Top PDF Ultrasonic sensor platforms for non-destructive evaluation

Ultrasonic sensor platforms for non-destructive evaluation

Ultrasonic sensor platforms for non-destructive evaluation

As discussed in Chapter 3 a global positioning system can be used to enhance the positional accuracy of the robots. Building upon the work of M. Friedrich [8] the Cricket Indoor Positioning System [74, 75] was integrated into the system. The Cricket modules are set up in a pitch-catch arrangement. The relative distances be- tween transmit and receive modules is calculated by measuring the time of flight of an ultrasonic burst. The transmit module simultaneously emits a 433MHz RF pulse and a 40KHz ultrasonic pulse. The receiver calculates the time difference between these pulses, assuming the RF pulse is instantaneous. The distance is calculated by multiplying the transit time by the propagation velocity of sound. Equation 2.4 [76] provides this velocity, where θ is the temperature in degrees centigrade. By using three or more fixed beacons and a module mounted on the robot, a tri- lateration calculation can be performed to calculate the robot position. Only one RF/US transmission can occur at any one time to prevent interference of US signals. However one active beacon can be simultaneously received by several listeners. The active beacons are battery powered, so do not require any connections to the host PC. The listeners return the time of flight through a serial interface which must be interpreted by either the host PC or the robot’s embedded computer. It should be noted that the Cricket ultrasonic transmitter and receivers are incorrectly labelled in the manual, ‘US1’ is the receiver. This must be taken account of when positioning the beacons.
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Non Destructive Evaluation of Weld Structure Using Ultrasonic Imaging Technique

Non Destructive Evaluation of Weld Structure Using Ultrasonic Imaging Technique

The welding penetration depth and width measured by destructive inspection are very important items to evaluate welding quality. However, the destructive method has some limitations and disadvantages. In this study, ultrasonic measurement technique which can make the image of cross sectional macro structure non-destructively was investigated. As a result, it is concluded that signal processing of ultrasonic back scattering is effective to measure the penetration depth of welds. [doi:10.2320 / matertrans.I-M2011857]

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Acoustic metamaterials for medical ultrasound and non destructive evaluation

Acoustic metamaterials for medical ultrasound and non destructive evaluation

It has been stressed throughout the previous sections that metamaterials usually work for a certain specific single frequency (or a very narrowband frequency range) or for specific discrete set of frequencies. This is mainly due to their geometrical arrangement from which their extraordinary properties arise. Being able to realize them in such a way that they can be exploited along a broad-frequency range would allow them to be used on real applications, especially in the ultrasonic region for ultrasonic non-destructive testing applications and medical imaging. Moreover, since chirps and coded signals provide the well-described properties and gains described deeply in Chapter 2, they would be successfully used in combination with such broadband devices. As a consequence, metamaterials energy losses can be counterbalanced by using such coded excitation. Moreover, phase-time information can be restored after acoustic wave travel into the metamaterial by using such coded excitations.
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Application Research of the Non Destructive Testing Using Optical Fiber Sensor

Application Research of the Non Destructive Testing Using Optical Fiber Sensor

In the field of non-destructive testing, especially in oil and gas pipelines, there are five commonly used non-destructive testing technologies: Radiographic Testing (RT), Ultrasonic Testing (UT), Magnetic powder Testing (MT), Penetra- tion Testing (PT), Eddy Current Testing (ECT). Certainly, they have their own advantages and disadvantages. At present, ultrasonic testing (UT) technology [1] and Magnetic Flux Leakage Testing (MFLT) technology [2] are the most mature and widely used in pipeline and plate inspection. However, there are some shortcomings in ultrasonic testing technology, such as the need for coupling agent and the high requirement for the pipe surface cleanliness. For magnetic flux leakage testing (MFLT), it has some problems such as the low sensitivity of How to cite this paper: Dai, Z.Y., Zhang,
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Towards semi-automated non-destructive evaluation

Towards semi-automated non-destructive evaluation

Abstract. A demonstrator has been developed showing feasibility of semi-automatic characterisation of large planar flaws in steel using ultrasonic transducer arrays. The unit is based on a real-time ultrasonic imager deploying National Instruments hardware and software, is connected to an IMASONIC linear phased array containing 128 elements and incorporates a novel flaw characterisation algorithm, which is a model-based variant of Total Focusing Method, taking into account undulations in inspection surface. It has been shown to process RF data collected in immersion reasonably fast and be capable of detecting and characterising with reasonable accuracy large planar defects.
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Automatic detection, sizing and characterisation of weld defects using ultrasonic time-of-flight diffraction

Automatic detection, sizing and characterisation of weld defects using ultrasonic time-of-flight diffraction

Non-destructive testing (NDT) or non-destructive evaluation (NDE) of materials has been an area of continued growth for over seventy years. In simple terms, it is a group of methods and techniques to carry out tests on objects without destroying them or changing their physical characteristics. The objects can range from small devices to heavy equipment with different geometrical shapes and materials. The need and use for NDT has increased dramatically in recent years for various reasons such as product safety, in-line diagnostics, quality control, health monitoring, and security testing, etc. Besides the practical demands, the progress in NDT has a lot to do with its interdisciplinary nature. Industrial NDT of manufactured items is usually undertaken when a product is likely to be placed under extreme or long periods of stress or wear, or if any component failure is liable to result in a major incident. NDT methods and techniques involve both hardware and software components and modules. While the emphasis in NDT has long been on
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Design and Development of Ultrasonic and IR Insect Detector for Oilseeds Crop

Design and Development of Ultrasonic and IR Insect Detector for Oilseeds Crop

Ultrasonic sensors are used to convert ultrasound waves into electrical signals. There are the transducers that both receive and transmit ultrasound waves and are called as ultrasound transceivers. Above the limits of human audibility, the source of ultrasonic waves is sound waves. Ultrasound is divided into three categories depending upon frequency, namely, as a) power ultrasound (20 KHz-100 KHz) b) high-frequency ultrasound (100 KHz-1MHz) and c) diagnostic ultrasound (1MHz-50 MHz). The insect detection system detects the insect activity by detecting sound generated by insects in the audio frequency range (20 – 20,000Hz). “Acoustic Emission” technology can be advantageously used in detecting insects. This technology has been primarily used in non-destructive testing of metal parts and assemblies. Researchers found that using Acoustic emission technology we can detect the feeding insects that produce ultrasonic signals. As an insect feeds, it tears the fibrous tissue which creates mechanical disturbances which propagate throughout the material on which the insect is feeding. These mechanical disturbances produce ultrasonic waves which can be detected by the Acoustic Emission technology. Taking a “bite” out of the material will be defined as a “feeding event”. At ultrasonic frequencies, most human activities do not generate much acoustic energy. Therefore, the sounds detected by the transducer are those, caused by the tearing off plant tissue, occur during insect feeding. The action of the insect’s mouthparts
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Non-Destructive Testing by Ultrasonic and Thermal Techniques  of an Impacted Composite Material

Non-Destructive Testing by Ultrasonic and Thermal Techniques of an Impacted Composite Material

• Heating the component 14 seconds on average. 2) Ultrasonic Phased Array Technique: Phased array technology is among the non-destructive ultrasound controls that has proven itself in recent years [18]. Thanks to, the possibility of deflections in different directions and / or focusing a beam at different depths with one and the same multi-element sensor as shows in the Fig. 4.The principle of phased array relies on the use of a translator decomposed into individual elements that can be controlled independently [19]. These elements allow the conversion of an electrical signal into mechanical vibration and vice versa. So, The equipment like the Omniscan SX allows the excitation of the elements of the transducer ( probe) with an adequate delay. It also allows to receive the signals and put them in the form of different representations (cartography) :A-Scan, B-Scan, S-Scan, C-Scan...etc. The cartography represents an important point to visualizing and interpreting the information collected by the translator.
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Simulation of Non-destructive Testing Methods of Ultrasound in Concrete Columns

Simulation of Non-destructive Testing Methods of Ultrasound in Concrete Columns

The present Investigation evaluated, through simulations using the Toolbox for Matlab K- Wave, two non-destructive testing methods based on ultrasound (longitudinal transmission method and pulse-echo method). To perform the simulations, we established a computational model of the column on which a perturbation was applied (ultrasonic wave) through k-wave toolbox. Subsequently using the information gathered by the sensors, we performed the reconstruction of the column through the time-reversal algorithm, generating an image, in which after conducting the respective processing, it was possible to identify the reinforcements within the structure.
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Structural Health Monitoring By Using Damage Evaluation Techniques

Structural Health Monitoring By Using Damage Evaluation Techniques

Structural health monitoring is estimating the state of structural health, or detecting the changes in structure that affect its performance. It is often necessary to test concrete structures after the concrete has hardened to determine whether the structure is suitable for its designed use. Ideally, such testing should be done without damaging the concrete. The tests available for testing concrete range from completely non-destructive tests, where there is no damage to the concrete, through those where the concrete surface is slightly damaged, to partially destructive tests, such as core tests and pull-out and pull-off tests, where the surface has to be repaired after the test. The range of properties that can be assessed using non-destructive tests is quite large and includes such fundamental parameters as density, elastic modulus and strength as well as surface hardness, surface absorption, reinforcement location, size and distance from the surface. Non-destructive methods like rebound hammer test and ultrasonic test do not damage buildings and allow to having an inventory of structures and conditions. Non-destructive tests are widely applied to study mechanical properties and integrity of concrete structures.
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Architectural Evaluation of Asymmetric Algorithms in ARM Processors

Architectural Evaluation of Asymmetric Algorithms in ARM Processors

Abstract—This paper presents the performance evaluation of asymmetric cryptographic algorithms oriented to embedded platforms used in Wireless Sensor Networks (WSN). The algorithms RSA, ECC and MQQ were evaluated on ARM platform. We have used three criteria in our comparison: the processing time, memory and processor usage. We used the SimpleScalar tool for our simulations analysis. The MQQ algorithm achieved the best results in most of the evaluated criteria. Considering the same key sizes, the processing time for MQQ is at least 16 times smaller than the ECC and 230 times smaller than RSA. Regarding memory consumption, the MQQ had an occupation 61% lower than the RSA and 24% less than in the ECC. Besides these, other criteria such as misses on cache level 1, branches, replacements and write-backs were recorded in order to improve our assessment. Finally, we show the MQQ is a good algorithm for embedded systems since it is better than ECC e RSA. 
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Non Destructive Testing of Old R C C  Framed Structure

Non Destructive Testing of Old R C C Framed Structure

The objective of present case study is to obtained the Non Destructive Testing of 30 years old R.C.C. Framed structure with Rebound Hammer Test to know the probable Compressive Strength, Ultrasonic Pulse Velocity Test for access the condition of structure & Half cell Potentiometer Test to know the availability of corrosion in reinforcement and visual inspection.

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Non Destructive Evaluation of Reinforced Concrete Frames

Non Destructive Evaluation of Reinforced Concrete Frames

Rebound Hammer basically gives us the measure of hardness on the surface. If high accuracy and reliability is required, this test should be incorporated with another Non-Destructive test to get better results. Results that we get from these NDT’s are not exactly the same as that of compression test. As NDE tests give us a good measure of the strengths, these test should be carry out and then the decision should be made whether the structure should be demolished or is there any chance of retrofitting the structure.

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Strength Assessment of Jute Fiber Reinforced Concrete by Destructive and Non-destructive Test Methods

Strength Assessment of Jute Fiber Reinforced Concrete by Destructive and Non-destructive Test Methods

The low standard deviations and low standard error means within the batches for all measured clearly shows that the process of destructive and non-destructive tests are reliable. In the Fig.9. , the standard error of the mean are plotted to get the error bar to adjust the uncertainty of the value of compressive strength. From the standard error mean values of destructive and non-destructive methods, the destructive test has shown has shown 34.7% and 51.6% less standard error mean than UPV and RHT methods respectively.
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Eye tracking electronic wheelchair for physically challenged person

Eye tracking electronic wheelchair for physically challenged person

A robotic wheelchair with novel ideas which integrates three different options to all kinds of impairment as well as disabilities was designed in this project. The first option allows users that are not capable of moving their limbs, to navigate the wheelchair using their eye, namely the optical detector. The optical detector allows user that suffers severe disability such as amyotrophic lateral sclerosis (ALS) that paralyzes the victim mobility entirely to move by moving their eye to desired location. The secondary option provides common wheelchair users who are suffering from less severe disability to navigate using a touch input option which is accessible via their smart phones, namely touch and go APP. The touch and go APP can be controlled easily as well as adjusting the speed of the wheelchair. The third option works for users with limited mobility by using a voice command application. In addition, the robotic wheelchair is integrated with multiple safety features, an ultrasonic sensor and dual bump sensor. The ultrasonic sensor is to create a threshold distance between the user and obstacle in front and to prevent collision. The bump sensor works as a failsafe, where an object that is in contact with it will reverse the robotic wheelchair to a safe distance. This research combines both ease of access navigational technology with a safety features to help those who are in need of such technology to move with a high safety element. The newly designed wheelchair does not discriminate any kinds of disabilities with the integration of the three navigational options.
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Enhancement of root crack detection in friction stir welds using ultrasonic non-destructive testing and signal processing technique.

Enhancement of root crack detection in friction stir welds using ultrasonic non-destructive testing and signal processing technique.

There are two main ways to irradiate ultrasonic waves. First is magnetostriction. This is usually used for underwater sounding and uses low frequency in the range of 100 kHz. Ultrasonic testing, however, needs higher frequency than this, and is therefore based on the second method of piezoelectricity. Piezoelectricity is a method of producing high-frequency oscillation. When an electric field is applied across the piezoelectric material, the polarized molecules will align themselves with the electric field, resulting in induced dipoles within the molecular or crystal structure of the material. This alignment of molecules will cause the material to change dimensions. This phenomenon is known as electrostriction. In addition, a permanently-polarized material such as quartz (Si02) or barium titanate (BaTi03) will produce an electric field when the material changes dimensions as a result of an imposed mechanical force. This phenomenon is known as the piezoelectricity.
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Estimation of Compressive Strength and Member Size of Steel Fiber Reinforced Concrete Using Stress Wave-Driven Nondestructive Test Methods

Estimation of Compressive Strength and Member Size of Steel Fiber Reinforced Concrete Using Stress Wave-Driven Nondestructive Test Methods

within a specimen, uniformity and corrosion of speci- mens, compressive strength, elastic modulus, etc., and the scope is expanding continually (Naik and Malhotra 1991). As to the basic principle of ultrasonic pulse veloc- ity method operation, short and strong electric signals are sent to the converter and then the converter vibrates according to the resonance frequency. The vibration is transmitted to materials through the medium in con- tact, and then this is detected by the receiving converter at the opposite side. Depending on the arrangement of the transmitter and receiver, the ultrasonic pulse veloc- ity method is classified to the direct type, indirect type, rectangular type, etc. When material properties are to be assessed by measuring the ultrasonic pulse speed, the level of measuring precision needs to be quite high. The longitudinal ultrasonic pulse velocity V inside an elastic body is calculated as follows:
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Ultrasonic non-destructive testing of adhesive bonded aluminum plates

Ultrasonic non-destructive testing of adhesive bonded aluminum plates

Several methods have realistic potential for non-destructive inspection of adhesive joints, as example, ultrasonic waves, electromechanical impedance, and acoustic emission. Ultrasonic wave pitch-catch techniques have proven to be an effective method for inspection of adhesive bonds integrity of isotropic materials. Corrosion detection at locations with limited access gives rise to many inspection problems in daily practice. Hidden corrosion at inaccessible locations such as pipes on sleepers or supports, insulated pipe work, tank floor, clamping and complex joints made the inspection difficult to be done. For the solution, a new ultrasonic pulse echo method, the Long Range Ultrasonic System (LORUS) has been optimized for inspection over considerable distance (typically one meter) which can overcome most of the access problem. The technique utilizes optimized bulk wave transducers with a dedicated data recording system [7].
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Ultrasonic Inspection of Composite Resin Restorative Materials

Ultrasonic Inspection of Composite Resin Restorative Materials

Non-destructive ultrasonic tool can detect various discontinuities in a material. Especially, when using pulse- echo technique, various discontinuities can be characterized. So it is useful to predict the presence of cracks and the degree of their activation (e.g. exterior stress activation) [5- 6]. In addition, the critical crack velocity of the major crack- like discontinuities can be determined.

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REVIEW ON VARIOUS PIEZO ELECTRIC MATERIALS AND APPLICATION OF ULTRASONIC WAVES

REVIEW ON VARIOUS PIEZO ELECTRIC MATERIALS AND APPLICATION OF ULTRASONIC WAVES

Technological forecasting partly involves recognizing needs in industry. The energy, material quality, ecology, and economic situations in these years play vital roles to provide strong motivating factors, defining the need for new or better products, techniques, or services. This includes a need for equipments with higher accuracy involving less maintenance and rapid interpretation of data. The use of ultrasonic waves found numerous applications like reducing the viscosity of oil, in the process of plug removal in oil, non-destructive testing, and welding processes and even in coal application. Ultrasonic plastic welding has become now-a- days a large-scale industrial process while the considerably researched metallurgical and metal working areas have resulted in relatively high. The attention paid to a given ultrasonic area is largely influenced by the topic of the day, as evidenced by current interest in ultrasonic fuel treatment , waste treatment , oil well rejuvenation, etc., and is not always related to the true worth of the process. The cost of an acoustic watt has been declining and following the general technological trend will continue to do so in the future. This will make ultrasonic power more competitive with conventional processes. The second factor is that more ultrasonic equipment is now in use and more people are working with it. This increased exposure will undoubtedly lead to new uses.
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