A technique for imaging pyrometry of oxides will be presented which is capable of remotely determining the temperatures of an oxide surface with useful accuracy. The technique relies on the near-blackbody emittance properties of most oxides in the two-phonon spectral region. Most oxides in the longwave IR region are very highly emitting with an emittance that is almost temperature independent and Lambertian. We present a generalized calibration procedure for longwave cameras that allows spatially resolved surface temperature to be obtained from radiance measurements. Experimental results from a sapphire disk will be presented as a demonstration of the technique.

Within the framework of the future closed loop recycling process the automatic and economical sorting of plastics is a decisive element. The at the present time available identification and sorting systems are not yet suitable for the sorting of technical plastics since essential demands, as the realization of high recognition reliability and identification rates considering the variety of technical plastics, can not be guaranteed. Therefore the Laser Zentrum Hannover e.V. in cooperation with the Hoerotron GmbH and the Preussag Noell GmbH has carried out investigations on a rapid thermographic and laser-supported material- identification-system for automatic material-sorting- systems. The automatic identification of different engineering plastics coming from electronic or automotive waste is possible. Identification rates up to 10 parts per second are allowed by the effort from fast IR line scanners. The procedure is based on the following principle: within a few milliseconds a spot on the relevant sample is heated by a CO₂ laser. The samples different and specific chemical and physical material properties cause different temperature distributions on their surfaces that are measured by a fast IR-linescan system. This 'thermal impulse response' has to be analyzed by means of a computer system. Investigations have shown that it is possible to analyze more than 18 different sorts of plastics at a frequency of 10 Hz. Crucial for the development of such a system is the rapid processing of imaging data, the minimization of interferences caused by oscillating samples geometries, and a wide range of possible additives in plastics in question. One possible application area is sorting of plastics coming from car- and electronic waste recycling.

Recent developed thermal imagers using room-temperature IRFPA detectors have stimulated great opportunity in many commercial applications. This paper studies the possibility of using a low-density array detector for low-cost security- and-fire applications. Features on human body and plume were extracted by their IR signatures. The human information was obtained from his spatial distribution, while a hazardous plume was supplemented with an additional temporal distribution. The function of a smaller array sensor was implemented by a high-resolution commercial uncooled system through image downward re-sampling and pre-processing. Trade-off study between the recognition accuracy and the array size are also analyzed.

In a recent upgrade of the digital flight control computer for the F-16, there was serious consternation expressed about the quality of the soldering repair process. Dozens of circuit cards failed to function after the upgrade, even though all of these cards operated correctly before the modifications. The shop called for the use of the IR camera to assist in diagnosing and repairing these cards. What the Neural Radiant Energy Detection found was faulty and marginal chips.Of particular interest was the presence of degraded EPROM chips on the Program Memory cards. While it is known that EPROMs have a limited life cycle, the failure has been further characterized. Thermography provides a quantification of the degradation in thermal performance as the EPROMs are reused. Pristine EPROM chips have a rise rate of about 0.008 degrees C/sec. When the heat rates exceed 0.021 degrees C/sec, the EPROM chips will not accept a program. Some of the chips exhibited heat rates exceeding 0.1 degrees C/sec. Some chips with degradation of 0.018 degrees C/sec would accept a program, but fail other functional tests. What is clear from these results is that IR thermography can be used to identify degrading EPROM chips for replacement before failures become immanent.

In the recent years the IR thermography technique has been sued successfully as a new contactless instrument for gas and fluid flow research in pipes and on the surface of a flat plate. It is well known that most energy changes in the flow take place in the boundary layer. This is in turn important for the intensity of convective heat transfer in pipe flows and enables to measure processes connected with energy changes in the flow from outside the pipe. Series of measurements of suddenly accelerated and pulsating pipe flow were made at Satakunta Polytechnic, Technology Pori, Finland. The theoretical criterion describing the transition from laminar to turbulent regime is found depending on the critical thickness of the boundary layer of suddenly accelerated flow. At the moment of transition of the 'plug' type flow into turbulent flow, the velocities in the wall region diminish and this can be detected using the IR thermography from the wall temperature changes. the experimental results of the mean velocity development and transition criteria correspond to the theoretical calculations. The changes of the internal structure of the flow affect the convective heat transfer and this in turn influences the pipe wall temperature. IR thermography measures pipe wall temperature changes and consequently we can detect flow structure changes in the boundary layer in the accelerated and decelerated phase of the pulsating pipe flow.

For large scale chicken and turkey raising operations, automated 'candling' of eggs for monitoring embryonic development is effective and efficient. Candling is accomplished by the transmission of high intensity light such that it penetrates the translucent egg and gives indications of embryonic position and development. When monitoring the development of other species, however, mixed results are obtained with this technique. For instance, the Emu egg is virtually opaque to transmitted visible light, and thus cannot be candled by traditional means. During the development cycle all avian embryos, and for that mater all egg-laying creatures, exhibit changes in shell surface temperatures that indicate on-going development, or a lack of that development. Additionally, such hazards as bacterial or viral growth within the shell produce atypical thermal signatures. Analysis of the shell surface temperatures may be useful in monitoring the development of these embryos. Further applications of IR thermography in farming of avian species may make it an economically viable monitoring technique.

Fourier transform spectrometer (FTS) techniques are being used to characterize the relative spectral response, or sensitivity, of scanning thermistor bolometers in the IR region. The bolometers are being used in the clouds and the Earth's radiant energy system (CERES) program. The CERES measurements are designed to provide precise, long term monitoring of the Earth's atmospheric radiation energy budget. The CERES instrument houses three bolometric radiometers, a total wavelength sensor, a shortwave sensor, and an atmospheric window sensor. Accurate spectral characterization is necessary for determining filtered radiances for longwave radiometric calibrations.

In automotive manufacturing, the lack of nondestructive methods for assessment of spot weld integrity has been a critical shortcoming, with enormous economic consequences for both domestic and foreign auto makers. At present, auto body welds are subjectively evaluated using destructive pull tests, or visual examination after the weld has been mechanically separated using an impact tool. Pulsed thermographic evaluation of spot welds offers a fast, noncontact method for quantitative assessment of the weld nugget. The technique can be applied using either one or both faces of the weld. Results on steel resistance welds will be presented, along with correlation to weld process parameters.

Thermographic data is typically analyzed in terms of thermal time of light methods. Information regarding the depth of flaws in metal an composite materials can be obtained in this manner. Small discrepancies between experimental data and actual depth of flaw have been observed when the flaw diameter varies while the depth remains constant. The slope of the rising portion of the contrast curve has been shown to be more insensitive to these types of effects. Most of these types of analysis are empirical in nature and strongly depend on the material being studied. Simple calorimetric arguments have recently been derived which also allow for the deviation of the same depth information but at the same time provide more insight into the thermographic process. In this talk these simple calorimetric arguments will be presented and correlated to experimental results from samples with various flat bottom holes. Results on Al and polymer matrix composites will be presented.

Many electric utilities invoke a double breaker/double bus (DB/DB) arrangement in their generating plant switchyards. The sketch in this paper shows one line with one load for one phase of the DB/DB configuration. A switchyard will have three such configurations, one for each phase, plus several line inputs and several load outputs. This arrangement provides redundancy and flexibility, facilitating maintenance work and enhancing reliability. The focus of this paper is what happens when one side of the DB/DB has a phase with a hot spot. The hot spot could be the switch disconnect, a hinge, bolted plate or other connection. The heating is due to increased electrical resistance caused by bad electrical contact. A strength of the DB/DB system is that, in theory, a resistive contact will not overheat as the current follows the path of least resistance and will travel through the other bus. That is, for two resistors in parallel, the current is inversely proportional to the resistance in each leg. Thus, the only time there would be a problem is if a given phase had resistive contacts on both buses, or if the 'good' side was removed from service. Imagine our surprise, then, when we found with thermography a hinge on a switch disconnect with a 121 degrees C rise. A survey of the parallel bus revealed no problems. This paper is an analysis of this actual situation. We use a simple model with empirical measurements .

The use of sealant injection into leaking valves, piping joints and fixtures has long been a common practice for commercial industry. There are many companies available to industry that specialize in this process. if the process is successful, it allows industry to maintain production and plan for equipment outages at a much more convenient time to them. This time delay allows for more formal planning of an outage. Parts may be stagged for the job at hand and for any other outage related work that it may be advantages to accomplish. The process of injecting the sealant median into pressurized steam valves has always been done 'blind' . This is because there was no way of knowing where the fluid would or would not go internally in valve bonnets or pressure seals. As a result, several negative problems could be caused. Overfihling of a void could result in the sealing media being forced into the system process. The resulting process contamination can be costly to repair or recover from. Under filling of a void allows the steam pressure to work on the sealant fluid and not allow it to harden. This will result in the leak returning after the steam energy has eaten away enough of the sealing fluid.

The Electric Power Research Institute and member utilities have sponsored since 1993 the Advanced Leak Detection - Research Evaluation Demonstration (all red) Project. The all red project utilizes an IR thermography system equipped with a high-temperature lens to detect internal boiler deficiencies and measure temperatures. Two high-temperature IR lenses were developed to perform internal boiler investigations. The lenses can operate in an environment that may reach as high as 2500 degrees F. The internal boiler areas and phenomena that are investigated include: tube temperatures, tube leaks, bowed tubes, and restricted flow; flame shape, flame temperature, and flame location; field distribution and identification of gas species. Detection of parameters that may assist with environmental NO_x concerns is also desired. The results of the current study of radiative interactions indicate that IR temperature measurements made inside large commercial gas-fired furnaces are feasible, but acquisition of accurate and repeatable data requires special consideration of radiative phenomena. This study comprised three related efforts - an extensive literature survey and analysis of existing data acquired with a high-temperature lens; an experimental study including acquisition and analysis of spectroradiometric data; and the development of techniques to correct IR thermographic data. Concerns regarding default imager temperature-conversion algorithms and reliability of system calibration are also discussed. This paper represent the culmination of investigations that shed new light on the complexity involved in making in-situ measurements of boiler stream tubes with an IR thermography high-temperature lens system.

Predictive Maintenance programs have been shown to be an effective and efficient approach to managing facilities maintenance. Cost savings through the reduction of time- based preventive tasks, and the reduction of unanticipated failures can be significant. Several inspection techniques have become standard, and are applicable to a broad range of equipment types and inspection scenarios. IR thermography of fan and compressor equipment presents a significant opportunity for cost saving applications in may facilities. Ventilation systems supply air to and remove air from working spaces, and mitigate environmental conditions for a number or purposes. Removal of hazardous pairs or gases, positive pressure atmosphere, or negative pressure atmosphere are a few examples. Vaneaxial fans are a common equipment type used to achieve this purpose. Both direct drive and belt driven fans are common for these systems. Belt drives present some unique imaging applications, where sheave and belt surface scan be observed. Compressor equipment has normally high operating temperatures, relative to other rotating equipment. The compression of gases is exothermic, and as a result, most compressors rely on an integral cooling process to function properly. Uniformity of temperature distribution on equipment surfaces, function of cooling systems, and verification of proper operation of loading and relief valves provide an overall illustration of equipment health.

The Tube Metal Temperature (TMT) distribution in thermal cracker operation is a critical parameter in respect to tube material lifetime, furnace production capacity and product selectivity. The Agema 470 IR camera is used in the present work to monitor the TMT distribution and the factors that influence on the TMT distribution. Flame shape, burner performance, refractory condition and insulation are visualized by the use of 3.9 micrometers and 3.36 micrometers filters attached to the RI camera. The 'invisible' methane/hydrogen flame is visualized by using a 3.36 micrometers IR filter, which is in the region of a typical vibration frequency in the methane molecule. The measurement errors due to CO₂ and H₂O absorption in the flue gas are theoretical calculated and also observed during measurement. The thermovision camera has proven to be a useful supplement to furnace basic instrumentation and hand held pyrometers in order to verify the true state of the tubes, refractory and the burners during nominal operation and during decoking of thermal crackers. the present work was done early in 1995 with a rather large and heavy IR camera based on a mechanical scanner. The use of IR cameras in the petroleum industry has recently become even more interesting with the appearance of high resolution 'Handy Cam' cameras on the marked.

The leakage in valves in general could mean high economic loses and also can cause many trouble to any industrial installation or power facilities. Especially in steam valves and traps must be carefully checked because a wrong close may cause loss of energy. Avoiding the leakage is the challenge in any maintenance organization. The test of how closed a valve is with IR thermography offers the users one quite approximate idea of what is the real situation in a valve inspected. Supplementing the IR inspection with passive ultrasonic test give to whole inspection more precision of what happened. This work seeks to bring near the IR thermography with ultrasound with the purpose of understanding that exists an excellent complement between both technologies.

There have been reports about moisture detection in building walls by reflective IR-thermography. Typically, only limited results could be obtained because of the emission coefficient variations, leaking radiation or inhomogeneous illumination of the object. In addition, the quantitative relation between remission spectra and the moisture has often been unclear. Reflectometry uses constant excitation illumination which is recorded by the IR camera. With the use of the 'lock-in-technology' a low frequency modulated signal of an IR radiation source is coupled with the thermo camera and a frequency and phase sensitive signal from the thermal images can be derived. The advantage is, that emission coefficient dependencies are eliminated and that leaking radiation does not have any influence on the measured signal. The selective water measurement is possible, because there is an interference filter mounted in front of the radiator which has its transmission maximum at the wavelength of an absorption band of water. The area investigated is therefore illuminated under well defined circumstances and quantitative moisture measurement on the surface of building materials becomes a possibility. The illumination modulation is done with a sine wave to facilitate the calculation of the temporal intensity behavior of the amplitude signal. Subsequently, the amplitude image is used to determine the distribution and the level of moisture quantitatively. Point measurements in the laboratory were carried out on several building materials with changing moisture levels. It could be shown that this method successfully eliminates disturbing contributions to the measured signal like surface effects or leaking radiation.

IR thermography was used in surveying dormitory debris of Tomsk High Military School of Communication Engineering in Siberia that collapsed on July 17, 1997, with 12 students dead. In total, the debris had the ambient temperature but plentiful joints between vertical brick-made columns and horizontal concrete beams were detected to be abnormally warm. The reasons for this temperature elevation are discussed. The arguments pro and contra possibility to identify temperature patterns as abnormal mechanical stresses are considered.

IR thermal images of land, water surfaces and buildings have ben taken from an airplane by means of an IR scanner which has been previously described. The scanner was mounted in a Porter aircraft. Several flights have been made over a region of the province of Buenos Aires, in Argentine, in different days, at different times, under various climatic conditions. The height of the flights ranged from 100 meters to 500 meters, with 300 meters as the standard altitude. In every flight thermal images in the 8-14 micrometers spectral region have been acquired and stored for later analysis. Real time visualization of the images in a PC monitor allowed to select the images to be stored. We have analyzed image of buildings in villages, isolated buildings, water courses, water surfaces, roads and fields with different types of vegetation, in a region with a relative low density of population. Some thermal images and the conclusions of the thermal studies performed are presented.

As part of major rehabilitation and repair of the 360,000 square foot reinforced concrete shell roof of the Kingdome in Seattle, a comprehensive nondestructive testing program reemploying IR thermographic and impact echo techniques was performed to evaluate various in-situ concrete conditions. Questions had developed regrading the extent and significance of areas that exhibited honeycomb or paste voiding near reinforcing steel on the underside of the roof shell following removal of acoustical ceiling tile. The objective of the nondestructive testing program was to identify locations of large, planar-type regions of deep voiding or delamination associated with the consolidation and reinforcement placement conditions. The combined use of IR thermography and impact echo techniques allowed for efficient and effective scanning of the large roof shell structure entirely from the interior. Anomalous areas identified by the testing were verified by additional nondestructive testing, visual inspection, local exploratory openings and core samples. Based on results of the nondestructive testing, a broad-based repair program was implemented to correct conditions of near surface voiding and through-thickness honeycomb. Repairs consisted of the application of structural shortcrete to restore integrity in thickened, key load transfer zones of the shell and the overall treatment of the entire underside of the shell with sprayed mortar. This paper present an overview of IR thermographic testing theories and discusses the specific applications, logistics, and result from testing of the concrete shell of the Seattle Kingdome.

IR thermography allows to identify the thermal anomalies due to moisture in ancient walls. Wet zones can appear warmer or colder in IR images, according to the atmospheric conditions during the scanning; furthermore, thermal monitoring, even in qualitative thermography, allows to obtain a more effective diagnosis of the defects because it records thermal behaviors of the material in different environmental conditions. Thermographic system allows an accurate analysis of transpiration effects on buildings and precise measurements of water content starting from environmental temperature, relative balance and wind speed. These variables play a major role in the causes of damages in buildings. Particularly, the evaluation of transpiration is essential to determine the evaporative rate of water content within the wall. The research has been carried out on two ancient buildings during a period of several months. The main experimental tests were on the church of 'Guardia di Sotto', Corsico, a seventeenth century building on the bank of Pavese Canal. Five thermal scanning have been disposed in different seasons from March 14, 1996 to June 16, 1997. The causes of the wet zones were identified at the basis of the walls were rising damp and rain spread in the ground. The repeated thermographies and thermo-hygrometric test allowed to distinguish the size and the location of the areas damaged by the different causes. In other cases studied - Addolorate Church, Gessate the thermal scanning and the other supporting tests confirmed the list of optimal environmental condition required to detect humidity in walls by thermography.

Electric buses are one of the solutions for improving air quality in our cities. Many states are adopting 'no new diesel bus' policies, thus increasing the pressure to develop alternative vehicles. The fledgling electric vehicle technology suffers from acceptance problems by major transit authorities due primarily to limited travel range from each battery charge. Utilizing electric buses in the Northeast has the added problem of maintaining an adequate cabin temperature without the availability of heat from a diesel motor. Heating the passenger cabin with an electric heater which draws from the batteries' stored energy significantly reduces the already modest range of these vehicles; therefore, energy conservation measures play an important role in allowing electric vehicles to provide practical transit services. IR thermography, in conjunction with air leakage pressurization diagnostics, has proven to be an excellent tool for developing energy-efficient bus designs as well as a valuable in-service performance testing method. This paper is based on tests performed on several Advanced Vehicle Systems, Inc. electric buses during research performed under Northeast Alternative Vehicle Consortium and Defense Advanced Research Projects Agency grants. The work demonstrates the thermographic methods used and the real- world increased performance of retrofitted and newly designed buses resulting from this initial Portland Transit retrofit project and in a follow-up project to develop a cold weather specification for a new generation of electric buses. Early diagnostic and new-technology follow-up thermographic performance testing was paralleled by energy modeling of early baseline and re-designed vehicles. Modeling and performance data are included. As a result of this research, thermography, air-leakage/pressurization testing, and fog analysis techniques are now being used regularly in research and development and quality assurance procedures by electric bus manufacturers.

Visual and IR imaging of rotating objects, such as tires under load test conditions is desirable but presents several obstacles, such as blurring and component obstruction. If an imaging system capable of high enough frame rates to capture the data without aliasing effects is used, the entire object is often not in view and therefore could not be analyzed. The authors present a system that uses a standard Inframetrics 760 to synthetically reconstruct an image by using high speed imaging techniques in conjunction with a shaft encoder, rotational tracking, and specialized data sampling software to capture three sides of a tire that is being tested at 50 mph. This process has proven valuable in providing non-intrusive thermal analysis in recent quality tests of tires. Current accepted testing techniques for tires include endurance test and x-ray. Both provide limited information, but neither provides the thermal information that is a dominant factor in tire failure. By setting the IR camera in a position to face the edge of the tire, using mirrors to bring the sidewall into the field of view, and using our methodology we have collected data on the entire tire under two minutes. This data can be viewed as flat data array images or rendered onto a 3D wireframe representation.

Recent advances in IR system technology coupled with significant reduction sin cost are making thermography a viable tool for on-line monitoring of industrial processes. This paper describes the implementation of a novel rugged thermal imaging system based on a dual-wavelength technique for a large intelligent process monitoring project. The objective of the portion described herein is to deploy a non-contact means of monitoring die cast tooling surface thermal conditions and analyzing the data in the context of the process monitor. The technical and practical challenges of developing such a non-contact thermal measurement system for continuous inspection in an industrial environment are discussed, and methods of resolving them are presented. These challenges include implementation of a wavelength filter system for quantitative determination of the surface temperature. Additionally, emissivity variations of the tooling surface as well as IR reflections are discussed. The primary issues that are addressed, however, are compensation for ambient temperature conditions and optimization of the calibration process. Other issues center on remote camera control, image acquisition, data synchronization, and data interpretation. An example application of this system, along with in-plant images and thermal data, is described.

The paper industry has used IR cameras primarily for troubleshooting, where the most common examples include the examination of the condition of dryer fabrics and dryer cylinders and the analysis of moisture variations in a paper web. Another application extensively using IR thermography is non-destructive testing of composite materials. This paper presents some recently developed laboratory methods using an IR camera to examine paper structure. Specific areas include cockling, moisture content, thermal uniformity, mechanism of failure, and an analysis of the copying process.

A multiple-element, forward looking IR system is used to measure the subsurface temperature field produced by dry grinding of steel with both aluminum oxide and cubic boron nitride (CBN) grinding wheels. The technique is base don imaging the IR radiation obtained from the side of the specimen. A recent theoretical analysis of heat partition and surface temperatures in grinding is reviewed. The analysis partitions heat on the two length scales pertinent to grinding between the workpiece, wheel, coolant and chips. Spectral analysis is combined with FFT techniques to calculate subsurface temperature contours from the predicted heat partition. The numerical predictions of the model are shown to agree wit the experimental results taken for a range of grinding conditions. It is found that heat partition varies over a wide range depending on grinding conditions. Also, heat partition is a strong function of position inside the grinding zone. The presence of the fluid inside the grinding zone can reduce the heat flux into the workpiece and the workpiece temperature significantly. For typical grinding of steel with CBN, or creep feed grinding of steel with aluminum oxide or CBN, it is possible to keep the fluid active and therefore to reduce thermal damage. However, the analysis suggests that the fluid may not be effective inside the grinding zone, in the conventional grinding of steel with aluminum oxide, due to boiling. It is also found that a moderate ratio of the workpiece velocity to wheel velocity gives high temperatures and therefore should be avoided.

We describe a pulsed method for measuring the principal values of the thermal diffusivity tensor of an anistropic materials. The technique utilizes IR imaging of a shadow as a function of time and space.

For any given thermal imager, a pulsed temporal pattern exists that will give a higher probability of detection than any other stimulation. This paper investigates different temporal patterns that best fit the thermal properties and thickness of the materials under test, such as pulse width, pulse rate, and intensity modulation, as well as the IR equipment. An experimental analysis of the thermal inspection of composite and metal structures is presented.

Cooling down thermography represents a novel approach to thermal nondestructive testing: the sample is previously heated in an oven in order to obtain a uniform temperature, then it is exposed to a lower ambient temperature. An IR camera monitors the surface temperature decay in order to reveal internal defects. While this approach presents clear disadvantages in terms of versatility, it allows for a faster and deeper penetration in the sample, and it has therefore mainly been used in order to reveal deep defects in insulating materials.

Results of inspecting a CFRP specimen with the impact damage defect are reported. The accent is made on dedicated data processing including the so-called defect maps production which are of special interest for end-users. Comparison of thermal tomography and pulse phase thermography is made while applying these methods to both defect detecting and characterizing.

Thermographic imaging is increasingly being utilized for inspection and characterization of materials and structures. Thermal diffusivity imaging provides a means for quantitative characterization of a materials which is independent of apparatus and measurement configuration. This enables more precise imaging of variations in the material or structure needed to track changes resulting from fatigue or aging processes.

Recent advances in thermal imaging technology have spawned a number of new thermal nondestructive evaluation (NDE) techniques that provide quantitative information about flaws in aircraft structures. Thermography has a number of advantages as an inspection technique for aircraft. It is a totally noncontacting, nondestructive, imaging technology capable of inspecting a large area in a mater of a few seconds. The development of fast, inexpensive image processors have aided in the attractiveness of thermography as an NDE technique. These image processors have increased the signal to noise ratio of thermography and facilitated significant advances in post-processing. The resulting digital images enable archival records for comparison with later inspections thus providing a means of monitoring the evolution of damage in a particular structure. NASA Langley Research Center has developed a thermal NDE technique designed to image and quantitatively characterize the thickness of thin aluminum sheets. The technique involves the movement of a thermal line source across the outer surface of a sample followed by an IR imager at a fixed distance behind the line source. Images of the material loss due to corrosion are reconstructed from measurements of the induced surface temperature variations. This paper will present a discussion of the development of the thermal imaging system as well as the techniques used to reconstruct images of flaws. The application of the thermal line source coupled with the analysis technique represents a significant improvement in the quantification of flaws over conventional thermal imaging. Results of laboratory experiments on specimens with fabricated material loss region swill be presented to demonstrate the capabilities of the technique. An integral part of the development of this technology is the use of analytic and computational modeling to optimize the technique and reduce the data. The experimental results will be compared with simulations to demonstrate the utility of such an approach.

High resolution pulsed IR thermography has been assessed, selected and developed for the inspection of brazed metallic honeycomb sandwich thermal protection system parts for the X-33 space vehicle. This inspection is fast, reliable and less costly than alternative methods.

Following several years of investigating active thermal imaging techniques, Lockheed Martin Aeronautical Systems Company (LMASC) has introduced a portable, time-dependent thermography (TDT) system into the production inspection environment. Originally pursued as a rapid, non-contacting, nondestructive evaluation (NDE) tool for inspecting large surface areas, the TDT system has proven most useful as a rapid verification tool on advanced composite assemblies. TDT is a relatively new NDE methodology as compared to conventional ultrasonic and radiography testing. SEveral technical issues are being addressed as confidence in the system's capabilities increase. These include inspector training and certification, system sensitivity assessments, and test results interpretation. Starting in 1991, LMASC began a beta-site evaluation of a prototype TDT system developed by the Institute of Manufacturing Research at Wayne State University. This prototype was the forerunner of the current production system, which is offered commercially as a fully integrated thermal NDE system. Applications investigated to data include quality assurance of advanced aerospace composite structures/assemblies for disbonds/voids between skin and core. TDT has a number of advantages over traditional NDT methods. The process of acquiring thermal images is fast, and can decrease inspection time required to locate suspect areas. The system also holds promise for depot level inspections due to its portability. This paper describes a systematic approach to implementing TDT into the production inspection arena.

Thermal methods have been recognized above other NDI methods for rapid inspection of large structures. Thermal methods are safe, convenient and relatively inexpensive. Coating tolerant thermography is specifically designed to meet the demands of more challenging field conditions.The technique's ability to differentiate between chipped paint and structural flaws is essential to field performance. However, equally important is the packaging of the system. The system must be lightweight, safe and inexpensive to maintain. This technique utilizes thousands of watts of radiant energy emanating from a hand held system. Inefficiencies in the projection optics can result in heating of the system itself, which then would necessitate significant cooling. This paper describes a unique projection system that can efficiently convert the energy emitted by an inexpensive incandescent line source into several projected stirpes for coating tolerant thermography.

Automotive brake systems are energy conversion devices that convert kinetic energy into heat energy. Several mechanisms, mostly related to noise and vibration problems, can occur during brake operation and are often related to non-uniform temperature distribution on the brake disk. These problems are of significant cost to the industry and are a quality concern to automotive companies and brake system vendors. One such problem is thermo-elastic instabilities in brake system. During the occurrence of these instabilities several localized hot spots will form around the circumferential direction of the brake disk. The temperature distribution and the time dependence of these hot spots, a critical factor in analyzing this problem and in developing a fundamental understanding of this phenomenon, were recorded. Other modes of non-uniform temperature distributions which include hot banding and extreme localized heating were also observed. All of these modes of non-uniform temperature distributions were observed on automotive brake systems using a high speed IR camera operating in snap-shot mode. The camera was synchronized with the rotation of the brake disk so that the time evolution of hot regions could be studied. This paper discusses the experimental approach in detail.

Results of a defect visualization process based on pulse IR thermography are presented. Algorithms have been developed to reduce the amount of operator participation required in the process of interpreting thermographic images. The algorithms determine the defect's depth and size from the temporal and spatial thermal distributions that exist on the surface of the investigated object following thermal excitation. A comparison of the result from thermal contrast, time derivative, and phase analysis methods for defect visualization are presented. These comparisons are based on 3D simulations of a test case representing a plate with multiple delaminations. Comparisons are also based on experimental data obtained from a specimen with flat bottom holes and a composite panel with delaminations.

There is increasing pressure in the Automotive Industry to reduce the time it takes to bring new components to production. Typical development times have been shortened from approximately five years to around two years over the last decade. The challenge for the testing community is to meet these time constraints without affecting quality. In order to remain competitive in the automotive industry, it is necessary for the vehicles developed to possess certain properties such as low weight, high stiffness, good fuel efficiency, high reliability, good ride and handling characteristics, good NVH ( Noise, Vibration, and Harshness), as well as good aerodynamical characteristics. It is generally recognized that these objectives cannot be met by developing the components through a series ofmechanical tests, since these methods are both too time consuming and expensive. New testing methods should be introduced in order to meet the aggressive goals associated with shorting the concept-to-customer (CTC) development cycle. These new methods need to be non-destructive (NDT), relatively easy to use and set-up, effective, and able to meet short timing constraints. Test results have to be reliable, repeatable, and accurate. One ofthe new technologies that has been introduced recently at Ford VISTEON, Chassis Systems, Experimental Engineering Department (BE) to meet the short CTC is Infrared.

Measurements of both through-thickness and lateral thermal diffusivities are described for a SiC/SiC ceramic matrix composite material. The measurement approach is one-sided and is based on the time-resolved IR radiometry method in which the specimen is illuminated with a step heating pulse and the resulting temperature rise is monitored with an IR focal plane array. An area heating source is used for the through-thickness measurement of thermal diffusivity and a line source is used for the lateral thermal diffusivity measurement. The result indicate that the thermal diffusivity values obtained using a model assuming surface absorption and emission have to be corrected since the composites show some IR transparency accompanied by strong scattering. Additional measurements are presented on CMC components structures with possible porosity at bonds.