117 results about "Hooke's law" patented technology

The invention discloses a Brazilian split method for measuring an elastic parameter of a rock under an extension condition, which comprises the steps of: A. horizontally putting a machined disc-shaped sample between the load bearing plates of a press machine by using a Brazilian disc split method, placing a hard steel wire respectively between the upper load bearing plate and the sample and between the lower load bearing plate and the sample, arranging a filler strip perpendicular to the symmetrical surfaces of the sample, and applying pressure on the upper load bearing plate and the lower load bearing plate to make the sample generate tension perpendicular to the action directions of an upper load and a lower load; B. carrying out analysis by using the Hooke's law in classical elasticity mechanics by combining specific conditions of the Brazilian split method; C. analyzing the stress condition of the rock and the measurement principle in the Brazilian disc split method; and D. obtaining the strain in the stress direction according to the Hooke's law from the stress condition sigma3=0, measuring epsilon1 and epsilon2, obtaining the elastic parameter of the rock sample, and arranging a strain gauge in the center position of the rock sample for measurement of epsilon1 and epsilon2. The method has the advantages of easiness for operation and use, clear principle, low material consumption, and the like. The method is suitable for wide popularization and application.

The invention relates to a method for measuring sheet welding residual stress. The method comprises the steps of sticking two rows of symmetrically distributed resistance strain gages on a weldment at first and enabling the direction of a strain grid to be consistent with the direction of a weld joint, next, cutting the weldment into two parts with the same size in a direction perpendicular to the weld joint so that the residual stress is released, observing and recording the changes of readings of the two groups of strain gages to obtain two groups of strain values released in the direction of the weld joint, and performing numerical value averaging on the obtained two groups of strain values of the two cut surfaces of the weldment, carrying out polynomial fitting through EXCEL, and finally, obtaining an original residual stress distribution curve in the direction of the weld joint through conversion according to Hooke's law. The method has the beneficial effects of high measurement accuracy, multi-point measurement, high reliability, convenient operation and low equipment cost.

The present invention discloses an overall roadway displacement and strain stress monitoring device. The overall roadway displacement and strain stress monitoring device is fixed on the surrounding rock of a roadway and comprises three or more detection lines; a steel wire in a rope displacement sensor in each detection line passes through a plurality of stress hanging rings and is terminated at a fixing device; and the rope displacement sensor is connected with a data acquisition device, a data conversion device, a data transmission device and a data processing device sequentially. The invention also provides a monitoring method. According to the monitoring method, initial data are measured; and the strain stress and pressure of different geological formations and engineering reinforcement surrounding rock or channels are calculated through using Hook's law and derivative laws. The overall roadway displacement and strain stress monitoring device has the advantages of simplicity, long service life, high adaptability and high generalization performance. According to the overall roadway displacement and strain stress monitoring device and method of the invention, monitored distances can be changed according to needs, so that the repeated installation of sensors can be avoided. The device is applicable to complex and harsh environments, can improve measuring precision, can measure the deformation condition of a section of the roadway or the whole roadway and can remotely and automatically detect the deformation, convergence and strain stress condition of surrounding rock.

The invention discloses a prediction method for discrete pre-tightening force of a rotation angle method, and the prediction method is mainly used for design and assembling processes of main bolts of engines. The method is divided into two conditions of: in an elastic range, carrying out force balance on a bolt connection pair by utilizing a generalized Hooke's law: a combined computation of <Sigma> F=0 and deformation compatibility <Theta>=(<Delta>Lpull+<Delta>Lpush)*360 / P, so as to obtain pre-tightening force distribution of the rotation angle method; and if plastic deformation occurs to the bolt connection pair, adopting a law of conservation of energy: obtaining a false stress greater than real stress and a false strain less than the real strain under elastic assumption, obtaining a real stress and a real strain by adopting the law of conservation of energy, and finally obtaining the pre-tightening force distribution of the rotation angle method through nonlinear iterative computations of force balance and deformation compatibility. The method disclosed by the invention has the advantages of being simple in computation and well-organized.

The invention discloses a method for modeling high-temperature multi-axis stress and strain relationship under tension and torsion loads. The method comprises the following steps of utilizing single-axis test data to fitting model parameters, and utilizing a single-axis stress and strain hysteresis loop to verify; analyzing the stress and strain states of each multi-axis component under the tension and tension loads; refining the loading process into enough load steps, and utilizing a yield criterion to judge whether each load step is elastic loading or non-elastic loading; for elastic loading step, utilizing an elastic matrix and a Hooke's law multi-axis type to solve the multi-axis stress states; for plastic loading step, utilizing a stress return algorithm to calculate the multi-axis strain increment, and utilizing a radial backflow method to solve the multi-axis stress state; according to the model predicting result and the stress and strain hysteresis loop drawn by the high-temperature tension and torsion test results, finding that the plastic strain and stress peak and valley values are close to the loop shape. After proofing by predicting results, the method can well calculate the high-temperature multi-axis stress and strain relationship under tension and torsion loads.

Residual stress is generated inside a polycrystalline material after the polycrystalline material (such as aluminum alloy and steel) is machined. The invention provides a short-wavelength X-ray diffraction plate-like internal stress fixed-point non-destructive testing method aiming at a polycrystalline plate-like material or plate-like workpiece with a weak texture by utilizing a short-wavelength X-ray diffraction instrument. The method is used for directly measuring a certain (hkl) crystal face diffraction spectrum in a plurality of phi angle (wherein phi is more than or equal to 45 degrees and less than or equal to 90 degrees) directions, and calculating based on the Bragg principle and a stress-strain relationship of in the generalized Hooke's law to obtain the stress of a measured part in the measured direction. With the method, through the translation of X, Y and Z, the stress of the other part can be measured; the stress in the other direction can be measured by allowing the plate-like material or plate-like workpiece to rotate around the normal of a plate surface. For the polycrystalline plate-like material or plate-like workpiece with the weak texture, the stress of any part inside the polycrystalline plate-like material or plate-like workpiece in any direction of an XY plane can be measured.

The invention discloses a method for testing braking force of a muzzle brake. The method is characterized in that four measuring points on the outer surface of a barrel close to the muzzle brake are symmetrically selected, a unidirectional strain gauge is adhered on each measuring point, and directions of sensitive grids are coincided with the axial direction of the barrel; the strain gauges of the measuring points on upper and lower surfaces of the barrel form a bridge system, the strain gauges of the measuring points on left and right surfaces of the barrel form another bridge system, and an average value is solved via strain on the two bridge systems; a gun shoots, the muzzle brake is impacted by a gas flow of the gun in an aftereffect period, tensile force is applied to the barrel by the muzzle brake, and accordingly the barrel stretches and deforms; and the strain gauges sense that the barrel stretches and deforms, electric signals are generated and are transmitted to a data acquisition unit by a dynamic strain indicator, the axial strain of the barrel caused by the muzzle brake is acquired via data processing, and the braking force is acquired by the aid of the Hooke's law. The method has an epoch-making significance in studying a law of recoil resistance of guns, reducing shooting exciting force and vibration of muzzles and improving shooting dispersion of the guns.

The invention discloses an elastic modulus measuring method and device for flexible concrete with the strength of 1-5MPa. The device comprises an axial pressurizing frame, wherein the axial pressurizing frame is connected with an axial auxiometer; the axial auxiometer is connected with an upper pressure transferring plate; an axial displacement meter is connected between the upper pressure transferring plate and a lower pressure transferring plate; the lower pressure transferring plate is in transmission connection with a conical gear of a rotating wheel, so as to enable the lower pressure transferring plate to be lift up and down. The invention further discloses the elastic modulus measuring method for the flexible concrete with the strength of 1-5MPa. In the method, the device is adopted. Compared with a large-scale universal experimental machine and an experimental method of the large-scale universal experimental machine, the elastic modulus measuring device is simple to operate, relatively high in accuracy, and convenient to transport and can be rapidly applied to construction site operation; the experimental theory is based on the Hooke law; according to a stress-strain relation curve chart, the stress value at a starting point of a straight section and the slope of a stress-strain curve are taken as the elastic modulus; compared with other methods, for the method disclosed by the invention, no repeated pre-pressurizing operation is needed; elements to be tested are not damaged because of pre-pressurizing; the method is easy to master and suitable for measuring the elastic modulus of the flexible concrete with the low strength (1-5MPa).

The invention discloses a driving compensation method for a rope-driving continuum robot. The method specifically comprises the following steps of establishing a kinematic model of the continuum robot by combining a segmented constant curvature arc hypothesis and a geometric analysis method; solving Jacobian matrix of the robot based on differential transformation principle; establishing a statics model of the robot based on virtual work principle; building a force transmission model of a rope-wheel drive system based on Coulomb friction; solving the elongation of a robot driving rope based on Hooke's law; and feeding back the driving rope length compensation amount to a control unit to realize error compensation of the transmission system of the continuum robot and improve the motion control precision of the robot. The method of has the characteristics of simplicity, high efficiency, low cost, good universality and the like, avoids using expensive measuring sensors, and realizes thepurpose of improving the motion control precision of the robot by establishing a driving error compensation model of the continuum robot system.

The invention discloses a method and a device for accurately measuring a bridge boom and tensioning the boom. The device consists of an anchor backing plate with a central hole, a sleeve with an adjustment window, fixing nuts, a through lifting jack, a through force sensor, a dynamometer, a limit nut, and a tension rod; and the method comprises the following steps of: determining the through force sensor according to a Hooke's law and the maximum design tension of the boom, calculating the maximum stress of the tension rod, selecting the materials of a tension rod body according to the maximum stress, determining the lectotype of the through force sensor, sequentially assembling, and tensioning the boom by using the through lifting jack, reading the dynamometer, and displaying the force value of the through force sensor. The device has a simple structure, is high in accuracy and low in cost, and is detachable, and can be used repeatedly.

The present invention discloses a synchronous test method for asphalt mixture dynamic stretching, compression modulus and Poisson's ratio. The method places the asphalt mixture split test piece in a split metal fixture of a loading test system, installs a horizontal radial displacement sensor and a vertical radial displacement sensor on end surface of the test piece, and applies a vertical dynamiccompression load to the test piece at a prescribed temperature and frequency. According to Hooke's law under a two-dimensional plane stress state of the split test, the present method deduces an analytical expression of the dynamic compression modulus and dynamic stretching modulus of the asphalt mixture, according to a relationship model between the dynamic compression modulus and the Poisson'sratio, through the method of simultaneously determination of the dynamic compression modulus, the dynamic stretching modulus and Poisson's ratio of the asphalt mixture, the method greatly improves test efficiency and accuracy, and is beneficial to further scientifically and reliably evaluate dynamic response characteristics of the asphalt mixture under the two-dimensional stress conditions, and has good application and promotion value.

The invention discloses an algorithm for calculating the initial rigidity and plastic failure strength of a variable-section metal lattice structure. The algorithm includes the steps of s1, building aplane-coordinate system, and using the plane-coordinate system and the section size of a BCC variable-section metal lattice unit cell rod to obtain the radius expression of the section of the BCC variable-section metal lattice unit cell rod; s2, building a space coordinates system, and using the space coordinates system, the Hooke's law and a bending and compression combined deformation formula to obtain the relational expression of spatial tangential force, bending moment and spatial displacement borne by the node of the unit cell rod; s3, using the energy conservation law and the relationalexpression of spatial tangential force, bending moment and spatial displacement to obtain a quadratic equation in one unknown related to the tangential force of the node of the unit cell rod, solvingthe quadratic equation in one unknown to obtain a tangential force expression which does not contain the spatial displacement of the node, and using the tangential force expression and the relation between the tangential force at the node and axial force and the bending moment to obtain the expression of the axial force and the bending moment; s4, using the Hooke's law and the expression of the tangential force, the bending moment and the axial force to obtain the initial rigidity and plastic failure strength of the BCC variable-section metal lattice structure.

The invention discloses an underground structure construction-oriented soil performance monitoring device and a working method thereof. Corresponding laser transmitters and receivers are arranged on the outer walls of circuit protection boxes and the inner walls of soil pressure contact plates, and circuits in each circuit protection box are connected in parallel and turned on after two metal conductive rods are conductive in water. Disturbance of soil is reflected by monitoring the displacement of the soil pressure contact plates via a laser ranging technology, and accurate measurement on multi-directional deformation of soil is realized; meanwhile, the pressure change value of the soil in each direction is calculated via the displacement measured by laser ranging with the use of Hooke's law; besides, the change of underground water level can be displayed via the change of main circuit trunk current by using the Ohm's law; multi-depth and multi-directional automation degree test on the soil is realized, the monitoring data is reliable, the safety of underground structure construction and surrounding buildings is ensured, and the device has broad engineering application prospect and will produce remarkable social and economical benefits.

The invention discloses a lever type laser detection device for material tension. The lever type laser detection device comprises a support frame and laser detection assemblies, wherein at least two groups of laser detection assemblies are arranged in parallel along the tensile direction of a test piece; staff gauges for reading laser line corners are correspondingly arranged on laser transmission lines of lasers of the laser detection assemblies; and a gauge length setting fork is arranged on the support frame. According to the lever type laser detection device disclosed by the invention, a structure with a plurality of lasers is arranged on the test piece and is twisted for a certain angle along the tension of the test piece; the deflection angle of the transmitted laser light path is read by the staff gauge; and material tensile strain multipoint data are obtained according to respective reading of each laser and the material tensile Hooke's law is verified. Therefore, the lever type laser detection device can be used for testing multiple points of the test piece; the test process is direct-viewed and open, thus the test process and the change of parameters can be clearly seen by people on the scene and the lever type laser detection device is suitable for classroom teaching and testing. The invention has the advantages of simple structure, easiness for disassembly, assembly and operation and lower test cost compared with that of equipment in the prior art.

The invention discloses a multipoint laser detection device for shearing strain of a material. The multipoint laser detection device comprises a test piece support assembly, a torque applying assembly and a laser detection assembly, wherein the support assembly comprises a test piece support seat for fixedly supporting the test piece and enabling the test piece to be horizontally arranged; the laser detection assembly comprises at least two lasers which are longitudinally distributed along the test piece; the lasers are respectively and fixedly arranged on laser clamps which are in one-to-onecorrespondence with the lasers; and staff gauges for reading laser line corner are correspondingly arranged on the laser lines of the lasers. According to the multipoint laser detection device disclosed by the invention, the relationship between the shearing strain and the torque as well as the relationship between the shearing strain and the distance between a stressed point and a fixed point can be obtained and the material shearing Hooke's law is verified. Therefore, the multipoint laser detection device can be used for simultaneously testing a plurality of sections of the test piece; the test process is directly-viewed and open, thus the test process and the change of parameters can be clearly seen by people on the scene and the multipoint laser detection device is suitable for classroom teaching and testing. The invention has the advantages of simple structure, easiness in disassembly, assembly and operation and lower test cost compared with that of equipment in the prior art.

The invention discloses a non-contact micro-cantilever beam rigidity measurement method based on an electrostatic force. The method comprises the following steps: establishing an experimental platform, controlling a nanometer micropositioner to drive a micro-cantilever beam to be tested to perform periodic equidistant stepping motion on a vertical direction, measuring a capacitance change betweenthe micro-cantilever beam to be tested and a plate electrode in real time by using a capacitance bridge, and performing mathematical treatment on the experimental data; and using a DC power source toload a periodic equidistant stepping voltage between the micro-cantilever beam to be tested and the plate electrode, using a laser interferometer to measure the displacement change of a free end of the micro-cantilever beam to be tested in real time, and performing mathematical treatment and fitting on the experimental data to obtain a rigidity measurement value of the micro-cantilever beam to betested. The non-contact micro-cantilever beam rigidity measurement method disclosed by the invention is based on the Hooke's law, the electrostatic force is used as the load, the nanometer micropositioner, the capacitance change, a stabilized voltage supply and the like are adopted, a micro-cantilever beam rigidity measurement platform is established, a mathematical relationship among the micro-cantilever beam rigidity, an interelectrode voltage and the displacement of the free end is established, and the non-contact measurement of the rigidity of the cantilever beam is achieved.

The invention discloses an experiment device and method for measuring a large displacement well drill column clamping point. The experiment device comprises a simulation shaft casing pipe section, a simulation shaft naked eye section, a simulation drill column and a measuring instrument. The experiment device is simple in structure and convenient to install and operate. The effect on a correction factor eta of the clamping point position from a water droop ratio lambda is analyzed through a mathematical statistics method, a relation curve, conforming to eta=f (lambda), between eta and lambda is established, the situation that in the process of drilling a large displacement well, the stress state of a drill is complex, and a drill column connector and the well track change affect the measuring errors is corrected as much as possible, the clamping point position is worked out based on the shearing Hooke law, and accordingly the testing precision is improved.

The invention discloses a method for measuring residual stress generated by metallic material pressure processing. The method comprises steps of: cutting a certain position of a to-be-measured metallic material subjected to pressure processing, measuring the specific volume of a cut to-be-measured test sample in a block-shape, and measuring the specific volume of the to-be-measured metallic material prior to pressure processing or in a annealing state; computing the average residual stress inside the corresponding position of the to-be-measured metallic material in virtue of a Hooke's law in a stress-strain relationship according to the measured specific volume; measuring the cut test samples of different positions of the processed to-be-measured metallic material, and measuring the average residual stress of the different positions of the to-be-measured metallic material in virtue of the Hooke's law in the stress-strain relationship according to the specific volumes of the different positions and accordingly acquiring the residual stress distribution of the to-be-measured metallic material in a processed state. The method is simple in test sample preparation, universal in measuring instruments, convenient in operation, high in experiment data precision, good in repeatability, and reliable in data.

The present utility model discloses a force adjustable spring-clamp capo, comprises a string-engaging arm and a damping arm, the string-engaging arm and the clamping arm are hinged together by a composite pressing rivet, wherein a pressure adjustment mechanism is further arranged in a middle of the clamping arm, including: a pressure spring, a regulation screw and a regulation nut, by the pressure adjustment mechanism, a collapsing length of the pressure spring is adjusted, making the force of the spring change (Hooke's law), which makes the clamping force of the capo adjustable, it can also be operated by a single hand of a player as the spring-damp capo, thus owns a simple and easy operation, making a player be able to adjust to a best clamping force according to a requirement of the instrument thereof, to achieve a role of a tune transfer assistance perfectly. By a planar thrust bearing embedded in the regulation nut, the present utility model further reduces the resistance generated by the friction between the regulation nut and the clamping arm greatly, thus simplifies the operation of a force adjustment, and achieves the purpose of effort saving.

The invention discloses an electric pressure cooker with adjustable pressure limiting values. According to the Hooke's law of elasticity mechanics, and based on structures of pressure limiting valves and production and assembly of existing electric pressure cookers, a pressure adjusting knob (6) is adjusted, so that an elastic part (5) is compressed and deformed, the pressure of the upper end port of a sealing exhaust pipe (2) of a gravity valve body (3) is changed, adjustment of the pressure limiting values of the electric pressure cooker is achieved and the cooking performance of the electric pressure cooker is improved with the smallest change, the lowest cost, the simplest operation and the most reliable structure on the basis that characteristics and operation of existing electric pressure cookers are reserved.

The invention discloses a Brazilian split method for measuring an elastic parameter of a rock under an extension condition, which comprises the steps of: A. horizontally putting a machined disc-shaped sample between the load bearing plates of a press machine by using a Brazilian disc split method, placing a hard steel wire respectively between the upper load bearing plate and the sample and between the lower load bearing plate and the sample, arranging a filler strip perpendicular to the symmetrical surfaces of the sample, and applying pressure on the upper load bearing plate and the lower load bearing plate to make the sample generate tension perpendicular to the action directions of an upper load and a lower load; B. carrying out analysis by using the Hooke's law in classical elasticity mechanics by combining specific conditions of the Brazilian split method; C. analyzing the stress condition of the rock and the measurement principle in the Brazilian disc split method; and D. obtaining the strain in the stress direction according to the Hooke's law from the stress condition sigma3=0, measuring epsilon1 and epsilon2, obtaining the elastic parameter of the rock sample, and arranging a strain gauge in the center position of the rock sample for measurement of epsilon1 and epsilon2. The method has the advantages of easiness for operation and use, clear principle, low material consumption, and the like. The method is suitable for wide popularization and application.

The invention provides a prestressed pipeline friction loss test and calculation method. The test and calculation method comprises the following steps: (1) carrying out multiple times of asymmetric tensioning and symmetric tensioning operations on a prestressed steel bundle, and recording related data; (2) deducing a calculation formula of a friction influence coefficient of the prestressed pipeline based on a stress uniform distribution principle in a Hertz contact theory; and (3) according to the deduced calculation formula, calculating a friction influence coefficient of the prestressed pipeline by utilizing the elongation difference of the prestressed steel beams which are tensioned twice, and evaluating the prestressed friction loss. The method is based on the stress uniform distribution principle of the Hertz contact theory and skillfully utilizes the Hooke law; the test method is convenient and economical, can effectively and reasonably calculate the friction influence coefficient and the prestress friction loss value of the prestress pipeline, and is suitable for prestress concrete bridges with symmetrically arranged prestress steel beams; and the prestressed pipeline friction loss test and calculation method is convenient and fast in test, high in efficiency, low in cost, good in economy and high in accuracy.

Disclosed is a double elastic modulus method under the condition of short initial tangential path of a load-deformation curve of a material. Data merging method and energy ratio method are used to determine the initial tangential path of a load-deformation curve and the elastic modulus E of the tangential path in the double elastic modulus method; after a graphic shifting method is used, a complementary line from point Pp which is the end point of the initial tangential path to Pc which is a point in a special interval above the point Pp is drawn when the value of point Pp is smaller than the value of point Pc, and the elastic modulus E1 of the complementary line is determined. As for a brittle material, the point Pc is chosen between 0.5 Pb and 0.55 Pb; as for a plastic material without a yield stage, the point Pc is chosen between 0.5 Pp0.2 and 0.55 Pp0.2. The double elastic modulus method leads out bilinear Hooke's law, and makes application range of Hooke's law and calculation accuracy greatly increased, thereby being of good value for engineering application.

The invention discloses a method for rapidly generating agile imaging satellite earth observation requirement plans, and aims at providing a method for rapidly determining appointed satellite task observation time from an angle of enabling the whole imaging quality to be optimal. The method is realized through the following steps of: establishing a spring-particle system model on the basis of a Hooke's law and force balance; calculating constant machine time of each observation task and all the other observation tasks according to a geographic position of an observation object and maximum comprehensive angle observation ability of a satellite, so as to form a constant machine time matrix; sorting the observation tasks, adding the observation tasks into a spring-particle system in sequence, calculating a position of each task sliding block when the spring-particle system keeps a force balance state after each observation task joins by applying a satellite attitude mobility table and the constant machine time matrix, obtaining an optimal observation time of each task, and generating an agile imaging satellite earth observation requirement planning scheme.

The invention discloses a gas-containing coal body expansion deformation measurement method comprising the following steps that (a) drilling is performed through a coal seam to reach a bottom plate and then stopped; (b) a gas-containing coal body expansion deformation measurement device is fed to the drilling bottom; (c) the drilling section of the interface of the coal seam and a top plate is sealed by a hole sealing wooden plug, the upper space of the hole sealing wooden plug is filled by polyurethane and the numerical value P0 of a digital display stress meter is recorded; and (d) the numerical value P1 of the digital display stress meter is recorded after pushing the lower working surface, and spring deformation deltax, i.e. the expansion deformation of a gas-containing coal body, is calculated and obtained according to the Hooke's law deltap / k=deltax, wherein deltap=P1-P0. Drilling instability and hole collapse and other liable factors are overcome so that the expansion deformation of the gas-containing coal body can be accurately measured. Besides, the Hooke's law can be ingeniously utilized, and the expansion deformation of the gas-containing coal body can be indirectly reflected by the change of the spring stress so that the principle of measurement is simple and convenient; meanwhile, the measurement device is simple in the whole structure, easy to operate and suitable for large-scale popularization.

The invention belongs to the technical field of equipment detection, and particularly relates to a steam turbine generator unit shafting periodic fluctuation vibration diagnosis method which comprisesthe following four steps: 1, performing vibration preliminary analysis according to operation and vibration measurement data; p 2, carrying out stress analysis on steam turbine generator unit shafting; 3, drawing a shafting bending strain schematic diagram; and 4, introducing Hooke's law to perform vibration analysis. For the vibration problem that the vibration amplitude fluctuates periodically,conditions actually encountered in engineering are relatively few, and periodic fluctuation vibration of a steam turbine generator unit with data records at present only relates to beat vibration andfriction vibration. However, if the periodic vibration law and characteristics of the steam turbine generator unit are not completely matched with friction vibration or beat vibration, the Hooke's law is applied to vibration analysis by using the diagnosis method, so that the defect reason can be accurately positioned, and the engineering practical problem is solved.

A retractable cord queue barrier system uses a spring-biased pulley refraction mechanism acting on a stretchable cord. A constant-force coiled metal spring is used, such that the retraction force on the cord does not increase as the cord is extended—as it would for a helical spring governed by Hooke's Law. The use of a constant-force spring avoids abrupt snap-back of the extended cord when released, as well as the need for excessive pulling force on the cord as it approaches full extension, which tends to cause the stanchion to tip over. Dynamic balance between the contractive force of the stretchable cord and the retractive force of the constant-force spring achieves a taut but not unyielding tension in the interconnecting cords between stanchions.

The invention provides a tension torsion steady-state cyclic stress-strain modeling method based on basic mechanics parameters. The tension torsion steady-state cyclic stress-strain modeling method based on the basic mechanics parameters comprises the following steps of: step (1). obtaining the basic mechanics parameters of a material; step (2). calculating relevant material parameters by using the basic mechanics parameters; step (3). dispersing load steps, and calculating the stress tensor by using the Hooke's law; step (4). using the yield criterion to judge whether the stress state in step(3) is in the elastic loading stage, if yes, performing the next calculation according to step (6), otherwise, performing the next calculation according to step (5); step (5). calculating an additional strengthening coefficient, a non-proportional band factor, a plastic modulus, plastic strain tensor, bias stress tensor and back stress tensor; and step (6). judging whether the loading is completed, if yes, obtaining the multi-axis steady-state cyclic stress-strain, and otherwise, repeating steps (3) to (6). The tension torsion steady-state cyclic stress-strain modeling method based on the basic mechanics parameters avoids the complicated multi-axial fatigue test, and considers the non-proportional additional strengthening effect of the material, and is convenient for engineering application.

The invention discloses a method for identifying internal force of a main cable of a large-span suspension bridge, and relates to the technical field of maintenance of the main cable of the suspensionbridge. The method comprises the following steps: acquiring an unstressed radial load set q per unit length, an equivalent elastic modulus E of a main cable strand, a net area A of the main cable, acable force Pi of a sling, and vertical and longitudinal relative coordinates of a lifting point during blanking of the main cable; Due to the fact that the bending rigidity of the cable is very small, and no fixed shape exists, for cable structure calculation of the suspension bridge, the following assumptions can be adopted: (1) the cable is ideal and flexible, cannot resist pressure, and cannotresist bending; 2, the cable material conforms to Hooke's law; And (3) the acting direction of the cable unit load and the cable curve are in the same vertical plane. By deducing the relationship between the internal force of the main cable and the structure system parameters, the internal force of the bridging main cable can be accurately obtained only by actually measuring the structure systemparameters of the main cable, and the problem that the internal force of the main cable of the existing large-span suspension bridge is huge and inconvenient to identify is solved.

The invention discloses multi-nano carbon filament composite carbon fiber which is multi-nano carbon filament composite convolute carbon fiber, wherein the scalability conforms to the Hooke's law, andthe rigidity exceeds 9.8Gpa. The convolution diameter of the composite carbon fiber is 0.1-10mu m, and the thread pitch is 0.1-5.5mu m; the diameter of the carbon subfiber forming the composite carbon fiber is 0.05-1.5mu m; the subfiber is obtained by combining a plurality of carbon filaments with diameter of 50-500nm; the composite carbon fiber is convoluted regularly with constant convolution diameter and thread pitch along a convolution shaft. With the technical scheme, the multi-nano carbon filament composite carbon fiber disclosed by the invention has the following advantages in comparison with the prior art: the preparation technology is simple and easy to implement; the multi-nano carbon filament composite carbon fiber disclosed by the invention has a regular convolute form, certain thread pitch and elasticity and rigidity, and is suitable for being used independently as a micro mechanical element.