激波管内挡板附近激波作用下狗胸廓表面的荷载过程

SHOCK WAVE LOADING PROCESS ON CHEST SURFACE OF ANESTHETIZED DOGS NEARBY BLIND PLATE OF SHOCK TUBE

本实验应用自行研制的微机激波信号采集系统，同步多点采集了激波管内规则反射区中狗胸廓周围的压力分布，主要结果如下：１反射区中机体的荷载过程不同于自由场中机体的荷载过程。大致可分为三个阶段：（１）类似于自由场的一次绕流、拖曳荷载，方向与入射波一致；（２）由挡板反射回来产生的二次绕流、拖曳荷载，方向与入射激波方向相反；在这两个阶段中，体表不同部位的压力荷载有较大差异。（３）等压荷载阶段，机体不同部位受到的压力荷载大小基本一致，持续时间接近于自由场的相应阶段。这三个阶段中，一次及二次绕流、拖曳荷载的时间较短，仅为２～３ｍｓ。２规则反射区内，狗体表不同部位的荷载有显著的差异，特别是在一、二次绕流荷载、拖曳荷载的过程中。在冲击伤研究中应注意到这一点，以避免由于机体表面各点受激波压力均匀作用的假定可能带来的误差。由于不同部位的荷载差异，机体结构（如胸。

Multichannels pressure-time histories were recorded synchronously on chest surface of anesthetized dog nearby blind plate of shock tube and analyzed with an author-devised microcomputer system. The main results were as follows: 1 In the reflection area, the shock wave loading process on chest surface was different from that in the free field and might be divided into 3 stages: 1) similar to that in the free field, the primary diffraction and drag loading being in direction with similar that of incident shock wave; 2) the secondary diffraction and drag loading being in direction opposite to that of incident shock wave as a result of plate reflection; and 3) the iso-pressure stage in which the pressure loading in different areas of body surface being essentially similar. 2 In the reflection area, a significant difference was observed between shock wave loading at different sites of chest surface, especially during the first two stages. These results might be important in the studies of blast injury so as to avoid errors and incorrect inference derived from the incorrect presumption of similar pressure loading sustained at different sites of body surface. Attention should also be paid to the characteriatics of pressure-loading difference in the dynamic monitoring and inferring of biomechanical responses of body surface to shock wave.