157 results about "Statically indeterminate" patented technology

The invention provides a finite element analysis method for the temperature action on a prestressed reinforced concrete continuous rigid frame bridge. The finite element analysis method is used for analyzing and calculating the stress and displacement distribution in the construction and finished bridge stage under different temperature gradient models, and provides references for designing and optimizing the prestressed reinforced concrete continuous rigid frame bridge. Through calculational analysis based on finite elements and the structural mechanics, the forward-calculation method is adopted for structural distortion and stress analysis according to the actual construction loading sequence of the bridge structure, so that the complex mechanics problem of box girder temperature self-stress, temperature secondary internal force in a prestressed reinforced concrete statically indeterminate structure and secondary stress of the temperature secondary internal force is solved easily, conveniently and efficiently, and the finite element analysis method has important practical value.

The invention discloses a design method for longitudinal pre-stressing tendons of a variable-cross-section pre-stressed concrete continuous bridge. The optimization design method for the longitudinal pre-stressing tendons of the pre-stressed concrete continuous bridge is built based on the design principle of the pre-stressed degree and through combining an analytic method with a finite element method and compressively considering dead load and live load action effects. A three moment equation of the variable-cross-section pre-stressed concrete continuous box girder bridge is established to solve the internal force of the structure under the action of the self weight on the basis of the average bending moment method. A calculation formula of pre-stressed effective pre-pressure is built through a load equal effect method and a unit load method; a creep effect calculation formula is built through a force method; the temperature effect and the automobile load effect are calculated through the finite element method; and a variable-cross-section statically indeterminate structure pre-stressing tendon reinforcement calculation formula is obtained through combination of the stress ratio with the definition of the competitive pre-stressed degree.

The invention provides a calibration method and device for an arm length and a zero point of an SCARA (Selective compliance assembly robot arm) robot, a memory medium and a computer device. The methodcomprises the steps of acquiring measurement parameters when an end calibration needle of the SCARA robot is aligned to a preset first hole and a preset second hole at different arm series; establishing a kinematic equation set of the SCARA robot; carrying out transformation and variable substitution on the kinematic equation set of the robot through a trigonometric identity, so as to acquire statically indeterminate homogeneous linear equations; solving the statically indeterminate homogeneous linear equations; and calculating the arm length and the zero point of the SCARA robot based on a solution result, the kinematic equation set and the known distance between the preset first hole and the preset second hole. According to the method, transformation and variable substitution are carried out on the kinematic positive solution equation of the robot through the trigonometric identity during the entire process, the kinematic positive solution equation is transformed from a nonlinear equation to a linear equation, the linear equation is solved, the entire processing and calculation process is simple, and the arm length and the zero point of the SCARA robot can be accurately calculated at the same time.

The accelerometer includes an inertial mass, a fixed base and at least one or more supports/sensors for supporting the mass from the base rendering the support system statically indeterminate. The supports/sensors are preferably double-ended dual beam tuning forks suspended between mounting pads and vibrated by an oscillator. By adding one or more supports/sensors beyond those supports/sensors necessary for a statically determinate support system, the support system is rendered statically indeterminate and therefore sensitive in one or more directions.

The invention relates to a method for calculating the stability safety factor of a concrete gravity dam under a multi-dam-section combined skid resistance condition and belongs to the field of gravity dam stability analysis. According to the method, a three-dimensional stability analysis calculation model is established on the basis of a three-dimensional rigid body limit balance analysis and strength reduction method by aiming at a situation that key slots are formed or grouting is performed between dam sections of the concrete gravity dam so as to combine slide resistance; by introducing a plurality of reasonable assumption and unbalanced force transfer concepts, the statically indeterminate problem of combined anti-sliding stability of multiple dam sections along a dam foundation surface is converted into a statically determinate problem; on the basis of solving out the independent anti-sliding safety factor of the dam sections, the transfer of unbalanced forces of adjacent dam sections on a river valley side is considered, circulation calculation is performed, and the overall stability safety factor of combined slide resistance of multiple dam sections, the sequence of sequentially achieving limit balance by each dam section and the local stability safety factor of the dam sections are solved out. The method has the characteristics of easiness for realization of programming, reasonable calculation result and the like, and is convenient in popularization and application in practical engineering.

A manufacturing method for a rod member of a three-dimensional statically indeterminate truss structure is provided, which includes the following steps. A first conical connection element is provided, which has a guide slot and a coupling portion on a front and a rear end respectively. A first screw connection is made to penetrate from the coupling portion of the first conical connection element, such that a screw portion of the first screw connection penetrates out of the guide slot, and a head portion of the first screw connection is confined within the first conical connection element. The coupling portion of the first conical connection element is aligned and engaged with a first end opening of a tube member, and the first end opening of the tube member is joined to an engaging portion in the coupling portion of the first conical connection element by applying a magnetic pulse welding technique.

The invention relates to a calibration method for the indention load-depth curve of a micro-bridge of a micro-electro-mechanical system, belonging to the field of testing of the mechanical properties of materials. The bending load-deflection curve and the indention load-depth curve of a micro-bridge structure are synchronously acquired through a nanoindentation test on the micro-bridge structure, wherein the characteristic size of the micro-bridge structure is of a micron order, and two ends of the micro-bridge structure are fixed; and quantitative testing is carried out on the rigidity, Young modulus, hardness, yield stress and breaking strength of a bridge structure of a micro-electro-mechanical system device. Through analysis of a statically indeterminate structure of the micro-bridge, the actual maximum displacement of the tip end of an indenter is accurately parsed to be a sum of the maximum flexural deflection of the micro-bridge and the maximum indention depth of the indenter embedded into the surface of the micro-bridge; and a method for estimating a load-depth curve under the condition of elastic semi-infinite half-space by using the actually-measured indention load-depth curve is established on the basis of both the actual maximum displacement of the indenter and theoretical analysis of maximum depth of indentation by an elastic deflection surface and elastic deflection at the edge of an indentation micro-area; so a novel measuring method is provided for research on the mechanical behaviors of the micro-electro-mechanical system device under stress induction.

The invention discloses an identification method for beam structure damage of vibration mode weighing modal flexibility. The method comprises the following steps: obtaining frequency and the vibration mode of the beam structure before and after the damage through a modal test; calculating vibration mode curvature sign function weighing damage index based on the frequency and the vibration mode before and after the damage to locate the damaged structure, calculating a beam structure node damage degree according to a relative change of the vibration mode curvature sign function weighing damage index before and after the damage, and then calculating a unit damage degree. The identification method for the beam structure damage of the vibration mode weighing modal flexibility can effectively determine a damage location of a single-damage and multi-damage working condition for the beam structure, the calculation method of the damage degree of the corresponding index under a statically determinate structure and a statically indeterminate structure can be used to identify the damage degree accurately, the shortcomings that the existing modal flexibility curvature index cannot be used to identify the damage degree are overcome, and the method can be applied to the nondestructive testing and damage degree assessment of the beam structure.

The invention provides a mechanical experiment device applied to the technical field of experimental equipment and also relates to a method for conducting an experiment by applying the experimental device. One end of the bottom of an upright post (2) of the experimental device is connected with a base (1); the other end of the upright post (2) is connected with a cross beam (3); weight support bar plates (4) for placing weights (28) are respectively arranged at two end parts of the cross beam (3); strain gauges (29) are respectively attached to parts, positioned on two sides of the upright posts (2), of the cross beam (3); each strain gauge (29) is connected with a static resistance strain indicator (5). According to the experimental device disclosed by the invention, multiple mechanical experiments such as bending normal stress determination of the cross beam, a bending combination deformation experiment, an internal force determination experiment of a truss, internal force determination of a statically determinate structure, internal force determination of a statically indeterminate structure and the like can be performed conveniently and quickly; besides, the steps are simple and convenient, and the operation is simple, so that the experiments can be finished conveniently and quickly and the experiment result is accurate and reliable.

The invention discloses a statically indeterminate modular main beam amplitude adjustable low-frequency vibration tension and relaxation screen. The screen comprises a screen body, a spring support base, a vibration reducing spring, a motor, a bracket, and a statically indeterminate excitation main beam consisting of a pipe beam and a fixed plate; a floating screen frame is arranged on the screen body; elastic screen surfaces are arranged on the screen body and the flowing screen frame; the floating screen frame is hung and mounted at the lower part of the screen body through a rubber hinge; the flowing screen frame can enable the polyurethane elastic screen surfaces to swing up and down under the effect of materials to accelerate the operation speed of the materials to prevent the load concentration; the polyurethane elastic screen surfaces are connected by multiple rectangular screen plates; and two ends of each screen plate are respectively mounted on a fixed cross beam of the screen body and a floating cross beam of the floating screen frame. The floating screen frame and the screen body are in hanging connection by the rubber hinge; and an amplitude adjusting spring is mounted between the two. Vibration exciters are arranged in a side plate and the statically indeterminate main beam. The screen is compact in structure, high in reliability, convenient to adjust the motion mode and the working amplitude and suitable for dry deep screening of wet fine-particle coals in coal preparation plants.

The invention discloses a universal-type statically indeterminate hydraulic support, mainly composed of a top beam, a base, eight hydraulic vertical columns, a front beam, a telescopic beam, a tail beam, a connection plate, a hydraulic control valve assembly, a pushing device, etc. The eight hydraulic vertical columns are symmetrically arranged between the top beam and the base in a cross mesh shape, the upper ends of the eight hydraulic vertical columns are hinged with the top beam, and the lower ends of the eight hydraulic vertical columns are hinged with the base; the front beam is hinged with the top beam, the telescopic beam is arranged in the front beam, and a protective side plate is hinged with the telescopic beam; the upper end of the tail beam is hinged with the top beam, the lower end of the tail beam is hinged with the upper end of the connection plate, the lower end of the connection plate is hinged with a lifting frame, and the lifting frame and the base are welded together; the hydraulic control valve assembly is installed on a bridge-crossing box, and the bridge-crossing box and the base are welded together; and the front end and the rear end of the pushing device are hinged with the base and a scraper conveyor respectively. The universal-type statically indeterminate hydraulic support can be used for a fully-mechanized mining face or a blasting mining face, is simple in structural process, good in stability, safe and reliable in use, and wide in practicability.

Embodiments of the invention provide a synchronous statically indeterminate mesh-beam excitation large-scale vibrating screen, including a screen box, a support spring group, a spring base, a motor mount, a tire coupling, and a motor, wherein, a statically indeterminate mesh-beam excitation body is arranged on the screen box, and the statically indeterminate mesh-beam excitation body has at least one synchronous eccentric block vibration exciter group and two self-synchronous eccentric block vibration exciter groups in it; each self-synchronous eccentric block vibration exciter group includes a self-synchronous transmission shaft fixed to the side plates of the screen box via a bearing chock, and self-synchronous eccentric blocks fixed to the side plates of the screen box in symmetry are arranged on the self-synchronous transmission shaft; the self-synchronous transmission shaft of the self-synchronous eccentric block vibration exciter group at the side of the motor is connected with a reducer via the tire coupling, and the reducer is connected to the motor via a transmission belt.

The invention relates to structural mechanics experimental devices, particularly to a bending moment influence line test experimental device of a continuous beam as the statically indeterminate structure. Vertical DOF (degree of freedom) of two ends of a beam is limited by a pair of double-roller supports which are fixed on a stand, and downward DOF of the middle of the beam is limited by a single-roller support, accordingly forming a symmetrical two-span continuous beam structure; moving load is applied on the beam by a roller with a weight hanging, the roller is pulled by a pull line to an optional position of the left span of the beam, strain sensors are symmetrically arranged on the optional positions of the bottom of the beam and connected with a data collecting device, and through a ruler, load acting position and a measuring point are given accurately. According to the arrangement, under moving load action of the continuous beam, bending moment influence lines generated on different positions are quantitatively obtained, and wide application to the structural mechanics experiments of high engineering colleges is achieved.

The invention puts forward a combined emergency bridge and an erection method thereof which are designed for solving the problems that in the prior art, the quick restoration on the traffics at the gap positions of highway subgrades and the derogative areas of subgrades is realized by way of building shortcuts, therefore, the restoration is restricted by terrain conditions and affected by secondary geological disasters, meanwhile, the restoration is long in time, time-consuming, labor-consuming and the like. The combined emergency bridge comprises cubic steel frames, triangular prism-shaped steel frames, bearing wire cables, fixing wire cables and road slabs. The combined emergency bridge and the erection method thereof have the following beneficial effects: the bearing wire cables and combined steel frames of the bridge constitute a statically indeterminate self-bearing structure system, horizontal pressures produced by the steel frames are transmitted to the ends of the bridge, and the loads of the triangular prism-shaped steel frames are balanced by the tension of the bearing wire cables; the steel frames of the combined emergency bridge provided by the invention can not be fabricated on site, and the fabrication of the steel frames can be standardized and serialized; and the erection method of the combined emergency bridge is simple without carrying out excessive treatments on disaster sites, therefore, the method has the characteristics of emergency, speediness and convenience.

The invention discloses a basic module of an extra-large marine floating structure. The basic module is composed of a lower-portion floating body structure, an upper-portion structure and middle connecting structures. The lower-portion floating body structure comprises multiple dispersedly arranged floating bodies and is wholly in an extra-large water plane area form, the sum of the water discharging areas of the floating bodies is greater than the equivalent-quantity water volume of the whole weight of the floating structure, the upper-portion structure is a frame structure or a box body structure, the middle connecting structures are dispersedly arranged in space, and the lower-portion floating body structure is connected with the upper-portion structure through the middle connecting structures to form a hyperstatic combined space structure. Two basic modules can form the kilometer-level extra-large marine floating structure through one-time splicing. The basic module has very strong wave exciting load resistance and load change capability, has very strong sway-resistant stabilizing rigidity and can remarkably decrease relative motion during basic module splicing and connector load after splicing.

The invention relates to a vehicular weighing method which can be used for conveniently measuring the weight of on-board goods in real time. The vehicular weighing method comprises the following steps: additionally installing a plurality of strain sensors on an axle; additionally installing test bodies in different positions of a truck bed, and reading the reading of each sensor during each additional installation; constructing a statically indeterminate equation according to a test body weight array, a sensor reading array and a distribution coefficient array of each sensor, and solving a least square solution of the statically indeterminate equation to obtain an optimal distribution coefficient of each sensor; additionally installing test bodies in any position of a compartment in proper order, reading the practical weight of the test bodies during each additional installatio, reading the reading of each sensor during each additional installation, and determining measuring errors during each additional installation; performing polynomial fitting to determine a relationship between a measuring error value and the measured weight, and obtaining the practical weight of the on-board goods according to the sum of the actual measured weight and measuring errors of the on-board goods.

The present invention relates to a double-girder and multi-lifting point crane, which comprises a main beam, a lift mechanism, a translation mechanism and an electric control system. The invention is characterized in that the main beam refers to unevenly arranged double girders, while each girder is provided with a variable cross-section which is a high and narrow composite beam composed of three box-shaped beams; the lift mechanism is composed of a plurality sets of winch systems; each set of winch system respectively connects and controls a plurality of lifting points and all the lifting points are synchronously driven by the electric control system; the cinch system is provided with a rope arrangement mechanism which adopts a single-linkage and multi-layer winding rope system; the translation mechanism is a girder self-propelled bidirectional translation mechanism arranged on both ends of the lower girder; the electric control system is an electric control system of a multi-lifting point crane statically indeterminate system. The crane of the invention has the advantages of super-large lifting weight, super-large lifting height and super-large span, and is applied to the lifting and docking of super-large loading capacity of offshore drilling platform large-scale subsection, which will promote the alteration of drilling platform manufacturing mode, create enormous social benefits and have a far-reaching influence over the manufacturing of the offshore industry projects in China as well as the world.

The invention discloses a beam structure damage identification method based on support counterforce and deflection curvature. The method mainly comprises the steps of applying load to a damaged back beam structure to obtain an actually measured deflection curve and support counterforce; solving the curvature of the actually measured deflection curve; calculating the bending moment value of each position of the beam structure through the support counterforce and the load; obtaining the stiffness of each position of the beam structure by dividing the bending moment value of the corresponding position by the deflection curvature, and identifying the damage position through the sudden change of the stiffness curve of the damage state; eliminating the stiffness of the damaged position, and fitting the residual stiffness curve to obtain a stiffness curve of an undamaged state; and calculating the damage degree according to the stiffness curves of the damaged state and the undamaged state toobtain the structural stiffness of the damaged position. If the beam structure is a statically indeterminate structure, loads are applied to different positions of the structure for multiple times, damage positions, damage degrees and stiffness results under the action of multiple loads are obtained, and damage judgment is comprehensively conducted. The method can accurately position and quantifythe damage of the beam structure, and is applied to damage evaluation of the beam structure.

Disclosed is a lifting-force determination and displacement control method of active underpinning of statically indeterminate bridge pile foundations. The method includes: determining the underpinningdesign of a statically indeterminate bridge and setting ground pre-supported roof measures at the position of a pier corresponding to an underpinning bridge pile; determining the required lifting force in underpinning; during underpinning, digging earthwork downward to the bottom elevation of an underpinning bearing platform, performing mechanical construction of pile underpinning at the positionof the bottom elevation of the underpinning bearing platform, and after completion of the pile underpinning, performing construction on the underpinning bearing platform; arranging a jack for activelifting between an existing bearing platform and the underpinning bearing platform; after lifting force is determined for active underpinning, cutting off the underpinned bridge pile between the bearing platform and the underpinning bearing platform, and pouring and sealing concrete to complete active underpinning. Therefore, the size of the lifting force during the active underpinning process ofthe statically indeterminate bridge pile foundations can be determined accurately, deformation of the statically indeterminate bridge pile foundations during active underpinning is effectively controlled, and more accurate force conversion and deformation control is realized.

The invention relates to a girder crane for a three-lifting joint statically indeterminate lifting system. A crane frame adopts a rhombohedral frame structure. The frame structure comprises a top rhombohedral structure body, an upright post rhombohedral structure body, a chassis rhombohedral structure body, a rear pull rod and a front stay bar, and the three pieces of rhombohedral structure bodies are tied together through space connection, wherein the upper end of the rear pull rod is hinged with the upright post structure body, and the lower end of the rear pull rod is hinged with the tail end of a main longitudinal girder of the chassis rhombohedral structure body; and the upper end of a main limb of a sway rod is hinged with the front end of a main longitudinal girder of the top rhombohedral structure body, and the lower end is connected with a flange bolt at the front end of the chassis rhombohedral structure body. A method for controlling the crane comprises that: lifting reversing winches of the girder lifting joints on both sides are synchronously controlled, and a middle lifting joint reversing winch adopts synchronous track and load proportion control. The girder crane solves the problems that three girder nodes of a steel girder have unstable structure because of not forming a bridge and are easy to deform in the hoisting process. The girder crane evenly applies the weight of the steel girder onto the formed bridge, improves the figure of the steel girder nodes formed into the bridge and solves the problem of the influence of the cable force of a steel cable.

The invention discloses a high-precision ultra-large-stroke painting robot telescopic arm adopting a statically indeterminate structure. The high-precision ultra-large-stroke painting robot telescopic arm comprises a fixed base, an n-regular-polygonal connecting structure, a tail end workbench structure and a plurality of sets of shear fork serial mechanisms. The shear fork serial mechanisms comprise the n sets of shear fork serial mechanisms which are hinged to the fixed base and the tail end workbench structure. The vertexes of the n-regular-polygonal connecting structure are hinged to the shear fork serial mechanisms. Each set of shear fork serial mechanism comprises a long connecting rod, a short connecting rod, a top revolute pair, end revolute pairs and a middle revolute pair. Compared with the traditional telescopic arm design, the requirement for machining and assembling can be effectively lowered, the lateral rigidity of the telescopic arm is improved, better lateral positioning precision can be achieved during movement, the effect that the position of the center of the tail end workbench structure is unchanged on the plane in the telescoping process of the telescopic arm can be guaranteed, and the motion stability and the vertical positioning precision are guaranteed.

The invention discloses a bridge maintenance overhead working equipment lifting device, which comprises a frame, a frame walking trolley which is installed at the bottom of the frame, three steel suspension arms which are equidistantly arranged, a guide rope tightness adjusting mechanism which is arranged along the axes of the steel suspension arms, track longitudinal beams which are perpendicular to the three steel suspension arms and are detachably connected with the extension ends of the steel suspension arms, and overhead working equipment which is effectively connected with the track longitudinal beams. Through safe system conversion from a statically indeterminate structure with the three steel suspension arms to a statically determinate structure with two steel suspension arms, the lamp post passing device of the self-suspension mechanism of the bridge maintenance overhead working equipment can be enabled to safely and rapidly pass through columnar obstacles such as streetlamps by alternately disassembling and assembling one steel suspension arm under the on-load situation, the troubles in disassembling and assembling the equipment are avoided and the continuous operation is realized.

Provided is a combined H-shaped steel cast-in-situ box beam support adjoining to and overpassing existing lines. The combined cast-in-situ beam support comprises a steel pipe column strip foundation, steel pipe buttresses, triangular diagonal braces on the two sides of steel pipe uprights, main crossbeams and main longitudinal beams. The triangular steel pipe column buttresses, the main crossbeams and the main longitudinal beams are of a combined structure, stress decomposition is conducted on H600 type steel of the main longitudinal beams through the triangular diagonal braces on the two sides of the steel pipe uprights, force is transferred to a transverse pier body and a longitudinal concrete strip foundation, deflection deformation occurring after the H600 type steel of the main longitudinal beams is stressed is greatly reduced under large span conditions, a statically indeterminate structure of the support is formed, structural stability of the support is enhanced, the construction problem that the left space, right space, upper space and lower space of a cast-in-situ box beam adjoining to and overpassing the existing lines are limited is solved, and it is guaranteed that lower deflection of H-shaped steel under large span conditions and the driving clear height of the existing lines are within specified permissible ranges.