In situ ice and structure thickness monitoring using integrated and flexible ultrasonic transducers

Two types of ultrasonic sensors are presented for in situ capability development of ice detection and structure thickness measurement. These piezoelectric film based sensors have been fabricated by a sol–gel spray technique for aircraft environments and for temperatures ranging from −80 to 100 °C. In one sensor type, piezoelectric films of thickness greater than 40 µm are deposited directly onto the interior of a 1.3 mm thick aluminum (Al) alloy control surface (stabilizer) of an aircraft wing structure as integrated ultrasonic transducers (UTs). In the other sensor type, piezoelectric films are coated onto a 50 µm thick polyimide membrane as flexible UTs. These were subsequently glued onto similar locations at the same control surfaces. In situ monitoring of stabilizer outer skin thickness was performed. Ice build-up ranging from a fraction of 1 mm to less than 1.5 mm was also detected on a 3 mm thick Al plate. Measurements using these ultrasonic sensors agreed well with those obtained by a micrometer. Tradeoffs of these two approaches are presented.

[1]  V.V. Varadan,et al.  Wireless IDT ice sensor , 2002, 2002 IEEE MTT-S International Microwave Symposium Digest (Cat. No.02CH37278).

[2]  M. Liao,et al.  Modeling the effects of prior exfoliation corrosion on fatigue life of aircraft wing skins , 2003 .

[3]  Ahmad Safari,et al.  Novel Processing of 1‐3 Piezoelectric Ceramic/Polymer Composites for Transducer Applications , 1995 .

[4]  Joseph L. Rose,et al.  Summary of results from an ultrasonic in-flight wing ice detection system , 2002 .

[5]  C. Jen,et al.  Integrated and flexible high temperature piezoelectric ultrasonic transducers , 2007 .

[6]  Christina Narlis.  Development of Ice Samples for Comparison Study of Human and Sensor Capability to Detect Ice on Aircraft , 2006 .

[7]  D. Levesque,et al.  Flexible ultrasonic transducers , 2006, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[8]  A. Fowler,et al.  High vinylidene-fluoride content P(VDF-TrFE) films for ultrasound transducers , 1998, 1998 IEEE Ultrasonics Symposium. Proceedings (Cat. No. 98CH36102).

[9]  N. Mrad,et al.  Exfoliation detection using structurally integrated piezoelectric ultrasonic transducers , 2006 .

[10]  J. M. McGuirl,et al.  Presenting in-flight icing information: a comparison of visual and tactile cues , 2001, 20th DASC. 20th Digital Avionics Systems Conference (Cat. No.01CH37219).

[11]  S. Roy,et al.  Miniature ice detection sensor systems for aerospace applications , 1998, Proceedings MEMS 98. IEEE. Eleventh Annual International Workshop on Micro Electro Mechanical Systems. An Investigation of Micro Structures, Sensors, Actuators, Machines and Systems (Cat. No.98CH36176.

[12]  W. Walker,et al.  A fundamental limit on delay estimation using partially correlated speckle signals , 1995, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[13]  M. Migliore,et al.  MICROWAVE DEVICES FOR ICE DETECTION ON AIRCRAFT , 1996 .

[14]  Frank Lynch,et al.  Effects of ice accretions on aircraft aerodynamics , 2001 .

[15]  Marcia K. Politovich,et al.  Aircraft icing detection using dual-wavelength and polarization radar observations , 1998, IGARSS '98. Sensing and Managing the Environment. 1998 IEEE International Geoscience and Remote Sensing. Symposium Proceedings. (Cat. No.98CH36174).

[16]  B. Jakoby,et al.  A Love-wave ice detector , 1999, 1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027).

[17]  C. Jen,et al.  Piezoelectric thick bismuth titanate/lead zirconate titanate composite film transducers for smart NDE of metals , 2004 .

[18]  Nezih Mrad,et al.  Integrated ultrasonic transducers made by the sol–gel spray technique for structural health monitoring , 2007 .

[19]  D. H. Wang,et al.  Health Monitoring and Diagnosis for Flexible Structures with PVDF Piezoelectric Film Sensor Array , 2000 .

[20]  R. Alfano,et al.  Ice detection on metal surfaces using the degree of polarisation of diffusely reflected light , 1996 .

[21]  A. G. Molyar,et al.  Corrosion of Aircraft Structures Made of Aluminum Alloys , 2003 .