超声波检测培训资料

Training materials USTUTS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。

3.Modes of Sound Wave Propagation. 声波的传播模式In solids, molecules can support vibrations in other directions, hence, a number of different types of sound waves are possible. Waves can be characterized in space by oscillatory patterns that are capable of maintaining their shape and propagating in a stable manner. The propagation of waves is often described in terms of what are called “wave modes.”在固体中，分子能支持在其它方向的震动，因此，声波的不同形式是可能的。

波在太空传播的特性是维持原有的形状和以稳定的方式传播。

波的传播经常用“波的模式”来描述。

As mentioned previously, longitudinal and transverse (shear) waves are most often used in ultrasonic inspection. However, at surfaces and interfaces, various types of elliptical or complex vibrations of the particles make other waves possible. Some of these wave modes such as Rayleigh and Lamb waves are also useful for ultrasonic inspection.如前所述，纵波和横波是最经常使用的在超声波检测中。

然而，在表面和内表面，不规则的结构和复杂的离子运动也有产生其他波形的可能。

像瑞利波和兰姆波在超声波检测中也是使用的。

The table below summarizes many, but not all, of the wave modes possible in solids.下面表格中是一部分波的模式：Wave Types in Solids 固体内波形Particle Vibrations 离子震荡方向Longitudinal 纵波Parallel to wave direction 平行波的传播方向 Transverse (Shear) 横波Perpendicular to wave direction 垂直波的传播方向Surface - Rayleigh 表面瑞利波 Elliptical orbit - symmetrical mode 椭圆轨道-对称 Plate Wave – Lamb 板波- 兰姆波 Component perpendicular to surface (extensionalwave) 分量垂直于表面Plate Wave – Love 板波-拉乌波 Parallel to plane layer, perpendicular to wave direction平行于平面层，垂直于波的方向Stoneley (Leaky Rayleigh Waves) 斯通利波 （漏瑞利波）Wave guided along interface 波沿界面传播Sezawa 波 Antisymmetric mode 反对称模式Surface (or Rayleigh) waves travel the surface of a relatively thick solid material penetrating to a depth of one wavelength. Surface waves combine both a longitudinal and transverse motion to create an elliptic orbit motion as shown in the image and animation below. The major axis of the ellipse is perpendicular to the surface of the solid. As the depth of an individual atom from the surface increases the width of its elliptical motion decreases. Surface waves are generated when a longitudinal wave intersects a surface near the second critical angle and they travel at avelocity between .87 and .95 of a shear wave. Rayleigh waves are useful because they are very sensitive to surface defects (and other surface features) and they follow the surface aroundcurves. Because of this, Rayleigh waves can be used to inspect areas that other waves might have difficulty reaching.表面波（或瑞利波）是在相对厚的材料表面大约一个波长的深度传播的播。