B. Tittmann - Academia.edu (original) (raw)

Papers by B. Tittmann

Journal of Sensors and Sensor Systems, Apr 1, 2016

AIP Conference Proceedings, 2019

2011 IEEE International Ultrasonics Symposium, 2011

The testing, validation, and monitoring of aerostructural design and health conditions require a ... more The testing, validation, and monitoring of aerostructural design and health conditions require a non-intrusive and in-situ means to provide real time strain/stress and vibration data of turbine engine structures. However, taking such a measurement is difficult due to the extremely harsh environment in turbine engines. The SAW-RFID sensor provides a promising tool to operate in such a harsh environment, because it takes advantage of being passive, wireless and tolerant for high temperatures. These characteristics give it the ability to measure the strain/stress and temperature on engine blades in real time. In this paper, we present our work on the design, fabrication and testing of SAW-RFID devices as wireless temperature and strain sensors. The SAW-RFID sensors were first designed based upon the Finite Element Modeling (FEM). The aero structural designs sensors are then fabricated with micro-fabrication techniques. The antennas of the SAW sensor and RFID reader were also developed. The fabricated sensors were tested. Finally, we demonstrate the capability of our SAW sensor for the temperature and strain measurements, which show the consistence with the simulation values.

$Research paper thumbnail of A technique for studies of ductile fracture in metals containing voids or inclusions$

Metallurgical Transactions A, 1976

... 60, p. 651. 12. M. Oka and CM Wayman: Trans. ASM, 1969, vol. 62, p. 370, 13. ... NED W. POLAN... more ... 60, p. 651. 12. M. Oka and CM Wayman: Trans. ASM, 1969, vol. 62, p. 370, 13. ... NED W. POLAN AND DONALD H. AVERY An investigation of mechanical-thermal processing of the B-titanium alloy, TS6, (Ti: 10 pet Cr, 7 pct V, 3.5 pet Mo, 3 pct A1) has been recently reported. ...

Applied Physics Letters, 2010

Structural health monitoring (SHM) techniques are needed to maintain the reliability of aging pow... more Structural health monitoring (SHM) techniques are needed to maintain the reliability of aging power plants. The high temperature transducers are necessary to realize SHM under the working condition of power plants. In this paper, a high temperature transducer was developed using lithium niobate (LiNbO3) single crystal, which is well known as a high Curie temperature piezoelectric material. The LiNbO3 was bonded onto a stainless steel substrate. The transducer was heated in an electric furnace while measuring the bottom echoes from the substrate. We confirmed that the high temperature transducer could work up to 1000 °C.

The studies of ultrasonic wave propagation in fiber-reinforced laminates comprise many techniques... more The studies of ultrasonic wave propagation in fiber-reinforced laminates comprise many techniques. This study is to experimentally evaluate the effects of the impact-induced damages of Carbon Fiber Reinforced Plastic (CFRP) laminated composites under no stress and pre-stress conditions. A mechanical scanning acoustic reflection microscope (SAM: pulse-wave mode) was used to detect and evaluate interior damage (e.g., delamination) of the impact-induced specimens. The studies show that ultrasound provides an attractive means for non-invasive evaluation and thereby a means for understanding the results of high-velocity impact upon laminate composites.

Review of Progress in Quantitative Nondestructive Evaluation, 1993

Ceramic Transactions Series, 2013

Proceedings SENSOR 2015, 2015

Applications for non-destructive evaluation (NDE) and structural health monitoring (SHM) in princ... more Applications for non-destructive evaluation (NDE) and structural health monitoring (SHM) in principle can be performed at various temperatures provided the transducer can reliably operate under those conditions. For are high temperature materials such as Lithium Niobate that can be used for NDE a coupling medium is required to aid in wave propagation between the transducer and system of interest. Traditional methods require either pressure contacts or a high temperature bonding medium, which can deteriorate over time. The sol-gel spray-on technology eliminates the need for this coupling medium and allows for an actuator that can be custom tailored to the specific application of interest. As nuclear reactors reach the end of their projected lifetime it is critical that the systems within the containment structure be continuously monitored. This spray-on technology allows for efficient on-line monitoring of a system at any operating temperature providing the proper transducer selection. The current objective is to develop a class of spray-on ferroelectrics that do not require a bonding medium and enable custom tailoring of composite transducers adapted for different combinations of efficiency and temperature. For example, if a high-temperature application is anticipated, the composition of the sol-gel can involve constituents that favor ultrasonic properties, while the powder could involve constituents that still function ultrasonically at high temperature. This paper presents details of the deposition method without requiring a bonding medium. It also shows results on the effects of varying the weight percent of the composite Lead Zirconate Titanate/ Bismuth titanate transducers on the Curie temperature and efficiency of the composite Piezoelectrics. Results for several composites are given with d 33 values ranging from 20 to 60 x10-12 Coulomb/Newton along with temperature dependencies of the signal amplitude in pulse-echo experiments. These composite ferroelectrics are modeled using a micromechanics analysis code based on the "generalized method of cells" program.

1998 IEEE Ultrasonics Symposium. Proceedings (Cat. No. 98CH36102)

Electromagnetic acoustic transducers (EMATs) are well known devices that are commercially availab... more Electromagnetic acoustic transducers (EMATs) are well known devices that are commercially available. Their advantage is that they do not require a coupling medium and/or contact to the part being inspected; the disadvantage is their low transduction efficiency. In order to optimize their efficiency, the EMATs are best customized to their particular application with special attention to the material properties and

MRS Bulletin, 1988

The preservation of U.S. aeronautical leadership is an economic and military necessity, but it is... more The preservation of U.S. aeronautical leadership is an economic and military necessity, but it is by no means assured. The rise of Airbus, Ariane, and Embraer has been lightning fast; tomorrow could see the development of Japan's FSC or Israel's Lavi. Our competitors are well organized and often enjoy the support of their governments. Our capabilities are no longer unique; thus our future work is clearly defined for us.The key to continued U.S. preeminence in aerospace is to be found in the further research, development, and application of a group of revolutionary technologies in the areas of propulsion, numerical and symbolic computation, laminar flow modeling, and advanced materials and structures. Exploitation of the emerging technologies in these areas by industry, government, and universities will significantly impact the performance and cost of future aerospace vehicles and systems. Materials science and engineering, particularly the discipline of nondestructive evalua...

1976 Ultrasonics Symposium, 1976

Current generation light water reactors (LWRs), sodium cooled fast reactors (SFRs), small modular... more Current generation light water reactors (LWRs), sodium cooled fast reactors (SFRs), small modular reactors (SMRs), and next generation nuclear plants (NGNPs) produce harsh environments in and near the reactor core that can severely tax material performance and limit component operational life. To address this issue, several Department of Energy Office of Nuclear Energy (DOE-NE) research programs are evaluating the long duration irradiation performance of fuel and structural materials used in existing and new reactors. In order to maximize the amount of information obtained from Material Testing Reactor (MTR) irradiations, DOE is also funding development of enhanced instrumentation that will be able to obtain in-situ, real-time data on key material characteristics and properties, with unprecedented accuracy and resolution. Such data are required to validate new multi-scale, multi-physics modeling tools under development as part of a science-based, engineering driven approach to reactor development. It is not feasible to obtain high resolution/microscale data with the current state of instrumentation technology. However, ultrasound-based sensors offer the ability to obtain such data if it is demonstrated that these sensors and their associated transducers are resistant to high neutron flux, high gamma radiation, and high temperature. To address this need, the Advanced Test Reactor National Scientific User Facility (ATR-NSUF) is funding an irradiation, led by PSU, at the Massachusetts Institute of Technology Research Reactor to test the survivability of ultrasound transducers. As part of this effort, PSU and collaborators have designed, fabricated, and provided piezoelectric and magnetostrictive transducers that are optimized to perform in harsh, high flux, environments. Four piezoelectric transducers were fabricated with either aluminum nitride, zinc oxide, or bismuth titanate as the active element that were coupled to either Kovar or aluminum waveguides and two magnetostrictive transducers were fabricated with Remendur or Galfenol as the active elements. Pulse-echo ultrasonic measurements of these transducers are made insitu. This paper will present an overview of the test design including selection criteria for candidate materials and optimization of test assembly parameters, data obtained from both out-of-pile and in-pile testing at elevated temperatures, and an assessment based on initial data of the expected performance of ultrasonic devices in irradiation conditions. BACKGROUND Current generation light water reactors (LWRs), sodium cooled fast reactors (SFRs), small modular reactors (SMRs), and next generation nuclear plants (NGNPs) produce harsh environments in and near the reactor core that can severely tax material performance and limit component operational life. To address this issue, several Department of Energy Office of Nuclear Energy (DOE-NE) research programs are evaluating the long duration irradiation performance of fuel and structural materials used in existing and new reactors. In order to maximize the amount of information obtained from Material Testing Reactor (MTR) irradiations, DOE is also funding development of enhanced instrumentation that will be able to obtain in-situ, real-time data on key material characteristics and properties, with unprecedented accuracy and resolution. Such data are required to validate new

The Journal of the Acoustical Society of America, 1990

In order to identify and eliminate flawed ceramic preforms prior to metal infiltration, several a... more In order to identify and eliminate flawed ceramic preforms prior to metal infiltration, several approaches for nondestructive evaluation were studied. The techniques chosen include immersion ultrasonics, scanning acoustic microscopy (SAM), and radiography. Undesirable irregularities in the preforms include cracks, voids, density gradients, and shot. The latter represents spherically shaped particles of alumina, with diameters that may exceed ten times that of the fibers, and that are incorporated into the porous fiber preform. It is generally thought that shot with sizes greater than 100 μm affects the mechanical properties of the resulting metal matrix composite. With the aid of SAM and scanning electron microscopy (SEM), shot in near-surface areas could be evaluated. Cracks and voids could also be located using SAM and SEM. On a larger scale, the ultrasonic immersion equipment was capable of detecting and quantifying density gradients, which were verified using radiographic techni...

The Journal of the Acoustical Society of America, 1980

If the nondestructive evaluation (NDE) of flaws in structural materials it is often important to ... more If the nondestructive evaluation (NDE) of flaws in structural materials it is often important to distinguish between a single flaw or cavity, two cavities separated by a finite distance and a compound flaw when two cavities intersect. Using the T-matrix method, numerical results have been obtained for P waves incident on such geometries as a function of incident wave frequency and the scattering geometry. In each case, results have been obtained using several approaches. Approximate solutions including only single scattering effects are compared with exact results as the distance between the scatterers change. The compound flaw can be treated as a single flaw or as two flaws in contact. The above results will be compared with experimental results showing good agreement.

Nondestructive Characterization for Composite Materials, Aerospace Engineering, Civil Infrastructure, and Homeland Security 2008, 2008

The structural health monitoring of structures during active use (in service) has long been of in... more The structural health monitoring of structures during active use (in service) has long been of interest to the NDE community. One technique uses passive ultrasound or Acoustic Emission (AE). However, the interpretation of the AE signals is difficult especially when the operator tries to distinguish between the growth of harmless micro-cracks and the development of harmful delaminations. This paper focuses on two types of structures, i.e., aluminum plates such as used in wing structures in aircraft and graphite plates such as encountered in aircraft disc brakes where carbon-carbon composite is used. The objective in this work is to distinguish the acoustic emissions (AE) caused by delaminations from those associated with microcracking. The technical approach is to use finite element methods (FEM) to simulate AE from sources represented by piezoelectric wafers embedded in the composites. In flat panels of graphite and aluminum-alloy AE waveforms were modeled from transverse cracks and longitudinal delaminations. The results show distinct differences in the amplitudes, durations and frequency content creating a potential avenue for distinguishing between these two flaw types.

Applied Physics Letters, 1970

Journal of Applied Physics, 1964