128 results about "Added mass" patented technology

The invention relates to a method for predicting a fluid-solid coupled characteristic value of an elastic hydrofoil and belongs to the technical field of turbomachinery simulation. The method comprises the steps of establishing a two-dimensional drainage basin-hydrofoil geometric model, dividing the gridding of a two-dimensional drainage basin, establishing a computational fluid mechanical model, calculating an initial steady flow field value and an unsteady flow field fluid-solid coupled value, and then performing after-processing on the calculation results to obtain the dynamic change process of the deformation of the flow field structure and the hydrofoil with time. The method for predicting the fluid-solid coupled characteristic value of the elastic hydrofoil has the advantages that the influence of an added mass effect on flowing is taken into account so that the stability of value calculation and the reliability of a numerical prediction result are improved, quick high-accuracy numerical prediction on an oscillation phenomenon induced by flowing around the elastic hydrofoil can be realized, and the flexibility of selection of numerical computation methods can be enhanced by virtue of secondary development of computational fluid mechanical software in combination with an embedded fluid-solid coupled algorithm.

A control system (18) and method for an automotive vehicle (10) includes a pitch rate sensor (37) generating a pitch rate signal, a longitudinal acceleration sensor (36) generating a longitudinal acceleration signal, and a yaw rate sensor (28) generating a yaw rate signal. A safety system (44) and the sensors are coupled to a controller. From the sensors, the controller (26) determines an added mass and a position of the added mass, a pitch gradient and/or a pitch acceleration coefficient that takes into account the added mass and position. The controller controls a vehicle system in response to the added mass and the position of the added mass, the pitch gradient and/or pitch acceleration coefficient variables.

An acceleration sensor having a vibrating body includes: a base fixed to a pedestal; an oscillating arm extended from the base in a beam-like shape, oscillating transversally in a planer direction at a predetermined resonant frequency. Here, the oscillating arm includes: an oscillating block defined by a through hole opened through a thickness direction at a widthwise center of the oscillating arm, the through hole extending in a lengthwise direction thereof; an added mass being a junction of a distal end of the oscillating block defined by the through hole; and an excitation means installed on the oscillating arm. At this time, the oscillating arm is supported by the base and by the added mass, either in a pseudo-dual anchor structure or a single anchor structure. With the above configuration, the acceleration sensor detects a resonant frequency variability of the vibrating body caused by an inertial effect of the added mass under acceleration.

The invention relates to a large-sized axial eddy current damper manufactured by using screw drive. The damper comprises a drive component and an eddy current damping generator, wherein the drive component comprises a screw drive pair, a stator and a rotor; the stator and the rotor are made of a magnetic conductive material; the screw drive pair comprises a screw and a nut which is arranged on the screw in a sleeving manner; the screw penetrates through an upper flange central hole of the stator and a lower flange central hole of the stator in sequence, and the nut is arranged in the stator; the rotor comprises an outer rotor and an inner rotor of which the bottom is provided with a lower connecting flange; one or more eddy current damping generators are arranged between the stator and the rotor. According to the damper, the damping coefficient and the inertial mass moment of the rotary eddy current damping part can be enlarged by hundreds of thousands of times to be converted into extremely large axial damping coefficient and axial equivalent added mass; meanwhile the problem that the axial damper with a large damping coefficient and the anti-seismic damper with a simulation speed index of being less than 1 are difficult to manufacture by using the rotary eddy current damping is solved.

Dynamic motion decoupling is effected with the use of mass, added mass, buoyancy, submerged weight and drag in areas of relatively low tension. High curvatures of lines on some configurations, together with their low slope may be utilized. The original line configuration may or may not be modified. Known motion suppressing device designs can be used. Because of the low slope on some configurations, said motion suppressing devices can be installed on arbitrarily long line segments to achieve objections required. Novel, drag and added mass enhancing devices effective in all directions can be used to increase the suppression effectiveness and/or in order to reduce the number of devices used. This invention is suitable for use on new designs and it is also suitable for retrofitting on existing, already installed lines.

The invention relates to a non-linear particle impact damper. The non-linear particle impact damper comprises an additional flange outer ring, a mass inner ring, variable stiffness springs, damper cavity units and particle groups. The additional flange outer ring is connected with a main system through bolts, the additional flange outer ring and the mass inner ring are arranged concentrically, in the horizontal direction, the mass inner ring is connected with the additional flange outer ring through the variable stiffness springs, a spring unit is composed of eight variable stiffness springs which are arranged uniformly and symmetrically in the circumferential direction, each damper cavity unit is a single cuboid or cylinder structure, the interior of each cavity is provided with a layer of the particle groups, and the particle groups are composed of round or out-of-shape metal or nonmetal particles. By reasonably arranging the rigidity of the variable stiffness springs and the added mass, different rigidities can be provided in all directions on the horizontal plane in order to tune the frequency of the structure. Under the action of wind/earthquake, the non-linear particle impact damper provides different rigidities in all directions to tune the frequency, spring rigidities are not changed linearly, and kinetic energy of the structure can be transferred and dissipated through friction and impact of the particle groups.

The invention provides a vibration enhanced device of electric vibration table, comprising a substrate and a test bed; the device is characterized in that: a spring is connected between the substrate and the test bed; a rigid guide bar leading the test bed surface to do vertical movement is installed between the substrate and the test bed; an additional mass block is placed at the center of the test bed; selection of the rigidity of the spring and the resonance frequency of the spring quality system satisfy the following relationship: omega n2=k(M+m)/Mm. Compared with the prior art, the technical proposal is easier to be implemented, and can effectively limit the transverse vibration and conveniently control the vibration enhanced frequency. The vibration enhanced ability can arrive more than 10 times. The technical proposal and the method can be used in various dynamic test apparatuses for enhancing the vibration acceleration or displacement and providing special dynamic excitation source.

The invention discloses a method for testing the local mode of an automotive sheet part. A white noise signal is used as an excitation source. The method comprises the steps as follows: a tested sheet part is suspended, a point which can excite a frequency-response function of the tested sheet part most is selected as a primary optimal excitation point, a connection instrument adopts the optimal excitation point, the sheet part is tested by a laser vibrometer, and test data are saved; and the tested data are subjected to data analysis, the frequency-response function of the sheet part is obtained, and a mode shape for testing an outside plate of an automotive door is obtained. According to the method, the laser vibrometer is used, a test object model is not required to be established, effects of structural nonlinearity and added mass on test precision can be avoided, the test time is saved, the test precision is guaranteed, and the test efficiency is improved.

A flywheel arrangement with a drive-side transmission element and a driven-side transmission element which is rotatable relative to the drive-side transmission element includes at least one annular added mass fastened to at least one of the transmission elements. In order to produce the added mass, a blank formed from strip material is shaped in its longitudinal direction to form a ring, so that the corresponding ends of the blank are directed toward one another with a predetermined intermediate gap and are fixed in this position relative to one another by a retaining mechanism.

The invention discloses a method for improving the seismic performance of a bridge through girders. Under the conditions that the external added mass does not need to be introduced, and the installing space does not need to be found on pier bodies, harmful vibration of bridge piers at the natural frequency band is effectively eliminated, the stress of the pier bodies is reduced, and the seismic performance of the bridge piers is improved. The girders, the bridge piers and a support system arranged between the tops of the bridge piers and the longitudinal end portions of the girders are included. The method comprises the following steps that the natural vibration frequency fi, the equivalent modal mass Mi and modal rigidity Ki of the bridge piers in the longitudinal direction and the transverse direction are obtained through the numerical value modal analysis or the experiment modal test; the mass mi of the girders is determined; the connecting rigidity ki between the girders and the bridge piers is calculated; the connecting damping ci between the girders and the bridge piers is calculated; and the support system with the values of the above connecting rigidity ki and the above connecting damping ci is selected, and in the other words, the girders can serve as a power vibration absorber for improving the seismic performance of the bridge piers.

A method to rotate individual pad of a batch disk to an implant angle and lock them in place, with the pad surface having conical or near conical surface to minimize the implant angle variation across a wafer on the pad for both tilt angle and twist angle, at large tilt angle implant. The implanter includes a disk with multiple attached pads that can hold substrates securely when the hub is at rest or rotates. The disk rotates around its spin axis, which moves laterally at a programmed speed profile so that all substrates on the hub can get evenly touched by the fixed ion beam. The pad rotation axis is at an angle with the disk spin axis, and the angle is preferable 90 degrees. The nominal of the pad surface is at an angle, i.e., a tilt angle, relative to the incident ion beam. A rotation mechanism is applied to each individual pad to rotate the pad to the desired tilt angle. A locking mechanism is applied to each individual pad assembly to lock the pad at the desired tilt angle with minimum angle variation under high centrifugal force during fast disk spin. The locking mechanism includes: a) add brake to the rotation mechanism in the pad assembly so that the pad cannot rotate due to mechanical friction force or lock-key. B) use motor to hold the pad assembly. The sum of the friction torque and the motor holding torque should be larger than the centrifugal torque. A torque balancing mechanism is applied to pad mechanical design to minimize the total pad rotation torque under centrifugal force during fast disk spin by adding mass to counter balance the original wafer pad mass.

The invention discloses a method for accurately measuring the cable force of a short boom of a boom arch bridge. A relevant measuring model is designed, boundary conditions of the boom are simplified into damping and spring supporting of a simple support boom in a corresponding transverse position, the boom is further equivalent into a simple support stretching rope with the equivalent calculation length, a mass block is additionally arranged in the middle of the boom, a vibration balance equation of ropes is set up before and after the mass block is additionally arranged in the middle of the boom, an algorithm of recognizing the equivalent calculation length L0 of the boom by using measured frequencies of the boom before and after the additional mass block is arranged is finally and optimally formed, and therefore the method for accurately measuring the cable force is set up. According to the method for accurately measuring the cable force, measurement is convenient to conduct, and a user only needs to conduct vibration frequency measurement twice on the boom before and after the additional mass block is arranged. The measuring accuracy is high, and the difficult problem of accurately measuring the cable force of the short boom can be well solved. When the method is applied to the field of detection or construction monitoring of boom arch bridges, the cable force of the short boom can be rapidly and conveniently measured at high accuracy, and therefore reliable essential data are provided for detection and monitoring of the boom arch bridges.

The invention relates to a damage identification method for a light high-strength beam structure. According to the method, a comprehensive damage index of the structure is obtained based on an added mass frequency sensitivity damage equation and a modal strain energy damage equation, and the damage position and damage degree of the light high-strength beam are identified. The damage index calculated through a modal shape and modal strain energy can accurately express the damage position and damage degree of the light high-strength beam structure, calculated damage parameters are more accurate, and the method of solving the structure damage parameters is more accurate compared with the prior art.

The invention provides a ship structure impact experiment boundary condition simulation device. The ship structure impact experiment boundary condition simulation device comprises two horizontal flat plates and two vertical flat plates. The horizontal flat plates are connected with the vertical flat plates through triangular supporting plates to form two right-angle L-shaped frames respectively, a boundary steel fixing plate is arranged at the center of the inner side of each vertical flat plate, tools used for fixing experiment components are arranged on the boundary steel fixing plates and the two ends of an experiment beam model are fixed between the two right-angle L-shaped frames respectively. The principle that when a steel plate moves in the plate face normal direction in water, huge added mass is generated, the added mass generated through the structure is used for replacing the boundary constraint borne by the model, and added inertia force and torque of the rigid fixing boundary can be obtained. By means of the ship structure impact experiment boundary condition simulation device, the boundary conditions of rigid fixing at the two ends of the model can be well simulated. The ship structure impact experiment boundary condition simulation device further has the advantages of being simple in structure, convenient to machine and assemble and capable of bringing convenience to quality control.

The present invention provides a small and highly sensitive acceleration sensor. The acceleration sensor (1) is a vibrating body (10) composed of a base (20) fixed on a base and a beam-shaped vibrating arm (21) extending from the base and bendingly vibrating in a plane direction at a predetermined resonance frequency , wherein the vibrating arm has: a vibrating arm part (23, 24) that is divided in the central part in the width direction by a through opening (22) perpendicular to the vibration direction and set in the length direction; An additional mass part (25) with the same or greater mass as the base of the front end of the vibrating arm part; and excitation electrodes (31-34) arranged on the vibrating arm part, the vibrating arm is fixed by the base part and the additional mass part with pseudo double ends Structurally supported, the acceleration sensor detects a change in the resonance frequency of the vibrating body brought about by the inertial effect of the additional mass portion when acceleration is applied.