[en] The Twymann-Green interferometry is applied to measure surface deformations of mechanical components in industrial areas with non-contact since it requires relatively simple optical arrangement. In this study, a tapered canti-lever beam was used to measure out-of-plane displacement by Twymann-Green interferometry. The surface of the specimen was polished to be shown as that of a mirror. Fringes observed from the specimen with a shiny surface include speckle noise and are similar to those obtained from the specimen sprayed by white paint. Gussian blur which is a commercial software is used to eliminate high frequency speckle noise. Phase shifted four fringes using PZT were captured and were used to calculated phased image. Experimental results of the tapered canti-levered plate analyzed by 4-step phase shifting method are close to the theoretical expectation.

[en] In the temperature range from room temperature to 973 K and the mechanical loading range from 0.1 to 3 MPa, a Li₂TiO₃ pebble bed was successively loaded and the packing behaviour of the bed was observed. Deformation caused by the mechanical loading is partly relaxed when the bed is heated without the load. After a large numbers of thermal and mechanical loading cycles, the packing factor of the bed increased from the initial packing factor of 66.9% to finally about 68.5%. This progressive increase in packing leads to production of a cavity region at the top of the pebble bed, therefore it is important to obtain a high initial packing factor.

[en] The parametric effects of a PZT beam that is simultaneously used as a vibration absorber and a power harvester were investigated in this study. A cantilever beam paved with PZT layers and with added tip mass has been widely used as a harvester or sometimes as a Dynamic vibration absorber (DVA). However, the beam is rarely considered a collocated device. In this study, the first step was theoretical derivation of a distributed beam covered with bimorph PZT layers. Then, the beam was attached to a 1DOF vibratory main system. Two indicators for vibration absorption and power harvesting were defined. Numerical results demonstrated that the lumped mass ratio favored both of the abilities, but that the DVA mass ratio influenced these two abilities in exactly the opposite way. The conjunction of a harvester circuit into a DVA shifted its resonance frequency up to 5 % (an extreme case of open circuit R→∞). Simultaneous power harvesting diminished the absorption capability up to 35 % for each set of mass ratios. To achieve the maximum degree of power harvesting, a corresponding load resistance that somewhat increases with the lumped mass ratio is applied. Experimental results verified the existence of the best load resistance, but the measured harvested curve was lower than the theoretical calculation because of structure damping and deviations of PZT material properties

[en] Electric field and aging time are two important factors that affect the mechanical strength and long-term reliability of lead zirconate titanate or PZT actuators. In the present work, a commercial PZT-5A aged four years was examined using ball-on-ring (BoR) mechanical testing under coupled electric fields. The electric field range of −3E_c to +3E_c (E_c, coercive electric field) was studied (i.e., −3E_c, −E_c, 0, +E_c, +2E_c, and +3E_c) with a controlled electric loading path. A Weibull distribution was used to interpret the mechanical strength data. With an electric field preloaded from 0 to −3E_c, it was found that subsequent increases in the electric field resulted in an asymmetrical V-shaped curve of mechanical strength against the electric field. The bottom of the V curve was located near the zero electric field level. Microscopy analysis showed that pores were the strength limiter for the tested PZT under electromechanical loadings. (technical note)

[en] Usually to study the polarization reversal phenomenon, the applied field is varied gradually and the polarization is measured which give the hysteresis P–E loop. In many applications, such as in memory components, a fast switching (less than 100 ns) is required. For a fast switching the applied field must generally be of order 2E_C, where E_c is the coercive field. In this case the polarization is balanced between saturation polarizations + p_s and − P_s very quickly. Thus it is difficult to study the polarization reversal evolution. In this paper we have chosen to apply on poled PZT ceramic samples a depolarizing field slightly greater than the coercive field which permits a low polarization switching.

[en] For high electrical loads, the electromechanical characteristics of PZT actuators are impacted by nonlinearities. This work presents a procedure, derived from nonlinear analysis, to assess separately the electrostriction and the elastostriction parameters of bulk PZT ceramics. A detailed investigation has shown that the electrostriction is dominant in actuator applications, while the elastostriction affects sensor applications. Further, the relationship between electrostriction and polarization in PZT material is discussed

[en] This paper describes the methods applied to the some chemical analysis of PZT ceramics during processing, and particularly in the finished ceramic, since small compositions changes can produce marked changes in final piezoelectric properties. Data on two samples (powder and high-fired ceramic material) are presented. The major constituents - Pb,Zr and Ti; nine trace elements and compound concentrations - Nb,C, Si, Al, Sr, free lead oxide, acid-insoluble matter, free oxygen and crystalline phases were determined using x-ray fluorescence, x-ray diffraction, thermal neutron activation, direct combustion, atomic absorption, vacuum fusion/gas chromatography, gravimetry, titrimetry and spectrophotometry. The major constituents were determined by more than one method, with good agreement between the various methods. (author)

[en] By real-time acquisition information of lithium titanate battery packs and single battery in the auxiliary battery system of rail vehicles, we have extracted the operating condition of the train auxiliary battery system, and emphatically established the battery float charging test under the influence of temperature, voltage and other factors. Then have analyzed the aging state information of the battery. Combined with the thermodynamic and dynamics characteristics of the power battery, established the law of change of the battery characteristic parameter with the battery float charge, and determined the recession mechanism of battery (paper)

[en] We investigate temperature hysteresis of magnetization in a two-layer composite structure composed of magnetocaloric and electrocaloric materials. The proposed model describes the simultaneous application of electric and magnetic fields. Such an approach allows analysing features of multicaloric effect in bilayer FeRh/PZT structure. To verify the correctness of the developed model, the theoretical results are compared with the experimental data for the multicaloric effect in the FeRh-PZT structure. (paper)

[en] Published in summary form only