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Sensors Provide Early Diagnosis Of Microcracks In Aircraft |
 Today's aircraft are in service virtually around the clock and must operate reliably and safely at all times. An active sensor system helps to detect concealed fatigue cracks in aircraft bodies, thus reducing maintenance times considerably.
If a tiny crack in the hull of an aircraft remains undetected for a long time, it can easily spread and put passengers’ lives at risk. Each component is therefore subject to international maintenance regulations: Aircraft bodies must be thoroughly inspected every 15 to 18 months, depending on the type of plane. This often requires the technicians to dismantle an aircraft’s interior lining – an expensive and time-consuming process involving several days of downtime in the hangar. Researchers at the Fraunhofer Institute for Structural Durability and System Reliability LBF in Darmstadt are developing a sensor system that allows engineers to continuously monitor the condition of their aircraft and detect any damage at an early stage.
The system is based on piezoceramic sensors that are attached to the aircraft body in a network pattern. What is special about these sensors is that they start to oscillate when a voltage is applied to them – and when they are subjected to pressure, they generate voltage. The scientists make use of both effects: While the piezo foils cause part of the hull to oscillate, the others measure the component’s response to this stimulation. “We investigated the oscillation behavior of damaged struts and rivets in an aircraft body and compared it with that of intact parts,” explains LBF project manager Dirk Mayer. “If a component is defective, it oscillates at a different frequency from one that is intact when stimulated by the piezoceramics – just as a cracked glass sounds different from an undamaged one when you tap it with your fingernail.” In this way, the researchers can accurately track down faults and monitor their development – be it fatigue cracks in the hull and wings, or rivets and other joining parts coming loose. This form of observation is also referred to as ‘structural health monitoring’ (SHM).
“With the help of this system, any damage behind the lining or in difficult-to-reach places can be identified quickly and easily, thus reducing maintenance times and inspection costs,” says Mayer. The researchers have already performed tests on a hull component in the laboratory, and are now implementing the new technology with standardized piezo and electronic components. The system will then also be suitable for use in vehicle manufacture or engine and plant construction.
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Dear Editor,
I hope you can help me or at least point me in the right direction. My neighbor just put up a huge CB Radio antennea, the thing is higher that the roof of his home, the problem is, now I have interference through our television set speakers. We can hear him speaking although it is not too clear. How can I fix the problem so that we can watch t.v. without hearing this noise? Any help you can give me would be greatly appreciated.
Sincerly,
Donna R.
Dear Donna,
If your neighbor's transmissions are interfering with your TV, the best thing for you to do is complain to the Federal Communications Commission. The FCC investigates cases of interference and they will determine if your neighbor's transmissions contain out-of-band signals. You might also try talking to your neighbor. If his antenna is for amateur radio rather than Citizens Band, "ham" radio operators have a policy of supplying a free filter for your TV in such cases.
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ElectronicDesignNet News
HBM Force Transducer Improves Production Line Efficiency |
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Product Showcase - Friday
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Thursday, 10 May 2007 |
The stainless steel U93 force transducer from HBM reduces production cycle times in the monitoring of fitting processes such as stamping, riveting, clinching, or press-fitting. The U93 has a compact design and flange connections on both sides making it easy to install, particularly where space is a constraint. For integration with process controls the U93 includes TEDS transducer identification enabling data to be automatically transferred to the process controller. When combined with the MP85A FASTpress, the U93 can control, record and evaluate processes at up to 300 fitting processes per minute....more  (0) Comments |
Emerson Introduces Portable Multi-Channel Monitor |
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Product Showcase - Friday
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Thursday, 10 May 2007 |
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Emerson Process Management announces a monitor for plant-wide predictive machinery health monitoring. The CSI XP32 Machinery Health Expert fills the gap between the two-channel portable analyzer and the permanently-installed online vibration monitor. The CSI XP32 can be carried into the field and attached to turbo machinery for continuous monitoring on a temporary basis. The portable CSI XP32 Machinery Health Expert includes a transient processor for sleeve bearing turbo machinery and a PeakVue processor specifically for balance of plant rolling element machines and gearboxes. The CSI XP32 allows users to record hundreds of hours of continuous-time waveforms, monitor the machines live, and even play back the data as an "instant replay" from multiple camera angles....more (0) Comments |
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Banner Tips Chemical-Resistant Displacement Sensors |
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Product Showcase - Friday
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Thursday, 10 May 2007 |
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Banner's WORLD-BEAM Q12 chemical-resistant sensors are miniature photoelectric sensors with liquid-tight PFA jackets for use in wet and corrosive industrial environments. The sensor is capable of sensing up to 1.5 m in the opposed mode and 15, 30 and 50 mm fixed-field ranges. The sensor has been tested for 1200 psi washdowns. The PFA jacket is a $98 addition to the sensor’s list price....more (0) Comments |
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