Phase coherence imaging is a new approach for processing ultrasonic signals generated during nondestructive testing. This article shows how it compares with amplitude-based focusing methods for detecting hydrogen-related microfissures, creep-induced damage, and stainless-steel weld voids.

Ultrasound is widely used for nondestructive evaluation, structural health monitoring, acoustic emission, sound navigation ranging, and in sensors for automobiles, medicine, and many other applications. Next-generation, small-form-factor sensors have been achieved through advances in piezoelectric micromachined ultrasonic transducers (PMUTs) that can be positioned on either a flexible polymer or a silicon substrate to form an array. This article describes a materials and design optimization study that used finite element analyses to improve designs for robust and practical PMUT sensor arrays.

Resonant ultrasound spectroscopy (RUS) is an emerging ultrasonic measurement technique. By measuring the natural vibrational frequencies of test samples, RUS can determine Young's modulus, shear modulus, and Poisson's ratio for isotropic materials. By comparing the vibrational spectra of a test sample to those obtained from a standard, it is possible to infer the causes of the differences (if any) and detect various part defects, such as size variations, cracks, and pores. Thanks to advances in computer technology, codes and software are now available for data reduction, analysis, and interpretation. This article addresses fundamentals of the technology and applications in research and industry.

Automobile performance and passenger safety both rely on sound spot welds in advanced high-strength steels. A new, high-frequency ultrasonic matrix phased array probe performs nondestructive inspection of these welds, saving time and cost.

Modeling and simulation are proving to be an effective alternative to the trial-and-error practices often used when developing and evaluating nondestructive tests for materials characterization. This article demonstrates the benefits of modeling in different cases where eddy current and ultrasonic inspection methods are employed.

Tie bolts used in aircraft wheels take the brunt of landing forces and are also heavily loaded during takeoff and taxiing. Because tie-bolt failures typically originate as small cracks either in the root of a bolt thread or where the bolt head joins the shank, early detection of cracks in those areas is essential. This article compares and contrasts nondestructive test methods that have been to inspect aircraft tie bolts, including liquid penetrant, magnetic particle, ultrasonic, and eddy current testing.

This article provides an overview of nondestructive test methods and their application in the study of material properties and structures. It covers the most widely used NDT technologies, including optical examination, radiography, acoustic emission, and ultrasonic testing, and discusses the impact of recent advancements.

This article compares two nondestructive test methods that are widely used to assess impact damage in carbon fiber-reinforced polymer composites. Infrared line scanning thermography (LST) and immersion ultrasonic testing (UT) are shown to be equally capable of detecting delaminations and internal cracking caused by low-velocity impacts, although LST was easier to use and provided results more quickly that were easier to interpret.