Displacement Meter Research Articles

Comparison of different approaches to calculate a final meter factor for rotary-type natural gas displacement meters

The meter factor is the ratio between the reference volume and the indicated test meter volume for a particular flow rate. In some applications, a final and a single meter factor that covers all the flow meter rates is required, and there are several approaches to calculate it. However, none of them are specific to rotary-type natural gas displacement meters. In this paper, certain established approaches, such as AGA 7, AGA 9, non-weighted and weighted regression lines were applied to calibration data of this type of meter and their results were compared. An Excel spreadsheet was developed to calculate the final meter factors using all these approaches and to indicate users the one with the lowest uncertainty, based on input data in order to configure the flow computer. In the specific case studies shown, the approaches using linear regression were found to be more suitable.

Vibration Behavior and Rebound Angle on the Collision of Mirror Models inside a SLR Camera (Measurement of Collision Behavior of Rotary Support Rectangular Plates)

This study deals with the rebound vibration characteristics of a SLR camera's internal mirror model. The mechanism of the mirror rebound phenomena is considered by using six types of rectangle metal plate models. In the experiment, the behavior of vibration during the rebound phenomena is observed. The mirror models are supported with rotational axis at long axis of the model. The mirror models swing down freely from the horizontal plane and then hit with a stopper. Amount of rebound is measured by a laser displacement meter. The results indicate that the rebound amount depends on the stopper position. The vibration behavior after the collision varies by stopper position. The vibration after the collision depends on the deformation while in contact with the stopper at the time of collision. We observed that when the amount of rebound is small, there is a tendency that the vibration after the collision becomes large.

Comparative Performance Test of an Inclinometer Wireless Smart Sensor Prototype for Subway Tunnel

Structural health monitoring of operating subway tunnel has become a new challenge to engineers. In order to make structural monitoring cheaper, smarter and more ecient, new technologies such as micro- electro-mechanical system (MEMS) sensors and wireless sensor network (WSN) have recently been introduced to compensate the defects of conventional methods. A wireless MEMS inclinometer prototype was developed by Tongji University. Many adaptability tests on both developed and commercial sensors are carried out in labora- tory under the same condition. The comparison shows that the inclinometer prototype has a higher resolution, larger range, lower cost, better electric property and less temperature disturbance than the commercial product but is slightly bigger in size. Then, a full size shield tunnel segment deformation experiment is carried out. Tilt angles at some particular locations are measured by the MEMS inclinometers so as to calculate the global deformation of the segment. Conventional displacement meter is used to verify the calculated results. The feasibility of utilizing inclination of segments to evaluate convergence deformation of shield tunnel is studied in this paper. The geometry method is adopted in analysis, and the convergence deformation of shield tunnel is assumed as a function of segments inclination. The experiment shows a solid feasibility of inclinometers being used to monitor convergence displacement of shield tunnel. Problems discovered in the research and future work are also discussed.

Detection of Small Cracks for Rotating Bending Fatigue Specimens (The First Report; A Method with Measuring Small Displacement during Fatigue Test)

A replica method is commonly used to detect a crack initiation and propagation for rotating bending fatigue cracks. But in this method, a length of crack on the surface can be detected at only the certain cycles, and can't detect the crack initiation accurately or observe the change of fatigue crack length continuously. In this report, small fatigue cracks are detected by measuring the displacement at a notch root of specimens during fatigue test with a laser displacement meter. As a result, we can observe the propagation of fatigue cracks by measuring the amount of displacement change in real time.

G051056 振動する液面上に保持された液滴の保持位置と液面波形の関係([G051-05]流体工学部門,一般セッション : 液膜・液滴)

It is known that a droplet is held on the vertically vibrating pool of the same kind of liquid. When the frequency of oscillation is at the resonance of the apparatus, the droplet is found to a certain position on the pool regardless of the initial dropped position. In this case, the lifetime of a droplet is as long as several hours, perhaps because of the larger amplitude of vibration acceleration than the gravity as previously reported. Then we investigated waveform at the resonance frequency to clarify the relationship with the position where the droplet is retained. The amplitude, phase, and average displacement of the surface of oscillating pool were measured by a laser displacement meter and FFT analyzer. The average displacement is relevant to the position of a droplet, while the amplitude and phase are not; in the distribution where the regression plane of the average displacement is subtract, its minimum position is almost the same as the retained droplet.

J031032 繰り返し電気負荷によるパイモルフ型圧電アクチュエータの性能劣化([J031-03]圧電材料と弾性振動)

Bimorph piezoelectric actuators were subjected to cyclic electric loading with bias DC voltage V_b=0, 50, 100V. When specified number of cycles was preceded, electric loading was interrupted and resonance and anti-resonance frequencies were measured by an impedance analyzer. In addition, displacement of the actuator due to DC voltage was measured by a laser displacement meter. Electromechanical coupling coefficient k_<3l> and piezoelectric constant d_<31> were calculated from resonance and anti-resonance frequencies and the relationship between DC voltage and displacement of actuator. Degradation of bimorph piezoelectric actuators due to cyclic electric loading with positive bias voltage was indicated. Moreover, variation in material properties of piezoelectric ceramics used in actuators under cyclic electric loading was indicated, too. When the positive bias voltage was superposed on AC electric loading, piezoelectric ceramics below the center electrode was depoled, and it was found that the degradation of actuators was caused by the variation in piezoelectric material properties due to the domain switching.

Experimental Study of Sandwich Panels Subjected to Foam Projectile Impact

Similar blast loading characteristics can be obtained using impact of aluminium foam projectiles, which enables blast tests to be mimicked in a laboratory scale and in a safer environment. The purpose of this study is to determine the back-face deflection history of aluminium sandwich panels experimentally by aids of a laser displacement meter when panels are subjected to the impact of metal foam projectiles. This information was usually determined using finite element analysis (FEA) due to the difficulty in the experiment. The projectiles are cylindrical ALPORAS aluminium foam with diameter of 37 mm, length of 50 mm and nominal relative density of 10%. The sandwich panels consist of two 1 mm aluminium face-sheets and an aluminium honeycomb as the core. There are five different core configurations with a brand name of HEXCEL. The projectiles are fired towards the centre of the sandwich panels at different velocities using a gas gun. During the tests, a laser optical displacement measuring device is used to record the history of the back-face deflection experimentally. The deflection of the back-face is found to reach the maximum before coming to rest at a smaller value. The final back-face deflections of the sandwich panels show exponential relationship with the projectile impulse. The final deflections are compared with the deflection of monolithic plates with equal mass. The sandwich panels deflect less than the monolithic plate with an equal mass up to a critical value but continue to increase significantly afterwards. Care should be taken when using sandwich panels as protective structures against foam projectiles as beyond this point, the monolithic plates outperform the sandwich panels in absorbing the impact load.

D113 細管内加速流における初期速度の液膜厚さへの影響(一般講演(5))

The effect of initial flow velocities on the liquid film thickness in micro-channel accelerated slug flow under adiabatic condition is experimentally investigated. Laser focus displacement meter was used to measure the liquid film thickness. Distilled water was used as a working fluid. Circular tube with inner diameter of 1 mm and length of 500 mm was used. The effects of the initial steady flow velocities, acceleration, and axial distance were evaluated. As the initial flow velocity increases, the liquid film thickness slightly increases at the constant acceleration and axial distance. The experimentally obtained results were compared to the previous correlation in which initial flow velocity is not considered. For each Bo, the liquid film thickness at small axial distance is deviated from the correlation which becomes large with increasing initial flow velocity. At large Z, the correlation well predicts the liquid film thickness which means that the effect of initial flow velocity is negligible at large Z. Also the deviation becomes significant with increasing Bo. The effect of initial flow velocity should be considered in low Bo and Z.

506 動圧浮上遠心血液ポンプのスラスト軸受形状がインペラ浮上特性に与える影響(OS9 オーガナイズドセッション《ライフサポートによる光学技術》)

We have developed a hydrodynamically levitated centrifugal blood pump as a bridge to decision pump. However, since the bearing stiffness of the hydrodynamic bearing is small, the bearing gap tends to become narrow. The purpose of this study is to evaluate the improvement of the impeller levitation performance due to the effect of the thrust bearing geometry with spiral groove on impeller levitation performance in a hydrodynamically levitated centrifugal blood pump. We compared the geometric models that have different groove width. The numerical analysis was performed in order to calculate the bearing stiffness. The impeller levitation performance test was conducted using a mock circulation loop and a laser focus displacement meter. As a result, it was found that the sudden contraction model achieved an improvement of the impeller levitation performance in a hydrodynamically levitated centrifugal blood pump.

Shockproof Experimental Study of Automated Stocker System in the High-Tech Factory

This study, with the shake table experiments in the National Earthquake Engineering Research Center, investigated the seismic behavior of automation stocker system. The automation stocker system provided a fast and effective method for stocking products in the high-tech facilities. Firstly, the original machine tests for testing common stocker system were to investigate the seismic capacity and failing modes. Secondly, the team completed 2 kinds of reinforcement tests to investigate the seismic behavior: 1) the installation of bracing to improve overall stiffness; 2) the installation of the viscous dampers to improve the overall damping ratio. In comparing the results and performance of the three experiments, we learned from the results of the top-layer acceleration: the installation of bracing had the largest acceleration value, the original machine the second acceleration value and the damper the lowest acceleration value; the best effect was the installation of the damper. The result of the comparison of the top floor displacement meter showed that the highest data was the original machine; the second data was with the damper, the lowest data was the installation of the bracing. Based on the preliminary assessment on the best seismic retrofit ways of the storage system, we further examined the feasibility and applicability of automatic storage seismic retrofit in the high-tech factory.

Comparison of displacement and acceleration transducers for the characterization of mechanics of muscle and subcutaneous tissues by system identification of a mechanomyogram

The purpose of this study was to clarify the performance of transducers for the mechanical characterization of muscle and subcutaneous tissue with the aid of a system identification technique. The common peroneal nerve was stimulated, and a mechanomyogram (MMG) of the anterior tibialis muscle was detected with a laser displacement meter or an acceleration sensor. The transfer function between stimulation and the MMG was identified by the singular value decomposition method. The MMG detected with a laser displacement meter, DMMG, was approximated with a second-order model, but that detected with an acceleration sensor, AMMG, was approximated with a sixth-order model. The natural frequency of the DMMG coincided with that in the literature and was close to the lowest natural frequency of the AMMG. The highest natural frequency of the AMMG was within the range of the resonance frequencies of human soft tissue. The laser displacement meter is suitable for the precise identification of the MMG, which has a natural frequency of around 3 Hz. The acceleration transducer is suitable for the identification of the MMG with natural frequencies of tens of hertz.

Unsteady turbulent properties in negative waves in open channels

In an open channel, a sudden drop in free-surface elevation is associated with the development of a negative wave. While some simple analytical solution is widely described in textbooks, little research was conducted to date on the unsteady turbulence properties beneath negative waves. A series of new physical experiments were conducted in a rectangular channel. The unsteady free-surface profile and turbulence characteristics were measured in a negative wave propagating upstream against an initially steady flow using non-intrusive acoustic displacement meters, video imagery and acoustic Doppler velocimetry (ADV). For one set of flow conditions, the experiments were repeated 25 times at two longitudinal locations and four vertical elevations to yield ensemble-averaged data. The wave leading edge propagated upstream with a speed which was a function of time and space. The velocity data showed that the upstream propagation of the negative wave was linked with a gentle drop in water elevation associated with an acceleration of the flow, while some increased turbulence occurred beneath the wave associated with large velocity fluctuations and large Reynolds stress components. The velocity fluctuations and turbulent stresses were significantly larger than in the initially steady flow and in the final flow motion.

Restitution coefficients and sticking velocities of a chondrule analogue colliding on a porous silica layer at impact velocities between 0.1 and 80 m s−1

To study the accretional growth of rimmed chondrules and their agglomerates in the solar nebula, we measured the restitution coefficients, ε, and the sticking velocities to a porous silica layer, vc, by impacting the silica layer with a glass ball at velocities from 0.1 to 80ms−1. We used a porous silica layer covering a basalt block with thicknesses ranging from 1/5 of the glass ball radius to equal to the glass ball radius as a rimmed chondrule analogue, and the porosity of the silica layer was set to be 70%, 80%, 85%, and 90%. Collisional experiments were conducted by means of the free fall method or by the use of a spring gun or a gas gun, allowing us to vary the impact velocity. We used a laser displacement meter to estimate the impact and rebound velocities as well as the acceleration during the collision at impact velocities below 1ms−1. As a result, the sticking velocity, vc, of 90%- and 85%- porosity layers with a thickness equal to 1/2 of the glass ball diameter was 0.44 and 2.4ms−1, respectively. On the other hand, we found a distinct barrier to sticking for smaller-porosity layers: the silicate layer with a porosity smaller than 80% never exhibited sticking at any impact velocity below 1ms−1. Instead, we observed a rebound effect with restitution coefficients larger than 0.2. In the case of a silica layer with a porosity smaller than 80%, we observed the sub-sticking condition defined by ε<0.1 at velocities extending from 5ms−1 to 70ms−1.

Formation, Dissolution, and Transfer Dynamics of a Millimeter-Scale Thin Liquid Droplet in Glycine Solution by Laser Trapping

The formation, dissolution, and transfer of a millimeter-scale dense liquid droplet are demonstrated by focusing a CW near-infrared laser beam into a thin film of glycine solution in heavy water. The entire process is investigated by directly monitoring the temporal change in the two-dimensional surface profile using a laser displacement meter. Upon laser irradiation, the surface depression is initially induced by laser heating, followed by the formation of the shallow convex-shaped droplet around the focal spot, in which the droplet is always in contact with the surrounding solution through the ultrathin solution layer. After the laser is switched off, the dissolution occurs through the recovery from the ultrathin layer toward the original solution film. When the laser is set to the outside of the droplet, the solution depression is similarly induced, and subsequently the droplet starts moving toward the focal spot. These processes are summarized and discussed in view of laser-induced effects of concentr...

변형률계를 이용한 강재보의 건전도 평가 시스템 개발에 관한 연구

This study aimed to develop a Structural Health Monitoring System for steel beams in the manner of suggesting and verifying a theoretical formula for displacement estimation using strain gauges, and estimating the loading points and magnitude. According to the results of this study, it was found that when a load of 160kN (56% of the yield load) was applied, the error rate of the deflection obtained with a strain gauge at the point of maximum deflection compared to the deflection measured with a displacement meter was within 2%, and that the estimates of the magnitude and points of load application also showed the error rate of not more than 1%. This suggests that the displacement and load of steel beams can be measured with strain gauges and further, it will enable more cost-effective sensor designing without displacement meter or load cell. The Structural Health Monitoring System program implemented in Lab VIEW gave graded warnings whenever the measured data exceeds the specified range (strength limit state, serviceability limit state, yield strain), and both the serviceability limit state and strength limit state could be simultaneously monitored with strain gauge alone.

Development of on-chip vacuum generation by gas–liquid phase transition

In this paper, we developed on-chip vacuum generation technique using gas–liquid phase transition. Fabricated quartz chip was composed simply of a structural vacuum chamber and a diaphragm for pressure measurement by laser displacement meter. Efficient reduction of pressure in the chamber was accomplished by the phase transition with the simple design of the fabricated chip. The pressure was reduced by decreasing the temperature of low boiling point liquid filled into the chamber after closing its valve. The lowest pressure attained to 50.8kPa (diethyl ether) or 23.2kPa (water) at 7min from atmospheric pressure by using diethyl ether and water, respectively. The highest performance of micro vacuum pump was achieved. The absolute pressure below 25kPa was maintained about 20min due to low leakage of the fabricated chip.

OS0505 画像解析を用いた有限変形の計測に関する基礎研究 : 単軸引張後の単純剪断下で発生する局部変形の計測について

The method of finite strain measurement based on the image analysis is suggested by using the Natural Strain theory. The effectiveness of this measurement method is verified by comparing the strain measurement by the image analysis with the conventional measurement based on the displacement meter, and the validity of this method has been examined for uni-axial tension and simple shear. However, in our previous study, the validity of this method was confirmed by the measurements within the uniform deformation, and the local deformation has not been examined yet. So, the measurement under local deformation is examined in this paper. Especially, the measurements of local deformation for simple shear after uni-axial tension are conducted by using the image analysis, and the result obtained at the middle portion of the specimen is compared with the result of upper portion of the specimen.

J041034 回転曲げ疲労試験片の微小き裂の検出 : 第1報 疲労試験中の微小変形測定による方法

A replica method is commonly used to detect a crack initiation and propagation for rotating bending fatigue cracks. But in this method, a length of crack on the surface can be detected at only the certain cycles, and can't detect the crack initiation accurately or observe the change of fatigue crack length continuously. In this report, small fatigue cracks are detected by measuring the displacement at a notch root of specimens during fatigue test with a laser displacement meter. As a result, we can observe the propagation of fatigue cracks by measuring the amount of displacement change in real time.

G100025 リニア駆動の小型振動アクチュエータに関する基礎検討

In this study, we consider the utilization of vibration as a mean of information transmission in place of utilization of the sound. In order to achieve reliable vibration transmission and for realizing a variety of vibration patterns, we investigate the basic design of small linear actuator driven by magnetic force. Using only a coil and permanent magnet, we study whether it is possible to generate the vibration with various frequencies. The magnetic force acting between the magnet and the coil is measured in the experiment, and using measured force, numerical simulation is conducted to evaluate the amount of vibration induced by the actuator. Vibration waveform is mesured by non-contact laser displacement meter. We also pay attention to compact and simple structure of the actuator. The frequency of the continuous vibration could be confirmed until 180 Hz. Frequencies above 200 Hz vibration was not continuous. The amount of vibration is 1.1 〜 1.8 times larger than conventional vibration equipment.

Calibration of prover tanks making use of a Coriolis mass flow meter as the master meter

Calibration of volumetric proving tanks can be done using different methods. For the calibration of large proving tanks the master meter method can be used as a good alternative to the volumetric transfer method or the gravimetric method. When the master meter method is used in most cases a positive displacement meter is used. A better option is to make use a Coriolis mass flow meter as the master meter. Test data is presented of a calibration of a proving tank with a nominal volume of 500 L. Small repeatability figures can be obtained of consecutive calibration runs with a Coriolis mass flow meter. Also the linearity of the meter factor curve of the Coriolis mass flow meter makes this a better option for the master meter method.