James P. Dunne

Active damage interrogation system for structural health monitoring

An integrated and automated smart structures approach for in situ damage assessment has been implemented and evaluated in a laboratory environment for health monitoring of a realistic aerospace structural component. This approach, called Active Damage Interrogation (ADI), utilizes an array of piezoelectric transducers attached to or embedded within the structure for both actuation and sensing. The ADI system, which is model independent, actively interrogates the structure through broadband excitation of multiple actuators across the desired frequency range. Statistical analysis of the changes in transfer functions between actuator/sensor pairs is used to detect, localize, and assess the severity of damage in the structure. This paper presents the overall concept of the ADI system and provides experimental results of damage assessment studies conducted for a composite structural component of the MD-900 Explorer helicopter rotor system. The potential advantages of this approach include simplicity (no need for a model), sensitivity, and low cost implementation. The results obtained thus far indicate considerably promise for integrated structural health monitoring of aerospace vehicles, leading to the practice of condition-based maintenance and consequent reduction in life cycle costs.

Overview of the SAMPSON smart inlet

The SAMPSON program will demonstrate the application of Smart Materials and Structures to large-scale aircraft and marine propulsion systems and show that smart materials can be used to significantly enhance vehicle performance, thereby enabling new missions and/or expanding current missions. Two demonstrations will be executed in relevant environments and at scales representations of actual vehicle components. The demonstrations will serve to directly address questions of scalability and technology readiness, thereby improving the opportunities and reducing the risk for transitioning the technology into applications. The aircraft application to be examined is the in-flight structural variation of a fighter engine inlet. Smart technologies will be utilized to actively deform the inlet into predetermined configurations to improve the performance of the inlet at all flight conditions. The inlet configurations to be investigated consists of capture area control, compression ramp generation, leading edge blunting, and porosity control. The operation and demonstration of this Smart Inlet is described in detail.

Synthesis and processing of intelligent cost-effective structures phase II (SPICES II): smart materials aircraft applications evaluation

The second phase of the synthesis and processing of intelligent cost effective structures (SPICES II) program sought to identify high payoff areas for both naval and aerospace military systems and to evaluate military systems and to evaluate the benefits of smart materials incorporation based on their ability to redefine the mission scenario of the candidate platforms in their respective theaters of operation. The SPICES II consortium, consisting of The Boeing Company, Electric Boat Corporation, United Technologies Research Center, and Pennsylvania State University, surveyed the state-of-the-art in smart structures and evaluated potential applications to military aircraft, marine and propulsion systems components and missions. Eleven baseline platforms comprising a wide variety of missions were chosen for evaluation. Each platform was examined in its field of operation for areas which can be improved using smart materials insertion. Over 250 smart materials applications were proposed to enhance the platforms. The applications were examined and, when possible, quantitatively analyzed for their effect on mission performance. The applications were then ranked for payoff, risk, and time frame for development and demonstration. Details of the efforts made in the SPICES II program pertaining to smart structure applications on military and transport aircraft will be presented. A brief discussion of the core technologies will be followed by presentation of the criteria used in ranking each application. Thereafter, a selection of the higher ranking proposed concepts are presented in detail.

Smart-actuated continuous moldline technology (CMT) mini wind tunnel test

The Smart Aircraft and Marine Propulsion System Demonstration (SAMPSON) Program will culminate in two separate demonstrations of the application of Smart Materials and Structures technology. One demonstration will be for an aircraft application and the other for marine vehicles. The aircraft portion of the program will examine the application of smart materials to aircraft engine inlets which will deform the inlet in-flight in order to regulate the airflow rate into the engine. Continuous Moldline Technology (CMT), a load-bearing reinforced elastomer, will enable the use of smart materials in this application. The capabilities of CMT to withstand high-pressure subsonic and supersonic flows were tested in a sub-scale mini wind- tunnel. The fixture, used as the wind-tunnel test section, was designed to withstand pressure up to 100 psi. The top and bottom walls were 1-inch thick aluminum and the side walls were 1-inch thick LEXAN. High-pressure flow was introduced from the Boeing St. Louis poly-sonic wind tunnel supply line. CMT walls, mounted conformal to the upper and lower surfaces, were deflected inward to obtain a converging-diverging nozzle. The CMT walls were instrumented for vibration and deflection response. Schlieren photography was used to establish shock wave motion. Static pressure taps, embedded within one of the LEXAN walls, monitored pressure variation in the mini-wind tunnel. High mass flow in the exit region. This test documented the response of CMT technology in the presence of high subsonic flow and provided data to be used in the design of the SAMPSON Smart Inlet.