【摘要】 针对强度型线性啁啾光纤布拉格光栅(LCFBG)传感器测量爆轰波、冲击波波阵面位置时不仅需要LCFBG被完全破坏,而且需要其反射长波长处先于短波长处被破坏的缺点,建立了一种波长-时间映射型LCFBG传感器技术。该技术通过高重频、锁模飞秒激光器和色散光纤将爆轰波、冲击波作用下LCFBG的瞬态反射谱,转为相同形状的脉冲信号,然后根据该脉冲信号的3 d B时宽计算出LCFBG的长度,即为爆轰波、冲击波波阵面位置。对波长-时间映射型LCFBG传感器的时间分辨本领、波阵面位置的相对测量不确定度进行了分析,得出它们的值分别为10 ns和1.7%;针对波长-时间映射型LCFBG传感器,提出了一种二维时间映射数据处理方法,将脉冲信号的一维时间映射为二维时间,从而将脉冲信号转换为二维图形,再通过一系列变换,就可获得爆轰波、冲击波波阵面位置的二维图形。为验证该技术的有效性,用波长-时间映射型LCFBG传感器测量了JB-9014炸药的爆轰波波阵面位置,对位置曲线进行线性拟合得到的爆轰波速度为7.58 km/s,与电探针测量值7.63 km/s能很好地吻合,相对偏差小于1%。更多还原

【Abstract】 A new wavelength-time mapping linear chirped fiber Bragg grating(LCFBG) sensor is proposed,to resolve the problems in which the LCFBG needs to be entirely destroyed and be damaged accordingly to the reflective position for the longer wavelength prior to the shorter wavelength in the intensive LCFBG sensor. In this sensor, the reflective spectrum of the LCFBG destroyed by the detonation and the shock wave is transferred into the same temporal pulse by the high-repetition rate mode-locked laser and the dispersive fiber, which is then used to obtain the length of the LCFBG. The time-resolution and the relative uncertainty of the wave-front position in this sensor are analyzed and their values are found to be 10 ns and 1.7%,respectively. For the data analysis, the experimental data is transformed to 2 D image and the wave-front position of the detonation and the shock wave is calculated from this 2 D image. The detonation speed of the JB-9014 explosive is linearly fitted to be 7.58 km/s from the wave-front position of the detonation, which is coincidental with the electrical pin’s result of 7.63 km/s(relative error less than 1%).更多还原