Dynamic Measurement Method Research Articles

Experimental Study of Pile Foundation Dynamic Testing Used in the Anchor Rod Nondestructive Testing

The dynamic testing of stress wave reflection method is an easy, economical, rapid and reliable nondestructive testing technology and has been perfected used in the pile foundation dynamic testing. Anchor rod is more in line with the wave theory of one-dimensional elastic rod than pile foundation whether to theory or the geometric solid, material, stress state and other factors. The quality of anchor rod is determined by using small strain method (hammering method) of pile foundation dynamic measurement. Four testing anchor rods with different length and integrity were made in project of "China Marine Sport School", stress wave time domain curve of anchor rod was obtained by ZK-7E portable intelligent testing of piles instrument, defect location, length of anchor rod and integrity reflected by measured waveform are consistent with the actual situation, the method using pile foundation dynamic testing technology for anchor rod nondestructive testing is proved feasible and reliable.

Studies of Large-Range Dynamic and Static Motor Torque Tester

This paper discusses the composition, structural features, working principle, and technical performance of a kind of motor torque measurement system. This system adopts two kinds of torque measurement methods, dynamic torque measurement method and static torque measurement method, uses microprocessor to collect data including rotational speed of load motor and torque signals of to-be-tested motor, figures out the rotational speed and torque through software algorithm, as well as displays and output them. This system also makes actual measurement of a type of motor. The measurement period is short; the measurement precision is high; and the performance is stable.

Electric field induced conductive network formation of MWNTs and MWNTs-COOH in polycarbonate composites

Using polycarbonate (PC) as a matrix, and multi-wall carbon nanotubes (MWNTs) and acid-treated MWNTs (MWNTs-COOH) as fillers, PC/MWNTs and PC/MWNTs-COOH conductive composites were prepared, respectively. The conductive network formation induced by electric field in both the PC/MWNTs and PC/MWNTs-COOH composites were investigated by the dynamic percolation measurement. It was found that the electrical resistivity–time curves showed a certain self-similarity under various electric fields, i.e., the electrical resistivity decreased sharply as the percolation time (tp) was reached. And the dynamic percolation time was shorten with the increase of the electric field intensity for both MWNTs and MWNTs-COOH filled PC composites. However, the percolation time and the formation activation energy of conductive network under electric field for MWNTs filled composites decreased greatly as compared to those of the MWNTs-COOH filled composites. These results indicated that the interaction between MWNTs and PC molecules played an important role in the conductive network formation under the electric field. Furthermore, the tp values under the electric field for PC/MWNTs and PC/MWNTs-COOH composites were successfully predicted by a modified thermodynamic percolation model. And this dynamic percolation measurement method could be recommended to investigate the zero-shear-rate viscosity at the different temperatures.

A New Method for Dynamic Position Measurement While Drilling String Rotating

This paper describes the commonly used for oil drilling directional sensor’s structure and the measured parameters, provides a method for dynamic position measurement while drilling string rotation, detailed analyzes on how to calculate a real time accurate gravity tool face based on a precisely theoretical derivation, and the calculated value by this method verified by experimental results. This article provides a measurement technology solution for any rotary steerable tool developing and it can be applied to such a purpose.

Dynamic Testing of Corrugated Steel Plate Culvert Using Radar

The paper presents the results of selected experimental tests under dynamic loads that were conducted on a corrugated steel plate culvert. The tested railway object in the cross section has two spans in shape of closed arch. The effective length of shells is L1 = L2 = 4400 mm. The dynamic loads were caused by the passages of various trains. The displacements and vibration frequencies of the culvert were determined. The microwave interferometric radar was used for monitoring of displacements of this railway culvert. The maximum displacements of the culvert crown do not exceed 0.65 × 10 -3 m. The typical frequencies of the railway culvert to passing trains were usually in the range of 0.6 to 3.0 Hz. They were obtained during passage of the heavy freight trains. Conclusions drawn from the tests can be helpful in the measurements of such culverts using the microwave interferometry method. The dynamic and static tests of bridges and culverts are conducted in order to confirm structural specifications, or to provide diagnostic surveys for planning maintenance and modernization. Typical experimental tests are usually carried out using accelerometers, strain and inductive (or dial) gauges. These gauges are quite accurate and reliable. Moreover, testing of structures can give rise to accessibility problems, often requiring the use of scaffolds. For these reasons, the application of radar measurements is a quite good alternative. The interferometric radar applied in tests, is a precision microwave instrument suitable to the non-contact vibrations and displacements monitoring of various engineering structures. The high accuracy and quickness of measurement are among of the main characteristic features of the radar. The comparison of the interferometric radar vs. the accelerometer used for dynamic monitoring of various large bridges is given by Pieraccini et al. (1) and Gentile and Bernardini (2). The interferometry method for non-contact dynamic and static measurement of the vibration of various engineering structures was described by Dei et al. (3), Gentile (4), Fratini et al. (5). The main aim of this paper is the evaluation of possibility of the interferometric radar application for the measurements of corrugated steel plate (CSP) culvert under dynamic train loads. The vertical displacements and vibration frequencies were determined during the field load tests. The

Research on Multi-variables Dynamic Equilibrium Design and Measurement Method Based on Effective Working-age

To improve the life of mechanical product,a mathematical model of multi-variables dynamic equilibrium design is constructed based on effective working-age estimation,which uses to solve the problems of the different components life estimation leading to products failure.A multi-variables dynamic equilibrium design optimization method is put forward based on the analysis and measurement of effective working-age of component.Based on the mathematical model the Pareto set for the multi-objective optimization problem is obtained using multi-objective algorithm.The optimal preventive maintenance schedules optimize the failure rate of components to be the same as the design required by replacing or maintaining the components before it fails.It minimizes the total cost of preventive maintenance schedule and the system failure rate of the mechanical product.The efficiency and effectiveness of the proposed method are illustrated by multi-variables dynamic equilibrium design of turbine inflation host machine of large air separation plants.

A New Method on Illumination Measurement to Dynamic and Static Light Sources

A novel measurement system for the dynamic and static light sources is designed in this paper. The method of dynamic gain adjustment measurement is proposed according to the national standards on luminous intensity of dynamic and static light sources. The method is achieved by the way that microcontroller controlled the analog switches to switch automatically in different ranges and adjust the gain automatically depend on the light intensity. By designing the overall structure of the system and using the dynamic gain adjustment method, the range of dynamic measuring illumination can be from 0.001 up to 2000 . The illumination measurement to static light source and the dynamic light source in the peak luminous intensity are achieved via the combination of interval control and dynamic gain adjustment.

A method for linearization of a laser interferometer down to the picometre level with a capacitive sensor

This paper describes methods for dynamic measurement and correction of laser interferometer periodic nonlinearity down to the picometre level. A capacitive sensor is used as an external reference for measuring and calculating the periodic interferometer nonlinearity correction function. The experimental interferometer setup is a heterodyne interferometer with symmetrical paths to detectors and time-interval-based phase detection. The periodic nonlinearity is represented as harmonic Fourier components. The time evolution of the nonlinearity function is tracked during measurement. The method is verified by spatial and temporal repeatability of the measured nonlinearity. Linearization repeatability in the 10 pm range is observed.

Comparison of two dynamic measurement methods of odor and odorant emission rates from freshly dewatered biosolids

Odor and odorant emission rates from freshly dewatered biosolids in a dewatering building of a Water Reclamation Plant (WRP) are measured using the EPA flux chamber and wind tunnel methods. Experimental results are compared statistically to test whether the two methods result in similar emission rates when experiments are performed under field conditions. To the best of our knowledge the literature is void of studies comparing the two methods indoors. In this paper the two methods are compared indoors where the wind velocity and air exchange rate are pertinent field conditions and can be measured. The difference between emission rates of odor and hydrogen sulfide measured with the two methods is not statistically significant (P values: 0.505 for odor, 0.130 for H(2)S). It is concluded that both methods can be used to estimate source emissions but selection of the most effective or efficient method depends on prevailing environmental conditions. The wind tunnel is appropriate for outdoor environments where wind effects on source emissions are more pronounced than indoors. The EPA flux chamber depends on the air exchange rate of the chamber, which simulates corresponding conditions of the indoor environment under investigation and is recommended for estimation of indoor pollution sources.

Research on Dynamic Design Method Based on Measuring Information for Printing Press

Printing machinery’s reliability is one of the most important index parameter and good dynamic characteristics are essential for high speed printing press. The dynamic characteristic is predictable for printing machine with dynamic design. With the complexity of printing technique and printing machine, information, such as load on components is lack, leading to the difficulty of dynamic model solving and further more the dynamic parameters needs to be verified. Firstly, according to the dynamic design method, a dynamic design process based on measuring information for printing machine was put forward. Secondly, on the basis of principle and structure analysis to typical printing machine, dynamic characteristics measurement item and method was determined. With a wallboard of a two-color offset press acting as an example, the utilizing method was illustrated through dynamic modeling, theoretical model analysis, experiment model analysis based on vibration measurement and comparing the theoretical and experimental results. Finally, a Dynamic Design Assistant Platform based Vibration Measurement for Printing Machine was developed and had been used in 10 kinds of printing machine measurement and analysis. The conclusion shows that the tolerance of the theoretical model analysis results and experiment results is allowed. A new approach for new printing machine design and optimal design for existed printing machine is given.

The Measurement of Dynamic Stress for The Top-Cutter Machine of Cotton

In this paper, we used the dynamic strain measurement method to measure the top-cutter machine of cotton’s stress under its working state. With sorting out data and analyzing it, we obtained the stress condition of the framing and the working parts. And the measurement result could be used to analyze the axle’s fatigue strength and check whether it was safe or not. It provided integrant basis for the further design of the machine.

On the dynamic measurement of constants of piezoelectric single-crystal materials

An error in the estimation of piezoelectric material properties can arise when applying the common measurement procedures in the IEEE Standard to determining constants of piezoelectric materials with exceptionally high coupling coefficients, in particular, single-crystal materials. The probable sources of inaccuracy in the resonance-antiresonance method, when applied to bar samples made of single crystals are considered. An additional method of dynamic measurements that helps to avoid the shortcomings of the resonance- antiresonance method is proposed, and its application is illustrated with examples of measurement of single-crystal piezoelements of different compositions.

A novel method of fast dynamic optical image stabilization precision measurement based on CCD

Dynamic image stabilization precision is a key technical indicator in optical image-stable device, however, the fast dynamic test is difficult to implement. A novel fast dynamic image stabilization precision testing system for optical image-stable instrument is developed. The large-aperture collimator with the designed cross divisional board is used to simulate the infinity goal. A motion simulator with six-degree of freedom is adopted to simulate the moving state of the installed image-stable instrument. Combined with the optical lens designed in accordance with the analysis of the whole optical system in detail, the high speed camera installed behind the eyepiece lens of the measured device acquires images rapidly and real-timely. The local energy maxima center of the cross light spot can be obtained accurately through the proposed fast image stabilization precision test algorithm on the basis of Hessian matrix. The actual test results show that the test error of dynamic image stabilization in the proposed method of this paper is less than 0.7″, and the time of the frame image acquisition and processing is not more than 10 ms, which demonstrates the effectiveness of the test equipment and algorithm.

Influence of moisture content of wood on sound velocity and dynamic MOE of natural frequency- and ultrasonic runtime measurement

This study comprises the analysis of the influence of the moisture content of wood on the dynamic properties—sound velocity and dynamic MOE (considering the density)—of green and dry sawn timber. The main objective was to find applicable functions or factors for the adjustment of the determined properties on the reference condition (moisture content u=12%) for the moisture content range below and above fiber saturation. Therefore, two dynamic measurement methods—measurement of the natural frequency and ultrasonic runtime—were considered. Possible differences in the results, pros and cons of both methods should be identified on the one hand. On the other hand, the applicability of already published moisture adjustments to the given data of both methods should be proved.

Dynamic measurement and modeling of the Casimir force at the nanometer scale

We present a dynamic method for measurement of the Casimir force with an atomic force microscope (AFM) with a conventional AFM tip. With this method, originally based on the phase of vibration of the AFM tip, we are able to verify the Casimir force at distances of nearly 6 nm with an AFM tip that has a radius of curvature of nearly 100 nm. Until now dynamic methods have been done using large metal spheres at greater distances. Also presented is a theoretical model based on the harmonic oscillator, including nonidealities. This model accurately predicts the experimental data.

In Vivo MR Angiography and Velocity Measurement in Mice Coronary Arteries at 9.4 T: Assessment of Coronary Flow Velocity Reserve

To demonstrate the feasibility of coronary magnetic resonance (MR) angiography in living mice and to evaluate a dynamic MR angiographic method for coronary flow measurement at 9.4-T field strength. This study was conducted according to European law and was in full compliance with National Institutes of Health recommendations for animal care and a local institutional animal care committee. Mice were anesthetized by using isoflurane. First, time-of-flight MR angiography was performed in 10 mice to measure coronary diameters at 80-mum isotropic resolution. Second, left coronary artery (LCA) velocity measurements were performed at seven cardiac phases in nine other mice to assess the velocity curve profile. Third, coronary velocities were measured at the middiastolic phase in 13 mice at rest and during adenosine-induced hyperemia to calculate coronary flow velocity reserve (CFVR). The Pearson coefficient compared the correlation between isoflurane dose and CFVR. Paired t tests compared R-R intervals and respiratory rates between rest and hyperemia. Proximal diameters were, respectively, 404 mum +/- 34 [standard deviation] and 259 mum +/- 22 for the LCAs and the right coronary arteries, which were in accordance with reported values. The velocity curve profile throughout the cardiac cycle was similar to values from the literature. Baseline and hyperemic velocities were, respectively, 19.0 cm/sec +/- 4.4 and 33.7 cm/sec +/- 4.7 (P<.001), resulting in a CFVR of 1.77 +/- 0.19. CFVR did not correlate with isoflurane dose (r = 0.05, P = .88). R-R intervals shortened by 2.5% during hyperemia (P = .04). Respiratory rates showed no difference between rest and hyperemia (P = .39). High-spatial-resolution three-dimensional coronary MR angiography is feasible in living mice. Dynamic MR angiography depicts coronary velocity changes throughout the cardiac cycle and between rest and maximum hyperemia, providing a tool for CFVR assessment.

In vivo validation of MRI vessel caliber index measurement methods with intravital optical microscopy in a U87 mouse brain tumor model

The vessel caliber index (VCI), a magnetic resonance imaging biomarker of the average blood vessel diameter, is increasingly being used as a tool for assessing tumor angiogenesis and response to antiangiogenic therapy. However, although the VCI has been correlated with histological vessel diameters, good quantitative agreement with histology has been lacking. In addition, no VCI validation studies have been performed in vivo where the structural deformations frequently associated with histological tissue preparation are not present. This study employs intravital optical microscopy (IVM) measurements of cerebral blood vessel diameters in a mouse orthotopic glioma model to provide the first such in vivo validation. Two VCI correlation models, both a linear and a 3/2-power dependence on the DeltaR2*/DeltaR2 ratio, were compared with the IVM data. The linear VCI model, determined from steady-state susceptibility contrast (SSC) images, was found to be in excellent quantitative agreement with the intravitally determined VCI for separate tumor size matched groups of mice. In addition, preliminary data indicate that the VCI is independent of whether a dynamic susceptibility contrast or SSC measurement method is used.

环形掺铒光纤激光器自混合散斑及动态目标距离测量

A new method of dynamic target distance measurement based on self-mixing speckle in an erbium-doped fiber-optic ring laser is studied. The model of self-mixing speckle measurement system is presented, and the theoretical analysis of the production of self-mixing speckle signal is also given. Through the experiments, the dynamic speckle signal is obtained. The spectrum energy density analysis is applied to the dynamic speckle signals, and a linear relationship between the spectrum energy density and the detection distance is obtained. The result shows that highly precise distance dynamic measurements can be performed by using self-mixing speckle and fiber laser.

Development of a Dynamic Strain Measurement Method using the Piezo Cable by Applying a Constant Cyclic Load

Development of a Dynamic Strain Measurement Method using the Piezo Cable by Applying a Constant Cyclic Load

726 Carreアルゴリズムを基礎とするバーチャルスペックルパターンを用いた動的面外変形計測(GS-15・16 画像処理)

726 Carreアルゴリズムを基礎とするバーチャルスペックルパターンを用いた動的面外変形計測(GS-15・16 画像処理)