Two-wave laser displacement meter

A two-wave laser displacement meter based on Michelson interferometer has been developed for measurements at an unknown temperature profile at the measurement trace. The requirements for meteorological parameters support during displacement measurements using the offered laser interferometer are less strict compared to using an one-wave interferometer. The article describes the optical schematic of the device. The results for the measurements of the developed laser interferometer for realization of the displacement unit within the limits of 60 m are presented. The weather condition influence on measurements was estimated. The application of pseudorandom displacement of the interferometer’s reference arm with accumulation made possible the reflector position resolution down to 0.01 μm the stoped-displacement mode, and down to 0.05 μm at the displacement mode. It was shown that such resolution allows to measure displacements at trace up to 60 m with inaccuracies less than 10 μm at the temperature profile amplitude up to 1 °C.

Investigation of Nozzle Height Control to Improve Dispenser Printing of E-Textiles

Dispenser printing is a versatile way of manufacturing prototype and bespoke e-textiles that uses a robotically actuated nozzle to dispense pastes. Investigation of printing on a flat substrate, however, revealed that the nozzle must be kept between 50 and 200 µm above the material’s surface in order to print effectively. In order to maintain this clearance when printing on uneven materials, the surface topography of the substrate must be measured and compensated for. However, the accuracy of the laser displacement meter used here was reduced when measuring the translucent interface layer necessary when printing on textiles. Adding various concentrations of dye to the interface was explored. A single layer of interface with 20 mg of dye added per gram showed significantly improved results with an average error of 146 µm compared to the 550 µm for the clear interface. Crucially, the standard deviation in the error was only 31 µm, down from 101 µm, meaning that an offset could be applied to get measurements that would keep the nozzle’s clearance within the necessary 150 µm range.

Application and Analyzation of the Vision-Based Structure Model Displacement Measuring Method in Cassette Structure Shaking Table Experiment

In the shaking table test of large cassette structure, story drift is an essential set of experimental data. The traditional method of displacement measurement is limited to problems such as necessary full contact with the structure model for installation of sensors, large work of installation, and easily interfered by environment. The noncontact displacement measurement method, such as optical measuring technology, can solve the above problems and serve as an effective supplementary method for traditional displacement measuring in the shaking table test. This paper proposed a vison-based displacement measuring method. Predesigned artificial targets which act as sensors are installed on each floor of the cassette structure model. A high-speed industrial camera is used to acquire the series of the images of the artificial targets on the structure model during the shaking table test. A Python-OpenCV-based structural calculation program combining computer vision and machine vision is developed to extract and calculate the displacement of the artificial targets from the series of the images acquired. The proposed method is applied in a shaking table test of a reduced-scale fifteen-floor reinforced concrete cassette structure model, in which the laser displacement meter and the seismic geophone are also applied as a comparison. The experimental results acquired by the proposed method are compared with the results acquired by the laser displacement meter and the seismic geophone. The average error of the story drift obtained by the proposed vision-based measurement method is within 5% and is in good agreement with the laser displacement meter and the seismic geophone, which confirms the effectiveness of the proposed method.

Estimation of ion dimension doped in conducting polymers electrochemically

ABSTRACTElectroactive conducting polymers are suitable for soft actuators (artificial muscles). The actuation is induced by electrochemical oxidation of conducting polymer (film) in an electrolyte solution, due to insertion of bulky counter ions (dopant ions). The magnitude of deformation (strain) depends on the size of dopant ions and the degree of oxidation. It is worthwhile to know the relationship between the magnitudes of deformation and ion size. An electrodeposited Polypyrrole film was electrochemically cycled in aqueous electrolytes of NaCl, NaBr, NaNO3, NaBF4 and NaClO4. The strain of film during electrochemical oxidation and reduction was precisely measured using a laser displacement meter and a handmade apparatus. From the strain and electrical charges inserted in the film during oxidation, the volumes and radii of dopant ions were estimated, assuming the isotropic expansion of the film. The estimated anion radii of Cl-, Br-, NO3-, BF4- and ClO4- were 235, 246, 250, 270 and 290, respectively. The results were discussed taking the crystallographic and hydrated ion radii in literatures into consideration.

Stress Dependence of Magnetostriction and Magnetic Properties in Electrical Steel

The magnetostriction and magnetic properties of electrical steel are depended on the external stress. In this paper, a noncontact magneostriction measuring system using laser displacement meter with high resolution of 10 nm has been built. The grain-oriented electrical steel with dimensions 500 mm × 100 mm × 0.3 mm was measured between 20 MPa and-20 MPa. The magnetostriction and magnetic properties were highly sensitively to stress. A clear relationship between power loss and magnetostriction under stress was found, and the underlying mechanism has been discussed.

Theoretical and Experimental Analysis of Dielectric Elastomer Unimorph Cantilever

Unimorph cantilever is widely used in many applications with its bending and tip-deflection. In this paper, a model of the cantilever with the applied voltage and tip-deflection is presented. With the use of this model, a prototype, fabricated by VHB and polycarbonate, is estimated for its bending tip-deflection under a high voltage. And the experiment system is established with a signal generator, high voltage amplifier and laser displacement meter. The experimental results and the theoretical ones are both the same. The conclusions in this paper can be used to make further research on the deformation control of structures.

A Piezoelectric Feeder with Magnetic Spring

Proposed a new type of piezoelectric feeder uses the magnet principle to change the vibration performance and the system resonance principle. The working principle of the piezoelectric feeder was analyzed, the kinetic model was established, and the main factor which affects the delivery performance of the resonant feeder was obtained by calculation, and then designed the prototype. The resonant frequency of the system obtained by the impedance analyzer, and the displacement magnification of the piezoelectric vibrator were obtained by using the laser displacement meter. Design the speed experiment device of the resonant feeder, obtained the influence of the magnetic spring gap on output speed. The experimental show that when the input voltage is 150v, the frequency is 140Hz and the magnetic spring gap is 8mm, the system achieved the desired working condition, the displacement magnification of the piezoelectric vibrator is about 2.46 times, the optimum speed is 80cm/min.

Effect of Thickness Measurement Procedure on Stress Analysis of Pipes With Local Metal Loss

Fitness-For-Service (FFS) assessment using Finite Element Analysis (FEA) has been a problem in deciding yes-no which vary from evaluator to evaluator. The difference in decision making is caused by the degree of freedom in modeling a FEA model. In this study, burst pressures of pipes with local metal loss were calculated by using FEA in order to investigate the influence of thickness measurement intervals on FFS assessment. The analyzed pressures by FEA were verified by burst tests. A pipe specimen, which was thinned by corrosion under insulation in the actual plant, was used for the burst tests. Shape of the pipe specimen was measured by laser displacement meter and extracted at several types of interval. It is concluded that the analyzed pressures in various measurement intervals showed almost no difference, but were higher than the actual burst pressure of the specimen.