56 results about "Back stress" patented technology

An apparatus used during weighted barbell exercises for reducing body stress on the wrists and lower back comprises identical assemblies mounted for rotation on the end sleeves of the barbell. Weights are suspended on the assemblies below the barbell. Each assembly comprises first horizontal tubular member having a sidewall defining an annulus adapted to receive the barbell end sleeves; a vertical extension member welded perpendicular to the first horizontal tubular member; and, a second horizontal member, parallel to the first horizontal tubular member welded to and suspended from the vertical extension member for carrying the weights. During the lift and recovery, the apparatus keeps the combined dynamic centers of gravity of the weights and apparatus close to the body reducing back stress. The apparatus reduces wrist stress by minimizing torque about the wrist.

The invention relates to a six-dimension force sensor calibration device with medium measurement range, which comprises a rotary table base vertically arranged at one end of a working platform through bolts, wherein the front of the rotary table base is provided with a rotary table turnplate and the side is provided with a rotary table handle, and the rotary table turnplate drives an adapter plate, a six-dimension force sensor and a loading plate to rotate together through rotating the rotary table handle, wherein the adapter plate, the six-dimension force sensor and the loading plate are arranged on the rotary table turnplate. Weights with different masses and numbers are respectively hung on a back stress-applying level, a front stress-applying level and a center stress-applying level of the loading plate through drop hangers and ropers so as to realize the loading of Fx, Fy, Mx, My and Mz of the six-dimension force sensor, the adapter plate provided with the six-dimension force sensor and the loading plate is taken down from the rotary table turnplate to be arranged in a circular unthreaded hole chiseled on the working platform to calibrate the Fz. The invention has simple structure, convenient operation and high calibration precision, ensures that the position and the direction of point of loading force application are accurate through mechanical design and processing and installing precision, and is suitable to the calibration and the test of the six-dimension force sensor with medium measurement range.

The invention relates to a calibration method for a six-dimension force sensor calibration device with medium measurement range. When in calibration, a rotary table handle is rotated, a rotary table turnplate drives an adapter plate, a six-dimension force sensor and a loading plate to rotate together, wherein the adapter plate, the six-dimension force sensor and the loading plate are arranged on the rotary table turnplate; the rotating angle is controlled by the rotary table handle and is read form scale on the rotary table turnplate; weights with different masses and numbers are respectively hung on a back stress-applying level, a front stress-applying level and a center stress-applying level of the loading plate through drop hangers so as to realize the independent loading and the compound loading of Fx, Fy, Fz, Mx, My and Mz of six force or moment componenets through the change of loading positions, a loading matrix and a corresponding output matrix of the six-dimension force sensor are obtained and are performed the decoupling computation to obtain a coupling matrix, i.e. the calibration of the six-dimension force sensor is completed. The invention has simple structure, convenient operation and high calibration precision, and is suitable to the calibration and the test of the six-dimension force sensor with medium measurement range.

The invention discloses a method for establishing a crystal plastic constitutive model in a face-centered cubic material fatigue process. According to the method, the problem that mesoscopic scale plastic evolution and material microstructure characteristics cannot be considered in the process of calculating material damage and fatigue failure is solved, and a more accurate and innovative mesoscopic crystal modeling method, a crystal plastic constitutive model and related stable and efficient calculation methods are provided. According to the crystal plastic constitutive model and the calculation method, the normal direction and the sliding direction of the crystal sliding face are considered, the back stress effect is considered through the motion and isotropic hardening criterion, and finally the face-centered cubic metal material crystal plastic constitutive model of the crystal sliding and dislocation density and plastic shear strain rate function relation is established. The influence effect and contribution degree of the microscopic characteristics of the material on the damage and fatigue life of the material can be studied from the mesoscopic scale, important theoretical guidance and technical support are provided for studying the damage evolution and fatigue failure process of the material, and the method has important scientific significance and engineering application value.

The invention discloses a customized insole preparation method based on biomechanics. The method comprises the steps that a motion condition and a sole pressure distribution condition of a user are subjected to three-dimensional motion collection and dynamics measurement respectively, wherein the motion condition refers to the situation that the user stays at a standing posture, walks and moves upand down a slope, and a pressure distribution peak value area is determined; foot three-dimensional data of the user is collected, and a foot three-dimensional solid model and an insole primary modelare established; the contact area is increased, the material performance is changed, the height of an insole of an area where pressure peak values are located is adjusted according to the method, thepressure peak values are lowered in sequence, the front-back stress ratio and internal-external stress ratio of the feet are improved, and the stability of a transient-state posture is improved. According to the customized insole preparation method based on the biomechanics, the prepared customized insole effectively improves the sole pressure distribution condition of a user, increases the comfort degree, has the prevention and orthopaedic functions, and can meet demands of various types of users.

The invention discloses a high-manganese nitrogen-free high-strength and high-toughness anti-hydrogen embrittlement austenitic stainless steel and a preparation method thereof. The austenitic stainless steel comprises the following chemical components of less than 0.05% of C, less than 0.50% of Si, 6%-10% of Mn, 12%-16% of Cr, 4.5%-6.5% of Ni, 0.5% -3% of Mo, less than 0.01% of S, less than 0.03%of P, and the balance Fe and trace added Nb, Ti, V, Al, Cu and inevitable impurity elements. The manufacturing method comprises the steps of smelting (casting), forging (hot rolling), rolling, tempering and the like. The high-strength and high-toughness stainless steel prepared by the preparation method disclosed by the invention is characterized in that the high-strength and high-toughness stainless steel is based on 13Cr-5Ni-2Mo / 15Cr-6Ni-2Mo super martensite stainless steel, the austenitic stainless steel is subjected to austenitizing by adding cheap Mn elements, the high strength is achieved through the residual martensite back stress strengthening and the fine crystal strengthening of an austenite matrix, the high toughness is obtained through phase change, and the H2S (hydrogen embrittlement) stress corrosion resistance of the material is improved through the austenitizing. The prepared high-strength steel has extremely high toughness and anti-hydrogen embrittlement performancewhile maintaining good corrosion resistance. The method disclosed by the invention is simple in process, easy to realize industrialization, and capable of being used for an oil pipe containing H2S oil(gas) and an environment with high corrosion resistance and anti-hydrogen embrittlement requirements.

The invention discloses a method for confirming a heat engine multi-shaft stress-strain relationship with dynamic strain aging influence. The method comprises the following steps: (1) confirming basicparameters; (2) upgrading stress tensors by accumulating stress tensors; (3) judging whether the stress tensors calculated in the step (2) enter a non-elastic period or not according to yield criterion, if the stress tensors are still in an elastic period, carrying out a next step of calculation in step (5), and if the stress tensors are in the non-elastic period, carrying out a next step of calculation in step (4); (4) according to values of the yield criterion, calculating an accumulation non-elastic strain rate, a non-elastic strain rate tensor, an elastic strain rate tensor, a back stressrate deviator and an isotropic hardening parameter rate, upgrading the back stress rate deviators by accumulating the back stress rate deviators, and upgrading isotropic hardening parameters by accumulating the isotropic hardening parameter rates; and (5) judging whether loading is completed or not, and if loading is completed, acquiring the heat engine multi-shaft stress-strain relationship withthe dynamic strain aging influence.

A bath aid is provided for supporting a person kneeling at a bathtub. The bath aid comprises a lower pad, a middle pad, and an upper pad which includes a tub attachment mechanism fixed to a bottom surface thereof. A first hinge mechanism pivotally connects a front edge of the lower pad to a lower edge of the middle pad, while a second hinge mechanism pivotally connects an upper edge of the middle pad to a lower edge of the upper pad. The bottom surface of the lower pad rests on a floor surface, while the bottom surface of the upper pad may be fixed to the bathtub by the tub attachment mechanism when in an open position.

The invention relates to a device for detecting the motion state of fingers of a human hand and feeding back stress borne by the corresponding knuckles of the hand, in particular to a far knuckle force feedback device. The far knuckle force feedback device aims at solving the problems that a joint measuring mechanism and a force feedback mechanism of an existing force feedback device are separated, the system is complex, the structure is overstaffed, maintenance is difficult, bidirectional active driving cannot be achieved, and the price is high. A joint detecting mechanism and the force feedback mechanism are integrated, and are arranged through a unique connecting mode and ingenious knuckle measuring points, when an operator uses the device, the detected finger can be kept flexible to the maximum degree, the motion state can be precisely detected, the corresponding knuckle of a controlled human hand can move consistent with the corresponding knuckles of the operator in a cooperating mode, and the stressing condition of the hand in the specific work environment can be fed back to the operator so that the sense of immediacy of virtual reality or teleoperation can be enhanced.

The invention provides a high-strength and large-plasticity multi-stage heterostructure medium-entropy alloy and a preparation method thereof. Multiple strengthening mechanisms are introduced at the same time through component, process and structural design, so that the yield strength of the alloy is improved to 3-4 times. And each strengthening mechanism has obvious contribution, wherein the contribution of solid solution strengthening, dislocation strengthening, grain boundary strengthening and back stress strengthening to the strength is 274 MPa, 175 MPa, 189 MPa and 366 MPa respectively. However, the alloy still keeps an fcc matrix, so that the alloy still possesses good toughness while the strength of the alloy is improved. The high-strength and large-plasticity multi-stage heterostructure medium-entropy alloy has the advantages that the room-temperature mechanical property is excellent, the yield strength of the NiCoCr medium-entropy alloy is improved by 3.6 times to about 1100 MPa, the tensile strength is improved by 2 times to about 1400 MPa, and meanwhile, the alloy possesses 20% of tensile ductility. The NiCoCr medium-entropy alloy with the double-phase multistage heterostructure is excellent in comprehensive mechanical property, the process is simple and feasible, and the alloy has great engineering application prospects.

Methods and systems using a numerical model to describe polymeric material properties are disclosed. FEM model of a product is defined. FEM model includes one or more solid elements of polymeric material. In a time-marching simulation of the product under loads, stress state of the solid elements is calculated from deformation gradient tensors. Stress state incorporates the Mullins effect and strain hardening effect, also includes elastic stress, viscoelastic stress and back stress. A yield surface is defined to determine whether the elements are under plastic deformation. Plastic strain is obtained to update the deformation gradient tensor, which is then used to recalculate the stress state. Calculations continue until updated stress state is within a tolerance of the yield surface, at which time the results of polymeric material elements are obtained. The numerical model takes into account all characteristics of a polymeric material.

The invention discloses a pipe based flange thickening implementation method. The method is characterized in that back pressure is applied to a reverse ejection male die, and a core rod is arranged tomove upwards at a constant speed, so that upsetting and extruding treatment is performed on a pipe, the portion, located in a protection cavity, of a pipe material is gradually extruded into a forming cavity along with gradual increase of deformation force inside the pipe, the portion, in the forming cavity, of the side wall of the pipe is thickened in an accumulated mode accordingly, and finallythe flange is formed. According to the method, the side wall material is gradually accumulated for forming so that the defects of pipe wall twisting or incomplete filling and the like can be effectively overcome, and flange thickening forming limit and forming efficiency are improved; and a positioning cavity is additionally formed in the male die, one-time forming of the flange at any position of the pipe wall is achieved, and the process application range is widened.

The invention discloses a method for predicting fatigue life by an energy method considering machined surface integrity, and belongs to the technical field of life prediction of high-strength steel materials, and the method comprises the following steps: obtaining geometric-mechanical-metallurgical properties before a fatigue test; obtaining hysteresis loop data and fatigue life data of different circulation cycles; obtaining a revision coefficient of the surface topography and the surface hardness to the total energy through a micro-crack non-propagation threshold value; obtaining a surface layer residual compressive stress energy revision coefficient considering different depths; importing the revision coefficient of the total energy into a surface layer residual compressive stress energy revision coefficient item of a single-cycle energy density-life method; obtaining one-cycle plastic strain energy when the fatigue test is stable through a back stress equation; and realizing fatigue life prediction and characterization of the material under different processing surface integrity parameters by adopting a correction single-cycle cycle energy density-life method. The method effectively solves the problem of life prediction of the material under the action of different surface integrity of medium and low cycle fatigue.

The invention discloses a determination method for a high-temperature multi-axis constitutive relation considering non-proportional additional hardening. The method comprises the steps that (1) basicparameters are determined, a high-temperature multi-axis strain history is read, and back stress deviators and isotropic hardening parameters are assigned to be 0; (2) stress tensors are calculated byuse of the Hooke's law; (3) whether the stress tensors calculated in the step (2) enter an inelastic stage is judged by use of the yield criterion, if the stress tensors are still at an elastic stage, next calculation is performed according to the step (5), and if the stress tensors enter the inelastic stage, next calculation is performed according to the step (4); (4) a value, calculated in thestep (3), of the yield criterion is utilized to calculate accumulated inelastic strain, inelastic strain tensors, elastic strain tensors, back stress deviators and isotropic hardening parameters; and(5) whether loading is completed is judged, if not, the steps (2), (3), (4) and (5) are repeated, and otherwise the high-temperature multi-axis constitutive relation considering non-proportional additional hardening is obtained.

The invention provides a heterostructure simulation method based on ABAQUS. The heterostructure simulation method comprises the following steps: establishing a 2D representative volume unit of a uniform structure and a heterostructure; correcting the sliding resistance model and the back stress model and writing the sliding resistance model and the back stress model into a user subprogram UMAT soas to define an elastic-plastic constitutive equation of the crystal; determining material parameters in the UMAT by utilizing the stretching curves of the three different structures; applying a periodic boundary condition and an external load, and calculating a stress-strain response of each crystal grain by utilizing ABAQUS; averaging stress and strain of all crystal grains; changing parameterssuch as microstructure and grain orientation of the model, predicting and analyzing corresponding macroscopic stress-strain response, strengthening effect and microcosmic deformation cloud atlas, andcomparing to obtain the optimal microstructure. According to the heterostructure simulation method, the grain size effect and extra back stress strengthening of the heterostructure are considered, theheterostructure can be simulated, and the heterostructure simulation method has the advantages of being visual, high in applicability and high in accuracy.

The invention belongs to the technical field of driving variable transmission and discloses a driving belt auxiliary extrusion conical disk belt-type variable transmission. The driving belt auxiliary extrusion conical disk belt-type variable transmission comprises spline shafts, conical disks, a driving belt, conical disk displacement control sleeves, support sleeves, servo motor shaft gears, stress application chains, double-piston tensioning assemblies, callipers, double ring tooth-shaped positioning springs, arc pressure block assemblies, a carriage body and the like. The driving belt auxiliary extrusion conical disk belt-type variable transmission is characterized in that back stress application mechanisms are arranged on the outer back surfaces of the driving belt at conical disk contact sections, or side stress application mechanisms are arranged on two side surfaces of the driving belt at conical disk contact sections, so that relative sliding between the driving belt and conical surfaces of the conical disks is limited; the driving belt is clamped between two sliding conical disks which are oppositely arranged on the same spline shaft, and is connected with the two groups of conical disks; and under the action of conical disk movement control mechanisms, along with the moving of the coaxial conical disks, the diving belt is reduced on the conical surfaces of the conical disks, so that the transmission ratio can be changed in a continuous manner or in a constant-value manner. By adopting the driving belt auxiliary extrusion conical disk belt-type variable transmission, the transmission efficiency and driving capacity of an ordinary conical disk steel belt variable transmission can be improved; power transmission can be cut off or connected through stress application mechanisms and conical disk control systems; and the driving belt auxiliary extrusion conical disk belt-type variable transmission can also be combined with other variable transmissions for use.

The invention discloses a folded hydraulic crushing device for a static sounding device. The folded hydraulic crushing device comprises an overturning platform which is hinged to a static sounding trolley operation platform and can be folded relative to the static sounding trolley operation platform, and a crushing mechanism which can move left and right relative to the overturning platform is arranged on the overturning platform; the crushing mechanism comprises a sliding rack, guide wheels arranged on the two sides of the sliding rack, a supporting seat fixed to the sliding rack, and a rotating rack which is provided with a rotating shaft and rotates relative to the supporting seat; the rotating shaft is mounted in the supporting seat; a locking device is arranged between the sliding rack and the overturning platform; a locating device is arranged between the rotating rack and the supporting seat; the guide wheels are matched in a first guide rail of the overturning platform; a lifting cylinder is fixed to the rotating rack; a fixed rack is fixedly connected on a travel rod of the lifting cylinder; and a hydraulic crushing hammer is arranged on the fixed rack. According to the folded hydraulic crushing device for the static sounding device, hard objects in a certain region range can be easily crushed, the front-and-back stress of a static sounding trolley is balanced through the unique folded structure, and transportation is facilitated.

The invention discloses a bucket tooth and tooth base connecting mechanism of an engineering machine, which has the advantages of low abrasion and difficult dropping of a bucket tooth and a tooth pin. Front and back stress surfaces of a plug and a socket are vertical, are parallel to the symmetry axis of the bucket tooth, and are divided into two-stage or multi-stage step stress surfaces; gaps are reversed between inclined surfaces of the plug and the socket in the two-stage front and back stress surfaces, between planes of the plug and the socket of the multi-stage front and back stress surfaces and between the two ends of the bottom surface of the plug; the bottom surfaces of the plug and the socket are arched; the arc of the bottom surface of the plug is contacted with the arc of the bottom surface of the socket for limiting a gap; the bucket tooth is strung on the tooth base by a screw, and one end is locked by a screw cap; and a screw thread is not beyond the outer edge of the screw cap.

A stress feedback unit for joints of a third finger and a middle finger relates to a device used for detecting movement state of fingers of a human hand and capable of feeding back stress of the corresponding finger joints of the hand. The invention aims to make up defects that a joint detecting mechanism and a stress feedback mechanism of a prior stress feedback device are separated with each other and a prior system is complex in structure, difficult to maintain, incapable of bidirectional driving and high in cost and the like, integrates the joint detecting mechanism and the stress feedback mechanism, and adopts a unique connection way and a skillful joint detection point arrangement, so that to-be-detected fingers of a user can keep flexibility to the largest extent when the user is using the device. Besides, the movement state of the fingers can be detected precisely, so that finger joints of a slave hand corresponding to the finger joints of the user can move exactly as the finger joints of the user and stress of the hand in a specific working environment can be fed back to the user for enhancing sense of immediacy of virtual reality or for remote operation.

The invention provides an application of a cyclic hardening model based on a weld dislocation winding precipitation phase in welded joint fatigue life prediction, and the cyclic hardening model is as follows: in the formula, the method takes the weld dislocation winding precipitation phase as a basis, and takes flow stress caused by a non-uniform dislocation structure of the weld dislocation winding precipitation phase into consideration at the same time; the influence of back stress caused by dislocation winding precipitation phases in a welding seam and back stress generated by the blocking effect of a welding seam grain boundary on dislocation on the cyclic yield strength is achieved, a cyclic hardening model of a welding joint is established on the basis, and the model well explains the relation among the maximum stress, the cycle index and the plastic strain; and a microscopic mechanism during fatigue failure based on a weld dislocation winding precipitation phase is explained, and the cyclic deformation behavior of the welded joint can be evaluated more quickly and accurately, so that a better theoretical basis is provided for prediction of the fatigue life of the welded joint.

The invention discloses a gamma-boron synchronous diffusion process mesa structure thyristor chip and a manufacturing process thereof. The chip comprises an N+-type cathode region 1, a front P-type short base region, a silicon single crystal wafer and a back P-type region which are arranged from the top to bottom. Two ends of the chip are provided with communicated isolation diffusion regions, thefront surface of the chip is provided with a SiO2 protective film, and the back surface is provided with a metal electrode. The front P-type short base region of the front side of the chip is internally provided with front trenches, and the back is provided with back stress balance grooves at the communicated isolation diffusion regions. A gate aluminum electrode and a cathode aluminum electrodeare arranged between the front trenches, and the N+-type cathode region is arranged under the cathode aluminum electrode in the front P-type short base region. According to the chip and the manufacturing process, the characteristic that a gallium diffusion coefficient is larger than a boron diffusion coefficient is utilized, a gamma-boron synchronous diffusion process is used, low vivo concentration and low capacitance can be obtained, thus a breakdown voltage VBR is close to a switch-on voltage VBO, a high surface concentration and short base region lateral resistance can be obtained, at thesame time, the diffusion time is short, and the production cost is saved.

The invention discloses a method for improving back stress of an IGBT. Photoetching and etching patterning are carried out on polyimide covering a front passivation layer of a silicon wafer; the surface of the overall silicon wafer is coated with an adhesive; and then a glass slide is bonded. Recesses and gaps formed after polyimide etching are fully filled with the adhesive; and the glass slide and the adhesive form a stress buffer layer.