64 results about "Tangential stress" patented technology

The present disclosure relates to the technical field of stability control of surrounding rock of tunnelling, and provides an excavation compensation method for tunnelling in deep rock engineering, including: acquiring an engineering geological information of the tunnelling in deep rock engineering; determining an engineering hazard type based on the engineering geological information; determining an excavation compensation support strategy for the surrounding rock of the tunnelling in deep rock engineering based on the engineering hazard type; and performing a supplementary support control on the surrounding rock of the tunnelling in deep rock engineering based on the excavation compensation support strategy. Through the supplementary support strategy, the difference value between a radial stress of the surrounding rock of the tunnelling in deep rock engineering and an initial crustal stress can be reduced to within a preset approximate value range, further effectively preventing a stress concentration phenomenon occurred in a tangential stress.

The invention discloses welding equipment for a high-strength steel plate welding structural part, and relates to the technical field of high-strength steel plate welding. Welding seam metal between the two high-strength steel plate bodies is hammered and rotated through the spherical hammer head, the welding seam metal can generate plastic deformation through the hammering effect, crystalline grains of the welding seam metal can be refined through the plastic deformation, pressure stress is generated in a welding seam, the possibility of cold crack generation is reduced, and the welding quality is improved. In the knocking process, along with rotation of the spherical hammer head, hammering force generates a tangential stress component on the surface of the weld joint, the tangential stress can enable weld joint metal to be subjected to certain compression and rubbing effects in the horizontal direction, the weld joint and base metal can be better combined more tightly, and the welding quality is improved. And the situation of cold cracks possibly caused by interlayer tearing and the like is further avoided.

The invention discloses a research method for a crack evolution law of fractured rock under thermal-mechanical coupling, and belongs to the technical field of rock mechanics. Aiming at the problem that most indoor tests and numerical simulation at present still lack systematic research on crack initiation, polymerization and failure behaviors of cracks in a multi-crack rock mass under the action of high temperature-stress coupling, the method comprises the following steps: defining an interaction coefficient and a thermal damage influence coefficient between the cracks on the basis of a tangential stress distribution theory around the cracks; establishing a tangential stress model sum of the inner and outer surfaces of the crack comprehensively considering the coupling effect of the two to predict a potential crack initiation position; based on a crack mode displacement decomposition method, defining a displacement ratio coefficient gamma, and quantifying a displacement field of rock material cracks; on the basis, the rock sample is subjected to mechanical test and PCF numerical simulation, and the crack evolution law of the rock sample containing the prefabricated crack under thermal-mechanical coupling is researched. Theoretical support and experimental basis can be provided for stability evaluation and safety control of deep high-temperature rock mass engineering.

The invention discloses a full-section tunnel boring machine capable of preventing rockburst and a construction method of the full-section tunnel boring machine. A plurality of stone cutting machines are arranged in the area where the disc face of a cutter disc is located and used for forming kerfs in a tunnel face and a tunnel wall; a rockburst micro-seismic monitoring system is arranged behind the shield and connected with a plurality of sensors, and the sensors are distributed on the two sides of the kerf in the tunnel wall. The full-face tunnel boring machine capable of preventing rockburst can cut the tunnel face and the tunnel hole wall, so that the tangential concentrated stress of the excavation tunnel face and the tunnel hole wall is effectively transferred to deep surrounding rock, and the tangential stress concentration level of the tunnel face and the tunnel hole wall is reduced; meanwhile, reduction of surrounding rock stress concentration degree and maintenance of completeness and stability of the surrounding rock are effectively combined. The full-face tunnel boring machine for preventing rock burst can organically combine joint cutting construction and tunneling, tunnel wall joint cutting operation can be carried out while TBM tunneling is carried out, safe and efficient construction is achieved, construction is convenient and fast, and disturbance to surrounding rock is small.

The invention discloses a grinding piece, and relates to the technical field of grinding pieces, the grinding piece comprises a base body layer and a wear-resisting layer, the wear-resisting layer comprises wear-resisting pieces and supporting blocks which are alternately distributed, and the wear-resisting pieces and the supporting blocks are directly installed on the base body layer; the wear-resisting layer is composed of the wear-resisting piece and the supporting block which are installed on the base body layer, the supporting block can support the wear-resisting piece from the side direction of the wear-resisting piece, and therefore the tangential stress bearing capacity of the wear-resisting piece is improved, the overall hardness and toughness of the grinding face are guaranteed, and the grinding face is not prone to cracking or cracking or other defects. Meanwhile, the wear-resistant layer is detachably mounted on the base body layer, so that the wear-resistant layer can be independently replaced in a conventional state, the base body layer is reserved, and more cost is saved; and in addition, during use, the wear-resisting unit can abut against the interior of the mounting groove by inertia or friction force and cannot fall off.

A risk assessment and control method for radial cracking and crack propagation and transfixion of cement sheath in fracturing wells is provided. Based on the thermo-solid coupling theoretical model of casing-cement sheath-formation combination and thick-walled cylinder theory, the tangential stress distribution of crack-free cement sheath when fracturing is obtained, the maximum tensile stress criterion is used to judge whether the cement sheath has radial initial cracking when fracturing and calculate the initial cracking length, based on the weight function method, the stress intensity factor of the tip of the radial initial cracking of the cement sheath when fracturing is calculated, the fracture mechanics criterion is used to judge whether the radial crack propagation and transfixion will occur in the cement sheath, and the performance parameters of the cement sheath are controlled by the double standards of preventing the radial cracking of the cement sheath and controlling the crack propagation.

The invention discloses a pile-soil interface shearing algorithm considering related characteristics of a soil body state. The pile-soil interface shearing algorithm is suitable for calculating pile side friction resistance after a pile foundation is driven in offshore engineering. The method mainly comprises the following steps: (1) transferring stress and strain tensors obtained by calculation of a constitutive model considering that rigidity and strength parameters of a soil body change along with the state of the soil body to a soil and structure interface shear model; (2) assuming that a soil and structure contact interface is in a simple shearing state, and iteratively solving the normal strain of the interface; and (3) calculating the normal stress and the interface tangential stress through the calculated normal strain, and considering the influence of the strength change of the pile-side soil body on the interface shear strength. According to the method, the soil constitutive model related to the state is introduced on the basis of traditional coulomb friction, constitutive responses of the soil in different confining pressure and shear strain states can be reflected, pile-soil interface mechanical behaviors are calculated, and the influence of soil characteristics on the interface behaviors is reflected more reasonably.

The utility model belongs to the technical field of micro-driving equipment, and provides a piezoelectric actuator which comprises a shell structure, a piezoelectric structure, a motion guiding structure and a transmission output structure, the shell structure is internally provided with a containing space with a first opening, and the piezoelectric structure is connected to the bottom of the containing space; the transmission output structure is located at the first opening to output the displacement generated by the piezoelectric structure, and the motion guide structure is located between the transmission output structure and the piezoelectric structure and used for providing motion guide for the piezoelectric structure and separating the piezoelectric structure from the transmission output structure, so that the transmission effect of tangential stress is reduced; and a connecting groove is formed in the motion guide structure, so that the length of a force arm of the piezoelectric structure is reduced, the risk of damage to the piezoelectric structure is further reduced, the deflection angle can be reduced, and the guide effect is improved. Therefore, the piezoelectric actuator has excellent structural stability, working reliability and applicability, and can adapt to various complex application scenes.

The invention discloses a seismic data-based pre-drilling evaluation method and device for vertical well wall stability. The method comprises the following steps of: obtaining related data of pre-drilling well drilling design of a target well; pre-stack and post-stack seismic inversion is carried out, and stratum elastic parameters of the target well position are obtained; calculating formation pressure and ground stress parameters of the target well position based on the formation elastic parameters; obtaining the strength parameter, cohesion and internal friction angle of the stratum rock at the target well position through a rock physical test experiment or based on the stratum elastic parameters; carrying out numerical simulation on the stability of the well wall around the well to obtain vertical stress, tangential stress and radial stress in different directions around the well; and analyzing the magnitude relationship of the vertical stress, the tangential stress and the radial stress along different directions of the well circumference so as to judge the tensional failure and the shear failure possibly occurring around the well circumference in the drilling process, and completing the pre-drilling evaluation of the well wall stability of the drilling well. According to the method, the pre-drilling evaluation of the vertical well wall stability can be realized.

The present invention discloses a self-sensing sliding friction characteristic modeling and control optimization method and device for unstructured terrain, including: S1. establishing a normal stress distribution model and a tangential stress distribution model when the wheel contacts the lunar soil; S2. adjusting the normal stress distribution model and the tangential stress distribution model based on the friction characteristics of the lunar soil, and establishing a sliding friction characteristic model based on the physical characteristics of the lunar soil; S3. correcting the traction force and driving torque of the wheel based on the sliding friction characteristic model, and feeding back into the PID control model, dynamically adjusting the control input through the error signal of the wheel speed, so as to accurately control the movement process of the lunar rover in real time; the present invention dynamically introduces the physical characteristics of the lunar soil into the modeling of the friction coefficient, and realizes accurate control of the lunar rover's driving process through the coupling of the dynamic state of the wheel and the dynamic feedback mechanism of the PID control, providing theoretical and technical support for the stable driving of the lunar rover in the complex lunar environment.

The invention relates to the technical field of railway engineering wheel-rail relationship, and provides a steel rail irregularity limit value determination method considering impact dynamics and material stability, which comprises the following steps: step 1, establishing a geometric irregularity model of any steel rail surface, and solving wheel-rail impact force at the irregularity of the steel rail surface by combining a vehicle-rail coupling system dynamics model; 2, establishing a wheel-rail rolling contact numerical model, and calculating normal and tangential stress distribution during wheel-rail contact; 3, determining a material constitutive model, establishing a rolling contact two-dimensional finite element model, calculating stress-strain time history data of the steel rail, and determining a material stability state of the steel rail; and 4, comprehensively considering the steel rail material, the traction coefficient, the friction coefficient and the wheel-rail contact state, considering the impact dynamics and the material stability service behavior, and forming a steel rail surface geometric irregularity limit value table. According to the method, the irregularity limit value of the steel rail can be well determined.

The invention provides high-precision body surface soft tissue multi-dimensional material property in-vivo detection equipment, which is characterized in that a rotating unit is arranged on a base, and a tension and compression stress-strain detection unit, a shear stress-strain detection unit and a torsion stress-strain detection unit are respectively arranged on the rotating unit; the tension and compression stress-strain detection unit is used for loading and measuring vertical tension and compression stress on the body surface soft tissue; the shear stress-strain detection unit is used for loading tangential stress to the body surface soft tissue and measuring the tangential stress; the torsion stress-strain detection unit is used for loading torsion stress on the body surface soft tissue and measuring the torsion stress, and the control unit is used for controlling the rotating unit to rotate and stop, and switching the tension-compression stress-strain detection unit, the shear stress-strain detection unit and the torsion stress-strain detection unit to measure the body surface soft tissue. In a word, the method can realize detection of multi-dimensional mechanical properties, and the size of the device is reduced.

To provide a wheel flat estimating device, a wheel performance testing device and a key control device for evaluating a wheel re-adhesion control method for allowing proper wheel sliding having the possibility of damaging a wheel and a rail.SOLUTION: The wheel flat estimation device 10 includes a motion analysis part 20 for calculating various parameters by analyzing the behavior between a wheel and a rail when the wheel is fixed, a frictional heat analysis part 30 for calculating the temperature of the tread of the wheel when the wheel is fixed by frictional heat analysis, and a calculation part 30 for calculating the wheel flat based on the calculated temperature of the tread and reference data. The shape estimation device includes a yield stress calculation unit 40 that calculates a wheel yield stress of a wheel, an area calculation unit 50 that calculates an area of a contact ellipse between the wheel and a rail, a comparison unit 60 that compares a magnitude relationship between a tangential stress calculated from a tangential force and the area of the contact ellipse and the wheel yield stress, and an estimation unit 70 that estimates, as a wheel flat shape, a contact ellipse having a minimum area in which the wheel yield stress is determined to be larger than the tangential stress by the comparison in the comparison unit 60.SELECTED DRAWING: Figure 1

A method of producing a centrifugal compressor impeller is provided. The impeller includes a hub with a rotational axis, a forward surface, and an aft surface. The aft surface extends between an outer radial surface of the impeller and a bore centered on the rotational axis. The method includes: analyzing the impeller to determine a stress field having tangential stress data values and radial stress data values as a function of radial position within the impeller hub and as a function of axial position within the impeller hub; contouring the aft surface so that the impeller hub has radial stress data values less than tangential stress data values for any radial position of the hub during operation of the impeller; and producing the impeller with the contoured aft surface.

The invention provides a strong tectonic stress rockburst section tunnel arch curve design method, and relates to the technical field of high crustal stress tunnel rockburst prevention and control. The method specifically comprises the steps that the basic building limit requirement of a tunnel is obtained, and the transverse maximum width and the vertical maximum height of a tunnel arch curve are determined according to the basic building limit requirement; determining a horizontal crustal stress, a vertical crustal stress and a surrounding rock grade perpendicular to the axial direction of the tunnel hole through crustal stress measurement, and calculating a lateral pressure coefficient; if the lateral pressure coefficient of the tunnel is not smaller than 1 and the surrounding rock grade is III or above, it shows that strong tectonic stress exists in the tunnel area, and then an arch curve of the tunnel is constructed; and drawing a tunnel cross-section diagram of the tunnel based on the arch curve of the tunnel. According to the method, the tunnel arch profile curve is optimized through the elliptic equation, and the problem that tangential stress concentration is likely to be generated in the design of an arc-shaped arch crown of a conventional tunnel section under strong tectonic stress is solved.

The utility model relates to an olivary air hole alloy saw blade. The olivary air hole alloy saw blade comprises a base body and tool bits. An olive-shaped air hole is formed in the middle of the base body; the air holes are uniformly distributed along the circle center of the substrate; each air hole is composed of two semi-ellipses with coincident long axes. 1 / 2 of the long axis of the ellipse close to the outer circle of the base body is C1, 1 / 2 of the long axis of the ellipse close to the center position of the base body is C2, and C2 is larger than or equal to C1; the dimension of the short axis is B, B: (C1 + C2) = 0.25-0.75, and the long axis of the ellipse is arranged along the radial direction of the base body; the distance between the outermost vertex of the outer ellipse of the air hole and the bottom circle of the chip pocket of the base body is L, and L is larger than or equal to 10% * D2 and smaller than or equal to 20% * D2; the distance between the innermost vertex of the ellipse in the air hole and the center of the base body is L1, and L1 is larger than or equal to 15% * D2 and smaller than or equal to 25% * D2; the beneficial effects of the utility model are that the olivary air holes are closer to the sector, which is beneficial to the uniformity of tangential strain in the radius direction and improves the additional tangential stress generated by uneven tangential strain in the radius direction; the curvature radius of the radial edge of the olive-shaped air hole is large, so that the circumferential pressure stress is released more thoroughly.

The application relates to a semi-analytical method for analyzing the response of deep-buried tunnel excavation, which comprises the following steps: step 1) establishing a deep-buried circular tunnel excavation mechanical model, and solving the stress at the elastic-plastic boundary in the model by using a numerical method, wherein the stress comprises three components, namely radial stress, tangential stress and axial stress; step 2) dividing the plastic zone into n circular rings based on the finite difference method, and sequentially solving the stress components of each circular ring from the elastic-plastic boundary to the tunnel wall; step 3) solving the radius of each circular ring based on the stress components of the circular rings and the balance equation; step 4) decomposing the strain components, and solving the strain components of each circular ring based on the finite difference method; and step 5) solving the radial displacement based on the strain components. Compared with the prior art, the application has the advantages of improving the calculation efficiency of the three-dimensional semi-analytical method of finite difference.

The invention discloses a method for transferring tangential concentrated stress of an excavated tunnel face and a tunnel wall to deep surrounding rock. The method comprises the following steps: cutting joints on the tunnel face and the tunnel wall surrounding rock along the direction of minimum principal stress; continuously observing the convergence deformation of the surrounding rock after joint cutting, monitoring the fracture and rockburst characteristics of the surrounding rock, and evaluating the effect that the joint cutting transfers the concentrated stress to the deep surrounding rock and reduces the stress concentration level of the surrounding rock of the tunnel excavation hole; and if the width of the kerf is too large and the kerf is not closed in the later period, the kerf is filled with cement paste. According to the method for transferring the tangential concentrated stress of the excavation tunnel face and the tunnel wall to the deep surrounding rock, the tangential concentrated stress of the excavation tunnel face and the tunnel wall can be effectively transferred to the deep surrounding rock through a simple joint cutting mode which is designed in a targeted mode, the tangential stress concentration level of the excavation tunnel face and the tunnel wall is reduced, construction is convenient, disturbance to the surrounding rock is small, and the construction efficiency is improved. Reduction of stress concentration degree of surrounding rock and maintenance of completeness and stability of the surrounding rock are effectively combined.

To provide a friction welding structure that can enhance the strength of welded components after joining.SOLUTION: A first workpiece comprises a workpiece body and a first welded structure, and a second workpiece comprises a second workpiece body and a second welded structure. Both the first welded structure and the second welded structure are positioned between the first workpiece body and the second workpiece body. The first welded structure has a first lateral mating surface, and the second welded structure has a second lateral mating surface. The first lateral mating surface and the second lateral mating surface are in contact with each other and are fusion-bonded by relative motion between the first workpiece and the second workpiece. Since the first lateral mating surface and the second lateral mating surface that perform friction are parallel to a first direction, when the first workpiece and the second workpiece tend to separate from each other, tangential stress is generated between the first lateral mating surface and the second lateral mating surface, whereby the first workpiece and the second workpiece can be joined more firmly.SELECTED DRAWING: Figure 2

The invention relates to the field of tunnel engineering rockburst grade classification methods, and provides a rockburst grade classification method and system considering rock mass quality and blasting damage. The method comprises the following steps: measuring the tangential stress of the surrounding rock by adopting a stress relieving method; the method comprises the following steps: punching a surrounding rock of an excavation line, carrying out sound wave detection on the surrounding rock after blasting, and measuring the sound wave longitudinal speed of each position in a hole and the sound longitudinal wave speed of an undamaged rock mass; calculating a geological strength index and a disturbance factor based on the acoustic longitudinal velocity and the acoustic longitudinal wave velocity of the undamaged rock mass; calculating a rock mass deformation modulus according to the geological strength index and the disturbance factor so as to further calculate the uniaxial compressive strength; calculating a shear stress rockburst evaluation standard according to the tangential stress and the uniaxial compressive strength of the surrounding rock; and multiplying the first rockburst breakage coefficient, the second rockburst breakage coefficient, the third rockburst breakage coefficient and a shear stress rockburst evaluation standard to obtain a shear stress rockburst evaluation standard after breakage, so as to judge the grade of the rockburst.

The invention relates to a multi-axial fatigue prediction method and medium based on non-linear coupling of normal and shear strain energy, and the method comprises the steps: calculating the normal strain and tangential strain of each group of experimental results at each angle under a loaded condition by using the fatigue experimental results of a to-be-predicted material, finding out the plane where the maximum shear strain amplitude of the maximum normal strain is located, and calculating the maximum shear strain amplitude of the maximum normal strain; taking as a critical surface; calculating each stress-strain component on the critical surface; acquiring material and shear performance parameters of a to-be-predicted material, and predicting by adopting the fatigue prediction model in combination with each stress-strain component; the model building process comprises the following steps: performing nonlinear coupling on normal strain energy and shear strain energy, obtaining a fatigue damage parameter by combining an average normal stress correction coefficient and an average tangential stress sensitivity coefficient, and obtaining a fatigue prediction model by combining the fatigue damage parameter with a fatigue damage equation in a shear form. Compared with the prior art, the method has the advantages of being high in fatigue life prediction precision, suitable for proportional and non-proportional loading, high in safety and the like.

The invention discloses a stress and rigidity analysis method under a multi-waveform diaphragm disc angular load, which comprises the steps of defining geometric and working condition parameters, constructing a segmented deflection model, establishing a non-axisymmetric stress analysis model and deducing an angular rigidity analysis formula. Deducing a deflection expression of the maximum deformation section by segmenting the corrugated molded line and setting continuous conditions of displacement, slope and curvature; establishing a bending-torsion coupling model through a cylindrical coordinate system, and obtaining radial, circumferential and tangential stress analytic expressions in combination with Hooke's law; and the total bending moment is solved by performing circumferential integration on the infinitesimal bending moment and the shearing force, and the angular stiffness is calculated, so that integrated analytic solution of the deflection, the stress and the stiffness is realized. According to the method, high-precision prediction of the angular mechanical behavior of the complex corrugated diaphragm disc is achieved, the calculation efficiency is high, the result is stable and consistent, a large amount of finite element iteration can be effectively replaced, and a reliable tool is provided for structural optimization and engineering design of the diaphragm disc coupler.

The invention belongs to the technical field of piezoelectric ceramics, and provides a piezoelectric device test device and test method.The piezoelectric device test device comprises a bearing assembly and a test assembly, the bearing assembly comprises a first bearing plate, a second bearing plate and a bearing back plate, and the first bearing plate and the second bearing plate are connected to the bearing back plate at intervals in the first direction; the test assembly is located between the first bearing plate and the second bearing plate and sequentially comprises a first flexible supporting piece, a second flexible supporting piece, a top end clamping plate and a force application structure, the piezoelectric device is arranged between the first flexible supporting piece and the second flexible supporting piece, the first flexible supporting piece and the second flexible supporting piece have rigidity in the first direction, and the top end clamping plate is arranged between the first flexible supporting piece and the second flexible supporting piece. The piezoelectric device has flexibility in the second direction and the third direction perpendicular to the first direction, decoupling of tangential stress and normal stress is achieved, the protection effect on the piezoelectric device is improved, the force application structure applies prestress or bearing stress to the piezoelectric device, the piezoelectric device is prevented from being damaged by dynamic stress, and the piezoelectric device testing device is suitable for testing of products of various specifications.

A method of producing a centrifugal compressor impeller is provided. The impeller includes a hub with a rotational axis, a forward surface, and an aft surface. The aft surface extends between an outer radial surface of the impeller and a bore centered on the rotational axis. The method includes: analyzing the impeller to determine a stress field having tangential stress data values and radial stress data values as a function of radial position within the impeller hub and as a function of axial position within the impeller hub; contouring the aft surface so that the impeller hub has radial stress data values less than tangential stress data values for any radial position of the hub during operation of the impeller; and producing the impeller with the contoured aft surface.

The invention provides a tunnel double-layer primary support construction opportunity calculation method and device, equipment and a medium, and relates to the technical field of civil engineering. Constructing based on the initial ground stress and a displacement expression generated after a preset support structure is constructed to obtain a support force expression provided by a first layer of primary support; performing optimization construction according to a tangential stress expression at the boundary of the viscoplastic zone of the tunnel, a support force expression provided by the first layer of primary support and the peripheral displacement of the tunnel wall to obtain a construction opportunity function; constructing according to the construction opportunity function and a preset physical constraint condition to obtain a target loss function; and constructing based on the target loss function and a preset transcendental equation method to obtain a transcendental neural network model, and solving the transcendental neural network model to obtain the optimal support opportunity of the initial stage of the second layer. The method solves the problem that in the prior art, the optimal initial supporting opportunity of the double layers of the tunnel cannot be rapidly and accurately obtained, and the construction safety of the tunnel is guaranteed.

The invention discloses a multidirectional dynamic strain detection structure, and belongs to the technical field of functional structures. The multidirectional dynamic strain detection structure comprises a regular hexagonal structure frame, a crank sliding block mechanism, a mechanical push rod mechanism and a fixing structure. Through the combination of the regular hexagonal structure frame, the crank sliding block mechanism and the mechanical push rod mechanism, independent movement or micro rotation of each part can be realized under the limitation of a wedge angle, so that multi-directional dynamic strain detection is completed. And the wedge angle is used as a fulcrum, so that the adjacent beams of the regular hexagonal structure frame symmetrically deform and accumulatively deform when being stressed, and the detection structure has relatively high flexibility and adaptability. The piezo-electric crystal material is in contact with or separated from the electrode through the movement of the piston push rod, voltage reactions at different positions are generated, and the voltage signals can reflect strain changes in all directions after being processed by the multi-channel charge amplifier. And through the design of the six-claw fixing plate and the fixing plate, the strength of the structure is improved, meanwhile, the self-adaptive capacity of the structure is enhanced, the influence of tangential stress on the structure is reduced, and the service life is prolonged.

The present invention discloses a method and system for obtaining the failure probability of TRISO-type fuel particles, relating to the technical field of nuclear reactor accident safety analysis. The method comprises the following steps: obtaining the temperature, internal pressure generated by the amount of fission gas released, and external pressure at any location in a TRISO-type fuel particle model; obtaining multiple strain types of the material behavior of the pyrolytic carbon layer in the TRISO-type fuel particle model under irradiation conditions, constructing a strain model, and obtaining radial and tangential stresses at any location based on the strain model; determining the tensile stress of the pyrolytic carbon layer on the SiC layer using the radial or tangential stress at any location, and obtaining the failure probability based on the tensile stress. The present invention considers the effect of creep and swelling of the pyrolytic carbon material caused by irradiation on the tangential tensile stress of the SiC layer, performs a comprehensive mechanical assessment of the fuel structure, and significantly improves the accuracy of predicting the failure probability of TRISO-type fuel particles.

The application provides a method for determining the supporting time of underground caverns, which is based on the crack closure degree to determine the supporting time of rock mass at each part of surrounding rock in the time-dependent deformation process. For the cavern surrounding rock in the low confining pressure compression state, the crack closure degree C3 in the radial stress direction is taken as the time-dependent supporting basis of the surrounding rock. The crack closure degree C3 changes with time in three cases. By setting anchor cables and anchor rods, additional radial compressive stress can be provided to compensate for the radial stress released by the surrounding rock, thereby reducing the difference between the tangential stress and the radial stress, maintaining the crack closure degree in a non-destructive stage, and ensuring the safety and smooth progress of the underground cavern construction. Such measures help to maintain the stability of the surrounding rock and can optimize the supporting design, improve the engineering efficiency and safety.

The present invention relates to the field of liquid-filled deep drawing of thin-walled curved surface parts. An auxiliary plate is added to assist the forming of the lower sheet material, and radial stress is applied to the upper auxiliary plate to promote its preferential deformation, thereby improving the forming quality of thin-walled parts. The preformed sheet material and the auxiliary forming sheet material are placed on the die in turn, the punch is lowered to a position flush with the upper plate and kept stationary, hydraulic pressure is applied to perform the pre-expansion process of the sheet material, and a reasonable liquid chamber pressure is loaded after the pre-expansion pressure value. At the same time, the punch is lowered to perform the liquid-filled deep drawing process, and a fixed radial pressure is applied to the upper sheet material through a special-shaped stepped push rod during these two processes. Therefore, the risk of instability and wrinkling in the suspended area of ​​the sheet material can be significantly reduced through the auxiliary support of the upper sheet material and the suppression of the tangential stress of the sheet material by the soft draw ribs formed in the pre-expansion stage. In addition, the auxiliary sheet material is deformed in advance under radial pressure, which can better drive the lower sheet material to be uniformly formed and improve the forming quality of the sheet material.