non-destructive testing

A substantial volume of oil and gas pipelines, particularly in petrochemical industries, are insulated with various materials. In many cases, a small opening or leak can allow water and other corrosive liquids to penetrate, leading to corrosion under insulation (CUI). This type of corrosion is not detectable through conventional methods over the insulation. With the usual methods of non-destructive inspection, such as visual and ultrasonic tests, it is not possible due to the lack of access to the metal of the pipeline. One of the most effective non-destructive methods for this purpose is the use of radiographic profiling devices. In this paper, using the Monte Carlo method, the common X-ray spectra for this technique at 70 keV and 90 keV were simulated. Industrial radioisotopes used, including Ir-192 and Co-60, were considered as sources. The pipeline phantoms implemented were made of 6mm thick carbon steel and 24mm thick polyethylene insulation. Artificial corrosion with a depth of 3mm was created on the pipeline wall. A single-energy linear detector made of CsI(Tl) with a thickness of 5mm and a pixel pitch of 1.6mm was implemented in the code, and the spatial signal was recorded on it. The transport of X-ray and gamma photons for the used sources was visually recorded for 20,000 photons, and the signal recorded on the detector, along with the accumulated energy in each detector pixel, was measured. The results indicate the suitable performance of the implemented system in locating and detecting CUI defects.A substantial volume of oil and gas pipelines, particularly in petrochemical industries, are insulated with various materials. In many cases, a small opening or leak can allow water and other corrosive liquids to penetrate, leading to corrosion under insulation (CUI). This type of corrosion is not detectable through conventional methods over the insulation. With the usual methods of non-destructive inspection, such as visual and ultrasonic tests, it is not possible due to the lack of access to the metal of the pipeline. One of the most effective non-destructive methods for this purpose is the use of radiographic profiling devices. In this paper, using the Monte Carlo method, the common X-ray spectra for this technique at 70 keV and 90 keV were simulated. Industrial radioisotopes used, including Ir-192 and Co-60, were considered as sources. The pipeline phantoms implemented were made of 6mm thick carbon steel and 24mm thick polyethylene insulation. Artificial corrosion with a depth of 3mm was created on the pipeline wall. A single-energy linear detector made of CsI(Tl) with a thickness of 5mm and a pixel pitch of 1.6mm was implemented in the code, and the spatial signal was recorded on it. The transport of X-ray and gamma photons for the used sources was visually recorded for 20,000 photons, and the signal recorded on the detector, along with the accumulated energy in each detector pixel, was measured. The results indicate the suitable performance of the implemented system in locating and detecting CUI defects.

The application of composite components has significantly increased in the various industries, including oil and gas, aerospace, marine, and automotive sectors. Among these, carbon fiber reinforced polymers (CFRP) are particularly prevalent in the aerospace industry due to their superior properties like high strength to weigh ratio. Given the critical nature of these composites, non-destructive inspection is essential to ensure their integrity and performance. Ultrasonic testing is one of the most widely used methods for inspecting these materials. Recent research has focused on the application of ultrasonic testing for the non-destructive inspection of CFRP parts. This study investigates the feasibility of using through-transmission ultrasonic testing with a water jet technique for inspecting of the CFRP components. Additionally, it examines the relationship between flexural properties and the intensity of transmitted waves in multilayer composite materials. For this purpose, some samples were fabricated from epoxy-carbon fiber using the hand lay-up method. A through-transmission ultrasonic non-destructive testing setup with a water jet system was designed and constructed, and ultrasonic testing was performed to identify defects in these samples. In this set-up, a uniform water column is used to transmit the pressure wave from the transducer to the surface of the samples under test, which replaces the couplant material. Subsequent bending tests were conducted to determine the flexural properties of the samples. The analysis revealed that an increase in the number of layers led to a decrease in both the final flexural strength and the average intensity of the transmitted wave, attributed to the higher likelihood of structural defects in samples with more layers. Subsequent bending tests were conducted to determine the flexural properties of the samples. The analysis revealed that an increase in the number of layers led to a decrease in both the final flexural strength and the average intensity of the transmitted wave, attributed to the higher likelihood of structural defects in samples with more layers.

Measuring defect sizes is very important in determining weld strength. This size is also used to evaluate the object on the test for accept or reject criteria according to the relative standards. One of the important methods for measuring different defects' sizes is industrial radiography testing (RT), a non-destructive testing method. Radiography is carried out using penetrating X or Gamma rays. Radiography is a volumetric method and can give information from the inside the different objects. Various factors, such as the magnification of the radiographic image, the fogginess of the radiographs, the non-point source, and the inherent scattering of X-rays, affect on the measurement and the accuracy of the defect sizing. In particular, size measurement for defects with larger distance respect to the film or radiography detector can be with more uncertainty. This is due to more shadowiness of rays with larger distances. For radiography imaging, an industrial Computed Radiography System (CR) was used. General purpose imaging phosphor plates with a laser resolution of 50 micrometers have been used. The X-ray source was an industrial powerful X-ray tube with a voltage of up to 300 kilovolts. In this research, utilizing the distance measurement between the lines in the duplex image quality indicator (DIQI) tool as a known length, the size of defects in standard parts in Sonakit educational test kit that have specific defects is estimated and compared with the original value. To decrease the blurring, a recursive filter method is used to make the edges sharper to better estimate the defect sizes. The results show that the measurement of defects is related to the accuracy of the user in estimating the pixels of the defect regions and the sharpness of the edges. The measurement error is reported between 6% and 19% for the defect measurement in the standard parts examined.

Investigating the integrity of structures and equipment such as airplanes, the pipelines, the oil platforms, the bridges and the pressure vessels is an essential task in the industry. Employing a reliable and accurate methods for investigating the health of the industries equipment’s is vital to increase the health and reduce the financial hazards. Nowadays, the use of thermographic inspection technique or the inspection using infrared waves as a useful and advanced tool among the various methods of condition monitoring and nondestructive evaluations is expanding. Infrared thermography is performed with the help of thermal information analysis using non-contact thermal imaging devices. The infrared thermography is used to detect hot spots, heat losses, leaks, insulation defects, etc., so that the nondestructive men and maintenance personnel can take appropriate actions to fix the problems. In this research, a steel plate with 20 flat bottom holes (FBH) with diameters of 2 to 10 mm and distances from the test piece surface (Defect depth) ranging from 0.5 to 2 mm was used as a test sample. A flash lamp and two projectors were used as heating sources and then the thermal image sequences were recorded. It was observed that only 11 defects can be detected in the thermal raw image. In order to improve capability of thermography test, 6 techniques of Thermal contrast including absolute thermal contrast, running contrast, normalized contrast (final value), normalized contrast (maximum value), standard contrast and differentiated absolute contrast (DAC) have been applied to the of thermal raw images. Thermal contrast based techniques found to be useful in improving defect detection by increasing contrast between the image of the defect and sound area and reducing effects of non-uniform heating. Normalized contrast (final value) had the best performance in terms of increasing the number of detected defects and was able to reveal 16 defects.

Modeling and simulation are crucial in designing and developing complex systems, such as cargo scanner systems. A cargo scanner is a device used to scan and inspect cargo transported by air, land, and sea. These scanners are usually used by customs and security centers to identify potential threats such as weapons, explosives, and contraband. One of the key benefits of using modeling and simulation is that it allows designers to test different scenarios and configurations without the need for physical prototypes. This can save time and money, as well as reduce the risk of costly mistakes. This study examines how the parameter angle affects detector responses in truck cargo scanner systems using the MCNPX code. The angle refers to the angle at which the beam generated from the beam generator interacts with the detector's normal surface, an important factor in ensuring the accuracy and reliability of cargo scanning systems in imaging. Initially, the X-ray spectrum output was calculated from the accelerated 6 MV electrons due to tungsten target impact and validated against spectra from other studies. The results demonstrated good agreement between the output spectra. The changes in counts recorded in the vertical direction of the detector arrays showed that the count difference between the lowest pixel and highest pixel is approximately 33%, while the count changes from the closest pixel to the farthest pixel to the beam generator in the horizontal direction are about 60%. Subsequently, the angle of each array was adjusted so that the emitted rays from the cone beam generator were perpendicular, and this case was compared to cases where the array angle was 20 and 30 degrees. The results revealed that when exposed to perpendicular radiation, the signal recorded in detectors is greater than that of a rotated detector, and the count rate in the detector decreases as the angle increases.

Additive manufacturing (AM) is based on the deposition of materials with high precision to make a final part or component using different methods. This process is considered one of the main developments in the fourth industrial revolution and is still growing. There are many different types of additive manufacturing methods, and today, the use of efficient inspection methods is required to ensure a certain level of quality and detect defects and discontinuities in the industry. Today, in industry, non-destructive testing (NDT) is widely used, especially in additive manufacturing, to ensure efficient quality control and predictive maintenance without changing the properties and initial state of materials. Each non-destructive testing method is based on different physical principles and the correct selection and use of each test depends on the application, manufacturing process, type of material and possible discontinuities and many other things. The most common defects created in AM parts in terms of appearance include porosity, entrapped impurity, cracks, and material defects, which are mainly caused by changes in manufacturing parameters, injection parameters, and initial material properties. In this article, the performance of non-destructive tests was investigated to inspect the parts produced by the additive manufacturing method. These tests include visual inspection, liquid penetrant testing, magnetic particle testing, eddy current testing, ultrasonic testing, XCT, acoustic emission testing and thermography test. The application of each of the mentioned NDT methods in additive manufacturing and their suitability for detecting the defects of parts manufactured by AM method were investigated. Also, the sensitivity, advantages and disadvantages of each method were evaluated and the types of defects and the ability to detect these defects by NDT methods were mentioned. Considering that there are 7 categories of production methods in additive manufacturing, in this research, the application of each NDT test for different categories of AM process was discussed and the challenges in each were mentioned.

During the past decades, imaging and spectroscopic techniques with wide applications have rapidly developed for determining the quality of agricultural products in a non-destructive manner. As a synergy between spectroscopy and imaging technologies, spectral imaging methods have emerged to deal with quality assessment problems along with ideas with effective and practical applications to food and agriculture industries. Agricultural commercialization has prompted the need to determine the quality of agricultural inputs, especially seeds, in order to optimize production and increase economic returns. Seed viability is a critical consideration to ensure high yields. Most of the time, farmers suffer losses after a significant percentage of seeds fail to germinate after planting. Seed viability is very important in the quality characteristics of seeds that reflect the potential of seed germination, and it is necessary to have a quick and effective method to determine the quality and state of germination and seed viability prior to cultivation and sale and during planting. Some research based on spectrum and/or image processing and analysis have been investigated to verify the external and internal quality of seed types. Spectroscopy is used to examine and measure the spectra produced by the interaction of matter with electromagnetic radiation or the radiation emitted from it, and the near-infrared (NIR) technique is one of these techniques for non-destructive tests of samples. Hyperspectral and multispectral imaging is another non-destructive technique that is used to obtain spectral and spatial information about materials, including seeds. The use of Raman spectroscopy is an alternative non-destructive method that is used to check seed viability with non-destructive laser radiation. Thermal imaging is a technique for converting the invisible radiation pattern of an object into visible images and extracting and analyzing the properties of the material without any contact. And finally, the use of electromagnetic waves with different wavelengths from 1 to 100 nm and energy of approximately 0.12 to 12-kilo electron volts. The low power penetration of these waves and their ability to detect internal changes in density makes soft X-rays suitable for use in evaluating agricultural products. This article refers to the comparative introduction and application of emerging techniques in the study of seed viability, including the near-infrared spectroscopy, hyperspectral and multispectral imaging, Raman spectroscopy, infrared thermography, and soft X-ray imaging.

Predicting defect detection capability by means of various non-destructive testing methods in test pieces with different geometries and thermal properties is a challenging issue. In this article, the capability of circular defect detection by thermography testing using analytical method has been investigated. Thermal contrasts produced over the surfaces of circular defects in AA 7075, AISI 1015 and SS316 samples by pulsed thermography (PT), step-heating thermography (SHT) and long pulse thermography (LT) were compared. The thermal contrast of defects in samples with thicknesses of 8, 6 and 4 mm made of AISI 1015 were also compared using the three stimulation methods mentioned. Results showed that PT is the best method in samples with high thermal diffusivity. On the contrary, LPT produces a higher thermal contrast in samples with low thermal diffusivity. Also, by increasing of the thickness, more thermal contrast occurs in all three stimulation methods.

Coating metals as a technique to increase the corrosion resistance of industrial parts is very practical and common in various industries, especially oil and gas, petrochemical and marine industries. Corrosion characterization in coated metals is a major challenge in the field of Non-destructive testing (NDT). In this work, 20 flat bottom holes (FBH) with diameters of 10, 8, 6, 4, 2 mm were drilled to distances from the test piece surface ranging between 0.5 and 2 mm on the St37 steel plate with epoxy coating simulate corrosion defect. Step heating thermography (SHT) has been applied to evaluate corrosion defects. Median filter and Gaussian low-pass filter are used for noise reduction and smoothing the thermal images. Principal component analysis (PCA) has been applied to raw thermal images to process thermographic signals and improve the defect detection capability. Results showed that after applying signal processing methods, the number of the detected defects increased from 12 to 14 holes. Also the signal-to-noise ratio (SNR) has more than quadrupled.

Computed tomography using gamma- and X-rays has been using as one of the most reliable imaging modalities for non-destructive testing purposes in different fields of industry. These devices can provide a three-dimensional image of the sections inside the object under inspection. Based on the shape of the beam, the output beams from the beam source are placed in front of the source in the tomographic devices, detectors are placed in front of the source and rotated 360 degrees around the object to obtain projections and finally, the image is reconstructed. In this paper, a portable industrial CT system with the shape of a fan beam is simulated using the MCNPX2.7e Monte Carlo code. The number of detectors was selected as 19 due to its portability, and an industrial standard phantoms and an innovative phantom were used to acquire projections for verification of simulation operation. Cobalt-60 gamma rays are recorded on the detectors after being transported from the object under study and generate important projection data for various angles. The results include a large number of projection functions that can then be used to create a sinogram matrix.

Digital image correlation (DIC) is widely used as a tool to measure displacements and surface strains. The generation of speckle pattern in DIC technique has some limitations. In addition to spray paint, other techniques including laser speckle have also been proposed to generate speckle patterns. In previous studies, the use of DIC as a non-destructive technique has been limited to detect the surface cracks. In the current study, the feasibility of DIC for detection of subsurface defects was investigated. A laser beam was utilized to generate the DIC speckle pattern. The tensile load was applied to a polypropylene specimen containing an artificial subsurface defect. The DIC images were recorded and analyzed before and after loading the specimen. The results of surface displacement in the direction of tension and perpendicular to tension revealed the defect. To study further, the surface strains of the specimen were determined. In the obtained results, the strain concentration indicated the defect in the specimen. The approximate size and shape of the artificial defect are recognizable in the measured strain distribution.

In this paper, the capability of non-destructive method of magnetic flux leakage in characterizing the microstructure and mechanical properties of API X65 steel has been evaluated. Magnetic flux leakage method is a popular non-destructive inspection method for oil and gas pipelines based on the detection of magnetic flux leakage from the surface of the part. This test is widely used to identify all discontinuities including surface and subsurface cracks as well as thickness changes due to latent corrosion in the inner wall of pipelines. In this study, four different microstructures subjected to four different types of heat treatment have been used. The results show that changes in microstructural characteristics, including morphology of the ferrite phase (polyhedral or needle) as well as the size of the ferrite grains, affect the density of magnetic flux lines emitted inside the part and the amount of magnetic flux leaked from the surface. Therefore, one can use the magnetic flux leakage test to efficiently determine the type of microstructure as well as the mechanical properties of the part.

Optical Spectroscopy, as a powerful and applicable Non-destructive Testing (NDT) technology, is capable of solving many problems in agriculture based on quality, safety and health assessment of the sample (plant or crop, food, soil, water, etc.). This non-destructive optical technology can be used for development of smart spectral sensors and systems, the most important objects that can be connected to the Internet with the potential to collect, store, process and analyze the spectral data and information, and control or communicate remotely. Recent advances in non-destructive Spectroscopy technology in combination with emerging and advanced technologies such as Internet of Things (IoT), Big Data, Cloud Computing, and Artificial Intelligence technologies, play an important role in developing Smart Agriculture and improving the agricultural productivity. This article aims to present the role of this Non-destructive Testing technology in the future of Smart Agriculture by introducing its most important applications in solving key challenges facing agriculture based on sample quality, safety and health assessment.

Defects and damage during the manufacture of composites or metal parts are inevitable. Therefore, non-destructive testing is essential to prevent failure and increase the reliability of composite structures or metal components. Non-destructive thermography technologies have shown many advantages in this regard. In the thermography technology, the temperature variation of the external surface of the work piece was determined by receiving the radiated infrared waves. These waves indicated the point temperature precisely. In this paper, a compelet and comprehensive study of non-destructive infrared thermgraphy test methods for metal and composite inspection, detailed analysis was performed and the developments of infrared therapeutic technologies were investigated. First, the basic concepts for non-destructive test theramography were introduced. Then different types of thermography with radiation stimulation are described and compared. In the following, research examples of the application of thermography methods and some of the strengths and limitations of thermography technologies were compared and described in detail.