166 results about "Nonlinear stiffness" patented technology

The invention discloses a parallel mechanism based multidimensional vibration platform. Standard zero stiffness of a vibration isolation platform at the equilibrium position and nonlinear stiffness nearby the equilibrium position can be realized by setting certain structural parameters, and the problem about difficulty in isolating low-frequency or ultra-low-frequency vibration for a traditional linear vibration isolation system; stiffness and damping can be easily and conveniently adjusted, vibration isolation of broad frequency domains are satisfied, and good engineering applicability is achieved; the multidimensional vibration platform is high in bearing stiffness, low in movement stiffness, small in static deflection, low in dynamic inherent frequency and good in vibration isolation effect; inherent contradictions restricting the traditional vibration isolation system, namely the contradictions of low-frequency vibration transmissibility and high-frequency vibration attenuation, can be solved by flexible adjustment of the stiffness and damping; the height and the static equilibrium position of the entire platform can be changed by adjusting a shock absorber spring base in height, and the multidimensional vibration platform is applicable to vibration isolation of objects of different weight.

A MEMS apparatus for scanning an optical beam comprises a mirror operative to perform a rotational motion to a maximum rotation angle around a mirror rotation axis, and a bouncing mechanism operative to provide a bouncing event and to reverse the rotational motion. The bouncing event provides the mirror with a piecewise linear response to actuation by intrinsically nonlinear electrostatic forces. The bouncing mechanism includes an element chosen to impart an overall nonlinear stiffness to the system and is selected from the group of elements consisting of a bouncer and a pre-curved nonlinear stiffness element.

A belt automatic tensioning device by rigidity-variable consists of eccentric displacement mechanism formed by pulley, roll bearing, eccentric wheel and debber; eccentric wheel rigidity-variable twisting mechanism formed by base plate, eccentric wheel, spring jacket base and cylindrical screw spring; damping formed by frictional damper between eccentric wheel and debber as well as frictional damper at end surface of eccentric wheel.

The invention discloses a six-degree-of-freedom parallel mechanism vibration attenuation platform. By setting a given structural parameter, the quasi-rigidness of the vibration isolation platform on a balance position and the nonlinear rigidness of the vibration isolation platform near the balance position can be realized, and the difficulty when the traditional linear vibration isolation system isolates the low-frequency or ultralow-frequency vibration can be solved; the rigidness and damping can be simply adjusted, the six-degree-of-freedom parallel mechanism vibration attenuation platform is suitable for the broadband-frequency vibration isolation and has good engineering applicability; while the supporting rigidness is high, the motion rigidness is low, the static deformation is small, the dynamic intrinsic frequency is low, and the vibration isolation effect is good; by flexibly adjusting the rigidness and damping, the intrinsic contradiction, i.e. the contradiction between the low-frequency vibration transfer rate and high-frequency vibration attenuation rate, for restricting the traditional vibration isolation system can be solved.

The invention belongs to the technical field of vibration noise control and energy collection, and relates to a mechanical device integrating the functions of broadband vibration absorption and vibrational energy collection. The mechanical device mainly comprises a baseplate, a nonlinear energy sink mechanism and a vibrational energy collection unit, wherein a buckling beam, the two ends of whichare compressed, and magnetic spring mechanisms arranged at the two sides jointly provide the pure cubic nonlinear stiffness required by the nonlinear energy sink; and the vibrational energy collectionunit mainly comprises an induction coil. The mechanical device can realize the fast, efficient and irreversible transfer of vibrational energy of external mechanical equipment to the non-linear energy sink mechanism in a broadband range, so that the equipment vibration is suppressed; energy absorbed by the non-linear energy sink mechanism can be further dissipated through electromagnetic dampingand is converted into electrical energy for storage, and thus, the dual functions of vibration control and energy collection are realized. The mechanical device has the advantages of wide vibration absorption frequency band, high vibration absorption efficiency, high energy collection efficiency and the like, is simple and compact in structure and has strong applicability.

The invention provides a high-linearity quasi-zero stiffness vibration isolator which comprises a supporting plate, an upper frame, a lower frame, eight sets of horizontal spring mechanisms, eight sets of connecting rod mechanisms, a three-permanent-magnet mechanism, four sets of vertical supporting mechanisms and a base. Mounting holes are machined in the supporting plate. Four of the eight sets of horizontal spring mechanisms are installed on the upper frame and connected with the supporting plate through bolts. The other four of the eight sets of horizontal spring mechanisms are installed on the lower frame and connected with the base through the four sets of vertical supporting mechanisms. The upper frame and the lower frame are connected through bolts. The connecting rod mechanisms are installed between the eight sets of horizontal spring mechanisms and the three-permanent-magnet mechanism and connected in a hinged mode. A groove is designed to be formed in the middle of the joint between the upper frame and the lower frame and used for fixing a middle permanent magnet of the three-permanent-magnet mechanism. According to the high-linearity quasi-zero stiffness vibration isolator, main nonlinear stiffness terms are counteracted, high linearity of the quasi-zero stiffness vibration isolator is guaranteed, dynamic behaviors of quasi-zero stiffness are more stable through the achievement of high linearity, the vibration isolation performance is more excellent, and the high-linearity quasi-zero stiffness vibration isolator can be better used for vibration control.

The invention discloses a flexibly adjustable quasi-zero rigidity vibration attenuation platform. The flexibly adjustable quasi-zero rigidity vibration attenuation platform comprises a fixed platform, a moving platform, a vibration attenuation component and thrust components, wherein the vibration attenuation component is connected with the fixed platform and the moving platform; the thrust components are arranged on the fixed platform and used for exerting a thrust force on the moving platform; the multiple thrust components are arranged around the moving platform. According to the flexibly adjustable quasi-zero rigidity vibration attenuation platform, quasi-zero rigidity in a static balance position and nonlinearity rigidity nearby a static balance position of the vibration attenuation platform can be achieved; the problem of failure in low frequency or ultra-low frequency vibration isolation in terms of traditional linear vibration isolation systems can be solved; inherent contradictions which restrict the traditional vibration isolation systems can be eliminated; problems in low frequency vibration transmission rate and high frequency vibration attenuation rate can be solved.

The invention discloses a multi-dimensional vibration isolation platform provided with multiple air springs and multiple dampers. The lower ends of the air springs and the lower ends of the dampers are connected with a base frame lower plate in a hinged mode through hinges. The upper ends of the air springs and the upper ends of the dampers are connected with a load disc through ball-shaped hinges. The load disc is connected with hydraulic cylinder piston rods of multiple hydraulic cylinders in a hinged mode through connecting rods. Cylinder bodies of the hydraulic cylinders are connected with a base frame upper plate in a hinged mode. The invention further discloses the air springs in the vibration isolation platform. By the adoption of the technical scheme, hydraulic pressure components serving as negative rigid components are in parallel connection with the air springs serving as positive rigid components, quasi-zero rigidity of the vibration isolation platform at a balance position and non-linear rigidity of the vibration isolation near the balance position are achieved, the difficulties caused when a traditional linear vibration isolation system isolates low-frequency vibration or ultra-low-frequency vibration can be solved, rigidity and damping can be adjusted simply and conveniently, and the multi-dimensional vibration isolation platform and the air springs are suitable for wide-frequency-domain vibration isolation and have good engineering applicability.

The invention relates to the technical field of bogies of railway vehicles, and discloses a draw gear of a bogie of a railway vehicle. The draw gear comprises a center pin and two draw rubber bags. Each draw rubber bag comprises a draw rubber pile and a rubber bag, the rubber bags are filled with liquid, and pressures can be set for the rubber bags; the draw rubber piles are connected with the rubber bags; the center pin is fixed to the lower surface of a body bolster of chassis of a vehicle body of the railway vehicle; one end of each of the two draw rubber bags is connected with the center pin, and the other end of each draw rubber bag is used for being connected with a transverse beam of a framework of the railway vehicle. The draw gear has the advantages that the draw gear has a nonlinear rigid characteristic, accordingly, high-frequency vibration of the framework can be prevented from being transmitted to the vehicle body and the body bolster of the chassis of the vehicle body via the draw gear while longitudinal loads are effectively transmitted, and the riding comfort can be improved.

Disclosed are a damping device (100) and a vehicle-mounted gimbal platform (10) using the damping device (100), wherein the damping device (100) comprises an upper damping connecting member (110), a lower damping connecting member (120) which is arranged opposite and spaced apart from the upper damping connecting member (110), a steel wire rope damper (130) arranged between the upper damping connecting member (110) and the lower damping connecting member (120), and a bearing damper (140) connected to the upper damping connecting member (110), two ends of the steel wire rope damper (130) being respectively connected to the upper damping connecting member (110) and the lower damping connecting member (120). In the above-mentioned damping device (100), the steel wire rope damper (130) is connected between the upper damping connecting member (110) and the lower damping connecting member (120), since the steel wire rope damper (130) has non-linear rigidity and non-linear damping characteristics, and has the advantages of high environmental adaptability, long service life, various mounting modes, good buffering and anti-impact performances, high damping, convenience in installation and the like, the above-mentioned damping device (100) has high performance under different vibration conditions, influences of external vibration on the gimbal platform (10) are weakened effectively, and the vibration frequency is reduced.

The invention provides a vibration isolation device for combining high and low frequency vibration. The vibration isolation device is composed of a base, a concave support table, a fixed bottom plate, a frame, a vertical stiffness-damping mechanism, a locking clamp, a horizontal stiffness-damping mechanism, a movable hinging chain seat, a guide rod and a straight line bearing. A realization device of nonlinear stiffness and nonlinear damping is provided based on special vibration isolation performances of the nonlinear stiffness and the nonlinear damping. A stiffness-damping mechanism comprised by the realization device has low dynamic stiffness to enlarge vibration isolation band and has high static stiffness to ensure that static deformation is small and does not lose stability; and the realization device also uses nonlinear damping to together suppresses the height of formant, and while reducing the height of the formant, the formant is moved left to broaden the vibration isolation frequency band and to suppress the transmission rate at high frequencies.

The invention provides a compound damping elastic support used for the cushion bases of the floating compartments and devices used for a ship, the elastic chair of a vehicle, the anti-shaking foundations of engineering constructions and engineering facilities and the elastic bases of various electromechanical devices and facilities, thus meeting the comprehensive technical requirements of shaking isolation, anti-shaking and cushion of an engineering system, specially the safety protection requirement on low-frequency large-displacement impact and interference. The compound damping elastic support which consists of an annular elastic body and a damping cushion mechanism is provided with a quasilinear comprehensive rigidness characteristic under a normal working situation which is automatically converted into a softening nonlinear rigidness characteristic under the transient large displacement working situation. The compound damping elastic support can lead the engineering system to realize excellent comprehensive dynamic technology performance of low-frequency shaking-isolation effect, impact safety, stability in a normal working state, and has the advantages of simple structure, long service life, high safety and reliability as well as low maintenance cost.

Disclosed is a design method for a rubber profile of a traction rod node. A mandrel, a jacket and a rubber layer vulcanized and adhered between the mandrel and the jacket are included. The method is characterized in that the outer end profile of the rubber layer is designed as an outwardly projecting arc convex surface, the arc convex surface gets gradually close to the inner wall of the jacket from outside to inside, the arc convex surface and the inner wall of the jacket are transitioned through a first transition surface, the arc convex surface and the outer wall of the mandrel are transitioned through a second transition surface, the first transition surface is designed as an inwardly recessed arc surface, and the second transitional surface is designed as an inwardly recessed cambered surface. By applying the design method for the rubber profile of the traction rod node, wrinkles and cracks of the rubber profile during the bearing process are decreased, the fatigue life of the traction rod node under large load is improved, and the nonlinear stiffness of the traction rod node under large load is met. The invention also provides the traction rod node.

Disclosed is a rubber-metal compound spherical hinge with axial nonlinear variable rigidity. The rubber-metal compound spherical hinge with axial nonlinear variable rigidity is composed of rubber andmetal materials in a compound mode and comprises a sleeve and a rubber-metal vulcanized body, which is pressed in interference fit inside the sleeve and composed of rubber and metal materials in a compound mode; the inside of the rubber-metal vulcanized body is provided with an axial variable rigidity adjusting device which can adjust the axial rigidity of the rubber-metal compound spherical hingeso that the axial rigidity of the rubber-metal compound spherical hinge can be changed nonlinearly. The axial variable rigidity adjusting device is composed of two parts including an axial small rigidity variable rigidity adjusting device and an axial high rigidity nonlinear variable rigidity adjusting device, which are combined to achieve axial nonlinear variable rigidity adjustment of the entire rubber-metal compound spherical hinge. Through axial variable rigidity adjustment, the rubber-metal compound spherical hinge with the axial nonlinear variable rigidity provides a nonlinear rigidityidea and accordingly brings about a new design idea for a bogie.

The invention relates to a nonlinear rigidity vibration isolator of natural frequency for high speed vehicle floating floor board. It is made from vibration reduction glue and frame board. It has the nonlinear hardening rigidity feature and low system natural frequency and low influence of load to natural frequency. It has good vibration reduction effect and keeps low noise in the vehicle.

The invention provides a structure reduced-order model-based geometric nonlinear static aeroelastic full-aircraft trim method. The method comprises the steps of firstly building a full-aircraft finiteelement model of an aircraft, giving a follow-up test load and solving corresponding test deformation through finite element software; secondly solving a nonlinear stiffness coefficient by performingregression analysis on the follow-up test load and the test deformation in a given nonlinear stiffness coefficient form to build a structure reduced-order model; and finally applying the model to thegeometric nonlinear static aeroelastic full-aircraft trim analysis of the aircraft, and establishing wing geometric nonlinear static aeroelastic deformation calculation and full-aircraft geometric nonlinear static aeroelastic trim analysis processes. The nonlinear stiffness coefficient in a cubic polynomial form is given, and the aerodynamic follow-up effect and the spanwise deformation under thewing geometric nonlinear large deformation are considered, so that the reasonability and accuracy of geometric nonlinear static aeroelastic analysis are improved and the efficient analysis calculation of geometric nonlinear aeroelastic deformation and trim is facilitated.

The invention aims at providing a rigid cylinder vortex-induced vibration testing device capable of achieving nonlinear boundary conditions. The rigid cylinder vortex-induced vibration testing device comprises nonlinear springs, a vertical restraining mechanism, a cylinder model, a support, a clamp, a supporting frame and a data collecting and analyzing processing part. The data collecting and analyzing processing part is used for collecting and analyzing vibration data of the cylinder model. The vertical restraining mechanism is composed of box iron, a cardan joint, a bolt and an aluminum alloy pipe. The adopted cardan joint has the advantages of being small in damping and flexible in structure. The vertical restraining mechanism is used for enabling vibration of the cylinder model to be kept in the same horizontal plane. A nonlinear boundary cylinder system is jointly composed of the vertical restraining mechanism, the support and the nonlinear springs. The rigid cylinder vortex-induced vibration testing device can be applied to rigid cylinder vortex-induced vibration tests of a circulating water channel or a towing tank, and the vortex-induced vibration mechanism under nonlinear rigidity such as contact between a seabed suspended span pipe and the seabed can be truly simulated.

The invention relates to a deep sea multi-column mooring floating platform vortex-induced motion pool test device. The device comprises a trailer, a longitudinal motion guide rail mechanism, a transverse motion guide rail mechanism, a yawing rotation mechanism, an optical measurement mechanism and a top plate for mounting a floating platform model; a longitudinal elastic piece for determining thelongitudinal rigidity is further arranged between the trailer and the transverse motion guide rail mechanism; a transverse elastic piece for determining the transverse rigidity is further arranged between the transverse motion guide rail mechanism and the yawing rotation mechanism, and an elastic restraining piece for determining the rotating rigidity is further arranged between a yawing rotatingsupport and a connecting main shaft. Compared with the prior art, the test device not only can accurately and equivalently simulate the three-degree-of-freedom rigidity of a mooring system in the horizontal plane under the actual sea condition, but also can simulate the vortex-induced motion response characteristic of a deep sea platform under the nonlinear rigidity equivalent constraint.

The invention relates to an inverse solution method for nonlinear stiffness characteristic parameters and a curve of a suspension of an air spring seat, and belongs to the technical field of vehicle seats. The inverse solution method is characterized in that the nonlinear stiffness characteristic parameters and the curve of the suspension of the air spring seat are obtained in an inverse solution mode through utilization of vertical vibration signals, obtained through measurement, of a cab floor and a seat surface and according to a built seat-human-body vibration model of a nonlinear stiffness characteristic-piecewise linear function Fk and target functions of inverse solution parameters (theta 1, theta 2, theta 3, theta 4 and theta 5), a vibration model of a nonlinear stiffness characteristic-odd power polynomial Fs, and optimization target functions of reverse parameters (Ks 1 and Ks 3). By means of the inverse solution method, the nonlinear stiffness characteristic parameters and the curve of an air spring seat suspension system can be accurately obtained, human body vibration modeling and analyzing precision of the seat is improved, and design level and quality of the seat suspension system are improved; meanwhile, testing expenses further can be lowered, and the product design and development speed is improved.

The invention discloses an elastic assembly capable of providing non-linear variable rigidity. The elastic assembly comprises a casing, a clamping assembly and a clamped piece, wherein the clamping assembly and the clamped piece are connected with the casing and are used for providing variable clamping forces, the interior of the clamping assembly is provided with an elastic piece which is used for providing all or part of clamping forces, the clamped piece is provided with a clamped surface for changing the clamped thickness of the clamped piece, and the clamped piece is used for outputting non-linearly-variable rigidity/force under the action of the variable clamping force provided by the clamping assembly. The elastic assembly has the advantages that the structure is compact, the running is reliable, and the elastic assembly can be applied to occasions requiring the non-linear rigidity; on one hand, the fixed non-linear rigidity is provided, and on the other hand, the rigidity is actively adjusted; the method is convenient for arranging robot joints, by utilizing the elasticity and variable rigidity, the safety problem of the robot in contact with people or unknown environments is favorably solved, and the variable rigidity property of human or animal limbs is favorably simulated, so the moving robot is more approximate to the variable rigidity property of the human or animals, the kinetic energy efficiency of the robot is improved, and the dynamic high-speed movement is realized.

The invention relates to a nonlinear stiffness vibration isolation system based on a hydraulic negative stiffness mechanism. The nonlinear stiffness vibration isolation system comprises hydraulic cylinders (2) and a rolling ball sliding channel bearing body (1), wherein, at least a pair of rolling ball sliding channels which is symmetrically distributed along the center axis of the side face of the rolling ball sliding channel bearing body (1) is arranged on the side face of the rolling ball sliding channel bearing body (1); each hydraulic cylinder (2) correspondingly abuts against a rolling ball sliding channel and the constant hydraulic force is applied to the rolling ball sliding channel bearing body (1) through the hydraulic cylinders (2), and the hydraulic cylinders (2) and the rolling ball sliding channel bearing body (1) form the hydraulic negative stiffness mechanism which provides the vertical negative stiffness; and a vertical positive stiffness spring (4) is further mountedat the bottom end of the rolling ball sliding channel bearing body (1), and vertical force is applied to the rolling ball sliding channel bearing body (1) through the vertical positive stiffness spring (4). According to the nonlinear stiffness vibration isolation system based on the hydraulic negative stiffness mechanism, compared with the prior art, nonlinear stiffness including quasi zero stiffness, piecewise linear stiffness and the like are achieved according to the required stiffness curve.

The invention discloses a buckling temperature analysis method of a plate structure considering a force load, which calculates a linear stiffness matrix and a thermal stress stiffness matrix of the structure considering a thermal effect, and calculates a structural displacement of the plate structure under the action of the force load. Linear stiffness matrix and nonlinear stiffness matrix of plate structure considering structural deformation are established, and the stiffness matrix of structural thermal stress under given thermal load is calculated. The buckling factor is calculated and thebuckling temperature of the plate is obtained. The error between the calculated buckling temperature and the given heat load is calculated, if the error value is within the allowable range, the finalbuckling temperature of the plate structure is equal to the obtained buckling temperature, otherwise, the obtained buckling temperature is taken as a new given heat load, the structural material parameters corresponding to the temperature are updated, and the buckling temperature of the plate structure considering the force load is recalculated until the final buckling temperature of the plate structure is obtained. The invention can effectively improve the analysis precision of the buckling temperature of the plate structure under the complex environment.

The invention relates to a deep sea steel catenary vertical pipe touchdown point power response analyzing method. The method includes: simulating a steel catenary vertical pipe a large-deflection camber beam model, using the movement of a floating platform as the top end boundary condition of the vertical pipe, using a P-y curve method to numerically simulate the mutual effect, including linear elasticity rigidity when a seabed does not deform, the suction force effect when the vertical pipe leaves the seabed and nonlinear rigidity in a reciprocation effect, of the steel catenary vertical pipe and the seabed, building the mutual effect model of the steel catenary vertical pipe and the seabed, combining the mutual effect model with the movement equation of the floating platform and the simulating module of the steel catenary vertical pipe, and applying the combined model to the steel catenary vertical pipe touchdown point power response analyzing. The method has the advantages the existing methods simulating the seabed into a linear elastic spring or a rigid seabed are modified, the mutual effect of the steel catenary vertical pipe and the seabed can be accurately simulated, and calculation precision of steel catenary vertical pipe touchdown point power response analyzing is increased.