Guided waves generated by Lead Zirconate Titanate (PZT) transducers are often used to detect structural damage for nondestructive evaluation (NDE) and structural health monitoring (SHM) applications. It is generally assumed that the surface-mounted PZT transducers are both undamaged and properly bonded to the host structure during usage. However, this assumption may not be valid, particularly u...

Ultrasonic waves form a useful nondestructive evaluation (NDE) probe for determining physical, microstructural, and mechanical properties of materials and parts. Noncontacting laser ultrasonic methods are desired for remote measurements and on-line manufacture process monitoring. Researchers at the Idaho National Engineering & Environmental Laboratory (INEEL) have developed a versatile new meth...

The results of a benchmark experiment for transient eddy-current nondestructive evaluation are reported. The benchmark configuration corresponds to the canonical geometry of an air-cored probe coil positioned above a conductive plate containing a long back-face slot. The coil is excited by an exponentially-damped step function current and measurements are made of the change in the transient mag...

The characteristic features and applications of linear and nonlinear guided elastic waves propagating along surfaces (2D) and wedges (1D) are discussed. Laser-based excitation, detection, or contact-free analysis of these guided waves with pump-probe methods are reviewed. Determination of material parameters by broadband surface acoustic waves (SAWs) and other applications in nondestructive eva...

The growing demand for power is putting tremendous stress on existing power plants for generating electricity. The plants are being operated for longer periods of time under heavy load conditions. Reliability of key components of the power plant such as steam or gas turbines and generators is of prime importance. Many utilities are interested in extending the life of turbine-generator component...

Ultrasonic back-scattered echoes resulting from the structures within a scanned object contain information of potential diagnostic value. The most common nondestructive evaluation (NDE) techniques use large-scale changes in the back-scatterer coefficients to reveal boundaries between materials with different density/elasticity properties or defects in homogenous material regions. Less common te...

Corrosion-fatigue, a cracking mechanism in fossil-fueled generating plants, predominately occurs in the water walls and economizers of sub-critical plants. Cracking attributed to corrosion-fatigue has occurred in water wall tubing of both membrane and tangential designs. The occurrence (particularly in membrane water wall tubing) presents a challenge for nondestructive evaluation (NDE) because ...

A concrete bridge over Interstate 70 east of Denver, Colorado was impacted by a fork lift being transported by a truck moving at a speed of approximately 75 mph. The forklift impacted the east face of the prestressed concrete I-beam bridge girder, resulting in severe cracking and concrete spalling on both sides of the eastmost girder. Polymer-modified repair mortar was used to repair spalled ar...

This paper addresses the challenging problem of ultrasonic non-destructive evaluation (NDE) imaging with adaptive transducer arrays. In NDE applications, most materials like concrete, stainless steel and carbon-reinforced composites used extensively in industries and civil engineering exhibit heterogeneous internal structure. When inspected using ultrasound, the signals from defects are signifi...

Ultrasonic testing (UT) has been used for nondestructive evaluation (NDE) of materials for more than half a century. A number of NDE techniques have been developed and specifi standards have been created for the UT applications in different areas of engineering. UT has two main goals related to inspection of solid objects, firstl , detection and characterization of material discontinuities (fl ...