冲击加载下PBX界面对热点形成和安全性影响

Effect of PBX Interface on Hot Spot Formation and Safety under Impact Loading

高聚物粘结炸药(Polymer-Bonded Explosive,PBX)界面结构对其热点形成和冲击安全性有显著影响。为研究冲击条件下PBX点火响应过程,通过图像数字化建模和矢量化技术,建立反映PBX真实细观结构特征的有限元模型。考虑材料内部摩擦生热、晶体变形温升以及晶体放热反应过程,对PBX冲击载荷下热点形成进行数值仿真,并引入热点密度作为依据来判断材料是否点火,进一步研究晶体表面粗糙度和晶体包覆缺陷对材料点火感度与安全性的影响。试验结果表明:在冲击加载过程中,PBX内部热量前期主要来源于摩擦生热和晶体变形温升;当温度逐渐升高后,热量主要来源于晶体放热反应;材料发生点火的临界热点密度为0.68 mm-2,降低晶体表面粗糙度并提高晶体表面包覆质量,有助于抑制热点的形成,使材料降感,进而提升PBX安全性;研究结果可用于高能炸药的点火感度及安全性评估,并指导其生产加工与制备工艺。

The interfacial structure of polymer-bonded explosive(PBX)has a significant effect on the hot spot formation and impact safety.In order to study the ignition response process of PBX under impact condition,a finite element model reflecting the real internal structural characteristics of the PBX is established by digital modeling and vectorization of images.The model considers the heat generated by friction,the temperature rises caused by crystal deformation,and the exothermic reaction.The hot spot formation under PBX impact load is numerically simulated.Hot spot density is introduced as a basis for determining whether material ignition occurs,and the effects of crystal surface roughness and crystal coating defects on the ignition sensitivity and impact safety of PBX are analyzed.The results show that the internal heat of PBX initially comes from frictional heat generation and crystal deformation during impact loading,and when the temperature gradually raises,the heat mainly comes from the exothermic reaction of crystal.The critical hot spot density for material ignition is 0.68 mm-2.Reducing the crystal surface roughness and improving the coating quality of crystal can help to inhibit the formation of hot spots and reduce the material sensitivity,which can improve PBX safety.This work can be used to evaluate the ignition sensitivity and safety of high explosives and guide their production and processing.