超声波机械振荡弹性特点简述.docx

1、超声波机械振荡弹性特点简述超声波机械振荡的弹性特点超声波是一种在弹性介质中的机械振荡 ,有两种形式 :横 向振荡 （横波）及纵向振荡 （纵波 ）。在工业中应用主要采用纵向 振荡。超声波可以在气体、液体及固体中传播 ,其传播速度不同。另外 ,它也有折射和反射现象 ,并且在传播过程中有衰减。 超声波在媒质中的反射、折射、衍射、散射等传播 规律 ,与 可听声波的规律并没有本质上的区别。与可听声波比较 ,超声波具有许多奇异特性：传播特性超声波的衍射本领很差，它 在均匀介质中能够定向直线传播 ,超声波的波长越短 ,这一特性就越显著。功率特性当声音在空气中传播时，推动空气中 的微粒往复振动而对微粒做功。在

2、相同强度下 ,声波的频率越高,它所具有的功率就越大。 由于超声波频率很高 ,所以超声波 与一般声波相比，它的功率是非常大的。 空化作用当超声波 在液体中传播时 ,由于液体微粒的剧烈振动 ,会在液体内部产 生小空洞。这些小空洞迅速胀大和闭合 ,会使液体微粒之间发 生猛烈的撞击作用 ,从而产生几千到上万个大气压的压强。微 粒间这种剧烈的相互作用 ,会使液体的温度骤然升高 ,从而使 两种不相溶的液体 （如水和油 ）发生乳化 ,并且加速溶质的溶解 , 加速化学反应。这种由超声波作用在液体中所引起的各种效 应称为超声波的空化作用。Ultrasound is a mechanical oscillatio

3、n in the elasticmedium, there are two kinds of forms: horizontal oscillation (shear wave) and the longitudinal oscillation (longitudinal wave). In industrial applications mainly adopts longitudinal oscillations. Ultrasonic can spread in gas, liquid and solid, the transmission speed is different. In

4、addition, it also has the phenomenon of refraction and reflection, and in the process of transmission attenuation. Ultrasonic in the medium such as reflection, refraction, diffraction, scattering and spread rule, and the rule of audible sound waves there is essentially no difference between. Compare

5、d with audible sound waves, ultrasonic has many strange properties: propagation characteristics ultrasonicdiffraction ability is very poor, it can directional rectilinear propagation in homogeneous medium, the ultrasound of the shorter the wavelength, this feature is more significant.Power features

6、when sound in air, pushing the particles in the air reciprocating vibration particles for doing work. Under the same intensity, the higher the frequency of sound waves, it has the greater the power. Due to the ultrasonic frequency is very high, so ultrasound compared with general sound waves, its po

7、wer is very big. Cavitation when the spread of ultrasound in liquid, due to theliquid particle vibration, can produce small hole inside the liquid. These small hole expands rapidly and closed, can make the liquid particles between violent impact effect, generating thousands to tens of thousands of a

8、tmospheresof pressure. The intense interaction between particles, canmaketheliquidtemperaturerise sharply, so that thetwodontmixliquid (waterandoil)emulsification,andacceleratesthedissolutionofthesolute, to speedupchemical reactions. This role by ultrasonic wave in the liquid caused by all kinds of

9、effect is called ultrasonic cavitationeffect.的距离 ;(3) 超声波与传声媒质的相互作用适中 ,易于携带有关传声媒质状态的信息 (诊断或对传声媒质产生效应 )Ultrasonic characteristics when: (1) ultrasonicpropagation,directionalityisstrong,energy easytoconcentrate;(2) ultrasoniccanspreadina varietyofdifferent media, and canbespreadfarenough;(3)ultrasonic

10、 andsound transmission mediuminteractionismoderate, easy to carry information about the state of sound transmission medium (diagnosis or effect on sound transmission medium).2.超声波传感器2. The ultrasonic sensor超声波传感器是利用超声波的特性研制而成的传感 器。以超声波作为检测手段 ,必须产生超声波和接收超声波。 完成这种功能的装置就是超声波传感器 ,习惯上称为超声换能器 , 或者超声探头。Ult

11、rasonic sensor is made using ultrasonic characteristics to the sensor. In ultrasonic testing means, must produce and receive ultrasonic. Complete the function of device is the ultrasonic sensor, traditionally known as ultrasonic transducer, or ultrasonic probe.超声波探头主要由压电晶片组成 , 既可以发射超声波也可以接收超声波。超声探头的

12、核心是其塑料外套或者金属外套中的一块压电晶片。构成晶片的材料可以有许多种。超声波传感器主要材料有压电晶体 （电致伸缩 ） 及镍铁铝合金 （磁 致伸缩 ）两类。电致伸缩的材料有锆钛酸铅 （pzt） 等。压电晶体 组成的超声波传感器是一种可逆传感器 ,它可以将电能转变成机械振荡而产生超声波 ,同时它接收到超声波时 , 也能转变成 电能,所以它可以分成发送器或接收器。有的超声波传感器既 作发送 , 也能作接收。 酿酒设备超声波传感器由发送传感器 （或 称波发送器 ）、接收传感器 （或称波接收器 ）、控制部分与电源 部分组成。发送器传感器由发送器与使用直径为 15mm 左右 的陶瓷振子换能器组成 ,

13、换能器作用是将陶瓷振子的电振动能 量转换成超能量并向空中幅射 ;而接收传感器由陶瓷振子换能 器与放大电路组成 ,换能器接收波产生机械振动 , 将其变换成 电能量 ,作为传感器接收器的输出 ,从而对发送的超进行检测。 控制部分主要对发送器发出的脉冲链频率、占空比及稀疏调 制和计数及探测距离等进行控制。Ultrasonic probe is mainly composed of piezoelectric chip, can emit ultrasonic already, also can receive the ultrasonic. The core of the ultrasonic pr

14、obe is its plastic or metal jacket coat of a piezoelectric wafer. Constitutes a material can have many kinds of chips. Ultrasonic sensor main material have piezoelectric crystal (electrostrictive) and nickel iron aluminum alloy (magnetostriction) two kinds.Electrostrictive material with lead zircona

15、te titanate (PZT),etc. Piezoelectric ultrasonic sensor is composed of a reversible sensor, it can transform electrical energy into mechanical oscillation produced by ultrasonic, it receives the ultrasound at the same time, also can change into electricity, so it can be divided into the sender or rec

16、eiver.Some ultrasonic sensors for send already, also can be received. Ultrasonic sensors sent by sensor (or wave transmitter), receives the sensor (or wave receiver), control part and power part. Sender sensor used by the sender and a diameter of 15 mm left and right sides of the ceramic vibrator tr

17、ansducer of transducer is used ceramic vibrator electric vibration energy conversion into energy and radiation into the air; And receiving sensor by the ceramic vibrator transducer and amplifying circuit, the transducer receives waves produce mechanical vibrations, its transformation into electric e

18、nergy, the output of the receiver as a sensor, to send for testing. Control part of the main chain of the transmitter sends out pulses frequency,duty cycle and sparse modulation and counting and detection distance control.二、超声波传感器的应用Second, the application of ultrasonic sensors1.超声波距离传感器技术的应用1. The

19、application of ultrasonic distance sensor technology超声波传感器包括三个部分 :超声换能器、处理单元 和输出级。首先处理单元对超声换能器加以电压激励 ,其受激后以脉冲形式发出超声波 ,接着超声换能器转入接受状态 ,处理单元对接收到的超声波脉冲进行分析 ,判断收到的信号是不 是所发出的超声波的回声。 如果是 ,就测量超声波的行程时间 , 根据测量吊车的时间换算为行程 ,除以 2,即为反射超声波的物体距离。把超声波传感器安装在合适的位置 ,对准被测物变化方向发射超声波 , 就可测量物体表面与传感器的距离。超声波 传感器有发送器和接收器 ,但一个超

20、声波传感器也可具有发送 和接收声波的双重作用。超声波传感器是利用压电效应的原 理将电能和超声波相互转化 , 即在发射超声波的时候 ,将电能 转换 ,发射超声波 ;而在收到回波的时候 ,则将超声振动转换成 电信号。Ultrasonic sensor consists of three parts: ultrasonic transducer, processing unit and output level. First processing unit voltage incentive for ultrasonic transducer, its after stimulated to emi

21、t ultrasonic pulse form, then the ultrasonic transducer into an accepting state, processing unit receives the ultrasonic pulse were analyzed, and the judge received signals are emitted by the ultrasonic echo. If it is, measured ultrasonic time schedule and according to the measurement of time conver

22、sion for stroke, divided by 2, is the reflection of ultrasonic object distance. The ultrasonic sensor installed in the right position, analyte on the change direction of launch ultrasonic wave, can measure the object surface and the sensor distance. Ultrasonic sensor with transmitter and receiver, b

23、ut an ultrasonic sensor can also have a dual role of send and receive sound waves. Ultrasonic sensors is using the principle of piezoelectric effect will power and ultrasonic wave transformation, which at the time of launch ultrasonic wave, converts electrical energy to emit ultrasonic; While at the

24、 time of the received echo, ultrasonic vibration is converted into electrical signals.2.超声波传感器在医学上的应用2. The ultrasonic sensors for applications in medicine超声波在医学上的应用主要是诊断疾病 ,它已经成为了临床医学中不可缺少的诊断方法。超声波诊断的优点是 :对受检者无痛苦、无损害、方法简便、显像清晰、诊断的准确 率高等。Application of ultrasound in medicine is to diagnose disease,

25、it has become the indispensable diagnosis method in clinical medicine. Ultrasonic diagnostic advantage is: the client without pain, without damage, the method is simple,clear imaging, diagnostic accuracy higher.3.超声波传感器在测量液位的应用3.The application of ultrasonic sensor in measuring liquid level超声波测量液位的基

26、本原理是 :由超声探头发出的超 声脉冲信号 ,在气体中传播 ,遇到空气与液体的界面后被反射 接收到回波信号后 计算 其超声波往返的传播时间 ,即可换算 出距离或液位高度。超声波测量方法有很多其它方法不可比 拟的优点 :(1) 无任何机械传动部件 ,也不接触被测液体 ,属于非 接触式测量 ,不怕电磁干扰 ,不怕酸碱等强腐蚀性液体等 ,因此 性能稳定、可靠性高、寿命长 ;(2) 其响应时间短可以方便的实 现无滞后的实时测量。The basic principle of ultrasonic liquid level measurement is: by the ultrasonic pulse s

27、ignal from the ultrasonic probe, propagation in gas, air and liquid interface is reflected, after receive the echo signal is calculated after the ultrasonic propagation time, back and forth to convert a distance or liquid level height. There are many other ultrasonic method of measuring incomparable

28、 advantages:(1) without any mechanical transmission parts, also not contact with liquid to be tested, belong to the non-contactmeasurement, not afraid of electromagnetic interference, not afraid of strong corrosive liquid such as acid and alkali, etc., so that stable performance, high reliability, long service life; (2) the short response time can easily realize the zero-lag real-time measurement.