水下爆炸船舱冲击响应时频特征的小波包分析

设计了带设备双层隔振系统的双层底船舱抗爆结构,进行了水下爆炸冲击试验。应用小波包分析方法,研究了水下爆炸压力和船舱冲击响应的时频分布规律,得到了船舱冲击响应时频特征与冲击环境之间的关系。研究结果表明:水下爆炸压力出现冲击波、滞后流和二次压力波过程,含有丰富的频率成分;冲击波主要作用在1kHz以上的高频段,易造成舰船局部结构的破损;滞后流主要作用在10Hz―1kHz的中频段,是舰船设备隔离系统产生冲击振动的主要来源;二次压力波主要作用在100Hz以下的低频段,会加速设备隔离系统的冲击响应;带设备双层隔振系统的双层底船舱抗爆结构,能有效提高船舶的抗爆性能。

WAVELET PACKET ANALYSIS OF TIME-FREQUENCY CHARACTERISTIC OF CABIN SHOCK RESPONSE DUE TO UNDERWATER EXPLOSION

A blast-resistant cabin structure with double bottoms was designed where the power equipment is mounted resiliently. Underwater explosion experiments were carried out with the blast-resistant cabin structure. Through wavelet packet analysis, the time-frequency distribution of the underwater pressure in the explosion was studied, and the cabin’s shock response was derived. The relationship between the time-frequency characteristic of the cabin’s shock response and the underwater shock environment was obtained. Results from the investigation show that the pressure in the underwater explosion contains abundant frequency components. The main frequency components of the shock wave are higher than 1 kHz which may cause the damage of the local underwater structure. The main frequency components of the after-flow are between 10 Hz and 1 kHz which is the important energy source of the shock and vibration of the ship. The frequency components of the second pressure pulse are generally less than 100 Hz which may cause a great displacement in the vibration isolation system for the power equipment. The blast-resistant cabin structure with double bottoms can markedly enhance the shock-resistant properties of the naval vessel with the resilient mounting system.