M2M Gekko PAUT Phased Array Instrument with TFM, UT, TOFD (2023) (2023)

FAQs

What is the difference between TOFD and phased array? ›

While PAUT uses reflection, TOFD uses diffraction. The transducer produces pulsed ultrasonic waves, which are diffracted to various degrees by irregularities in the scanned material, then collected on the material's far side by a receiver.

In practice, testing with the TOFD method is only applied by continuously moving the probe pair along the weld seam, while in traditional UT techniques the probe must be also moved perpendicular to the weld seam. Depending on the equipment the scan is performed either manually or by use of an automated manipulator.

Phased Array is an ultrasonic testing technique that uses specialized multi-element “array” transducers and pulses those elements separately in a patterned sequence called “phasing”. This phasing sequence allows wave steering, focusing, and scanning. This is all performed electronically.

A PAUT transducer uses multiple elements during a scan. Beams are emitted sequentially at multiple angles allowing PAUT to create a more detailed scan. Other UT methods, on the other hand, use a single probe to analyze an asset. By emitting multiple beams, PAUT allows for the inspection of even the most complex assets.

A disadvantage of TOFD is that the gain must be very high, which produces a very high back wall echo and it is not suitable for coarse grained materials. There is a dead zone for defect detection under the surface. It means, defects close to the surface could not be detected.

Principle of operation

In a TOFD system, a pair of ultrasonic probes sits on opposite sides of a weld. One of the probes, the transmitter, emits an ultrasonic pulse that is picked up by the probe on the other side, the receiver.

Generally speaking, on the premise of meeting the requirements of flaw detection sensitivity, the probe with lower frequency shall be selected as far as possible; for forgings, rolled parts and weldments with finer grain, the probe with higher frequency shall be selected, usually 2.5-5.0mhz.

Time of flight diffraction is an advanced non-destructive testing method used for weld inspection. Time of flight diffraction (TOFD) is one of the most reliable non-destructive testing methods in testing welds for both pre-service and in-service inspection.

The main disadvantages of phased-array systems are that (i) they are more expensive to purchase, (ii) operation and data interpretation are more difficult and (iii) there can be greater difficulty in achieving good ultrasonic coupling due to the larger probe dimensions.

PAUT improves weld testing performance over single-probe ultrasonic testing and other NDT methods. Choosing the right ultrasonic testing equipment can increase efficiency, improve test reliability, and provide company managers the peace of mind of knowing that their welds will hold.

What are the advantages of PAUT? ›

The advantages of phased array ultrasonic testing (PAUT) include faster scans, a higher probability of detecting flaws and anomalies and the best possibility of performing an inspection. The PAUT method of non-destructive testing uses multiple beams to scan an asset.

25 mm (1.0 in.).

There are two types of UT pulsers that are commonly used, the spike pulser and the square wave pulser; both have advantages and drawbacks.

Phased Array Ultrasonic Testing (PAUT) is an advanced nondestructive examination technique that utilizes a set of ultrasonic testing (UT) probes made up of numerous small elements, each of which is pulsed individually with computer-calculated timing (“phasing”).

Time of Flight Diffraction (TOFD) is a reliable method of nondestructive ultrasonic testing (UT) used to look for flaws in welds. TOFD uses the time of flight of an ultrasonic pulse to find the location of a reflector.

The lateral wave is simply the compression wave travelling parallel to the flat surface. If it is assumed to be travelling parallel to the flat surface (between the Tx and Rx probes) its refracted angle is therefore 90°.

An electric current passes through a cable to the transducer and is applied to the crystals, causing them to deform and vibrate. This vibration produces the ultrasound beam. The frequency of the ultrasound waves produced is predetermined by the crystals in the transducer.

In time-of-flight diffraction (ToFD) systems, a pair of ultrasonic probes are used, sitting on opposite sides of a weld-joint or area of interest. A transmitter probe emits an ultrasonic pulse which is picked up by the receiver probe on the opposite side.

For ultrasonic testing in low temperatures, a water-based couplant is not the best choice because they are more likely to freeze when the temperature drops. A better option in low temperatures is to use a silicone- or glycol-based couplant.

What is the best probe for vascular access? ›

Linear Array Probes

These high frequency probes are the commonest probes being used for peripheral vascular and small parts examination. They are good for both color as well as pulse doppler examinations. It is a better choice than a phased array transducer for vessel cannulation.

In eddy current testing, a coil carrying an AC current is placed close to the specimen surface, or around the specimen. The current in the coil generates circulating eddy currents in the specimen close to the surface and these in turn affect the current in the coil by mutual induction.

Pipes can be considered as one-dimensional structures along which the energy of axisymmetric guided ultrasonic wave modes propagates with little loss of energy, and propagation distances of up to 100 m have been achieved (Cawley et al.

The four main types of ultrasound transducers—linear, curvilinear, phased-array, and intracavitary—differ by crystal arrangement, size, and footprints, which determine their suitability in different imaging applications.

Disadvantages of Phased Array Ultrasound Testing

While PAUT has a wide range of abilities, it's not a preferred testing method for the detection of surface cracks, metal fatigue, or bolt hole inspections compared to eddy current testing.

Phased Array Ultrasonic Testing (PAUT), also known as phased array UT, is an advanced non-destructive inspection technique that uses a set of ultrasonic testing (UT) probes made up of numerous small elements.

Phased array technology offers the ability to generate multiple sound beams focused at different areas of the weld and at different angles. Also, the ability to generate multiple sound beams allows the weld to be scanned and results in complete coverage.

Phased Array Ultrasonics brings faster inspection:

By using a single probe, Phased Array Ultrasonics can process a linear or a sectorial scanning of the entire probe to cover a larger area than with conventional UT in a very short time.

Following are the disadvantages of Phased Array Antenna: ➨The coverage is limited to 120 degrees in both azimuth and elevation. ➨Lower frequency agility can be achieved. ➨Ray deflection is possible only in single plane using linear array configuration.

What is one of the advantages of ultrasonic inspection in relation to radiographic testing? ›

There is no radiation hazard in ultrasonic examination, and hence no disruption of work as there is with radiography. Volumetric and crack like defects can be detected, irrespective of their orientation.

Advantages of ToFD

ToFD is a single pass operation, not amplitude dependent and very accurate for sizing of vertical defects. The technique is found to be substantially more accurate in sizing the height of defects than conventional pulse echo techniques, which are based on echo amplitude.

When the signals are counter phase, they cancel each other. The three types of phased array antennas are 1) linear array, 2) planar array, and 3) frequency scanning array.

A phased array is a group of sensors located at distinct spatial locations in which the relative phases of the sensor signals are varied in such a way that the effective propagation pattern of the array is reinforced in a desired direction and suppressed in undesired directions.

It is a way to direct waves of radiation toward a desired direction. Advertisements. A phased array is also known as a phased antenna system.

Drawbacks or disadvantages of Phased Array Antenna

Following are the disadvantages of Phased Array Antenna: ➨The coverage is limited to 120 degrees in both azimuth and elevation. ➨Lower frequency agility can be achieved. ➨Ray deflection is possible only in single plane using linear array configuration.

The antennas radiate individually and while in array, the radiation of all the elements sum up, to form the radiation beam, which has high gain, high directivity and better performance, with minimum losses.

The near-$900 million structure, operated by the U.S. Missile Defense Agency (MDA), is by far the largest phased-array radar system on Earth.

Arrays are used when there is a need to use many variables of the same type. It can be defined as a sequence of objects which are of the same data type. It is used to store a collection of data, and it is more useful to think of an array as a collection of variables of the same type.

What is an example of a phased array? ›

For example, AM broadcast radio antennas consisting of multiple mast radiators fed so as to create a specific radiation pattern are also called "phased arrays".

There are three different kinds of arrays: indexed arrays, multidimensional arrays, and associative arrays.

Phased arrays are used for a wide variety of inspection and measurement applications, and they can be used for any job done by conventional ultrasonics. For example, phased arrays are used to detect and image defects including cracks, voids, and pits caused by corrosion.