Reciprocating internal combustion engines are typically used for backup, standby, or emergency power, and are now becoming increasingly popular for larger utility-scale power generation applications. One of the main advantages of reciprocating engines is their ability to provide incremental electricity quickly. Because these units can start and stop quickly and run at partial loads they can create thermal stress on various parts within the engine. Piston crowns are one of these components that could lead to catastrophic damage or fatalities if one should fail during operation. Prompted from recent failures in the USA, a multi-technique phased array inspection has been developed for a full volumetric inspection of these piston crowns while still in the engine. This novel approach ensures the piston crowns are free of thermal cracks in the high stress areas, and significantly cut decreases down time, and provided a much more comprehensive inspection over the manufacture recommendations.

Acoustic steady-state excitation spatial spectroscopy (ASSESS) is a full-field ultrasonic inspection technique that rapidly identifies damage in metal and composite structures over a 360-degree field of view. It uses a scanning laser Doppler vibrometer (sLDV) and LIDAR to resolve the steady-state surface wavefield and its geometry. Damage like corrosion, delamination, and cracks are identified from local wavenumber and wavefield discontinuities. Unlike traditional frequency-domain wavenumber processing, this method applies convolution in the spatial domain to wrap kernels to the geometry, accounting for perspective distortions due to curvature. This allows for the successful estimation of thicknesses in curved specimens from planar dispersion curves. Unlike previous curved surface wavenumber estimation methods, this method can process non-flattenable geometries like spheres without cutting or distorting projections. The method is demonstrated through thickness estimation experiments on an aluminum tire rim and steel hemisphere. Results show significantly smaller thickness estimation residuals compared to traditional planar processing techniques, indicating a significant advancement in defect detection workflows for arbitrarily curved surfaces. This approach also shows potential for composite materials and additive manufacturing, though challenges remain in dispersion characterization for non-isotropic structures.

The ultrasonic dissector uses high-frequency vibrations (30~60 kHz) to denature proteins and disrupt tissue structures, enabling precise cutting with concurrent hemostasis. Commonly applied in neurosurgery, urologic surgery, and minimally invasive procedures, it offers reduced operative time and minimizes thermal and electrical injury to surrounding tissues, thereby improving postoperative recovery.

This study used finite element analysis to evaluate the driving frequency and amplitude of an ultrasonic dissector blade. Experimental validation showed frequency and amplitude deviations within 2%, confirming the model’s accuracy given correct material properties. Based on these results, a structure-optimized design is proposed to improve the device’s precision and clinical safety.