The depolarization behavior of lead zirconate titanate 95/5 and 52/48 has been well characterized under uniaxial strain with strain rates on the order of 10 6 /s, and under quasi-static uniaxial stress loading with strain rates on the order of 0.1-100/s. This study examines the depolarization behavior under uniaxial stress at strain rates on the order of 10 to 10 3 /s. Specimens were loaded using a split Hopkinson pressure bar. Loading rates from 7.2 to 92.5 MPa/ms were investigated, with a maximum stress of around 900 MPa. The results show significant depolarization rate sensitivity in lead zirconate titanate 52/48, while lead zirconate titanate 95/5 exhibits two responses above and below the stress rate of 50-60 MPa/ms, both with little rate sensitivity.
A measurement and integration scheme is proposed to estimate the shape of a large planar structure in space. Lightweight sun sensors distributed on the structure measure the local angles relative to the sun. A reconstruction technique is introduced to estimate the shape of the satellite through a decomposition on a function basis. The estimated shape is determined by the coefficients associated with the basis functions which are calculated from the measurements. A trade-off study to analyze the influence of different reconstruction schemes and the position of the sensors is presented. An optimization scheme minimizes the RMS error between the estimated and true shape. An experiment was conducted to show the feasibility and performance of the proposed system at the lab scale. Finally, a simulation of the accuracy of the presented solution on a 60 m space solar power module is performed. The expected error is 0.7 mm RMS using sensors every 30 cm.
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