超声相控阵发射声场的计算与分析研究

建立了单探头和相控阵的发射声场计算模型,并以线性相控阵为例,讨论了相控阵探头的各种参数对相控阵发射声场的影响,对定量研究超声相控阵和超声相控阵技术的应用奠定了理论基础。

超声探头发射声场模拟及其缺陷响应研究

在超声检测时需要通过大量的实验才能实现缺陷的定量,确定合适的检测方案。通过建立基于多元高斯声束的探头发射声场模型,研究不同探头发射频率、探头尺寸、探头类型及不同界面下探头发射声场的分布规律,得出各检测参数对探头发射声场的影响,从而为确定合适的探伤方案提供一定的理论指导;基于建立的探头发射声场模型,结合波恩近似算法,建立夹杂类缺陷回波模型,并且通过实验验证了该模型的有效性,为夹杂类缺陷的定量分析提供了一定的理论指导。

相控阵超声检测DDF优化方法的研究

针对超声相控阵线性阵列在动态深度聚焦(DDF)扫查过程中,发射声场影响深度方向上检测灵敏度的问题,提出一种利用阵列探头相控延时原理形成多焦点聚焦声场的方法,改变发射声场声束轴线方向上的声压分布,改善DDF扫查中深度方向上检测灵敏度的均匀性,实现DDF检测的优化。介绍动态深度聚焦的原理和应用,分析改善深度方向上检测灵敏度均匀性的必要性;阐述多焦点聚焦发射声场的方法;利用声学理论和Matlab工具对线性阵列聚焦声场进行仿真,说明该方法对发射声场声束轴线声压分布均匀性的改善,通过DDF扫查实验验证该方法能够有效地改善深度方向上检测灵敏度的均匀性。

论声参量波幅的应用

对被测介质中存在的异常体波幅比声速反应更灵敏 ,但应用波幅必须保持换能器耦合的一致性。讨论了异常体在有效接收声场不同部位时 ,波幅及声时的变化 ,并用模型及工程测试结果说明了波幅在超声检测中的作用。

Research on vibration and near-field sound radiation of ring-ribbed cylindrical shell coated deadening and decoupling materials

The research on structural vibration and sound radiation of underwater ring-ribbed cylindrical shell, which is coated with a kind of deadening and decoupling materials, becomes a focus in recent years. This paper analyzes the problem on two aspects: model experiment and numerical calculation. The model experiment is carried out including three cases firstly, in which the structural vibration response and radiating acoustic field are measured respectively, and the results gained in these three cases are analyzed to discuss the effect of reducing structural vibration and radiating noise of the deadening and decoupling materials. The coupling FEM/BEM and the SEA methods are both used in numerical calculation, i.e. the arithmetic of the coupling FEM/BEM method is adopted to calculate the low frequency characteristics and the SEA method is adopted to calculate the medium-high frequencies characteristics of the model. By comparing experimental results with numerical calculation results, it is proved that the algorithm adopted in this paper is reasonable.