete and rockfill concrete, improving the existing test method, and eliminating the influence of the bending tensile stress in the II type fracture test.

The invention discloses an ankle joint fracture dorsal extension adduction position polymer splint positioning adjusting device which comprises a bottom plate, a clamping mechanism, a placing mechanism, an adduction adjusting mechanism and a foot abutting mechanism, a transverse through opening is formed in the bottom plate, a sliding groove is formed in the bottom plate, and the transverse through opening and the sliding groove are perpendicular to each other in the direction; the clamping mechanism is arranged on the transverse through opening, the placing mechanism is fixedly arranged at one end of the sliding groove, and the inward extending adjusting mechanism is arranged on the sliding groove in a sliding mode. And the inward stretching adjusting mechanism comprises an alignment plate, a pushing and pressing assembly, a pressing plate assembly, two arc plate blocks, two pushing and pressing assemblies and an adjusting assembly, so that the fractured feet of a patient can be accurately pushed and fixed through the device, accurate regulation and control and stable maintenance of the individualized dorsal stretching adduction angle are achieved according to the differential requirements of eversion type fractures of different types, and the individualized dorsal stretching adduction angle can be accurately adjusted and controlled. The ankle point relation is effectively guaranteed to be accurately reset and continuously kept, and the problem of poor reset caused by body position deviation is solved.

The application discloses a gel microsphere profile control agent application scene determining fractured core plugging experiment method, and comprises the following steps: S1, primary water flooding; S2, core fracture making: S2-1, making full open type fracture; S2-2, making closed type fracture; S3, gel microsphere profile control agent displacement; S4, secondary water flooding.The application provides a special fractured core plugging experiment method for the characteristics of high shear resistance and high salt tolerance of the gel microsphere profile control agent, especially when the closed type fracture is made, the influence of various factors is comprehensively considered, so that a more accurate fracture cutoff position is obtained, the demand of the gel microsphere profile control agent is met, the experiment result accuracy is improved, and the plugging effect of the full open type fracture is compared, finally, a perfect experiment step system is formed, so that the gel microsphere profile control agent has practical application value when being used in a reservoir with strong heterogeneity and large pore throat size difference.

The invention discloses a test method for multi-angle testing of tensile-fracture characteristics of extra-high core wall gravel-doped clay. The test method comprises the following steps: planning test working conditions; preliminarily assembling the front loading component and the front assembly body, and the rear loading component and the rear assembly body; adjusting the positions of the front loading assembly and the rear loading assembly; assembling the mold assembly, and preparing a test soil test piece; adjusting the relative positions of the front loading assembly and the rear loading assembly; connecting the mold assembly with the front assembly and the rear assembly; exposing the test soil test piece; and applying an acting force and recording test data. According to the invention, measurement of tensile and fracture characteristics of a test soil test piece at multiple angles is realized; when the angle between the loading force and the test soil test piece is 0 degree, a uniaxial tensile test and a tensile fracture test can be carried out; when the angle between the loading force and the test soil test piece is 90 degrees, a shear type fracture test can be carried out; when the angle between the loading force and the test soil test piece is 1-89 degrees, tension-shear and compression-shear fracture tests can be carried out, and the research on the fracture characteristics of the soil body under the influence of different angles is perfected.

The utility model discloses an assembly type fracture-resistant light partition board which comprises a wall body, an embedded plate is arranged on one side of the wall body, a connecting plate is arranged on the other side of the wall body, through holes are formed in the wall body, grooves are symmetrically formed in the connecting plate, the embedded plate can be clamped and embedded in the grooves, the through holes vertically penetrate through the wall body, the cross sections of the through holes are triangular, and the through holes are distributed at equal intervals in a staggered mode. The section of the embedded plate is in an isosceles trapezoid shape, a clamping groove is formed in the embedded plate, the position of the groove corresponds to that of the embedded plate, a mounting groove is formed in the connecting plate, a clamping block is arranged in the mounting groove, a limiting base is arranged on one side of the clamping block, the clamping block can be fixedly clamped in the clamping groove in an embedded mode, and the inclined face of one side of the clamping block is parallel to the inclined face of the groove. The triangular through holes are formed in the wall body, the weight of the wall body is reduced, meanwhile, the fracture resistance of the wall body is improved, meanwhile, due to the arrangement of the embedded plates and the connecting plates, rapid installation can be achieved, and practicability is higher.

The invention discloses a hybrid pultrusion plate I-type interlayer fracture toughness rapid prediction method, and relates to the field of composite material I-type fracture analogue simulation. The method comprises the steps that a hybrid pultrusion plate I-type interlayer fracture toughness geometric model is established, hexahedral grids are divided, grid components are extracted after the geometric model is divided into the grids, and a hybrid pultrusion plate I-type interlayer fracture toughness model is established; defining material attributes for each unit, determining boundary conditions and applying a load according to a loading mode for measuring the I-type interlayer fracture toughness, calculating the finite element model, obtaining a calculation result, extracting a load-opening displacement curve, and obtaining the I-type interlayer fracture toughness GIC of the hybrid pultrusion plate. According to the method, the I-type interlayer fracture failure behavior of the hybrid pultrusion plate can be effectively predicted and analyzed, and the structure safety is guaranteed.

The invention relates to a design method of a femoral neck minimally invasive fixing system. The design method comprises the steps that a femoral neck three-dimensional model containing a Pauwels III type fracture line is established based on CT scanning data, and bone material attributes are defined; importing an internal fixation system preliminary model containing a femoral neck power cross nail and a near-end hollow nail into the model, and setting the size and position parameters of the internal fixation system preliminary model; setting finite element analysis conditions for the model, and applying a load simulating a physiological state to calculate stress distribution, displacement and fatigue life; identifying a stress concentration area based on an analysis result, and adjusting design parameters according to the stress concentration area; and repeating the iteration steps of finite element analysis and parameter adjustment until the stress distribution is uniform and the maximum stress is lower than the yield strength of the material. Compared with the prior art, computer simulation is used for replacing a traditional physical test, the structure of the internal fixing system can be rapidly optimized, the research and development period is remarkably shortened, and the risk is reduced.

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 provides a method for determining the fracture toughness of a cemented carbide. The method comprises: obtaining the elastic modulus, Poisson's ratio and stress-strain curve of the cemented carbide sample; calculating the maximum cohesive force according to a fracture calculation formula; constructing a Mooney Rivlin model and a cohesive force model in a finite element simulation software to describe the characteristics of the cemented carbide sample; constructing a plurality of models of the cemented carbide sample with different fracture modes in the finite element simulation software; obtaining the I-type fracture energy and the II-type fracture energy by using J integral analysis according to the plurality of models of the cemented carbide sample with different fracture modes; performing finite element numerical simulation of nanoindentation uniaxial compression to obtain a simulation value of the stress-strain result, and performing a nanoindentation experiment on the cemented carbide sample to obtain an experimental value of the stress-strain result; and adjusting the parameters in the finite element simulation analysis according to the difference between the simulation value and the experimental value, and recalculating the I-type fracture energy and the II-type fracture energy.

The invention provides a three-type fracture grid insensitive strain energy density calculation method which comprises the following steps: S1, obtaining the size of a pipe joint subjected to three-type fracture, and obtaining basic parameters of a stress field analytical solution based on the size of the pipe joint subjected to three-type fracture; s2, performing finite element calculation to obtain a traction-force-based structural stress which is insensitive to a use grid; s3, calculating a first undetermined coefficient c and a second undetermined coefficient d based on the structural stress; s4, calculating a stress component of the notch based on the first undetermined coefficient c and the second undetermined coefficient d to obtain an analytical solution of a stress field; and S5, sequentially solving a notch strain field and a strain energy density field based on the analytical solution of the stress field, and finally obtaining the strain energy density. The invention provides a solving method of a stress field of a sharp V-shaped notch for describing structural stress based on traction force under type III fracture.

The novel fracture minimally invasive surgery positioning and guiding device comprises a positioning pipe, a guiding pipe and an arc-shaped movable arm, the arc-shaped movable arm comprises a first movable arm body and a second movable arm body, and one end of the first movable arm body is movably connected with one end of the second movable arm body through a locking structure; the other end of the first movable arm and the other end of the second movable arm are provided with a positioning pipe and a guiding pipe respectively, the second movable arm is provided with a first guiding opening formed in the extending direction of the second movable arm, and the first movable arm, the second movable arm and the first guiding opening are all in an arc shape and are the same in circle center. The locking structure comprises a positioning block, a first fixing piece for fastening or loosening the positioning block and the first guide opening, and a second fixing piece for fastening or loosening the positioning block and the first fixing hole, so that the first movable arm has a sliding state and a rotating state, and accurate positioning and dynamic adjustment of a three-dimensional space of the guide pipe are realized; and an efficient, accurate and safe solution is provided for the complex orthopedic surgery.