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Application of A Voice Coil Actuator for Punching Flexible Printed Circuit BoardsChen, Po-tzu 30 August 2007 (has links)
In the past the machinery used in punching of flexible printed circuit boards(FPCBs), it used mostly the rotary motor as the power source in the mechanism design. To transfer rotary motion to linear motion need a succession of mechanical conversion components, in order to achieve the purpose of linear output. However these mechanical parts for transforming bring some unavoidable problems such as the machinery itself huge volume, backlash and friction which created during the action process, all have harmful influences on the system dynamic performance and precision. Voice coil actuator has direct-drive output, high response and high thrust force these characteristics, therefore this research apply voice coil actuator to the punching of flexible printed circuit boards. For present industry, S-curve velocity profile is often used in point-to-point displacement intermittent action applications, due to its jerk-limited characteristic for reducing vibration and raising precision. Then integrating plans of S-curve velocity profile with voice coil actuator based on punching characters, to analyze the whole system dynamic performance in such a vertical linear output application. Then generalizing the dependence of influence factors of punching quality and motion characteristics of punching mechanism through experimental results. The achievement of this research could provide references for some related designers using similar linear actuators in vertical linear output applications.
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Fragility Based Assessment Of LowOzun, Ahsen 01 May 2007 (has links) (PDF)
In this study, the seismic fragility assessment of low-rise and mid-rise reinforced concrete frame buildings which constitute approximately 75 % of the total building stock in Turkey is investigated to quantify the earthquake risk. The inventory used in this study is selected from Dü / zce damage database which was compiled after the devastating 1999 earthquakes in the Marmara region. These buildings are not designed according to the current code regulations and the supervision in the construction phase is not adequate.
The building database is divided into sub-classes according to the height and absence of infilled walls. Each building in the database is represented by an equivalent single degree of freedom system with three structural parameters: period, strength, and post-elastic stiffness ratio. The ground motion records are selected from different parts of the world covering a wide range of characteristics. The capacity of the structure is represented for each sub-class by the limit states. Hence, a set of fragility curves for low- and mid-rise reinforced concrete structures are developed by making use of the building characteristics in the database. The generated fragility curve set is referred as &ldquo / reference&rdquo / since it forms the basis of a parametric study. A parametric study is conducted to examine the influence of post-elastic stiffness ratio, simulation and sampling techniques, sample size, limit state definition and degrading behavior on the final fragility curves. Estimated damage distribution after two consecutive major earthquakes is compared with the actual field data in order to investigate the validity of the generated fragility curves.
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