Technological evolution of industrial ultrasound: From simplicity to precision

Euclides Quiñonez.

October 25, 2023

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Autor: Euclides Quiñonez, 25 octubre 2023.

Introduction

Industrial ultrasound technology has come a long way since its beginnings in detecting defects in materials and measuring thicknesses. Over the decades, this technology has undergone constant evolution, enabling significant advances in the inspection and evaluation of components and structures in a wide variety of industries, from manufacturing to medicine ¹ .

Ultrasonic devices can detect objects, measure distances, perform deep cleaning, assist in manufacturing, and improve medical care and treatments. Uses continue to grow as advances are made in the manufacturing of ultrasonic components, often providing a less invasive and lower cost alternative. In this white paper, we will explore the technological evolution of industrial ultrasound , from its initial foundations to the most recent innovations.

Fundamentals of industrial ultrasound

The first steps ²

In 1880, the brothers Pierre and Jacques Curie made the discovery of the piezoelectric phenomenon, experimenting with quartz and tourmaline crystals, and discovered the generation of very high frequency sound waves.

En el año 1912, después del hundimiento del Titanic, el inglés Lewis Fry Richardson propone la utilización de ecos ultrasónicos para detectar objetos sumergidos, trabajando en esta idea durante la Primera Guerra Mundial, para intentar detectar submarinos enemigos. Pero no fue hasta el año 1917 que es diseñado el primer generador piezoeléctrico de ultrasonido por el francés Paul Langévin y el ruso Constantin Chilowsky quienes diseñaron un dispositivo de ultrasonido de alta potencia. Ese equipo poseía un cristal que servía como receptor y generaba cambios eléctricos al recibir las vibraciones mecánicas, empleando posteriormente para estudiar el fondo marino.

Fue en año 1924 cuando el científico ruso Dr. S. Y. Sokolov desarrolló algunas de las primeras técnicas de inspección en el que utiliza ondas ultrasónicas. Posteriormente, fue en la Segunda Guerra Mundial que ingenieros alemanes y soviéticos desarrollaron equipos de inspección ultrasónica con fines militares. Pero fueron los alemanes Josef y Herbert Krautkramer, quienes en 1948 perfeccionaron el ultrasonido como instrumento de inspección y desarrollaron equipos de inspección ultrasónica.

El ultrasonido industrial tiene sus raíces en la utilización de ultrasonidos como una herramienta para detectar defectos en materiales sólidos. A principios del siglo XX, se desarrollaron los primeros transductores ultrasónicos capaces de generar ondas de alta frecuencia las cuales, viajan a través de un material y rebotan en las interfaces entre diferentes medios, como una superficie interna o un defecto en el material. La detección de las ondas reflejadas permitió a los ingenieros y científicos identificar imperfecciones en piezas metálicas y cerámicas.

Defect detection equipment

During the 1940s, World War II spurred the development of nondestructive inspection technologies, including industrial ultrasound. Ultrasonic flaw detectors became an essential tool for evaluating the integrity of structural components used in aircraft and military machinery. These devices were relatively rudimentary compared to current technologies, but they ushered in the era of ultrasonic inspection.

Advances in transducers

Higher resolution and sensitivity

In the 1950s and 1960s, there were significant improvements in ultrasonic transducers, allowing for greater resolution and sensitivity in testing. Piezoelectric and ceramic materials became common choices for transducer manufacturing, increasing efficiency in converting electrical energy to ultrasonic energy. These advances made it possible to detect smaller defects and evaluate thinner materials ³ .

Advanced electronics

The electronics associated with industrial ultrasound also advanced rapidly. The introduction of controlled electronic pulses enabled precise timing measurements, resulting in better defect localization and more accurate thickness measurements. Additionally, signal amplification and processing technology improved in terms of speed and accuracy.

New applications and industries

The revolution in welding

Industrial ultrasound became an essential tool in the welding industry in the late 1960s. Ultrasonic welding allowed thermoplastic materials to be joined efficiently and cleanly. This technique has been used in the manufacturing of electronic components, packaging, medical devices, and other products, making it an essential process in many industries.

Non-destructive inspection

The Non-Destructive Testing (NDT) method with ultrasound was established as a reliable technique to evaluate the integrity of materials and components. It is used in the inspection of welds , equipment, pipes and other critical structures in industries such as nuclear energy, aviation, civil construction, metalworking, shipbuilding, petrochemical, oil and gas.

Innovations in the 1980s and 1990s

Phased Array Ultrasound

One of the most significant innovations in industrial ultrasound was the introduction of phased array ultrasound technology in the 1980s. Instead of using a single transducer, Phased Array systems use multiple emitting and receiving transducers to create ultrasound beams that can be focused and controlled electronically. This variable focus and steering control capability allowed for more efficient inspection and accurate defect detection in a variety of geometries.

As technology advances, more sophisticated and effective techniques emerge, and one of the most notable is the Total Focus Method (TFM) Ultrasound Technique. This technique has revolutionized the way defects are identified and characterized in a wide range of industrial applications. The TFM method is based on the same orientation and targeting methodology as Phased Array technology; but targeting is applied only in a region of interest and not in the entire depth.

Imagen2 4 — **Figure 2. Phased Array Ultrasonic Equipment**

Automated scanning techniques

The 1990s saw advances in the automation of ultrasonic scanning techniques. Robotic systems were developed in order to autonomously perform ultrasonic inspections in hazardous or hard-to-reach environments. These advances increased inspection efficiency and reduced operators’ exposure to high-risk situations.

Por ejemplo; para la inspección desde el interno de tuberías, los robots son capaces de medir espesores en tramos tanto horizontales como verticales y curvos. Gracias a su construcción autopropulsada, no es necesario empujar los robots a través de las tuberías. Esto significa que tienen libertad para inspeccionar cada punto a lo largo de la tubería. Los datos recopilados mediante ultrasonidos están inmediatamente disponibles para su visualización en línea. El robot de inspección ultrasónico está conectado a su unidad de control, inspeccionando tubería de cientos de kilómetros de longitud, transmitiendo a los comandos de control datos ultrasónicos y de imagen.

The 21st century: Digitization and simulation

Advances in digital electronics

The 21st century brought rapid evolution in digital electronics used in industrial ultrasound systems. Data acquisition and management systems became more powerful and versatile, allowing for more sophisticated ultrasonic signal processing and analysis. Control panels were modernized, providing friendlier user interfaces and integration with data management systems.

Added to all of the above is Big Data and the Internet of Things (IoT), with which conventional instruments use secure cloud storage solutions to make backup copies of the information collected on the site in real time. With this, you have a great tool, together with wireless communication, for immediate data exchange or for real-time reports, supported by Big Data information generated by equipment enabled by the Internet of Things.

The IoT will revolutionize the traditional way of performing periodic inspections with ultrasound to determine the useful life of components and with the use of alternative methods, such as condition monitoring, and will also allow integrated sensors to perform measurements continuously.

Finite Element Simulation

Finite Element Simulation ⁴ became a fundamental tool in the design of ultrasonic transducers and the optimization of inspection techniques. These simulations allow engineers to model the propagation of ultrasonic waves in materials and components, helping to predict how ultrasonic waves will behave in a variety of situations. This capability has led to significant improvements in the sensitivity and resolution of ultrasonic testing. Below are some examples of use:

In laboratory tests, phased array ultrasonic technology was applied to detect defects in welded samples. The pulse echo method was used to test a sample with defects and establish the corresponding numerical model. At the same time, the finite element (FEA) was used to simulate the propagation of ultrasonic waves in the defective specimens and figures for the sound pressure amplitude were obtained. The results show that the phased ultrasound system with finite element simulation is effective.

Ultrasonic inspection of defects within the bonding interface of materials is difficult due to the large grain size difference between the two sides. A model-based investigation on the ultrasonic characterization of the diffusion bonded interface was presented. A 2D finite element model was developed to describe the material, where the orientation of each grain was obtained using the EBSD technique . The ultrasound propagation in the sample was predicted and the reflection coefficient was calculated and verified with the experimental ultrasonic response.

The future of industrial ultrasound

Artificial intelligence and machine learning

One of the most important developments in industrial ultrasound is the incorporation of artificial intelligence (AI) and machine learning. These technologies allow for more sophisticated interpretation of ultrasonic data and automatic defect detection. AI algorithms can identify complex patterns in ultrasonic signals, making it easier to detect subtle defects and reduce false positives.

Real-time ultrasound and portability

Advances in hardware and software have allowed the development of real-time ultrasound systems and portable devices. These advancements give inspectors the ability to perform ultrasonic testing in the field more efficiently. Portable systems are particularly useful in predictive maintenance applications, where quick and accurate inspections can be carried out on site.

Communication and connectivity

The ability to share ultrasonic data quickly and securely has improved significantly with the adoption of communication and connectivity technologies. Ultrasonic test results can be sent to the cloud for analysis, shared with remote experts, and securely stored for future reference. This connectivity streamlines the decision-making process and collaboration in real time.

Conclusions

The technological evolution of industrial ultrasound has been notable over the decades. From its humble beginnings as a tool for detecting defects in materials to its critical role in nondestructive inspection and advanced manufacturing, industrial ultrasound has come a long way. Advances in transducers, electronics, scanning and simulation techniques have pushed the field toward greater efficiency and precision.

As we enter an era of artificial intelligence, industrial ultrasound is undergoing an even greater transformation. The ability to detect defects more accurately and automate inspection processes offers great opportunities for a wide variety of industries. Portability and connectivity are also changing the way ultrasonic testing is performed, enabling more efficient inspections and more effective collaboration.

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