A new method of electric energy metering considering harmonic responsibility

Aiming at the shortcomings of the existing electric energy metering method,combining with the harmonic responsibility analysis model based on the reference impedance method and the idea of apparent power decomposition in IEEE Std 1459-2010 standard,two new metering indicators—billing active power and billing power factor are defined.A new electric energy metering method is proposed and its specific implementation steps are given.The simulation model is built in Matlab/Simulink,and three different examples are set up.Using the simulation data,the various metering indicators need to be examined by the existing electric energy metering method and the new electric energy metering method are calculated.The calculation results show that the new electric energy metering method not only overcomes the shortcomings of the existing electric energy metering method,but also is very easy to be popularized and applied.

A method for establishing a bearing residual life prediction model for process enhancement equipment based on rotor imbalance response analysis

A rotating packed bed is a typical chemical process enhancement equipment that can strengthen micromixing and mass transfer.During the operation of the rotating packed bed,the nonreactants and products irregularly adhere to the wire mesh packing in the rotor,thus resulting in an imbalance in the vibration of the rotor,which may cause serious damage to the bearing and material leakage.This study proposes a model prediction for estimating the bearing residual life of a rotating packed bed based on rotor imbalance response analysis.This method is used to determine the influence of the mass on the imbalance in the vibration of the rotor on bearing damage.The major influence on rotor vibration was found to be exerted by the imbalanced mass and its distribution radius,as revealed by the results of orthogonal experiments.Through implementing finite element analysis,the imbalance response curve for the rotating packed bed rotor was obtained,and a correlation among rotor imbalance mass,distribution radius of imbalance mass,and bearing residue life was established via data fitting.The predicted value of the bearing life can be used as the reference basis for an early safety warning of a rotating packed bed to effectively avoid accidents.

3-D DYNAMIC RESPONSE OF TRANSVERSELY ISOTROPIC SATURATED SOILS

A study on dynamic response of transversely isotropic saturated poroelastic media under a circular non-axisymmetrical harmonic source has been presented by Huang Yi et al. using the technique of Fourier expansion and Hankel transform. However, the method may not always be valid. The work is extended to the general case being in the rectangular coordinate. The purpose is to study the 3-d dynamic response of transversely isotropic saturated soils under a general source distributing in arbitrary rectangular zoon on the medium surface. Based on Biot＇s theory for fluid- saturated porous media, the 3-d wave motion equations in rectangular coordinate for transversely isotropic saturated poroelastic media were transformed into the two uncoupling governing differential equations of 6-order and 2-order respectively by means of the displacement functions. Then, using the technique of double Fourier transform, the governing differential equations were easily solved. Integral solutions of soil skeleton displacements and pore pressure as well as the total stresses for poroelastic media were obtained. Furthermore, a systematic study on half-space problem in saturated soils was performed. Integral solutions for surface displacements under the general harmonic source distributing on arbitrary surface zone, considering both case of drained surface and undrained surface, were presented.

Dynamic Response Analysis of Motorized Spindle System

As to motorized spindle system, this paper builds a simplified 3D model of spindle and bearing, performs structure modal analysis, reveals its dynamic characteristics under the free model; furthermore, modifies bearing radial stiffness and number of model and studies the change of modal parameters. On this basis, through the harmonic response analysis of the finite element model, dy- namic response characteristic caused by imbalance of monitored spindle system and law of vibration response to different amount of unbalance is analyzed.

Dynamic simulation on rubber spring supporting equipment of vibrating screen

By ANSYS, dynamic simulation analysis of rubber spring supporting equipment used in vibrating screen was made. The modal frequency, mode, and harmonic displacement under working frequency were obtained. Variation of rubber spring supporting equipment＇s dynamic performance was discussed first, which is under the condition of existing spring stiffness difference and exciting force bias. Also, the quantitative calculation formulas were given. The results indicate that the performance of vibrating screen is closely related with rubber spring supporting equipment＇s dynamic performance. Differences of springs＇ stiffness coefficients reduce the modal frequency reduced, decrease the dynamic stiffness, and increase vibration displacement. Exciting force bias induces a larger lateral displacement. When rubber springs＇ stiffness coefficients exist, differences and lateral force accounts for 5% in total exciting force; rubber spring supporting equipment＇s side swing is larger than 1 mm, exceeding the side swing limit.

Structure and Dynamic Characters of New Radar Stabilized Platform

Aimed at requirements, a kind of radar stabilized platform with external rotor and orthogonal shafts is designed. Its dynamic characters are analyzed by using finite element theory and ANSYS software. Also, a traditional stabilized platform with inner rotor is designed for comparison. It is shown that the new platform reduces two transmission links and 20% of precise components, its weight decreases by 20%, its natural frequency and rigidity are enlarged, the operating accuracy and stationary are increased. The new stabilized platform is more superiority and practicability. Its design method and analysis results have already been used in development mission. It provides helpful reference for similar structure designs.

THE DESIGN AND ANALYSIS OF VIBRATION STRUCTURE OF VERTICAL DYNAMIC BALANCING MACHINE

A new type of vibration structure (i.e. supporting system, called swing frame cus- tomarily) of vertical dynamic balancing machine has been designed, which is based on an analysis for the swing frame of a traditional double-plane vertical dynamic balancing machine. The static unbalance and couple unbalance can be e?ectively separated by using the new dynamic balancing machine with the new swing frame. By building the dynamics model, the advantages of the new structure are discussed in detail. The modal and harmonic response are analyzed by using the ANSYS7.0. By comparing the ?nite element modal analysis with the experimental modal analy- sis, the natural frequencies and vibration modes are found. There are many spring boards in the new swing frame. Their sti?nesses are di?erent and assorted with each other. Furthermore, there are three sensors on the measuring points. Therefore, the new dynamic balancing machine can measure static unbalance and coupling unbalance directly, and the interaction between them is faint. The result shows that the new vertical dynamic balancing machine is suitable for inertial measurement of ?ying objects, and can overcome the shortcomings of traditional double-plane vertical dynamic balancing machines, which the e?ect of plane-separation is inferior. The vertical dynamic balancing machine with the new vibration structure can ?nd wide application in the future. The modelling and analysis of the new vibration structure will provide theoretical basis and practical experience for designing new-type vertical dynamic balancing machines.

DYNAMIC INTERACTION BETWEEN ELASTIC THICK CIRCULAR PLATE AND TRANSVERSELY ISOTROPIC SATURATED SOIL GROUND

A study of the dynamic interaction between foundation and the underlying soil has been presented in a recent paper based on the assumption of saturated ground and elastic circular plate excited by the axisymmetrical harmonic source. However, the assumption may not always be valid. The work is extended to the case of a circular plate resting on transversely isotropic saturated soil and subjected to a non-axisymmetrical harmonic force. The analysis is based on the theory of elastic wave in transversely isotropic saturated poroelastic media established. By the technique of Fourier expansion and Hankel transform, the governing difference equations for transversely isotropic saturated soil are easily solved and the cooresponding Hankel transformed stress and displacement solutions are obtained. Then, under the contact conditions, the problem leads to a pair of dual integral equations which describe the mixed boundary-value problem. Furthermore, the dual integral equations can be reduced to the Fredholm integral equations of the second kind solved by numerical procedure. At the end, a numerical result is presented which indicates that on a certain frequency range, the displacement amplitude of the surface of the foundation increases with the increase of the frequency of the exciting force, and decreases in vibration form with the increase of the distance.

Multi-harmonic equivalent modeling for a planar repetitive structure with polynomial-nonlinear joints

How nonlinear joints affect the response of large space structures is an important problem to investigate.In this paper,a multi-harmonic equivalent modeling method is presented to establish a frequency-domain model of planar repetitive structures with nonlinear joints.First,at the local level,the nonlinear joint is modeled by the multi-harmonic describing function matrix.The element of the hybrid beam is obtained by the dynamic condensation of the beam-joint element.Second,at the global level,the displacement-equivalence method is used to model the multi-harmonic Euler continuum beam equivalent to the planar repetitive structure.Then,the pseudo-arc-length continuation method is applied to track the multi-harmonic trajectory of response.Afterwards,an experiment is conducted to validate the correctness of the modeling method,considering the effect of hanging rope and air damping.In the numerical studies,several simulation results indicate the similarity of response between a single-degree-of-freedom system with a single nonlinear joint and the system of the planar repetitive structure with a large number of nonlinear joints.Finally,the component of higher-order harmonics is shown to be important for predicting the resonance frequencies and amplitudes.

Design and Performance Study of an Ultrasonic Bone Scalpel with Composite Horn Structure

The ultrasonic bone scalpel was often used in all kinds of clinical orthopedic surgery as a new type of medical instrument.Based on the working theory of the ultrasonic bone scalpel and combined with the design method of a quarter wavelength transducer and horn,this study proposed an optimization design method for the ultrasonic bone scalpel with a composite horn structure.The structure of the ultrasonic bone scalpel was simplified,and its length was shortened.Finite element analysis,modal analysis,and harmonic response analysis were used to optimize the design of the ultrasonic bone scalpel.The performance of the ultrasonic bone scalpel was explored through impedance analysis,amplitude measurement,temperature measurement,and cutting tests,and the feasibility of the design was verified through torque analysis.The results showed that when the torque force was 4.0 N,the resonance frequency of the ultrasonic bone scalpel was 30,540 Hz,and the maximum amplitude of the ultrasonic bone scalpel could reach 62μm.After spray cooling,the maximum surface temperature of the rear end cover was reduced from 51.8 to 36.3℃,the maximum surface temperature of the composite horn was reduced from 71 to 45.3℃,and the maximum surface temperature of the cutter head was reduced from 101 to 46.1℃,demonstrating a good cooling effect.Under 89 Voltage,the optimal cutting force for cutting chicken leg bones was 0.1 N,the optimal cutting force for cutting pork ribs was 0.3 N,and the cutting process showed tissue selectivity.

非线性光学数据库:理论预测助力材料的快速发现

现代激光技术迫切需要能够通过二次谐波产生相干光的非线性光学材料.然而,只有很少一部分非中心对称晶体材料的非线性光学性质被实验或者理论研究,针对高性能非线性光学晶体材料的探索仍非常有限.本工作建立了迄今为止最大的计算非线性光学晶体材料数据库,其中包含2354个非中心对称晶体结构,以及它们的倍频系数和带隙.本文提供了理论数据的计算细节和其与实验数据的对比验证,以及数据库的详细描述.该数据库的重要特点之一是它包含大量通过进化算法搜索发现的新的热力学稳定和亚稳定结构,这为寻找具有更好性能的新型非线性光学材料提供了可能性.

Excitation Current and Vibration Characteristics of DC Biased Transformer

In practical engineering,DC disturbance will lead to excitation saturation and vibration intensification on transformer core,as well as affecting the normal operation of equipment and power grid.According to the problem,a new idea is proposed in this paper.Based on the electromagnetic characteristics of DC biased transformer,excitation saturation and core vibration are studied by using excitation-vibration harmonic response analysis method.Excitation current is identified through electromagnetic coupling to characterize the excitation saturation degree.Then,vibration harmonic response model is established to analyze core vibration.Electromagnetic characteristics of DC biased Y/△transformer are simulated.The variation of excitation current and core vibration at different DC levels are studied.Excitation-vibration characteristics of three-phase group transformer and three-phase three-limb transformer are compared and sum-marized.With experimental platform built,the correctness of simulation results is verified by experimental data,and the effectiveness of the proposed method can be proved.