LAMSS Laboratory for Adaptive Materials and Smart Structures

Outline  Mechatronics – Micro-controllers Education Vibration Monitoring Enhancement Program (VMEP) E/M Impedance Structural Health Monitoring Wave Propagation Non-destructive Evaluation Smart Materials Actuation

EMCH 367 - Controllers Motorola MC68HC11EVB: $200 - Ideal for still applications - More memory suits bigger programs - Communicates directly with PC Same chip: MC68HC11 Homebuilt: $20 + labor - Cheaper - Smaller - Better suited for autonomous robots

EMCH 367 Projects USC Raceway Robert Legg Dave Durgin In memory of Dale Earnhardt 1951-2001

EMCH 367 Projects Guided Autonomous Vehicle David Butts Thomas Tisdale

Projects – Summer 2000 Peter James CD-Bot : Searching light and avoiding objects Peter James

Projects – Summer 2000 CD-Bot : IR detection Peter James

Outline  Vibration Monitoring Enhancement Program (VMEP) Mechatronics – Micro-controllers Education  Vibration Monitoring Enhancement Program (VMEP) E/M Impedance Structural Health Monitoring Wave Propagation Non-destructive Evaluation Smart Materials Actuation

VMEP Roadmap US ARMY NC, KY, MS-ARNG SC-ARNG AASF AMCOM RITA IAC VMEP/VMU SYSTEM PROTOTYPE BETA TESTING AT SCARNG SC-ARNG AASF UH-60 AH-64 O&S Cost Benefit Analysis Raw Data USC Data Repository Raw Vibration Data Crew Chief’s Laptop RT&B Vibration Management Condition Indicators Crew Chief’s Laptop VPROCs AMPs HUMS Vibration Monitoring RT&B and HUMS CI’s Diagnostics and Prognostics Parts and Maintenance Logistics Maintenance Data R&R VMU/VMEP Integrity ULLS-A AMCOM RITA VMEP data must be: Catalogued Time/aircraft synchronized Accessible and retrievable IAC VMU 1-- 50

SCARNG Vibration Management Enhancement Program (VMEP) A partnership has been established to conduct enhanced implementation of the VMEP project and experimentally identify life-cycle cost savings and benefits.

AVA System © 2000 by SC-ARNG

AVA RT&B Procedure Initial vibration patterns at various speeds Vibration reduction after RT&B correction © 2000 by SC-ARNG

VMEP Hardware-Software Smart Rotor Smoothing Algorithms Engine Vibration Health Monitoring Vibration Management Unit (VMU) Gear and Drive Train Monitoring Light-weight low-cost data acquisition and processing unit (COTS components), with easily upgradeable open architecture hardware and software © 2000 by SC-ARNG

VMEP RT&B Tests

USC-VMEP Data Repository ULLS-A (tapes) MATLAB (www) Engineering & Info. Tech. Data Repository Teradata computer Math Statistics Bio Statistics RITA-HUMS (www) AVA (Kermit)

AH-64 Drive-train Vibration Survey Tail Rotor Gearbox Hanger Bearing Main Transmission Input and Accessory Nose Gearbox T700 Engine Intermediate Gearbox

Outline  E/M Impedance Structural Health Monitoring Mechatronics – Micro-controllers Education Vibration Monitoring Enhancement Program (VMEP)  E/M Impedance Structural Health Monitoring Wave Propagation Non-destructive Evaluation Smart Materials Actuation

Health Monitoring of Aging Aircraft Structures Local-area health monitoring of a helicopter rotor blade. Giurgiutiu, et al (1997) AGING! Damage due to aging All of us are customers of commercial airlines and our major concern is flight safety. A new insitu non destructive technologies based on utilization of piezoelectric active sensors are elaborated to address online health monitoring of vital aircraft parts such as fuselage and wing junctions or engine turbo blades. Active piezoelectric sensors on an engine blade Aging aircraft panel with simulated crack

E/M Impedance Method Results by Giurgiutiu, Turner, 1998 The piezoelectric active sensors utilized for E/M impedance method was successfully employed in health monitoring of bolted joint. Due to electro-mechanical coupling, piezoelectric active sensor was able to monitor the dynamic stiffness of a host structure. The stiffness was modified by loosing the bold joint. The complex impedance then was gathered with Impedance Analyzer and processed later with PC to create a damage metric on a simple red, yellow, and green scale. In our example Root Mean Square (RMS) values of Impedance change below 20% correspond to green light which mean normal operational conditions, between 20% and 40% yellow light and above 40% RMS Impedance change correspond to red light which means failure. Results by Giurgiutiu, Turner, 1998

Outline  Wave Propagation Non-destructive Evaluation Mechatronics – Micro-controllers Education Vibration Monitoring Enhancement Program (VMEP) E/M Impedance Structural Health Monitoring  Wave Propagation Non-destructive Evaluation Smart Materials Actuation

Wave Propagation Theories Study Waves in solid were studied Waveform visualization Wave speed dispersion Lamb wave – symmetric mode Lamb wave – anti-symmetric mode Active sensor wave propagation technique is a relatively new method for in-situ nondestructive evaluation (NDE). Elastic waves propagating in material carry the information of defects. These information can be extracted by analyzing the signals picked up by active sensors. Due to the physical property of wave propagation, large area can be interrogated by a few transducers. This simplifies the process of detecting and characterizing defects. To apply this method, efficient numerical modeling is required to predict signal amplitude and time history of elastic wave scattering and diffraction. In order to construct the model, good understanding of these physical phenomena must be achieved. The wave propagation theory was studied in the Lamss lab. several types of elastic waves that exist in solid materials were considered, and the wave speed frequency curves were generated. To achieve further understanding of waves, the waveforms was visualized in mathematics software.

Embedded piezoelectric active sensor development PZT wafer transducers on beam specimen Wave propagation experiment at different frequencies Wave speed – Frequency curve Experiments were conducted on an aluminum beam. The specimen was made from aircraft grade sheet aluminum 2024 alloy, 1.6 mm thick. Piezoelectric active sensors were installed on both sides. One pair of the active sensors were excited with short burst of constant frequency signal, the response of the beam was collected from other sensors. Experiments were conducted at various frequencies, and the wave speed dispersion curve was generated.

Experiment on aircraft panels PZT wafer transducers array on aircraft panel Wave analysis Wave propagation experiments were also conducted on realistic aircraft panel specimens with a number of PZT active sensors affixed on it at various locations. Constant-frequency 10 kHz wave bursts were sent by the transmitter active sensor, and the response was collected at seven active-sensor receptors placed at various x-y locations. The transmission and reception time signals are shown here. It is apparent that the arrival time is consistent with the distance from the transmitter active sensor to the receptor active sensor. The larger the distance, the larger the time delay. This proves that the emitter-receptor damage detection is viable and implementable. Also significant to mention is that the #5, #6, and #7 active-sensor receptors are not in line with the active-sensor transmitter. This verifies the assertion, that the elastic waves generated by the transmitter, propagate in a circular front, and open the opportunity for the implementation of phase-array beam steering concepts to be explored in future experiments.

Development of Concepts for Automatic Health Monitoring System The future of such sensing is conceptualized as integrated part of real structures and could be compared with nervous systems of living organisms, so that the active sensors will “feel” the structure and provide a feedback in terms of information on the structural health. The future development of a Health Monitoring System allows wireless data transmitting from data clusters situated at the vital areas of a structure into central health monitoring station via data concentrators. When the data was analyzed the information about structural health is displayed on a structure’s model on a green, yellow, red scale for user convenience. The goal of the development is to approach the concepts of nervous systems used by living organisms. Wireless health monitoring system on board of civil aircraft

Outline Smart Materials Actuation Mechatronics – Micro-controllers Education Vibration Monitoring Enhancement Program (VMEP) E/M Impedance Structural Health Monitoring Wave Propagation Non-destructive Evaluation Smart Materials Actuation

Smart Materials Smart material Applied field  Upon the application of an external field, the material expands or contracts. Smart (active, intelligent, adaptive) materials: - piezoelectric materials  electric field - magnetostrictive materials  magnetic field - shape memory alloys  temperature Applications:- space technology - rotorcraft and aircraft industry - sonar technology - vibration and noise reduction

Characterization of the PiezoSystems Jena PAHL120/20 piezoelectric actuator Displacement (mm) Force (N) External stiffness Coupled electro-mechanical behavior of PAHL 120/20 Manufacturer: PiezoSystems Jena Model # : PAHL120/20 Maximum voltage (V): 150 Max. displ. (mm): 120 Blocked force (N): 3500 Capacitance (mF): 42 Actuator Voltage ke ki Force, Displacement

Impedance measurements on the ETREMA AA140J130 Magnetostrictive actuator Etrema actuator RE LE R URE UR ULE UT Measured : UT, UR, delay (phase) between UT and UR Impedance analyzer ~0V PhAngle method 23.0V PhAngle method 34.5V PhAngle method 46.4V PhAngle method 58.6V Frequency (Hz) Impedance (Ohms) Manufacturer: Etrema Inc. Model # : AA –140J013 Maximum current (A RMS): 3 Max. displ. (mm): 70 Max. dynamic force (N): 890 Blocked force (N): 1740 DC Resistance (W): 2.3 Inductance (mH): 3.5 Electric impedance change with current and frequency

Summary Mechatronics – Micro-controllers Education Vibration Monitoring Enhancement Program (VMEP) E/M Impedance Structural Health Monitoring Wave Propagation Non-destructive Evaluation Smart Materials Actuation