Papers by Keyword: Measurement

Abstract: This paper proposed a set of measurement system based on the method of stick vibration mode and LabVIEW virtual instrument technology, which is used for measuring the young's modulus of loudspeaker spider. The inherent frequency and young's modulus of a cotton spider are measured by this system. After the young’s modulus is obtained, modal analysis is conducted on the sample by using finite element simulation method. The measured results and the simulation results are compared. The difference between two results is 0.4% which verify the correctness of the system.

Abstract: The paper deals with experimental simulation measuring and the analysis of defect distribution in passenger car tire under dynamic loading. The main reason for detection of defect extension is to recognize an influence of closed air, small bubbles, separations in tire and it is mainly connected with its quality during its service in a vehicle in terms of road safety. This analysis should help constructors to solve critical conditions in tire casing, whether material selection and individual components proportions are suitable and fit or even the whole construction of tire casing is suitable. The reason for detection of internal defects in tire casing is to avoid the wear of those tires which already contain some internal defects and already recognised separations, which could propagate during the movement of vehicles. This is closely connected with the occurrence of tire destruction and the main purpose is to prevent its critical status and later vehicle crash and human life menace.

Abstract: The paper deals with the analysis of uncertainty of tilt measurement using accelerometer. Low cost accelerometer based on the principle of heat array is used for tilt measurement. One chip microcontroller is used for data processing from accelerometer. The knowledge of uncertainty of measurement for this measuring chain is necessary for our application.

Abstract: Paper deals with dust mass concentration measurement in working environment. The measurement is focused to respirable dust fraction, which is dangerous for people. Light scattering principle of dust mass concentration measurement is used for this purpose. Also cyclone as mechanical way of separation of respirable fraction can be used for this purpose. Next problem is determination of uncertainty of this measurement.

Abstract: This article describes the elastic element of the servo valve, elaborates the definition of the stiffness of elastic element, analyzes the characteristics of existing rigidity measurement system, points out the limitations of the existing rigidity measurement system when it measures the large-stiffiness elastic element, utilizes a new measuring principle based on the existing stiffness test systems, uses the more accurate laser displacement measurement method to overcome the weaknesses of the existing stiffness test system, improves the measurement accuracy, makes stiffness measurements more accurate and promotes the stiffness measurement technology of the servo valve elastic element.

Abstract: This paper reviews domestic and foreign study result of the calculation method and variation of solid propellant and other viscoelastic material ratio of solid propellant, the viscoelastic material's Poisson's ratio as well as Poisson's ratio's influence on the structure performance of solid propellant.

Abstract: In view of it is often needed to measure the value of the inductance capacitance and signal frequency in the welding and the debugging process of the electronic circuit, specialized equipment due to the huge volume of expensive equipment which is difficult to measure, we use SCM to design a portable measuring instrument which have low cost and can measure the value of inductance and capacitance, as well as signal frequency. It can meet the demand of precision after testing, so as to reach requirements for measuring instrument.

Abstract: Road roughness, the most direct automotive input, is a kind of basic data. Its analysis and applications have important effects on vehicle performance. Several methods such as wavelet analysis, amplitude-domain analysis, frequency-domain analysis are used to analyze the road elevation series of a highway. Through some disposal of the original survey data, a series of representative data has been taken to reproduction test in a 4-poster road simulator. Both analyses and test results show that, the proposed methods can be used for the actual data process of road roughness and in the vehicle bench test.

Abstract: An Approach that measuring static radial and axial runouts around rotational centre of spindle for cylindrical mills on milling machine was presented, its possible errors coming from imprecise location of gauge were theoretically analyzed. Milling force measuring experiments with variable feeds and cutting depths in low spindle speed was done to estimate the static runouts, these estimated values then were used to test the precision of measured values with this approach. Both results of theoretical analysis and experimental test showed that the relative errors of this measuring approach were small. This approach is to measure the runouts of installed mills, and its measured value is rather precise, its operation is simple, and it needs no special gauge. This approach can be used in study on force of cylindrical mills.

Abstract: Non-linear insulating material is widely used in the insulations of XLPE cable terminations and stator windings insulation of electric machines, and has obvious capability to improve the distribution of electric field. Actually, the dielectric loss factor of non-linear insulating materials is not equal to the tan δ describing linear insulating materials, and depends on applied voltage and their structures. This paper firstly discusses the difference between ac loss characteristic of non-linear dielectrics and linear dielectrics and presents a kind model of non-linear composite material. Based on the model, specific characterization and measurement methods and their numeric simulation analysis are given. Finally, a measuring system for non-linear insulating materials based on digital measuring technology is presented.