There are several basic types, classified by the energy source and by the medium into which the waves are being generated. Isbn 0849300 buy at amazon imagine an introduction to ultrasonics that brings a student from basic acoustics to the forefront of current ultrasonics research. Illustrate three methods used to detect ultrasonic waves. Previous post previous production of ultrasonic waves by magnetostriction method. A highperformance technique is suggested for generating ultrasonic waves by the magneticacoustic method without using a bias field. Principle, construction, working, advantages and disadvantages sound navigation and rangingsonar. The other method used to produce ultrasonic waves is magnetostriction effect. Engineering physics notes 1st year engineers papers. The term ultrasonic is used in acoustics to denote the frequencies which are beyond the range of human hearing.
Aug 30, 2012 magnetostriction effect production of ultrasonic waves when a rod of ferromagnetic material is kept in magnetic field parallel to its length the rod suffer a change in its length. General principle of production of ultrasonic waves general principle involved in generating ultrasonic wave is to cause dense vibration in a. The mechanical deformation in ferromagnetic material in presence of magnetic field is called as magnetostriction. Mar 27, 20 production of ultrasonic waves using piezoelectric generator a magnetostriction generator can produce ultrasonic waves of comparatively low frequency. A magnetostriction generator produces ultrasonic waves of comparatively low frequency, upto 200 khz. Hi friends, in this article, i am providing you some basic information about ultrasonic waves and industrial applications of ultrasonic waves. The technique is based on the frequency doubling of emitted ultrasonic wave as compared to the frequency of the field coil of electromagnetic transducer due to the evenness of magnetostriction.
Copper wire is then wrapped cylindrically around the. The first application of the magnetostrictive phenomena was possibly made in a magnetostrictive delay line, and the phenomena have been widely applied in the design of sensors that measure position, mass, field and others. Properties of ultrasonic wavesproperties of ultrasonic waves 1 they have a high energy content. Tech sem i engineering physics uv chapter 2ultrasonic. Refraction when a wave passes from one medium to another the frequency is constant, and since c changes then so must the wavelength. Online study material, lecturing notes, assignment, reference, wiki and important questions and answers. The variation of materials magnetization due to the applied magnetic field changes the magnetostrictive strain until reaching its saturation value, the effect was first identified in 1842 by james joule when observing a sample. In this method, the magnetostriction method is used for the production of ultrasonic. Questions1 explain the theory of production of ultrasonic waves using magnetostriction effect. The efficiency of excitation and reception of ultrasonic waves at. The word ultrasonic combines the latin roots ultra, meaning beyond and sonic, or sound. If the value of frequency of ultrasonic wave is known, the velocity of the ultrasonic wave through the medium can be calculated. A nonlinear magnetostriction finite element model is established, and the simulation results show that the amplitude of the ultrasonic wave generated by the magnetostriction based emat is.
The schematic diagram of an ultrasonic interferometer is shown in the figure. There are mainly two methods i magnetostriction and ii piezo electric method used for the production of ultrasonic waves. Download pdf ph8201 physics for civil engineering important question set 1 download pdf. Apr 12, 2018 this feature is not available right now. Explain the determination of velocity of ultrasonic using an acoustical grating. Because magnetostrictive transducers are costeffective and have simple structures, they have been widely used in non. Overview and experimental evaluation of magnetostrictive. The ultrasonic wave uw can be generated with the mechanical, electrostatic, electrodynamic, electromagnetic, magnetostrictive effect, piezoelectric effect, and laser methods.
A method for manufacturing rare earthiron magnetostrictive materials such as tb x dy 1x fe 2w wherein 0. Generationproduction of ultrasonic waves physics assignment. Construction, working and production of ultrasonics by magnetostriction method 4. It is the apparent change in the pitch of a note due to relative motion between observer and source. It generates very high frequency ultrasonic waves 500mhz we cannot obtain constant frequency of ultrasonic waves. Ultrasonic waves obey reflection, refraction, and absorption properties similar to sound waves. For generating high frequency ultrasonic waves, piezoelectric generator is used. Intense ultrasonic radiation has disraptive effect on liquids by causing bubbles to be formed. Principle, construction, working, advantages and limitations piezo electric crystals. This uses mechanical shock or friction for the generation of wave in. The properties of ultrasonic waves and production of ultrasonic waves are explained here. It is found that when crystals of some materials such as quartz, tourmaline, rocksalt etc.
Explain the principle, construction and working of magnetostriction oscillator. Magnetostrictive transducers work on the principle that ironrich metals expand and contract when they are placed in a magnetic field. Production of ultrasonic waves by magnetostriction method magnetostriction. Describe the production of ultrasonic waves by piezo electric oscillator method. Ultrasonic waves have been used for improved oil recovery especially from the marginal well in so many areas all over the world. Ultrasonic methods of ndt use beams of mechanical waves vibrations of short wavelength and highfrequency, transmitted from a small probe and detected by the same or other probes. Ultrasonic waves are an oftenoverlooked application of electrical and acoustic science which have a great effect in the manufacturing industry, among many other industries. It generates very high frequency ultrasonic waves500mhz we cannot obtain constant frequency of ultrasonic waves. By using modern methods of generation, it has become possible to produce ultrasonic wave vibrations up to frequencies of about 5 x 10 5 cs.
The wavelength of ultrasonic waves in air ranges from about 1. The main mechanism of the seismic pulses from ultrasonic waves is. Jacobsen department of physics and astronomy, university of rochester, rochester, new york, u. This transducer is working with the principle of magnetostriction effect.
Ultrasonic waves applications, features, principal of. When magnetic field is applied across the length of a ferromagnetic rod such as nickel, then change in the length of rod is observed. We can obtain constant frequency of ultrasonic waves. Dolphins, whales, dogs and some fishes can respond to sound that human ear cannot hear. Tech sem i engineering physics uv chapter 2ultrasonic waves. The shortest ultrasonic waves have nearly the same wavelength as visible light. Engineering physicsi i ultrasonics detection, properties, acoustic grating material prepared by. Page 2 of 8 detection of ultrasonic waves ultrasonic waves propagated through a medium can be detected in a number of ways. Engineering physics 1 ultrasonic and magnetostriction method. These are today being used for numerous applications in industry, communication systems and chemical and medical sciences. Here ab is a rod of nickel, which is clamped in the centre. Pdf fast measurement of magnetostriction coefficients for.
Ultrasonic waves are produced by the following methods. This is how the production of ultrasonics by magnetostriction method. A nonlinear magnetostriction finite element model is established, and the simulation results show that the amplitude of the ultrasonic wave generated by the magnetostrictionbased emat is. Introduction production of ultrasonic waves magnetostriction method piezo electric method detection of ultrasonic waves properties of ultrasonic waves use of ultrasonics for nondestructive testing applications of ultrasonics. Pdf fast measurement of magnetostriction coefficients. What is the main difference in the quality of ultrasonic waves produced by piezo electric and magnetostriction method. Since magnetostriction is due to the coupling of magnetic and elastic forces, it is of immense technological importance for the conversion of energy between magnetic and elastic degrees of freedom. In this 30 mins video lesson basic concepts, magnetostriction oscillator, piezoelectric oscillator, properties of ultrasonic waves, detection of ultrasonic waves, kundts tube method, piezoelectric detector, thermal detection, and other topics. When a ferromagnetic rod like iron or nickel is placed in a magnetic. Piezoelectric oscillator general principle of production of ultrasonic waves. Production of ultrasonic waves by magnetostriction method. Rare earth and iron raw materials are continuously fed into a plasma arc melting furnace having a plasma arc torch and a watercooled bottomless elongated mold located beneath the torch. The sound waves having frequencies above the audible range i.
A nickle rod 10 cm long gives out ultrasonic wave of frequency 24khz. Mechanical method or galton whistle method is an initial method for the generation of ultrasonic wave. Magnetostriction effect, magnetostriction oscillator working. Production of ultrasonic waves using piezoelectric. Production of ultrasonics by piezoelectric method tech glads. Explain the principle, construction and working of the piezoelectric oscillator for producing ultrasonic waves.
The variation of materials magnetization due to the applied magnetic field changes the magnetostrictive strain until reaching its saturation value. Magnetostriction electromagneticacoustic excitation of. The efficiency of excitation and reception of ultrasonic. Magnetostriction is the lattice deformation which accompanies magnetization see magnetoelastic phenomena. Ultrasonics, vibrations of frequencies greater than the upper limit of the audible range for humansthat is, greater than about 20 kilohertz. It generates low frequency ultrasonic waves 3mhz 1.
It is found that when pressure or compression is applied on two opposite faces of a quartz crystal, then charges are produced on a set of opposite faces which are perpendicular to the faces at which pressure is applied. The term sonic is applied to ultrasound waves of very high amplitudes. The raw materials are melted together by plasma flames to form a pool. The frequency of the oscillator can be adjusted by changing the capacitance of the condenser c. The production and use of ultrasonic waves utilize electronic circuits. Since magnetostriction is due to the coupling of magnetic and elastic forces, it is of immense technological importance for the conversion of. There are three methods for producing ultrasonic waves. Explain how ultrasonic waves can be produced by using piezo electric crystal and write any four application of ultrasonics.
Industrial applications of ultrasonic waves your electrical. Introduction to ultrasonics properties of ultrasonic waves ultrasonic production magnetostriction method ultrasonic production piezo electric method applications of ultrasonics worked problem 2 3. Properties and production of ultrasonic waves magnetostriction method. Generally these waves are called as high frequency waves. The development of materials that exhibit strong magnetostrictive effects, such as terfenold that is a giant. For generating ultrasonic waves of high frequency about 50 mhz a generator using the piezoelectric effect is employed. Magnetostriction effect is used for generation of ultrasonic wave in. Production of ultrasonics by magnetostriction method. A transducer that can generate and measure ultrasonic waves using magnetostriction is called a magnetostrictive transducer 2, 3. When a rod of ferromagnetic material like nickel is magnetized.
Propagation of ultrasound waves in tissue ultrasound imaging systems commonly operate at 3. Ultrasonic waves produce stationary wave pattern in the liquid while passi ng through it. Us5114467a method for manufacturing magnetostrictive. Longitudinally, it undergoes a very small change in length. The circuit diagram of magnetostriction ultrasonic generator is as shown in the figure1. The field of ultrasonics have applications for imaging. Ultrasonic waves are wellknown for their broad range of applications. Sep 16, 2012 questions1 explain the theory of production of ultrasonic waves using magnetostriction effect. The human ear is sensitive to sound waves in the frequency range from 2020, 000 hz.
Such mechanical waves can travel large distances in finegrain metal, in the form of. Experimental arrangement to produce ultrasonic waves by magnetostriction method is shown in figure. A characteristic presented in all applications is the simplicity of the instrumentation involved, even knowing that the methods are mostly very complex, sometimes requiring analytical and numerical. By varying the length of rod high frequency oscillations can be obtained. Frequencies ranging from 8000 hz to 20,000hz can be produced by this method. Phy4 ultrasonics free download as powerpoint presentation. Fundamentals and applications of ultrasonic waves, j. Ultrasonics production of ultrasonics by magnetostriction and. Explain how ultrasonic waves can be producing ultrasonic waves by magnetostiction effect. Describe the production of ultrasonic waves by magnetostriction oscillator method. Properties of ultrasonic waves and production of ultrasonic waves. Magnetostriction 1 is a phenomenon operated by coupling between magnetic and elastic. Pdf the effect of ultrasonic waves on the relative.
A magnetostriction oscillator producing intense audible sound and. This phenomenon is most pronounced in metals such as nickel, iron, cobalt and their alloys. This longitudinal vibrations, result in the formation of ultrasonic waves at resonance. The term ultrasonics applies to sound waves that vibrate at a frequency higher than the frequency that can be heard by the human ear or higher than about 20,000 hertz. Introduction to ultrasonics properties of ultrasonic waves ultrasonic production magnetostriction method ultrasonic production piezo electric method. A magnetostriction generator can produce ultrasonic waves of comparatively low frequency.
Thin plates of these metals are stacked up to make a core. This method is based on the fact that ultrasonic waves which consist of alternate compressions and rarefactions changes the density of the medium through which they pass. Describe principle, construction and working of magnetostriction. They can be employed in various fields of knowledge such as medicine, engineering, physics, biology, materials etc. Ultrasonic waves are used for the following purposes. It works under the principle of magnetostriction effect. Ultrasonic waves produce stationary wave pattern in. The frequency of ultrasonic waves produced is given by v v. Ultrasonic aa produces heat effect passes through the medium. Construction, working and production of ultrasonics by pizoelectric method 7.
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