论文部分内容阅读
1.序论AE(Acoustic Emission)换能器的类型主要有压电型、谐振型、静电电容型和光学型。其中,从使用方便、频率特性、重复性、检测灵敏度、实用灵敏度、价格等方面考虑,压电型换能器使用最普遍。压电型换能器,是计量那些超过一定门槛值的AE波数目。这些波大都是低于2MHz的横波和板波,通常很难检出微裂纹所产生的微弱AE信号和上升时间非常陡峭的高速AE波,特别是微弱的纵波信号。从而高速AE现象给材料内部的缺陷位
1. Introduction AE (Acoustic Emission) Transducer types are piezoelectric, resonant, electrostatic capacitance and optical type. Among them, from the use of convenience, frequency characteristics, repeatability, detection sensitivity, practical sensitivity, price, etc., piezoelectric transducers are most commonly used. Piezoelectric transducers measure the number of AE waves that exceed a certain threshold. Most of these waves are shear waves and plate waves below 2 MHz. It is often difficult to detect weak AE signals generated by micro-cracks and high-speed AE waves with very steep rising times, especially weak longitudinal waves. Thus high-speed AE phenomenon to the material within the defect bit