超声波检测培训资料

Training materials UST

UTS培训材料

1.Basic Principles of Ultrasonic Testing. 超声波检测（UT）的基本原理

Ultrasonic Testing (UT) uses high frequency sound energy to conduct examinations and make measurements. Ultrasonic inspection can be used for flaw detection/evaluation, dimensional measurements, material characterization, and more.

UT是用高频声音能量来检测和测量的。超声波检测能用于缺陷的检测和评估，尺寸的测量、材料的特性和其他。

Ultrasonic Inspection is a very useful and versatile NDT method. Some of the advantages of ultrasonic inspection that are often cited include:

超声波检测是很好用并且多功能的NDT方法。下面是它的一些优点：

•It is sensitive to both surface and subsurface discontinuities.

•对表面和亚表面的不连续性都很灵敏。

•The depth of penetration for flaw detection or measurement is superior to other NDT methods.

•缺陷检测和测量的深度方面优于其他的检测方法。

•Only single-sided access is needed when the pulse-echo technique is used.

•当用回波技术时，只需要单边。

•It is highly accurate in determining reflector position and estimating size and shape. •确定检测缺陷位置和测量大小和形状时非常精确。

•Minimal part preparation is required.

•只需要非常小的样品。

•Electronic equipment provides instantaneous results.

•电子设备可以提供瞬间结果。

•Detailed images can be produced with automated systems.

•可以自动产生详细的图像。

•It has other uses, such as thickness measurement, in addition to flaw detection.

•其他功能，除了缺陷的检测还有厚度的测量等。

2.Wave Propagation. 波的传播

Ultrasonic testing is based on time-varying deformations or vibrations in materials, which is generally referred to as acoustics. In solids, sound waves can propagate in four principle modes that are based on the way the particles oscillate. Sound can propagate as longitudinal waves, shear waves, surface waves, and in thin materials as plate waves. Longitudinal and shear waves are the two modes of propagation most widely used in ultrasonic testing.

超声波的检测是基于声波在物料上产生随时间的变化的变形和震动。在固体中，声波基于离子震荡有四种传播模式：即可以传播纵波、横波、表面波和薄板板波。纵波和横波是超声波探伤主要使用的两种模式。

In longitudinal waves, the oscillations occur in the longitudinal direction or the direction of wave propagation. Since compressional and dilational forces are active in these waves, they are also called pressure or compressional waves. They are also sometimes called density waves because their particle density fluctuates as they move. Compression waves can be generated in liquids, as well as solids because the energy travels through the atomic structure by a series of comparison and expansion (rarefaction) movements.

在纵波中，震荡发生在纵向或波传播的方向，由于压缩和扩张力激活了这些波，它们也叫压力波或压缩波，有时也称密度波，因为当它们移动时，它们的离子密度也在波动。压缩波在液体和固体中可以被激发，因为能量是经过原子结构用一系列的压缩和扩张而传递的。

In the transverse or shear wave, the particles oscillate at a right angle or transverse to the direction of propagation. Shear waves require an acoustically solid material for effective propagation, and therefore, are not effectively propagated in materials such as liquids or gasses. Shear waves are relatively weak when compared to longitudinal waves. In fact, shear waves are usually generated in materials using some of the energy from longitudinal waves. 在横波或剪切波中，离子震荡是沿直角度或垂直于传播方向进行的。剪切波的传播需要一种很好的声学传播材料，因此，它在液体或玻璃中是不能有效传播的。横波相对纵波较弱。实际上，在材料中横波的激发通常也是用纵波的能量实现的。