188 results about "Fatigue fractures" patented technology

The utility model discloses a rear release covered stent and a rear release system of the covered stent. According to the post-release covered stent, a bare stent part in an existing covered stent is omitted, the wave crest of the near-end first-section wave-shaped stent is not sewed with the covering film, and after the near-end first-section wave-shaped stent is compressed, the wave crest can extend out of the edge of the near end of the covering film by a certain distance; and the extended stent part is used as a hanging unit to be matched with the conveyor to finish the post-release of the covered stent. Meanwhile, when the wave crest of the first corrugated stent extends out of the edge of the near end of the covering film, the extending part is small in size, blood flow disturbance is not caused to branch blood vessels, the risk of thrombus formation is greatly reduced, the overall length of the covering film stent can be greatly reduced, and then the pushing stroke of the stent in a conveyor in the implanting process is shortened. Besides, the middle section and the wave trough position of the first section of corrugated stent at the near end are sewn with the covering film, sewing points are sufficient, the stent can be bound by sewing lines even though fatigue fracture occurs, and the risk of scratching blood vessels is reduced.

The invention discloses an oil and gas pipeline fracture phase field fatigue crack propagation calculation method, system, equipment and medium, and the method comprises the following steps: building a finite element model of a submarine oil and gas pipeline, and setting material parameters and fatigue fracture phase field calculation parameters; based on the finite element model, cyclic loading calculation is carried out by adopting a fatigue fracture phase field method; when detecting that the crack is about to generate catastrophic expansion, starting an arc length control algorithm on the finite element model, and performing combined solution on the displacement field, the load factor and the phase field by controlling arc length parameters; and outputting the fatigue life and the final fracture form of the pipeline according to the calculation results of the displacement field and the phase field. According to the method, the displacement increment, the load factor increment and the phase field increment are solved at the same time through the arc length constraint condition, and stable solving of multi-field cooperation is achieved. The intelligent switching mechanism ensures that calculation can still be steadily converged in a catastrophic propagation stage, and a complete crack propagation path and a final structural failure form are obtained.

The invention discloses a large-stroke hydraulic vibration horizontal test bed, which is used for solving the problems of interference, abrasion and easy fatigue fracture of a force transmission component caused by a centering error between a large-stroke hydraulic vibration exciter and a horizontal table board. The test bed comprises a base, a hydraulic vibration exciter, a horizontal table top and a spring plate assembly connecting the base and the hydraulic vibration exciter. A function decoupling design is adopted, wherein a guide rail compensation block with horizontal transverse elasticity is arranged in a guide mechanism between a horizontal table top and a base and is specially used for dynamically compensating centering errors in the horizontal direction; meanwhile, the spring plate assembly is constructed to be composed of multiple layers of stacked spring plates parallel to the horizontal table top, centering errors in the vertical direction are dynamically compensated through bending flexibility of the spring plates in the vertical plane, the working stress is greatly reduced through the multi-layer structure, and the fatigue life is prolonged. By means of the design, unification of high-rigidity excitation force transmission and multi-dimensional dynamic error compensation is achieved, the reliability and precision of equipment are remarkably improved, and the service life of the equipment is remarkably prolonged.

The invention discloses a method, device and equipment for analyzing the reliability of a welding seam process based on structure characterization, and relates to the field of welding seam process reliability analys.The method is characterized by comprising the steps that an EBSD data set of any site of a titanium alloy welding structure is obtained; selecting an area fraction, an equivalent circle diameter, a plate texture size, a KAM value and a Schmidt factor from the EBSD data set; determining an analysis result according to the area fraction, the equivalent circle diameter, the plate texture size, the KAM value and the Schmidt factor; and analyzing the reliability degree of the titanium alloy welding seam process according to an analysis result. Compared with a traditional welding structure which studies the process reliability according to the fatigue fracture life, the method better fits the actual and microcosmic principles of titanium alloy materials on the basis of microcosmic structure quantitative characterization, and the reliability of the welding seam process can be more accurately judged; and the risk of large reliability evaluation error caused by unstable service life of the fatigue component is reduced, and the analysis precision of the reliability of the welding seam process is improved.

The invention discloses a method for predicting fatigue fracture of a high-temperature discontinuous structure based on a phase field method under a variable-temperature working condition, and belongs to the technical field of fracture behavior prediction. Acquiring a stress-strain field of a coupling temperature field of the viscous-plastic material under any cyclic load; based on a stress strain field of a coupling temperature field, a phase field residual error and a phase field stiffness matrix are obtained by obtaining a fracture phase field of a viscous-plastic material under any cyclic load, a phase field variable is obtained through iterative solution, and a corresponding UEL subprogram is compiled; and correcting and updating a stress-strain field, a temperature field and a phase field by adopting a data interaction process of a UMAT subprogram, a UMATHT subprogram and a UEL subprogram, and predicting the fracture behavior of the viscous-plastic material under the temperature gradient by identifying a phase field variable and an evolution path thereof under a cyclic load.

The invention relates to the technical field of six-degree-of-freedom mechanical arm control, in particular to a six-degree-of-freedom mechanical arm control method and system. The method comprises the following steps: obtaining an assembly schematic diagram, carrying out multi-machine cooperation process analysis, and collecting the vibration frequency of a vehicle body structure by using an acoustic emission sensor; thirdly, vibration impact force disorder of the connection interface is simulated through the vibration frequency, pre-tightening force misalignment regression analysis is carried out, and therefore fatigue fracture failure of the connection structure is predicted; then, based on regression data and a prediction result, torque-angle compound control of the six-degree-of-freedom mechanical arm is implemented, and iteration is carried out; and finally, control firmware is designed and embedded into the mechanical arm, and precise control is executed. Through optimization processing of the six-degree-of-freedom mechanical arm control technology, the six-degree-of-freedom mechanical arm control technology is more perfect.

The invention discloses a blade vibration fatigue strength and three-dimensional fatigue crack propagation prediction method which comprises the following steps: carrying out uniaxial tensile test and fracture toughness measurement on a blade test piece material to obtain material mechanical parameters of the blade test piece material; performing a bending vibration fatigue test on the blade test piece to obtain the fatigue strength of the blade test piece; a three-dimensional fatigue fracture phase field model is constructed, and phase field simulation parameters are obtained through finite element calculation; based on material mechanical parameters and phase field simulation parameters, a blade three-dimensional simulation model is established by simulating a blade sample in a bending vibration fatigue test, a periodic pressure load is applied to a blade basin of the blade to simulate an aerodynamic load in the service process of the blade, the three-dimensional fatigue crack propagation behavior of the blade is calculated, and the vibration fatigue strength of the blade is predicted. According to the method, a three-dimensional fatigue fracture phase field model is established, numerical solution is performed by using a finite element method, the three-dimensional fatigue crack propagation behavior of the blade under the periodic vibration load can be effectively predicted, and the blade fatigue prediction accuracy is improved.

The utility model belongs to the technical field of cutter coating processing, particularly relates to a porous charging tray for cutter coating processing, solves the problem that the clamping effect and the safety of a cutter are influenced due to plastic deformation or fatigue fracture of an elastic insertion sheet caused by long-time use and frequent adjustment, and adopts the following scheme that the porous charging tray comprises a porous mounting plate, a mounting plate fixing block is fixedly mounted below the porous mounting plate, a mounting plate base is fixedly connected below the mounting plate fixing block, a second clamping block is fixedly connected to the upper surface of the mounting plate base, a sliding rod is fixedly connected to the outer wall surface of the right side of the second clamping block, and the outer wall surface of the sliding rod is sleeved with a first spring; and a first clamping block is slidably connected to the outer wall surface of the other end of the sliding rod, clamping grooves are formed in the inner sides of the first clamping block and the second clamping block, and a disc limiting base is fixedly installed outside the right side of the first clamping block. According to the utility model, the risk of safety accidents caused by falling off or shaking of the cutter is reduced.

The invention discloses a wind turbine blade root bolt group loosening degree online monitoring and fatigue life prediction method, which belongs to the field of wind power, and comprises the following steps: determining the blade shimmy direction of a monitoring unit; arranging strain gauges; acquiring strain data; setting early warning and alarm rules; establishing a monitoring bolt group K value curve; detecting the most unfavorable bolt axial force; calculating the average axial force of the most unfavorable bolt; calculating the tension increment in the screw under the action of the most unfavorable fatigue load on the bolt; the equivalent stress amplitude and the average stress of the most unfavorable bolt are calculated; and determining the residual fatigue life of the most unfavorable bolt. According to the method, the bolt loosening area and the most unfavorable bolt fatigue life prediction in the area are combined, the accuracy of blade root bolt life prediction is improved, and the blade root bolt loosening problem can be found and treated early and the possibility of fatigue fracture can be eradicated through accurate identification of the local bolt group loosening degree.

The invention discloses a thermoplastic elastomer dynamic fatigue performance testing device and method, and belongs to the technical field of elastomer material testing, the thermoplastic elastomer dynamic fatigue performance testing device comprises a test rack, a transparent partition plate is installed outside the test rack in a combined mode, and the transparent partition plate seals the test rack to form a test sealing bin; the loading units are symmetrically distributed on the test rack left and right and located in the test sealing bin, and an elastic material is connected between the two loading units; the temperature sensor is mounted on the inner wall of the transparent partition plate; the control mechanism is horizontally fixed in the experiment sealing bin of the test rack; the loading unit is mainly used for providing dynamic tensile stress for the elastic material, the industrial camera records the whole fatigue fracture process, and the steel knife mechanism can perform notch preforming on the surface of the elastic material through the steel knife seat, so that fatigue damage is formed at a single point or multiple points in the middle of the elastic material; therefore, the time required by the whole fatigue fracture process is obviously shortened, and the test efficiency is improved.

The invention discloses a motor vibration-based walking part framework fatigue damage assessment method, which comprises the following steps of: performing vibration test and dynamic stress test at a specified position of a bogie to obtain a motor acceleration signal and dynamic hot spot stress, and preprocessing the motor acceleration signal and the dynamic hot spot stress; a motor acceleration signal is used as input excitation, and the power spectrum density of the dynamic hot spot stress is calculated through a transfer function and the real-time motor acceleration; based on the obtained power spectrum density of the dynamic hot spot stress, reconstructing a stress time history by using fast Fourier inversion; and based on the stress time history obtained by reconstruction, performing fatigue stress estimation by adopting a frequency domain method. The fatigue damage degree of the bogie frame is evaluated through motor vibration, and harm caused by fatigue fracture of the frame is avoided.

A method for predicting ultra-high cycle fatigue life considering the orientation characteristics of crack initiation location. By obtaining a failed specimen, using a scanning electron microscope to scan the fatigue fracture surface of the failed specimen. When there is a fatigue crack initiation source in the fine-grained area of the fatigue fracture surface, repeat the steps; obtain the crack initiation area parameters of the fatigue crack initiation source in the fine-grained area, and the crack initiation area parameters include the projected area of the initiation area and the inclination angle of the initiation area; determine the true area of the initiation area according to the projected area of the initiation area and the inclination angle of the initiation area; obtain the stress intensity factor on the inclined surface of the initiation area of the fatigue crack initiation source in the fine-grained area; establish a fatigue life model according to the true area of the initiation area and the stress intensity factor; predict the fatigue life of the failed specimen according to the fatigue life model to obtain a more accurate life prediction model and improve the accuracy of fatigue life prediction.

The utility model provides a harmonic speed reducer bearing retainer, which belongs to the field of harmonic transmission flexible bearings and comprises an annular retainer end ring and a plurality of window beams arranged along the circumference of the retainer end ring at equal intervals, one end of each window beam is connected with the retainer end ring, and open pockets for accommodating rolling bodies are formed between the adjacent window beams. The window beam is provided with the turnup fins facing the outer ring face, the structural strength of the window beam is enhanced through the fins arranged on the window beam, and when the retainer is deformed under the action of external force, the fins can absorb part of deformation energy through elastic deformation of the fins. Once the external force disappears, the elastic recovery capability of the fins can promote the retainer to quickly recover to the original shape, so that the risks of accumulated stress and fatigue fracture caused by continuous deformation are reduced, and the retainer can effectively resist fatigue stress caused by continuous deformation in the long-term operation process. The service life of the retainer is prolonged, and faults and maintenance cost caused by fatigue fracture are reduced.

This invention belongs to the field of machining technology, specifically relating to a welded joint and its manufacturing method, aimed at solving the technical problem of low fatigue strength in welded joints. The welded joint includes at least two sequentially stacked plates, a weld nugget fixing the two adjacent plates together, and a nail-like member. The nail-like member is pressed into at least a portion of the plates and each weld nugget along the stacking direction of the at least two plates, forming receiving holes in the corresponding plates and weld nuggets that are adapted to the nail-like member. The edge region of the weld nugget, at least away from the nail-like member, has compressive residual stress. By suppressing the initiation and growth of cracks through compressive residual stress, fatigue strength is improved, and fatigue fracture of the welded joint is reduced.

The invention provides an arc thread double-end bolt assembly and a combined nut, and belongs to the technical field of bolt connection. The arc thread double-end bolt assembly comprises a double-end bolt, an embedded nut and a fastening nut, thread forms of external threads at the two ends of the double-end bolt comprise an outer thread top, a thread side linear section, a thread bottom arc and a thread side linear section which are sequentially connected, and the thread form angles of the external threads are all 60 degrees. The thread forms of the internal threads of the embedded nut and the fastening nut comprise a thread bottom arc, a thread side linear section, a thread top linear section and a thread side linear section which are connected in sequence, the thread form angle of the internal threads of the fastening nut is beta j, the thread form angle of the internal threads of the embedded nut is beta m, beta j is larger than beta m, and beta m is smaller than 60 degrees. The fatigue performance of the external threads at the two ends of the double-end bolt is different, the fatigue performance of the position, matched with the embedded nut, of the double-end bolt is better than that of the position, matched with the fastening nut, of the double-end bolt, when the double-end bolt is subjected to fatigue fracture, the fracture position is located at the position of the fastening nut more easily, and therefore the double-end bolt can be detached from a structural body conveniently, and on-site replacement operation is facilitated.

The utility model relates to an axial force limiting retaining device which is characterized by comprising an action rod (1) used for transmitting acting force, a fixing element (3), a first adjusting screw plug (2), a first disc spring set (4), a first guide rod (5), a second guide rod (7), a squeezing-off column (6), a second disc spring set (8), a second adjusting screw plug (9), the second guide rod (7), the first guide rod (5), the second disc spring set (8) and the first disc spring set (4). The second adjusting screw plug (9) and the first adjusting screw plug (2) are respectively and symmetrically arranged with the extrusion column (6); the head of the trailable column (6) is provided with a trapezoidal protrusion, the angle and the size of the trapezoid are consistent with those of the trapezoidal groove, and the tail of the trailable column (6) is provided with two symmetrical slopes. The device is simple in structure and high in reliability, so that the maximum limiting force of the rod piece can be kept under the condition that the device is not damaged, the problem of alternating fatigue fracture of the device is avoided, the reliability of equipment is improved, and the traveling efficiency is improved.

The invention discloses an X-ray three-dimensional imaging-based II-type and III-type crack in-situ testing device and method, belongs to the technical field of crack in-situ testing, and solves the problem that an existing crack in-situ testing device only tests I-type cracks and cannot test II-type and III-type cracks. The device comprises a tension-compression fatigue testing machine, a clamp main body and an X-ray monitoring assembly. Through the collaborative design of the translation reversing mechanism, the rotary reversing mechanism and the reversing switching piece in the clamp main body, the single vertical motion of the loading rod piece can be flexibly converted into horizontal shearing motion for testing type II cracks or rotary motion for testing type III cracks; therefore, in-situ testing of three basic crack types by one device is realized, the application range of the device is greatly expanded, the testing efficiency is improved, and a key experimental tool is provided for studying fatigue fracture behaviors of materials under multi-mode loads.

The invention belongs to the field of material characterization evaluation, and particularly relates to a method for quantitatively characterizing fatigue crack full-life characteristics. Selecting materials, preparing a fatigue test sample, and treating the surface of the sample into a smooth state; dividing the samples into a group A and a group B, and performing high-resolution X-ray three-dimensional imaging; putting the group A sample into an in-situ fatigue device, loading to fatigue fracture, and recording the fracture cycle times; selecting a sample similar to the microstructure feature of a certain sample in the group A from the group B, and carrying out step-by-step progressive in-situ fatigue three-dimensional imaging experiment, three-dimensional reconstruction, three-dimensional processing and three-dimensional visualization; according to the fracture position, reversely and sequentially determining fatigue crack information of each fatigue stage according to a three-dimensional scanning sequence, and performing three-dimensional quantitative characterization; drawing the fatigue crack sizes of all stages into a graph, and fitting and extrapolating to obtain cycle times when the fatigue crack sizes are 0; and establishing a fatigue crack full-life characteristic pattern.

The invention relates to the technical field of biological materials, and provides an absorbable self-repairing suture line for maintaining the stability of a mechanical biological microenvironment and a preparation method of the absorbable self-repairing suture line. According to the suture line, an absorbable high polymer material is adopted as a matrix, and PLA microcapsules containing a medical-grade cyanoacrylate n-octyl ester repairing agent are uniformly dispersed in the matrix through a melt blending spinning process. When the suture line generates microcracks at dynamic tissue parts such as cardiovascular and digestive tracts due to periodic stress, the stress at the tip of the cracks enables the microcapsules to be broken to release the repairing agent, rapid in-situ polymerization occurs under triggering of tissue fluid, the self-repairing efficiency of 90% or above is achieved, and the strength retention rate of 95% or above is maintained in the key rehabilitation period of the suture line. The defect that a traditional absorbable suture line is prone to fatigue fracture in a dynamic environment is overcome, the mechanical integrity is actively maintained through an intelligent self-repairing mechanism, all components can be completely degraded and absorbed, and a safer and more reliable solution is provided for dynamic tissue repairing.

The present invention discloses a high-strength and fracture-resistant automobile seat slide arch bracket mold design process, which includes using a progressive die to continuously stamp and punch a material strip to form the automobile seat slide arch bracket; the progressive die includes an upper die and a lower die, the upper die includes an upper positioning plate, a plurality of upper pads, an upper template, an upper pad, an upper fixed plate and an upper unloading plate arranged in sequence from top to bottom, and the lower die includes a lower positioning plate, a plurality of lower pads, a lower pad and a lower template arranged in sequence from bottom to top; a lower die insert is provided in clearance fit on the lower template, and an upper unloading plate insert is provided in clearance fit on the upper unloading plate. The present invention fundamentally solves the problem of the firmness of the connection between the arch bracket and the automobile seat slide rail, and avoids the problem that the seat bracket is not firmly fixed, causing it to be subjected to random alternating loads, thereby leading to fatigue fracture failure. The present invention uses a mold forming process and an insert clearance fit to prevent the arch bracket from breaking during continuous stamping.

The tibial plateau prosthesis comprises a tibial plateau surface and reinforcing ribs connected to a non-articular surface of the tibial plateau, the reinforcing ribs comprise a first reinforcing rib and a second reinforcing rib, the first reinforcing rib is arranged in the length direction of the tibial plateau prosthesis, the second reinforcing rib is arranged in the length direction of the tibial plateau prosthesis, and the third reinforcing rib is arranged in the length direction of the tibial plateau prosthesis. The second reinforcing ribs are perpendicular to the first reinforcing ribs, and a plurality of second reinforcing ribs can be arranged according to needs. The reinforcing rib is provided with a wire groove or a through hole structure, and the non-articular surface of the tibial plateau is provided with a pit structure with an unlimited shape. The strength of the tibial plateau of the unicompartmental knee joint can be enhanced, the probability that the tibial plateau is subjected to fatigue fracture under the action of cyclic load of flexion and extension movement of a human body is reduced, and the service life of the product is prolonged.

The utility model relates to a slidable platform mounting and fixing structure, which avoids failure forms such as fatigue fracture, open welding, even tearing and the like caused by repeated stress of a fixed structure platform. Comprising a platform, a fixing support, a rubber damping block, a first gasket, a spacer bush, a fastening bolt, a locking nut and a second gasket, the rubber damping block, the platform and the fixing support are sequentially arranged on the spacer bush in a sleeving mode through center holes, the fastening bolt penetrates through the center hole of the spacer bush, and the first gasket is installed between the fastening bolt and the rubber damping block in a pressed mode; holes for installing the spacer bush on the platform and the fixing support are oblong holes, the long axis directions of the platform and the fixing support are perpendicular to each other, the spacer bush is of a cylinder sleeve structure, a large cylinder at the upper end of the spacer bush is located in the rubber damping block, and a small cylinder is located in the oblong holes of the platform and the fixing support. The diameter of the spacer bush is matched with the distance between the platform and the short shaft of the fixing support, and when the fastening bolt and the locking nut are pressed, a certain pre-tightening gap can be provided between the large cylinder of the spacer bush and the upper end face of the platform.

The utility model relates to a transverse impedance multidirectional damping steel spring device which comprises a spring outer sleeve (1), a steel spring (5) and a spring inner sleeve, the spring inner sleeve comprises a spring inner sleeve cover (2) and a spring inner sleeve base (6), and a transverse impedance elastic body (3) for transverse limiting is arranged between the spring outer sleeve (1) and the spring inner sleeve base (6). Compared with the prior art, three-direction damping amplification is adopted, besides the main vibration isolation direction, the stability and vibration in the direction perpendicular to the main vibration isolation direction of the spring can be controlled, and meanwhile the problem that the spring is subjected to transverse shearing dynamic load to cause fatigue fracture and failure of the spring is solved; therefore, the transverse stability and reliability are improved, and the service life of parts is prolonged.

The utility model provides a rock debris sampler for geological prospecting, and relates to the field of geological prospecting, the rock debris sampler comprises a sampler body, the sampler body is movably sleeved with a connecting sleeve, the connecting sleeve is fixedly sleeved with a fixing ring, and the surface of the fixing ring is fixedly connected with eight fixing plates; a supporting shaft is rotationally connected between every two adjacent fixing plates, the supporting shafts are fixedly sleeved with supporting legs, and torsional springs are fixedly connected between the supporting legs and the fixing plates. Through cooperation of the supporting legs, the fixed rings, the sliding rings, the first connecting pieces, the second connecting pieces, the transverse plates and other structures, a plurality of triangular stabilizing units are formed together, loads such as vibration and impact generated when the sampler works are converted into tension and compression stress in the transverse plates from concentrated stress at the joints of the supporting legs, and the stability of the sampler is improved. Therefore, the stress concentration phenomenon of connecting points of the supporting legs is effectively avoided, and the risk of fatigue fracture of welding points is effectively reduced.

The invention provides a method for calculating the fatigue limit of an aluminum alloy by utilizing defects and yield strength, which comprises the following steps: S1, obtaining the yield strength of the aluminum alloy by utilizing a tensile test; s2, a fatigue test is utilized, a large load is loaded, the sample is broken within 2 hours, and a fatigue fracture is obtained; s3, observing a fatigue crack source, and measuring the defect area and the like of the crack source; s4, according to the results of the steps S1 and S3, calculating the fatigue limit by using a mathematical relationship between the yield strength, the defect area and the like and the fatigue limit to obtain a first fatigue strength value; s5, repeating the steps S2, S3 and S4 to obtain a second fatigue strength value; repeating the steps S2, S3 and S4 again to obtain a third fatigue strength value; and by parity of reasoning, after three or more fatigue strength values are obtained, an average value, namely the fatigue limit, is obtained. The method has the beneficial effects that the defect and the yield strength are comprehensively considered, the accuracy of the calculated fatigue limit is higher, and time, manpower and material resources are saved.

To provide a method for evaluating inclusions to enlarge an observation surface in a test piece, thereby enabling accurate measurement of the size and the type of nonmetallic inclusions that cause fatigue fracture in a desired steel material in a short time and at low cost.SOLUTION: A method for evaluating an inclusion evaluation includes: performing a tensile test on a test piece obtained by introducing hydrogen into a precursor metal piece having an internal hardness of more than 400 HV and a surface hardness of 250-400 HV, to cause fracture originating from a nonmetallic inclusion affected by the introduced hydrogen, and measuring the size and / or identifying the type of the nonmetallic inclusion acting as the fracture origin.SELECTED DRAWING: Figure 1

The invention belongs to the technical field of reinforcing steel bar straightening, and discloses a reinforcing steel bar straightening device for civil engineering construction, which comprises a fixed bracket, a driving assembly is arranged at the upper end of one side of the fixed bracket, a striking assembly is fixedly mounted on the top surface of the fixed bracket, and a connecting assembly is arranged on one side of the top surface of the fixed bracket. A straightening assembly is arranged in the middle of the top face of the fixing support, the connecting assembly comprises a rotating unit, and an abutting piece is fixedly installed at the top of the rotating unit. Through cooperation of a limiting ring, a connecting rod and other structures, a moving rod moves towards the position close to the connecting rod, a striking unit rotates, when an abutting piece does not abut against the moving rod, the striking unit continuously swings to impact a second straightening piece, a large amount of energy can be instantly released through impact, scratches and damage to the surface of a reinforcing steel bar are reduced, and the service life of the reinforcing steel bar is prolonged. And the good surface quality of the material is kept, and the effects that the material is not prone to deformation or fracture when stressed, and the fracture risk during fatigue is reduced are achieved.

The application discloses an extreme environment stable fatigue fracture self-adhesion ion skin and a preparation method and application thereof. The ion skin is formed by combination of chemically inert low cross-linked polydimethylsiloxane elastomer and perfluoroether rubber respectively with a stretchable ion conductive elastic fiber network through mechanical interlocking technology; wherein the polydimethylsiloxane elastomer is prepared by polymerization and curing of a silicone elastomer base and a PDMS curing agent, the perfluoroether rubber is obtained after solvent volatilization of a perfluoroether rubber solution, and the stretchable ion conductive elastic fiber network is obtained by electrospinning; the strength of the ion skin is greater than or equal to 9.9 MPa, the toughness is greater than or equal to 10 MJm ‑3 , the tensile strain is greater than or equal to 355%, the tensile toughness is greater than or equal to 5.7 MJm ‑3 , and the breaking energy is greater than or equal to 71.6 kJm ‑2 . The application of the ion skin in preparation of a flexible stretchable electronic device in an extreme environment. The application has simple process, excellent mechanical properties, extreme environment tolerance and self-adaptive surface adhesion capacity.

The application relates to a simulation method and platform dummy of a hub central piece crack acoustic emission signal, and the simulation method comprises the following steps: (1) preparing a standard fatigue test piece; (2) acquiring acoustic emission signals of a whole process of fatigue fracture of the standard fatigue test piece; (3) performing filtering and noise reduction pretreatment on the acquired acoustic emission signals; (4) generating simulation acoustic emission signals; (5) installing a hub central piece platform dummy on a model rotor test bed; (6) operating the model rotor test bed to complete rotor system hub central piece crack damage monitoring test verification; the waveform and spectrum characteristics of the crack acoustic emission signals are determined through fatigue fracture test of the hub central piece test piece made of the same material; the crack acoustic emission signals are simulated by using an acoustic emission signal waveform generator and a driver; finally, the simulation of the hub central piece crack acoustic emission signals is completed on the model rotor test bed, and the rotor system hub central piece crack damage monitoring test verification is realized.

The invention relates to the technical field of welding heads, in particular to a Pi-GPR-based welding head fatigue life prediction method and system, and the method comprises the steps: constructing an experiment system; welding materials are selected, welding parameters are set, and a cross section image of the welding test piece is collected; different gap sizes are set, stress-cycle number curve data are obtained, and fatigue testing is conducted on the welding test piece; performing correlation coefficient and total stress model analysis on the area and length characteristics of the welding seam; and constructing a Pi-GPR model, designing a Matern covariance function, and optimizing Gaussian parameters and covariance function hyper-parameters by using a logarithm marginal likelihood function. The problems that a traditional physical model is high in calculation complexity, long in analysis period and difficult to comprehensively cover physical phenomena related to fatigue fracture are solved.