272 results about "Strength design" patented technology

The invention discloses a service life based high-temperature container creep fatigue strength design method. The method comprises the steps of 1, performing structure preliminary design; 2 determining load and temperature conditions and the design service life requirement; 3, determining dangerous sections; 4, calculating the equivalent stress and strain range; 5, calculating reference stress; 6, determining whether plastic collapse occurs; 7 determining whether the plastic ratchet occur; 8, determining whether creep damage is important; 9, estimating fatigue damage of each cycle when the creep damage is not important; 10, determining whether the fatigue damage is important; 11, estimating the creep damage when the fatigue damage is not important; 12, estimating damage of each cycle when the creep damage and the fatigue damage are non-ignorable; 13, estimating creep-fatigue total damage; 14, performing result analysis and structural design improvement; 15, completing structural design. According to the method, the foundation is laid for national establishing of creep and fatigue failure mode based high-temperature pressure container design standards and achieving design and manufacture of high-temperature pressure containers according to the service life.

The invention belongs to the aircraft maintenance technology, and particularly relates to a repairing method for a honeycomb sandwich structure. The repairing method includes the steps that firstly, a placement layer and a honeycomb at the damaged portion are ground away, and a lower panel can not be damaged; secondly, a new honeycomb is prepared, and the surface of the honeycomb is glued; thirdly, the honeycomb is put in a cavity of the original honeycomb after being processed; and finally, placement layer replacement is carried out according to the original placement layer. Prepreg, glue film and glass cloth can not be spliced but in seamless butt joint. When the repaired structure is a surface concave as shown, the pneumatic outline can be repaired through filler. Raw materials are used for replacing the honeycomb and the placement layer, and the placement layer is repaired through a wet method. The strength design requirement is met, the structural weight after repairing is reduced, and good compatibility can be kept.

The invention discloses a comprehensive experiment platform for gear transmission strength design, which comprises a motor, a gearbox, a load and a computer processing module; the motor is connected with the load by the input shaft of the gearbox and the output shaft of the gearbox; a torque sensor is arranged on the transmission line between the motor and the gearbox, a gear to be tested in the gearbox is provided with gear strength test strain gauges, a to-be-tested gear output shaft on which the gear to be tested is mounted is connected with an angular displacement sensor, and the torque sensor, the gear strength test strain gauges and the angular displacement sensor are electrically connected with the computer processing module. By reasonably arranging the bending stress test strain gauge and the contact stress test strain gauge, the comprehensive experiment platform for gear transmission strength design can accurately measure out the contact stress and bending stress of the gear; because an attenuation-less rotary union is adopted as a signal output device, the contact stress signal and the bending stress signal can be more really, stably and reliably transmitted; and the replaceable gearbox ensures that the experimental teaching effect is more remarkable.

The invention discloses a load simulation method for a cataplane landing gear, and belongs to the field of strength design of the cataplane landing gear. The load simulation method mainly comprises the following steps: analyzing stress on the whole cataplane, a nose gear and a main landing gear of a cataplane, so as to establish a corresponding mechanic equilibrium equation; establishing a nose gear simulation analysis model, a main landing gear simulation analysis model and a whole cataplane dynamic simulation analysis model according to the nose gear mechanic equilibrium equation; finally, correcting the whole cataplane dynamic simulation analysis model according to testing gravity center data and a front main landing gear load curve during practical catapult launching of the cataplane. The corrected model is the model capable of being used for catapult launching load simulation of the cataplane, problems in load design and analysis of the landing gear during catapult launching of the cataplane are solved, and the flight test verification of a carrier-based aircraft in an aircraft carrier platform and a land-based training ground is guaranteed.

The invention discloses a triaxial stress strength designing method for a vertical well casing string. The triaxial stress strength designing method for the vertical well casing string comprises the following steps of: determining the steel grade, the wall thickness and the setting lengths of a first-section casing; performing internal pressure strength check and tensile strength check on the top of the first-section casing; calculating the setting lengths Lon and Lan of the first-section casing; and performing internal strength and extrusion strength check on the first-section casing till the designed well depth is met. By simultaneously considering the influence of coactions of an axial force, an external extrusion force and an internal pressure on the strength of the casing, the magnitude of the triaxial stress is calculated, an equivalent stress is calculated and supposed to be equal to the yield strength of the casing, and the strength of the casing is designed, so that the design is more reasonable and the designed vertical well casing string is more durable.

The invention discloses a centrifugal gas compressor impeller disc section shape optimization method. A parametric modeling mode is adopted in the centrifugal impeller disc section shape, the impeller disc section shape is described with fewest design parameters, and the impeller disc section shape is optimized by combining a neural network approximate model and an optimization design method, so that the equivalent stress of the impeller is effectively reduced by over 7.4 percent under the condition of ensuring that the weight of the impeller is not increased, and the work reliability of the impeller is improved. By the design method, the strength design period of the impeller is greatly shortened, the design result is reliable, and the design cost is saved; and the method has high socialbenefit and popularization value.

The invention belongs to the field of finite element modeling and relates to a finite element modeling simplification method of a honeycomb sandwich structure. The method comprises the following steps: partitioning the honeycomb sandwich structure according to the regionality of rigidity changes; performing mechanics equivalency according to the structural rigidity of different regions; partitioning a finite element grid according to the regions of the honeycomb sandwich structure; establishing spatial topological relation of a unit by use of finite element modeling software by a unit selection plate unit; filling honeycomb structure material property data; filling unit attributes of different regions according to the result of rigidity equivalency of the step 2, and finishing finite element modeling of the honeycomb sandwich structure. The method has the advantages that rigidity equivalency is performed on honeycomb stressed-skin structures of different regions, one honeycomb sandwich structure is simplified into multiple plate units with different rigidity, and simplification is performed respectively on in-plane rigidity and flexural rigidity according to rigidity equivalency, so that finite element modeling simplification of a honeycomb structure under a full-aircraft finite element model of an aircraft is realized, and the airplane structure strength design and calculation accuracy can be improved.

A long life fatigue strength design method for a metallic material is capable of allowing design of an optimum mechanical part according to a set service life by considering an increase in ODA (area affected by hydrogen observed blackish by a metallurgical microscope) size according to the assumed service life of the mechanical part. The method includes obtaining, from the results of a fatigue test, a functional relation between the number of stress cycles to failure and the size of a hydrogen affected area around an inclusion affected by trapped hydrogen. From the functional relation, equivalent defect sizes as the sizes of the inclusions after growth corresponding to the assumed number of cycles of working stress on the mechanical part using the metallic material are obtained, and the mechanical part is designed using the equivalent defect sizes in the calculation of a long life fatigue strength such as allowable stress, whereby a failure life design can be performed with the ODA size growth taken into account according to the assumed service life of the mechanical part.

The invention discloses a full depth buoyancy regulating seawater pump, which mainly comprises a flat valve module, a plunger piston shoe module, a plunger sleeve, a force transfer and reset mechanism and a pressure compensator, wherein the pressure compensator is used for balancing a lubricating cavity and environmental stress; the force transfer and reset mechanism drives the plunger piston shoe module to alternately cycle for a pressing travel and a sucking travel, so that the flat valve module alternately cyclically sucks water and presses water; the plunger piston shoe module has a fixed interval forced reset structure, so that a plunger is reset reliably; the force transfer and reset mechanism has a bidirectional stress structural design, so that the seawater pump meets the special working condition of regulating the buoyancy by the hydraulic pressure of seawater; and a stepped plunger is adopted, large and small plungers are connected through a spherical hinge, and the problems of strength design, sealing and frictional wear of the crucial friction pair, namely an ultrahigh pressure seawater pump are solved. The full depth buoyancy regulating seawater pump can regulate the buoyancy of a submersible in sea areas with all depth, and has the characteristics of simple structure, high applicability and working reliability.

The invention relates to a method for calculating the static strength of a cabin door structure and belongs to the field of airplane structures strength design. Static strength calculation is performed based on a linear contact analysis method, and a finite element model of the cabin door structure is firstly established; according to the cooperative relation of the cabin door structure and an airplane body structure, boundary conditions are determined; then, the loading conditions applicable to constraint conditions of the cabin door structure are determined according to the boundary conditions, finally constraint of a linear contact analysis model is performed, a constraint control file is established, and finally the result of linear contact constraint reaction is calculated. By comparing a calculation result of linear contact analysis with a calculation result of nonlinear contact analysis, the static strength of the cabin door structure can be more conveniently, quickly and accurately calculated through linear contact analysis.

The invention relates to a converter valve tower. The converter valve tower comprises valve tower bodies, supporting insulators for supporting the valve tower bodies and suspension devices for connecting the valve tower bodies and a suspension beam in a valve hall, wherein each suspension device comprises a suspension adjusting mechanism for adjusting the axial length, so that by the aid of the adjustment of the suspension adjusting mechanism, the valve tower bodies can be fixed through supporting force provided by the supporting insulators at the bottom and drawing force provided by the suspension devices, the suspension devices can greatly reduce the displacement and the stress of the valve tower under the action of seismic waves, the strength design requirement of the supporting insulators of the valve tower can be greatly reduced, more converter valve assemblies can be stacked on the valve tower as required, the number of the valve towers is reduced, and the area occupied by the valve hall is reduced; meanwhile, the supporting insulators at the bottom of the valve tower provide the supporting force, accordingly, the tensile stress borne by the suspension beam can be greatly reduced, the design requirement for the suspension beam of the valve tower is reduced, and the design difficulty of the valve hall is substantially reduced.

The invention relates to the technical field of construction waste recycling, and particularly discloses a design method of a cement stabilization recycled concrete aggregate (RCA) base or subbase. The design method comprises the steps: step one, determining materials and thicknesses of all structural layers of a pavement structure; step two, establishing a calculating model according to the materials and the thicknesses of all the structural layers, and determining the 7d cleavage strength design criteria and 7d unconfined compressive strength design criteria of the cement stabilization RCA base or subbase according to the calculating model; step three, carrying out the gradation composition design for the cement stabilization RCA on the base or subbase, and calculating and determining the design cement dosage Copt of the cement stabilization RCA, meeting the 7d cleavage strength design criteria and 7d unconfined compressive strength design criteria; the design is passed if Copt is smaller than or equal to 6%; if Copt is greater than 6%, the gradation composition design for the cement stabilization RCA is regulated to enable Copt to be smaller than or equal to 6%. By adopting the method, design is carried out rationally according to the technical nature of the construction waste RCA, the investment cost is low, use and operation are easy and simple, and the use effect is good.

The present invention provides a space manipulator full-state dynamic semi-physical simulation system, and relates to the field of dynamic physical simulation. The system comprises: a space manipulator controller module, a bus data conversion module, a space manipulator combined calculation module and a calculation result display and post-processing module. A space manipulator dynamic model is established by using ADAM software, a space manipulator speed parameter is output by the space manipulator dynamic model to MATLAB/SIMULINK calculation software to be calculated, and a calculation result map is generated by the calculation result display and post-processing module. The space manipulator full-state dynamic semi-physical simulation system is provided, the basis is provided for the mechanical structure strength design of a real space manipulator and the type selection design of a space manipulator transmission system, simulation verification is performed on a trajectory planning algorithm so as to assist in the motion planning based on space manipulator energy optimization.

A desk is designed for mounting to a wall or for mounting to either side of a door. The desk consists of a table surface attached via a hinge mechanism to the wall or door. When folded down into its utilized state, there is a leg support, with integral springs that supports the desk surface to the floor, wall or door. Additionally, a swing arm support supports the rear of the desk surface from the wall as well. Additional swing down components such as shelves, paper holders, and even a desk chair are also envisioned. All supporting hardware is of high-strength design and is locking for sure support. Any surfaces which may touch finished surfaces are provided with rubber bumpers for protection. The use of the desk allows those with limited floor space, or those who do not want the appearance of a permanent desk, to have a useful and functional desk to perform various activities that require a flat, horizontal surface almost anywhere in a home.

The invention discloses a universal damping device, relates to an energy dissipation damping device applied to building and bridge structures, particularly relates to energy dissipation support structures in the field of bridge engineering, and belongs to the technical field of structural engineering. The universal damping device comprises face plates and more than three leg plates. The face plates are geometrically circular or polygonal or can be geometrically in the shapes of regular polygons; the leg plates are geometrically in the shapes of U-shaped strips, and the appropriate quantity of the leg plates is equal to or larger than eight. The universal damping device has the advantages that the universal damping device is used for lateral force resisting systems of building and bridge structures and can be particularly used as a beam-bottom energy dissipation support for bridge structures, accordingly, plastic zones formed at arc-shaped sections of the leg plates in main deformation directions under uncertain multi-directional effects still can be guaranteed under random seismic effects, and effective universal damping effects can be realized; the universal damping device can be adjusted to have different lateral rigidity degrees in different directions by means of strength designs; the universal damping device is flexible in structure and reasonable in stress and has excellent technical and economical benefits.

The invention discloses a part service life prediction method comprehensively considering fatigue strength influence factors, and relates to the field of fatigue strength design, and the method comprises the following steps: (1) carrying out static analysis on a part structure by utilizing a finite element method, and determining a key dangerous point position with weak strength; (2) simulating acyclic load borne by the part, and obtaining a stress response process at a dangerous point; (3) calculating stress amplitude and average stress as damage parameters; (4) carrying out average stress correction by utilizing a Goodman equation; (5) determining a comprehensive fatigue strength factor; (6) predicting the fatigue life of the part; and (7) accumulating the fatigue damage of the materialby utilizing a Miner theorem, and when the fatigue damage of the material reaches 1, enabling the parts to fail. According to the method, the comprehensive fatigue strength factor is utilized to comprehensively consider the influence of the size and the surface state on the fatigue strength, the huge test amount for determining the size coefficient and the surface state coefficient can be avoided, and the design cost is reduced.

The invention discloses a fatigue life calibration method suitable for a structural connection piece, and belongs to the technical field of aircraft strength design. The method comprises the steps of1, establishing a stress spectrum of a key connection part; 2, calculating and establishing a stress severity coefficient of the connection part; 3, obtaining an S-N curve corresponding to the stressseverity coefficient of the key part; 4, determining a most sensitive parameter theoretical fatigue limit C in a nominal stress method; 5, performing optimization on the theoretical fatigue limit C; and 6, performing verification on the determined stress severity coefficient and the corresponding theoretical fatigue limit C. The life prediction under a load spectrum is performed by utilizing parameters obtained by optimization and a stress severity coefficient method, and the predicted and calculated stop life t' under the load spectrum and the actually measured life mid-value under the load spectrum are subjected to error comparison; and the life prediction under other load spectrums is performed by adopting the parameters obtained by the optimization and a nominal stress method through the verification, so that life calculation results under other load spectrums have relatively high precision.

The invention belongs to the field of airplane design and relates to a method for a verification test of combined loading of an airframe and an undercarriage. The method is characterized in that firstly, assessment of a load is conducted; secondly, a loading scheme is designed; thirdly, loading is tested; the load of the undercarriage serves as an examination working condition of a full-aircraft static test, combined loading of the airframe and the undercarriage is achieved in the full-aircraft static test, and an airframe structure static strength design envelope under the special working condition of the undercarriage can be fully verified.

The invention relates to a double-snap reversing ratchet wrench to solve the problems of the conventional ratchet wrench that a clutch device is complicated in structure, a plurality of components are arranged to cause low loading torsion, parts are positioned in a single way to cause high processing cost and the service life is short. The double-snap reversing ratchet wrench comprises a handle and a wrench body connected to one end of a stress application rod, and is characterized in that a ratchet perpendicular to the stress application rod is arranged in the wrench body; one end, facing the stress application rod, of the ratchet is provided with a direction switch; the direction switch comprises a direction handle and a steering body which is positioned below one end of the direction handle and is perpendicularly connected with the direction handle; two sides of the steering body are respectively provided with a snap; the bottom end of the steering body is provided with a spring hole seat; the wrench body at one end of the spring hole seat is provided with a cover plate. The double-snap reversing ratchet wrench is provided with a few parts, and is simple in structure and compact in integral structure, the positioning way between the components is flexible, a single component has sufficient strength design space, and the double-snap reversing ratchet wrench transfers large torque and is reliable, wear-resistant, easy to assemble and maintain, and easy and convenient to operate.

The invention provides a working device for extruding miniature thin-wall multi-hole flat pipes by using a multiple-step tower-shaped fishtail type core rod. A design mode of a tower-shaped fishtail type core rod is applied to a divergent die extrusion process of the miniature ultrathin-wall aluminum alloy flat pipes, the design is considered from the perspectives of increase of the contact area of metal in a welding-on region and improvement of welding-on possibility, and the overall dimension of the core rod is modified. The design idea facilitates the area of a material preparation region before welding-on through change of a series of cross-section shapes and design of a multiple-step cross-section transition region, the step number and the minimum critical dimension of the core rod can be designed for the divergent die extrusion of the miniature pipes according to the demands for different section bar cross sections and supporting strength of the core rods made from different materials, and an application range of the design idea of the core rod is not limited in section bars with certain shapes and is greatly widen in the production and application field of relevant aluminum alloy products. The dead-zone forming problem in a traditional process is also solved through selection of cross-section shapes in the design, and the design reasonability is further improved. The working device for extruding the miniature thin-wall multi-hole flat pipes by using the multiple-step tower-shaped fishtail type core rod has wide application prospect.

The invention discloses a structurally integrated cement stabilized gravel base layer or subbase layer design method. The method includes steps: working out a pavement structure combination; establishing a calculation model, and determining an age and modulus of each structural layer in the model; calculating a bottom layer tensile stress of a cement stabilized gravel base layer or subbase layer; determining a 7d compressive strength design standard [Rc7] and a 7d splitting strength design standard [Rs7]; designing mineral aggregate gradation; determining a maximum dry density Rhomax and an optimum water content wo of a cement stabilized gravel mixture material; testing a 7d unconfined compressive strength Rc7 and a 7d splitting strength Rs7, and determining a cement addition quantity which meets requirements that Rc7 is larger than or equal to [Rc7] and Rs7 is larger than or equal to [Rs7], so that designing is completed. The method has advantages of low input cost, simplicity and convenience in use and operation, great utilization effects and effectiveness in solving of problems of disjunction with pavement structures and proneness to shrinkage cracking of existing cement stabilized gravel design.

The invention discloses a prediction method for residual stress and damage caused by stress relaxation of a high-temperature material. The predication method mainly comprises the following steps: based on two creep deformation damage models and a stress relaxation strain model, establishing a corresponding stress relaxation continuous damage model; acquiring the material creep deformation performance data of a high-temperature component material at a temperature; based on the creep deformation performance data, fitting out corresponding material constants corresponding to the two creep deformation damage models; and by employing a data analysis technology and through program calculation, solving the stress relaxation continuous damage model, and finally converting the creep deformation data into stress relaxation data, so as to obtain a stress relaxation curve and a stress relaxation damage cure, and further to predict the residual stress and the damage degree caused by the stress relaxation of the high-temperature material. According to the method, the precise association of obtaining the relaxation behavior from the creep deformation data is established, and the complete prediction method for residual stress and damage caused by stress relaxation of the high-temperature is established, and a new approach is provided for stress relaxation strength design and management maintenance of high-temperature components.

The invention provides a TJC buckling restrained bracing member which is also called as a TJC buckling restrained brace. The TJC buckling restrained bracing member is characterized by comprising a core material part and supporting end part nodes, wherein the core material part is composed of a plurality of core veneers, while the supporting end part nodes are composed of a plurality of stiffening ribs; the first end surface of the two ends of each supporting end part node is at least provided with a first groove matched with the core material part; and the core material part is inserted into the first groove, so that the core material part is connected with the supporting end part nodes. According to the TJC buckling restrained bracing member provided by the invention, high-strength steel is adopted for the supporting end part nodes and low-strength steel or low-yield point steel is adopted for the core material part, so that the steel consumption quantity is reduced; the stiffening ribs of the supporting end part nodes penetrate through a sleeve so that the stability design is uncoupled with the strength design; the bending resistance ability of a supporting node is improved through an outer node hoop; and the breakage of the buckling restrained brace under heavy vibration is avoided through the design of locking plates and steel angles.

The invention discloses a method for load distribution of connection hinge joints of a fuselage and empennages based on load of a vertical empennage and relates to the technical field of aircraft structural strength design. The method for the load distribution of the connection hinge joints of the fuselage and the empennages based on the load of the vertical empennage comprises the following steps of step 1.creating a mathematical calculation model based on the load of the vertical empennage of the empennages according to the force transfer characteristics of a connection area of the back fuselage and the tail empennage of an aircraft; and step 2.computing a theory resolution of the load distribution of the connection hinge joints of the connection area of the tail empennage according to the model established in the step 1 and determining the relationship among a lateral distance between the connection joints and a symmetry plane of the aircraft, overall stiffness of the connection hinge joints and a vertical load value of the connection points. The method has the advantages that through application of a mathematical modeling method and creation of the mathematic model and an equation, the key factors for affecting the load distribution of the connection hinge joints of the connection area are explored, the algebraic relation between the factors is proposed, and meanwhile, the theory resolution and an optimal solution of the load distribution of the hinge joints of the connection area are quickly and effectively determined.