SBIR-STTR Award

Current manufacturing technology for cast titanium components cannot guarantee the absence of hard alpha inclusions. Under the effect of fatigue, such inclusions become likely sites for structural failure. By performing nondestructive inspections on the manufactured parts using phased array ultrasound, one can eliminate parts with the largest inclusions. Despite such quality control, undetected inclusions can be large enough to decrease the life expectancy of the parts by a factor of 20. To avoid such consequences, structural members can be made thicker but the added weight can decrease aircraft performance. Even a 50% reduction in the size of the smallest detectable inclusion would have significant life and/or weight benefits. Fortunately, the current phased array implementation has not been optimized. We therefore propose to optimally design a phased array for cast titanium inspection. We will explore reductions in beam diameter, changes in the number, size and arrangement of the elements, variations in frequency, and a variety of imaging techniques to improve detection while reducing grain noise. Along with reducing the size of detectable inclusions, we will explore techniques to allow phased arrays to adapt to the complex part geometries of titanium castings. By reducing the size of the smallest detectable inclusion in cast titanium components, the U.S. Air Force will benefit financially through an extension of the initial life span of new aircraft, and/or increases in aircraft performance through weight reduction. Our technology will also allow the use of phased array inspection on a broader class of component geometries. The development of an optimized ultrasonic array for titanium would also benefit the aircraft once they enter the Aging Aircraft phase of their service life. The Air Force is the primary customer for this application. Pending a successful Phase I effort, we will pursue further development of our technology into marketable products for the Air Force and large Aerospace contractors. Developments under this contract will have benefits well beyond titanium casting inspection. In particular, commercial engine and power systems forged disk inspections will benefit.

As a cost avoidance measure against expensive replacement of certain life-limiting components of turbine engines, the Engine Rotor Life Extension (ERLE) program was conceived by the Air Force Research Laboratory (AFRL) to extend component life without increasing the risk of component failure. Nondestructive evaluation is one of many important components of ERLE which, if successfully implemented, will lead to an estimated $600 Million in savings over five years. In this Phase II SBIR effort, Acoustic Ideas, Inc. will contribute to enhanced nondestructive evaluation of embedded defects employing phased array ultrasound by working within the Turbine Engine Sustainment Initiative (TESI), a component of ERLE. Through proprietary Acoustic Ideas technology, the optimized use of phased array ultrasound in this effort is expected to lead to reduced detection limits, expansion of the inspection window to currently uninspectable geometries, and reduced inspection times.

Keywords:
Phased Array Ultrasound, Turbine Inspection, Embedded Defect, Nondestructive Evaluation, Engine Rotor Life Extension (Erle), Turbine Engine Sustainmen