2017-2021
Life cycle monitoring of the reversible-adhesive bonded composite structures (RBCS).
This research is focused on the life cycle monitoring of the reversible-adhesive bonded composite structures (RBCS). To be specific this dissertation proposes a real-time ultrasound-based technique to monitor the lap-joint bond-line while manufacturing, in-service and during repair. Also, the developed system simultaneously predicts the Remaining Useful Life (RUL) of the components in real-time. |
NASA Ames research center - Fault detection and Performance Monitoring of Propellers in Electric UAV
Propellers are the fastest moving component in an UAV; even a minor defect in the propeller blades could cause performance deterioration, with consequent challenges in flying through the planned trajectory or adhere to the safety requirements of the operation. Monitoring and updating aerodynamic efficiency of each rotor would therefore enable the detection of off-nominal propeller conditions thus magnifying the state-awareness of powertrain monitoring systems based on the acquired electrical signals. An extended Kalman filter-based parameter estimation algorithm is being implemented that incorporates time history responses from UAV powertrain in conjunction with a full powertrain system model to identify changes in the propeller aerodynamic efficiency. Propeller fault detection is achieved by incorporating the aerodynamic parameters of the propeller into the powertrain model. The proposed technique is successfully validated with numerical simulations |
PROCESS MONITORING AND CONTROLLED FABRICATION OF
REVERSIBLE ADHESIVE BONDED LAP JOINTS Ultrasonic guided waves were made to propagate across the bond-line of the joint by exciting and sensing them using miniature piezoelectric wafers. Analysis of dispersion relations and dynamic wave propagation were performed using finite element modeling (FEM). Fundamental longitudinal mode L0 at 35 KHz was found optimal for bond process monitoring. Mapping between the FE-simulated transmission coefficient of L0 and actual temperature of the thermoplastic adhesive was established using the DMA test data. Realtime guided wave measurements were used as a feedback in the discrete control of the induction heater so as to provide optimal bonding and prevent adhesive charring. |
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DIAGNOSIS AND PROGNOSIS OF FATIGUE DAMAGE IN LAP JOINT
In this research work, dynamic framework for data-driven prognosis of fatigue damage growth in adhesively bonded lap-joint is presented. guided wave(GW) sensing is used for NDE of damage introduced in a lap-joint sample by cyclic fatigue loading. The guided wave signals are generated through surface-mounted piezo electric transducers (PZT) which enable on-line monitoring of bondline while they are in use. Displacement and force information from Mechanical Testing System (MTS) have high accuracy of damage estimation. Hence, damage area computed from MTS are considered as the ground truth. Further, Camera vision is also used to measure crack propagation. Prediction results of static and dynamic methods combined with GW data are compared with the ground truth to assess their prognostic capability |
2013-2017
Reliability Analysis on Barge ImpactFollow listed Articles for more details
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Scour monitoringFollow listed Articles for more details
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2012-2013
2011-2012
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Memory inclusion in Shape Memory alloy |