Study on influence of dense medium on impact pressure of detonation waves subjected to contact blasts

接触爆炸下密实介质对爆轰波垂直入射压力的影响规律研究

¹ School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
² Hubei Aerospace Flight Vehicle Institute, Wuhan 430040, China

Received: 17 April 2024

Abstract

In order to investigate the buffering effect of the different dense medium on the shock waves in the contact blasts, a dimensional analysis method by using the zero-pressure sound speed of dense medium was proposed. The present approach led to the establishment of a dimensionless relationship describing the influence of the impedance on the vertical incident pressure. To validate this methodology, the classical detonation wave propagation theory was employed to calculate the pressure values of shock waves propagating into typical dense medium. Additionally, finite element analysis software was used to simulate the initiation processes of three types of explosives with different dense medium acting as buffer layers. Explicit simulations accurately reproduced the reflection of shock waves/rarefaction waves within the explosives after passing through medium with varying impedances, with the error in pressure value calculations being controlled below 8%. Combining these results with the assumptions made in dimensional analysis and a large dataset, the specific form of the dimensionless relationship was established. Subsequently, a dimensionless model for pressure of shock waves incident on dense medium, based on the explosive density and detonation velocity, was developed. By comparing the predicted with the experimental results, it was found that the error was below 10%, thus confirming the accuracy of the model in engineering applications. Moreover, since obtaining the zero-pressure sound impedance is much easier than that by using the Hugoniot relation, the present model greatly simplifies the computational complexity and provides the useful references for predicting the pressure values incident on novel dense medium.

摘要

为了研究接触爆炸时不同密实介质对于爆轰波缓冲作用的影响规律, 提出用密实介质的零压体声速进行量纲分析的方法, 建立了阻抗影响垂直入射压力的无量纲关系式。为了验证所提方法的准确性, 通过经典爆轰波传播理论分析计算传入典型密实介质中冲击波的压力值; 利用有限元分析软件模拟了不同密实介质作为缓冲层的3种炸药起爆过程。显式仿真中通过压力云图的方式展现了爆轰波经过不同阻抗的介质后反射回炸药中的冲击波/稀疏波情况, 两者压力值计算结果的误差在8%以内。从而结合验证了量纲分析时的假设条件, 通过大量数据点确立了无量纲关系式的具体形式。拟合了通过炸药密度和爆速的预测爆轰波入射密实介质压力的无量纲数学模型, 经过与实验结果进行对比, 误差在10%以内, 验证了建立的预测模型在工程应用上的准确性。并且由于零压声阻的获取难度远远小于Hugoniot关系, 因此建立的预测模型大大节约了计算时间, 同时对其入射新型密实介质的压力值预测能够提供一定的参考。