Research On Multilayer Piezoelectric Ceramic Impact Sensors

Sensors have proved to be pivotal module of the automatic examining and controlling system, and are kernel, highly significant for digital, intelligent, informationization, miniaturization manufacturing. The performance of sensors determines the sensitivity, resolution, dynamic response of automatic controlling system. Piezoelectric sensor is one type of very important sensors, has been widely applied in consumer electronics, industrial controlling, system monitoring, national defense and military, and so on. The piezoelectric sensors' sensitivity, volume, cost, batch production have been required higher quality, with development of sensing technology for vibration and impact. Multilayer piezoelectric ceramic which is produced by Low-Temperature Co-fired Ceramics technology has very high piezoelectric constant, miniaturization size, and is easy for batch production. Using multilayer piezoelectric ceramic can vastly improve the charge sensitivity, and decrease the volume of impact sensors.The design theory of impact sensors, performance of multilayer piezoelectric ceramic and test technology of piezoelectric sensors are discussed and studied. Firstly, the development and working principle of piezoelectric sensors are introduced, the theoretic analysis and research of sensors are made, and then the design and simulation of high performance sensors are taken, orientation effect of piezoelectric impact sensor is also analyzed. Secondly, the mechanical and electrical properties of multilayer piezoelectric ceramic were studied; it has fine compressive strength and excellent piezoelectric property, and can satisfy the sensors' design requirements. Finally, piezoelectric sensors which have higher than 400pc/g charge sensitivity,50kHz natural frequency were made; the dynamic response was investigated, amplitude values of positive and negative output, delayed response time were tested and analyzed, and the results show that the delayed response time relates to the sensors'natural frequency, pulse duration, the mounting method, which are very helpful to the application of multilayer piezoelectric impact sensors.In this thesis, multilayer piezoelectric impact sensors have been studied, the key point of multilayer piezoelectric ceramic integration and mechanics designs were solved, and sensors with high sensitivity, high natural frequency were produced, the sensors'sensitivity and volume showed the unique technical characteristic.