【作者】 王驰；

【导师】 张国雄； 李醒飞；

【作者基本信息】 天津大学 ， 测试计量技术及仪器， 2009， 博士

【摘要】 近年来,全球很多地区地雷的剧增致使每年都有成千上万的平民伤亡,并已引起世界范围内人道主义探雷事业的关注。目前,塑料等非金属地雷已在全球范围内得以普遍使用,因它们和土壤之间的电学特性差异较小,使用最为广泛的手持金属探雷器以及探地雷达探测效果较差。相对而言,不管是塑料地雷还是金属地雷,它们与土壤的机械特性差别较大,这使得利用声波探雷显得更为可靠。正在研究的声-地震耦合技术已经显示出能探测多种材料地雷的应用前景。然而,由于雷区环境的复杂性、地雷类型的多样性以及系统庞大、成本高等原因,该技术仍处于实验室研究阶段;另外,在国内还很少见到有关声学方法探雷的有关报道。为此,本文在综述已有声波探雷技术成果的基础上,根据国外相关文献以及自己的创造性研究成果初步建立基本的声波探雷理论体系,并设计一个实验系统。本文所完成的工作以及创新点主要体现在以下几个方面:(1)简述声学理论基础,分析声-地震耦合现象的基本原理声波探雷方法属于声学技术应用范畴,涉及到很多声学概念、术语及声学原理。声-地震耦合现象之所以能用于探雷主要是基于土壤的多孔性,当声波入射到地面时,形成不同成分的地震波,遇到地雷时能与其发生独特的机械作用。(2)讨论土壤-地雷系统的共振机理用频响传递函数的方法求解土壤-地雷共振系统的物理模型,并用机械振动模态分析理论对频响函数做深入的特征分析,揭示土壤-地雷振动系统的共振、反共振现象。(3)构建室内声波探雷实验系统构建一个基于音响和地震检波器的实验系统装置,设计基于Labview软件平台的数据采集、分析和处理程序。结果显示地雷存在时能引起地表振动状态的明显变化,与理论分析吻合得较好。(4)提出数值模拟技术在声波探雷理论研究中的应用声波探雷技术,牵涉到声学、地质学、电磁学等多个学科的知识,硬件系统工作的物理环境也十分复杂。为此,提出用最新的多物理场耦合分析软件,以期灵活处理复杂参数的影响。(5)研究平均值曲线拟合算法在声波探雷信号处理中的应用,提出今后声波探雷研究工作的若干建议。更多还原

【Abstract】 In recent years, the proliferation of landmines in many regions of the globe leads to thousands of civilian casualties every year and has focused worldwide attention on humanitarian landmine detection. Plastic and other nonmetallic mines have been developed, and used on a global scale. Because of the small contrasts in electrical properties between soil and nonmetallic mines, the most widely used handheld metal detectors and ground-penetrating radars are not always effective. In contrast, the mechanical properties of plastic and metal mines vary significantly from those of the soil, which may make acoustic excitation a more reliable mechanism to detect mines.Acoustic-to-seismic (A/S) coupling techniques are currently being studied and have shown promise as a method of detecting mines made of different materials buried in a variety of soils. However, some of these approaches are still being investigated under laboratory conditions, due to the complexity of mine field terrain, the diversity of mine style, big bulkiness and high cost of the system. As far as we know, there are few reports published about landmine detection by means of acoustic methods in China. The aim of this thesis is to study acoustic mine detection technologies and develop their fundamental theory on the basis of relevant publications and our own creative achievements. Besides, a lab-scale experimental system has been designed. The main work done and the innovation points of this thesis are as follows.(1) The acoustic theory and the basic mechanism of A/S coupling are reviewed and analyzed.Acoustic mine detection method belongs to acoustic applications. It relies on many acoustic concepts, terms and principles. It is the porous nature of the ground that plays an important role for A/S coupling to be used successfully in the detection of buried land mines. The penetrating sound waves generate a series of seismic waves within the soil, which may mechanically interact with buried mines.(2) The resonance mechanism of soil-mine system is studied.Frequency response transfer function is used to solve the soil-mine resonance system model. Furthermore, modal analysis theory is adopted to study the function in depth. It is shown that the soil-mine vibration system may display resonance and anti-resonance mechanisms.(3) A lab-scale experimental system for acoustic landmine detection has been built.A loudspeaker and geophone based lab-scale experimental system is presented. The software development platform of Labview is used to realize data acquisition, analysis and processing. The experimental data show that the mines can result in distinct changes to the acoustically coupled ground motion, which is consistent with the theory analysis.(4) The numerical simulation technology for investigating acoustic mine detection is presented.The acoustic landmine detection method relates to a few subjects such as acoustics, geology, electromagnetism and many others. The surroundings around the hardware detection system are very complex. The latest multi-physics modeling technology is brought forward to deal with those complex parameters.(5) Average algorithm curve-fitting method is studied to process acoustic mine detection signals. The thesis ends with suggestions for some further work.更多还原