基于CIVA平台的材料中超声检测声场分布和小缺陷响应建模仿真及实验研究

发布时间：2018-05-27 14:11

本文选题：超声检测 + 声场分布　；参考：《浙江大学》2017年硕士论文

【摘要】：本论文研究是在多项国家、省部级科研基金项目资助下,以金属材料中板材和棒材以及碳纤维复合材料为研究对象,基于CIVA仿真平台,对材料中超声波声场分布和小缺陷的回波响应开展了建模仿真分析和实验研究。在超声声场计算方面,利用基于Penci1法修正的瑞利积分(Rayleigh Integration Method,RIM)模型建立了适用于各类探头及传播介质的超声传播模型,得到声场分布与工件、探头及检测参数之间的定量关系。为了解决在实际工程应用中,由于缺陷或结构的复杂性很难计算得到解析解的问题,引入了基尔霍夫(Kirchhoff)近似和伯恩(Born)近似等理论,建立了基于近似理论的缺陷和结构散射声场模型,使得快速计算复杂缺陷和结构散射声场能够得以实现。针对金属材料建立了碳钢棒材模型和铝制板材模型,将一些重要和常见的金属材料中毫米级以下小缺陷(比如夹渣和裂纹)等效为圆柱体缺陷,建立平底孔人工缺陷模型。使用超声仿真软件CIVA建模分析了多种检测条件对无缺陷金属材料中声场分布规律和含人工缺陷的金属材料中缺陷回波响应规律的影响。搭建了基于脉冲反射法的水浸式超声检测实验平台,使用含有0.8mm直径平底孔人工缺陷的20#钢棒材模拟试块和方形铝块板材模拟试块对缺陷回波进行了超声检测实验验证。针对碳纤维复合材料建立了32层薄板型无缺陷CFRP层压板理想模型和72层厚截面含平底孔人工缺陷CFRP层压板模型。使用CIVA仿真软件分别进行了声场分布和缺陷响应的仿真分析,并使用自建的超声检测实验平台进行了对应的超声检测实验。综上所述,本文主要基于CIVA仿真平台对材料中超声检测声场分布和小缺陷响应开展了建模仿真分析和相关实验的研究。研究了多种检测条件对金属和复合材料中声场分布规律和缺陷回波响应规律的影响,得到关键影响因素以及为如何选择合适的超声检测探头参数提供理论指导。
[Abstract]:This thesis is based on CIVA simulation platform, which is supported by many national, provincial and ministerial research fund projects, taking sheet metal, bar and carbon fiber composites as research objects. The ultrasonic field distribution and echo response of small defects in materials are simulated and studied experimentally. In the aspect of ultrasonic sound field calculation, a model of ultrasonic propagation suitable for all kinds of probes and propagation media is established by using the Rayleigh Integration method RIM-based modified Rayleigh Integration method model based on the Penci1 method. The quantitative relationship between the sound field distribution and the workpiece, probe and detection parameters is obtained. In order to solve the problem that it is difficult to calculate the analytical solution because of defects or structural complexity in practical engineering applications, the Kirchhoff-Kirchhoff-Kirchhoff approximation and Born approximation are introduced. The defect and structure scattering sound field model based on approximate theory is established, so that the fast calculation of complex defect and structure scattering sound field can be realized. The carbon steel bar model and aluminum plate model are established for metal materials. Some important and common small defects (such as slag inclusion and crack) in metal materials are equivalent to cylindrical defects, and the artificial defect model of flat bottom holes is established. The influence of various detection conditions on the distribution of sound field in non-defective metal materials and the echo response law of defects in metal materials with artificial defects is analyzed by using ultrasonic simulation software CIVA. An experimental platform of underwater ultrasonic detection based on pulse reflection method was built. The ultrasonic echo was verified by using simulated steel bar and square aluminum plate with artificial defects of 0.8mm diameter flat bottom hole. The ideal model of 32-layer thin plate CFRP laminates with no defects and the 72-layer thick section CFRP laminates with artificial defects with flat bottom holes were established for carbon fiber composites (CFRP). The sound field distribution and defect response were simulated by using CIVA software, and the corresponding ultrasonic testing experiments were carried out using the self-built ultrasonic detection experimental platform. To sum up, based on the CIVA simulation platform, the modeling, simulation and related experiments of ultrasonic detection of sound field distribution and small defect response in materials are carried out in this paper. The effects of various detection conditions on the distribution of sound field and the echo response of defects in metal and composite materials were studied. The key factors were obtained and theoretical guidance was provided for the selection of appropriate ultrasonic detection probe parameters.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG115.285

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