【作者】 陈健；

【导师】 胡时胜；

【作者基本信息】 中国科学技术大学 ， 工程力学， 2009， 博士

【摘要】 近年来,除了接触爆炸对防护结构所造成的种种破坏作用外,越来越多的场合需要考虑空中爆炸所形成强冲击波的破坏作用,特别是在近距离大药量的情况下。早先的研究大多聚焦在防护结构本身的响应行为和变形上,对在防护结构背后能否产生可能杀伤内部人员的次生冲击波超压缺乏研究。爆炸容器作为一种爆炸试验和爆炸加工的重要装置,有着广泛的应用。研究爆炸容器的动力响应以及防护问题有重要的意义。这题可以视为空中爆炸防护问题的另一种形态。泡沫金属材料因其压缩应力应变曲线存在应力平台,有着优良的能量吸收特性,经常作为三明治结构的夹心层,应用在爆炸和冲击防护的场合。本文针对上述空中爆炸防护中的若干问题进行了研究,并考察了泡沫铝在防护中的应用。首先讨论了泡沫金属材料的特点和力学性能,并对七种不同的泡沫铝材料分别进行了准静态和动态压缩试验。这几种泡沫铝的压缩应力应变曲线均为典型的三段式曲线:包含弹性段、屈服段和致密段,并有明显的应变率敏感性。设计进行了外部空中爆炸引起密闭容器内部次生冲击波的试验。证明这种情况下完全可以产生可能造成冲击伤的冲击波超压,而使用泡沫铝夹心防护结构可以使超压峰值大幅衰减。讨论了空中爆炸和流固耦合问题的数值模拟方法和步骤。对上面的次生冲击波试验进行了有限元仿真。模拟的结果和试验符合得较好。这里的处理方法也可以用于处理其他类似的流-固-流耦合问题。对爆炸容器的动力响应问题的数值模拟方法进行了讨论。对球形和组合式两种爆炸容器的动力响应进行了有限元仿真。并进一步对容器的固有振动特性和响应的频谱特性进行了分析,讨论了应变增长现象的原因。还对爆炸容器的防护进行了初步的模拟和讨论,提出容器防护的目标应该是减少容器中的交变应力带来的疲劳,防护应从隔爆和吸振两方面考虑。更多还原

【Abstract】 In recent years,except the damaging effects of contiguous explosion on protective structures,the effects of air-blast shock waves have to be evaluated in more and more situations,especially when the standoff distance is relatively close or the charge quantity is relatively large.The former studies mainly focused on the dynamic response behaviors and deformations of protective structures.It has not been investigated whether transmitted shock wave overpressure will occur at the back of the protective structure,which may cause blast injuries of the people inside.Explosion containment vessels have been widely used as important equipments in explosive experiments or explosive workings.It is of great importance to research the dynamics responses and protection of explosion vessels.The question here can be considered as another form of air-blast protection.The compressive stress-strain curve of metal foams has a long even region.So they have excellent energy absorption property and are widely used as the core of sandwich structures on protection of explosion and impact.In this thesis,some issues of air-blast protection mentioned above were investigated.And the utility of aluminum foams in protective structures is examined.First the characteristics and mechanical properties of mental foams were discussed.Quasi-static and dynamic compressive tests were carried out on seven different aluminum foam materials.Their compressive stress-strain curves are typically three-region curves,including elastic region,collapse region and densification region.And they show signally strain rate sensitivity.The experiments of transmitted shock wave in an airtight chamber due to air-blast outside were designed and carried out.It is proved that transmitted shock wave overpressure can occur here and may cause blast injuries.When aluminum foam sandwich structure panels were used,the peak overpressure was markedly attenuated.The numerical methods and process procedures on air-blast and fluid-structure simulations were discussed.And FEA simulations of the overpressure experiments above were carried out.The simulation results have good agreements with the experiments.In addition,the process method here can be used to solve other similar problems on fluid-structure-fluid interaction.The numerical simulation methods on dynamics response behaviors of explosion vessels were discussed.For a spherical explosion vessel and an assembled vessel, their dynamics responses were simulated by FEA.Moreover their vibration characteristics,the frequency spectrum characteristics of responses and the factor of strain growth were studied.The protection of explosion vessels was preliminarily simulated and discussed.The aim of protection should be reduce metal fatigue caused by alternating stresses.And the protection should be considered on two aspects:blast isolation and vibration absorption.更多还原