Browse Topic: Thermal testing

Items (89)
Find
Influence of the chemical composition on the generation of cracks in brake discs2021-36-04232/10/2022
Thermoelastic instabilities in the contact of brake friction material cause hotbands and hotspots on the surface of brake disc. These phenomena generate thermal stresses that result in generation of cracks, which limit the lifetime of the discs. In the present work, the influence of the chemical composition of brake discs on the thermoelastic behavior of the system and on the lifetime of the discs was investigated. The experimental evaluation was carried out in an inertial dynamometer using the SAE J3080 standard procedure applied on a brake system. Two discs (namely A and B) with different chemical compositions were subjected to the tests. The brake pad composition was kept fixed. The thermoelastic effects on the inner surface of the disc were observed by contact (thermocouple) and noncontact measurement techniques (thermography), as well as through photographic images of the disc’s surfaces. Disc A showed negligible amount of Nb while disc B exhibited 0.360%. Besides, disc B
Flores, Roberto, Ferreira, Ney Francisco, Neiss, Patric Daniel, Barros, Liu Yesukai, Poletto, Jean Carlos, Buneder, Diogo, Lorandi, Natalia Pagnoncelli, Pavlak, Rafael Paini, Fidler, Genesis Guilherme, Lopes, Carlos Henrique Raposo
Determination of Effect of Solar HeatingJ1559_202007 (Current)7/10/2020
This document specifies a test method for simulating solar heating in the laboratory and measuring the radiant heat energy from a natural or simulated source. This standard is applicable to all off-road, self-propelled work machines as listed in the scope of SAE J1116 (Rev Nov 2004) when equipped with an operator enclosure system.
HFTC6, Operator Accommodation
Temperature Measurement, Well Insert TypeARP175A (Current)4/14/2020
A-4 Aircraft Instruments Committee
The 6 Most Important Parts of a Temperature Monitoring SystemTBMG-3546211/1/2019
In the past few years, it has become increasingly common for hospitals, clinics, healthcare and life science organizations, and other businesses to use an electronic temperature monitoring system to safeguard their products and satisfy regulatory demands. You may know that you need a monitoring system, possibly with alarming capabilities, but aren't sure how to select the best one to meet your needs. To complicate matters, there are literally dozens of different types of temperature monitoring systems with different features and a wide range of prices.
Fusion Splice for Aerospace Fiber Optic CablesAS6506A (Current)7/11/2019
This document defines performance standards which fiber optic cable splices must meet to be accepted for use in aerospace platforms and environments.
AS-3 Fiber Optics and Applied Photonics Committee
High-Speed Wind Tunnel Tests of a Full-Scale Proprotor on the Tiltrotor Test RigF-0075-2019-147365/13/2019
The Tiltrotor Test Rig (TTR) is a NASA project, joint with the U.S. Army and Air Force, to develop a new, large-scale proprotor test system for the National Full-Scale Aerodynamics Complex (NFAC). The first wind-tunnel entry was completed in November 2018 with a modern, 26-ft diameter proprotor. The primary purpose was to complete the development of the TTR, including systems integration with the NFAC. The TTR and rotor were tested up to 273 knots in axial flow. This is the highest airspeed ever achieved by a full-scale proprotor in any wind tunnel. Extensive conversion-mode data were also acquired, and hover/climb conditions were explored. Additional testing included aerodynamic tares, motor tests, thermal tests, modal vibration tests, and other checkout activities. This paper summarizes the results of the test, including examples of the most significant data.
W., C., Sheikman, Alex, Norman, Thomas
Effects of Temperature on Mechanical Response of Lithium Ion Batteries to External Abusive Loads2019-01-10024/2/2019
This paper focuses on mechanical properties of lithium ion batteries subjected to mechanical loading. Researchers have studied mechanical properties of batteries under room temperature. However, the operating temperature for these cells can change from -20 to +60 degrees Celsius. Therefore, characterization of cell’s response under varying temperature is of utmost importance. We have tested battery components and cells at a range of temperatures and have documented the changes in mechanical properties. Our results show that extreme hot or cold temperatures can have a significant effect on the mechanical response of lithium ion batteries under crush and indentation.
Gilaki, Mehdi, Sahraei, Elham
Development of TLP-AI Technology to Realize High Temperature Operation of Power Module2019-01-06074/2/2019
Application of SiC power devices is regarded as a promising means of reducing the power loss of power modules mounted in power control units. Due to those high thermostable characteristics, the power module with SiC power devices are required to have higher operating temperature than the conventional power module with Si power devices. However, the limitations of current packaging technology prevent the utilization of the full potential of SiC power devices. To resolve these issues, the development of device bonding technology is very important. Although transient liquid phase (TLP) bonding is a promising technology for enabling high temperature operation because its bonding layer has a high melting point, the characteristics of the TLP bonding layer tend to damage the power devices. This paper describes the development of a bonding technology to achieve high temperature operation using a stress reduction effect. Called transient liquid phase bonding with an aluminum interlayer (TLP-AI
Asai, Rintaro, Ito, Hirofumi, Usui, Masanori, Aoshima, Masaki
The Heat Is On: A Guide to Specifying Insulation MaterialsTBMG-339193/1/2019
One of the first things an electrical engineer will learn is that the number-one enemy of designing and manufacturing any electrical/electronic product is heat. It's the one characteristic that can cause your idea of a hand-sized unit to turn into a tabletop unit. When discussing insulation with a manufacturer, the first question that seems to come up is temperature resistance. It is a very important characteristic but there are a few others that need to be addressed as well. In addition to temperature rating, voltage along with mechanical strength play a very important role in the selection of insulation.
Microscopy Technique Works at Extreme HeatTBMG-335881/1/2019
A stainless steel alloy — alloy 709 — has potential for elevated-temperature applications such as nuclear reactor structures. It is exceptionally strong and resistant to damage when exposed to high temperatures for long periods of time, making it a promising material for use in next-generation nuclear power plants.
Study on Brake Disc Dynamics under Asymmetric Thermal Loads2018-01-190110/5/2018
In order to explore the generation mechanism of hot-spots on the automotive brake disc, disc tests under non-frictional thermal loads are carried out on the brake dynamometer test bench. In the tests, the oxy-acetylene flame is used as the heat source, and the distribution characteristics of the disc temperature and displacement are measured and analyzed. To confirm the mechanism of the disc deformation, a disc thermal buckling model using finite element method is established, and the key factors for the disc thermal buckling under thermal loads are further analyzed. It is found that the temperature circumferential gradient is small but the temperature radial gradient is large. The disc presents waviness deformation mode with 5th order in circumferential direction, which is the first thermal buckling mode of the disc. A method using spatial frequency spectrum has been proposed to find the critical time and load of thermal buckling. The heat source power and the rotational speed have no
Meng, Dejian, Liu, Jialin, Zhang, Jingyi, Zhang, Lijun
Mechanical Splice for Aerospace Fiber Optic CablesAS5405 (Current)9/7/2018
This document defines performance standards which mechanical fiber optic cable splices must meet to be accepted for use in aerospace platforms and environments.
AS-3 Fiber Optics and Applied Photonics Committee
Fusion Splice for Aerospace Fiber Optic CablesAS6506 (Historical)9/7/2018
This document defines performance standards which fiber optic cable splices must meet to be accepted for use in aerospace platforms and environments.
AS-3 Fiber Optics and Applied Photonics Committee
Optical Interconnect Design Challenges in SpaceTBMG-329069/1/2018
More and more aerospace applications are incorporating fiber optics technology into their designs due to its many advantages over copper. The thinner fiber solutions provide higher speed over a longer distance, are more reliable, offer higher noise immunity and, in many cases, lower the cost of ownership. Additionally, for the same diameter, fiber can pack more data than copper. Fiber is faster than the category 5 and 6 copper cables, approaching the speed of light (31% lower). For copper, pushing the speed beyond 1G is a challenge, but for fiber 10G is quite common. Copper is limited by distance. Usually, signal degradation with copper will occur after about 90 meters (2.7 km maximum for custom systems), while fiber can achieve more than 1.5 km without a problem and can deliver over 80 km depending on transmission signal quality.
Tiny Probe Can See and Measure Body TemperaturesTBMG-290096/1/2018
A new probe developed at the University of Adelaide, may help researchers find better treatments to prevent drug-induced overheating of the brain, and potentially refine thermal treatment for cancers.
Enhanced Low-Order Model with Radiation for Total Temperature Probe Analysis and Design01-11-01-00035/16/2018
Analysis and design of total temperature probes for accurate measurements in hot, high-speed flows remains a topic of great interest in aerospace propulsion and a number of other engineering areas. One can apply detailed computational methods for simultaneous convection, conduction and radiation heat transfer, but such approaches are not suitable for rapid, routine analysis and design studies. For these studies, there is still a place for low-order approximate methods, and that is the subject of this article. Here, an enhanced, low-order model is presented that includes conduction with variable thermal conductivity, convection with varying convection coefficient, varying diameter (and thus area) along the length of the sensor and radiation, all implemented in a convenient MATLAB code. We have also developed a new novel procedure to integrate the enhanced low-order model with computational fluid dynamics/conjugate heat transfer (CHT/CFD) simulations to accurately predict the important
Vincent, Tyler, Schetz, Joseph, Lowe, K. Todd
Technique Measures Temperature of 2D Materials at the Atomic LevelTBMG-288695/1/2018
Newly developed two-dimensional (2D) materials such as graphene — which consists of a single layer of carbon atoms — have the potential to replace traditional microprocessing chips based on silicon, which have reached the limit of how small they can get. But engineers have been stymied by the inability to measure how temperature will affect these new materials, collectively known as transition metal dichalcogenides (TMDs).
Development of a Thermal Fatigue Test Bench for Cylinder Head Materials2018-01-14104/3/2018
An innovative specimen design and test system for thermal fatigue (TF) analysis is developed to compare the fatigue behavior of different cylinder head materials under realistic cyclic thermal loadings. Finite element analyses were performed to optimize the specimen geometry and thermal cycles. The reduced section of the TF specimen is heated locally by a high frequency induction heater and cooled by compressed air. The mechanical strain is then induced internally by the non-uniform thermal gradient generated within the specimen to closely simulate what valve bridges in cylinder heads experience in real operation. The resulting fatigue life is a function not only of the inherent fatigue resistance of the alloys, but also of other relevant properties such as thermal conductivity, modulus of elasticity, and coefficient of thermal expansion. This test is an essential tool for comparing different alloys for thermal fatigue applications. In this paper, four aluminum alloys were tested to
Lai, Wei-Jen, Engler-Pinto, Carlos
Phonon Confinement Effect in TiO2 Nanoparticles as Thermosensor MaterialsTBMG-287894/1/2018
TiO2 or ZnO nanoparticles (NPs) have a very strong finite-size dependency in their Raman spectra or photoluminescence (PL) spectra due to the phonon confinement effect or the quantum confinement effect. Together with a fast grain growth kinetics and a high stability under high temperature and pressure, they can forensically retain the complete thermal history of an event. By spatially distributing these NPs during thermal events such as blasts or weapon tests, a spatially and temporally non-uniform thermal environment can be determined by a direct read off their Raman or PL spectra at various locations.
Infrared TestingJ359_201801 (Current)1/9/2018
The scope of this SAE Information Report is to provide general information relative to the nature and use of infrared techniques for nondestructive testing. The document is not intended to provide detailed technical information, but will serve as an introduction to the theory and capabilities of infrared testing and as a guide to more extensive references.
Metals Technical Committee
ERRATUM: Enhanced Low-Order Model with Radiation for Total Temperature Probe Analysis and Design2017-01-2047.019/19/2017
Vincent, Tyler, Schetz, Joseph, Lowe, K. Todd
Adam Sidor, NASA Research Fellow, Georgia Institute of Technology, Atlanta, GATBMG-271026/20/2017
Thermal Protection Systems (TPS) — heatshields — form the outer surface of spacecraft and provide protection as the vehicle plunges through planetary atmospheres. Conformal ablative materials are currently being developed to improve TPS performance. Adam Sidor is developing a fresh approach to designing and manufacturing these materials to produce larger tile sizes while reducing labor, cost, and waste.
A Numerical Study of Radiator Performance under a Transient Thermal Cycle2017-01-06233/28/2017
Radiator thermal cycle test is a test method to check out the robustness of a radiator. During the test, the radiator is going through transient cycles that include high and low temperature spikes. These spikes could lead to component failure and transient temperature map is the key to predict high thermal strain and failure locations. In this investigation, an accurate and efficient way of building a numerical model to simulate the transient thermal performance of the radiator is introduced. A good correlation with physical test result is observed on temperature values at various locations.
Wang, Zun, Zhang, Yi, lenormand, Christophe, Ansari, Mohammed, Henner, Manuel
Acoustical and Thermal Materials Test ProcedureJ1324_201608 (Current)8/2/2016
This SAE Recommended Practice provides test methods for determining the characteristics of acoustical and thermal materials. Where applicable, methods of test developed by SAE and ASTM have been referenced.
Acoustical Materials Committee
Effect of Thermal Behavior of Friction Materials on Brake Squeal2014-01-25149/28/2014
Brake noise is an emerging concern in Indian Auto-industry; with brake squeal being the most evident form of brake NVH. Squeal noise generation attributes to many parameters including kinematics of braking parts during pressure application, structural dynamic behavior which in turn depends on coupling at resonant frequencies of different parts of a brake assembly, material of brake parts, operating clearances in the mating parts etc. The genesis of brake squeal lies in the generation of unstable frictional forces during braking event. These frictional forces induce uncontrolled amplification of brake parts vibration, which in turn tend to produce perceivable sound or noise. The magnitude this vibration induced squeal depends on co-efficient of friction, braking pressure, speed and temperature of friction material. It is known from typical squeal evaluations on dynamometer that at different temperatures of friction, the ability/ occurrence, of squeal is different, typically in the range
Mahale, Prashant, Bohari, Aziz, M P, Raajha
Thermal Performance of Disc Brake and CFD Analysis2014-01-24979/28/2014
In this paper an effective technology of virtual thermal test of disc brake with several advanced analytic techniques was presented. With the virtual thermal test process, thermal performance of brake system could be easily evaluated without any possibility of great errors that used to happen in the past. In addition to the classical result of CFD, this virtual thermal test produced several valuable applications such as thermal deformation of rotor, optimization of thermal performance and estimation of braking distance.
Choi, Bongkeun
Characterization of PU Foam for High Temperature Applications in Automobiles2014-01-10354/1/2014
Due to continuous demands from OEM's to reduce weight and make more compact vehicles, high heat generation from vehicle has become common phenomenon. Thermal insulation is a need of the hour to cater to such demands. The temperature rise is more critical around engine areas. OEM's use many design solutions to cater to such heat build up's. One of the design solutions includes use of thermally insulating materials e.g. Foams, insulating fabrics etc… First section of this paper deals with comparative study of polyurethane (PU) soft foam and rigid skin polyurethane foam. To define the base line, the samples were subjected to various tests to determine physical, thermal and chemical properties. Also both the types of foams were subjected to high temperature and low temperature heat ageing. From the experiments, it was observed that soft PU foam provides better re-bounce property than rigid skin PU foam. This is an important property to be considered, when foam is subjected to compression
Mehta, Shruti, Hatwalne, Mrunal, Dhule, Mangesh
A New Alloy for Medical Electronics ApplicationsTBMG-172839/1/2013
Although the deadline for RoHS compliance for medical device manufacturers is nearly a year away (July 22, 2014), there is more than ten years of testing and in-service data that can be used to ensure a smooth transition to lead-free medical devices and equipment.
Integral Molded Brake Pad with Long Fiber Thermosetting Molding Compound for Automotive Brake System2012-01-18349/17/2012
Recently, in view of environment, safety, comfort and convenience for cars, the demand of low fuel consumption is increasing more than before, and weight saving of the automotive parts is pursued. In the tide of weight saving, there is a strong demand of light weightening of the backing plate by replacing steel with plastics. We have been developing long fiber phenolic molding compound, which has excellent mechanical strength and excellent heat resistance, and have examined in order to apply it to the backing plate for brake pad. By applying this material to backing plate, the weight of brake pad can be reduced in half compared with that of conventional pad made of steel. In the automotive parts, it is said that reduction of part weight under the suspension is about ten times as effective for reducing fuel consumption as that of weight upper the suspension, therefore, phenolic brake pad has a big impact. Also, instead of simple replacement of steel plate with phenolic plate, it may be
Inokuchi, Hideaki
L.E.D. Signal and Marking Lighting DevicesJ1889_201106 (Historical)6/24/2011
This SAE Recommended Practice applies to functions of motor vehicle signalling and marking lighting devices which use light emitting diodes (L.E.D.’s) as light sources. This report provides test methods, requirements, and guidelines applicable to the special characteristics of L.E.D. lighting devices. This Recommended Practice is in addition to those required for devices designed with incandescent light sources. This report is intended to be a guide to standard practice and is subject to change to reflect additional experience and technical advances.
Signaling and Marking Devices Stds Comm
Analysis of Multilayer Thermal Insulation for ReentryTBMG-TB-0072892/1/2010
A paper presents a study of multilayer thermal insulations for protecting spacecraft against aerodynamic heating during reentry into a planetary atmosphere. A multilayer insulation considered in the study comprised (1) thin ceramic/composite foils coated with gold for high reflectance interspersed with (2) fibrous polycrystalline alumina spacers, all wrapped in (3) a bag made of ceramic fabric. The radiation heat transfer in the fibrous insulation spacers was modeled using the two-flux method assuming isotropic scattering. Combined radiative and conductive heat transfer in such blankets were computed by use of a finite-volume numerical model. The model was validated in steady-state and transient thermal tests of sample insulations.
Investigation of Thermal Test Effectiveness for Spacecraft Electronic Units Using Precipitation Efficiencies of MIL-HDBK-3442009-01-24097/12/2009
Thermal testing of spacecraft electronic units prior to flight provides effective detection of design, process and workmanship defects. Thermal testing subjects units to cold and hot thermal environments beyond those expected in flight. The strength of screening effectiveness depends upon the number of cycles, the temperature range, and the temperature transition rate. MIL-HDBK-344 provides insight into the incurred stresses and quantitative value (precipitation efficiency) of the screening environment using these three test parameters. In this paper, MIL-HDBK-344 topics applicable to thermal testing of space hardware are summarized and comparisons are made between test environment strengths computed from MIL-HDBK-344 and MIL-STD-1540E. The weighting of these aforementioned test parameters in the precipitation efficiency equation are discussed and assessed. It was found that the fatigue equivalency equations in MIL-STD-1540E specify a significantly larger number of required cycles for
Welch, John W.
Development of Thermal Fatigue Resistant Ferritic Cast Steel for Turbine Housing of Diesel Engine Automobile2009-01-02154/20/2009
In recent years, the temperature of automobile exhaust gas is on a rising trend due to lowering pollutant emissions and improving fuel economy, and exhaust gas temperature reaches as high as 1173K in the case of diesel engine cars. Against this background, Ni-resist D-5S cast iron has been chosen extensively as a turbine housing material for the diesel engine cars. But, Ni-resist D-5S has become a material of great cost volatility due to high Nickel content of 35 mass%, which price is expensive and unstable. On the contrary Ferritic cast steels, which possesses favorable thermal fatigue properties and good material cost stability, are considered to be promising substitutions for the Ni-resist D-5S. However conventional ferritic cast steels have relatively high melting points, which cause poor castability. For this reason, new ferritic cast steel, StarCast DCR3, has been developed by optimizing the chemical composition with keeping of the advantage of castability, productivity high
Takabayashi, Hiroyuki, Ueta, Shigeki, Shimizu, Tetsuya, Noda, Toshiharu
Advances in 3D Vision for Process Monitoring and Dimensional Gaging2007-01-37268/5/2007
Automotive assembly plants and subassembly suppliers have strongly recognized the need to continually improve assembly fit and function to enhance dimensional integrity of assemblies, maintain quality appearance, eliminate wind noise, water leaks, and other customer complaints. Ensuring that every part is made accurately cuts down on scrap costs and reduces downtime, warranty cost and assembly problems. Manufacturers have found these final inspection solutions valuable for 100% final inspection, but have expressed a need to have ability for in-process monitoring for rapid response to process variations, much earlier in the production process. This has lead to a new approach of monitoring the assembly operation with rugged 3D laser sensors which are installed in individual assembly tools to provide in-process monitoring.
Pastorius, Walter
Thermal and Mechanical Performance Analysis in Accordance with Disk Stiffness Changes in Automotive Disk Brake2007-01-36618/5/2007
Major vibration and noise problem relevant to brake disk NVH (Noise, Vibration and Harshness) is judder and squeal. The thermal distortion induced by thermo-elastic instability (TEI) makes hot spots on the surface of brake disk which incur low frequency vibration called judder vibration. In pad-induced squeal noise, out-of-plane mode coupling occur due to variation of friction coefficient between disk and pad induce high frequency noise. Through coupled analysis of these two important phenomena, judder and squeal, an optimum braking system can be designed for higher disk and pad performance. In this study, we conducted numerical and experimental analysis in accordance with variation of disk stiffness in the same friction material (lining) while simultaneously considering hot judder and squeal noise. Results are discussed about their performances in the view of hot judder and squeal problems.
Cho, Hojoon, Cho, Chongdu, Kim, Chang-Boo
Thermal Fatigue Design of Stainless Steel Exhaust Manifolds2007-01-05644/16/2007
The paper deals with the thermal mechanical fatigue (TMF) of stainless steels used for exhaust manifolds. A thermal fatigue test on V-shape specimen was early developed at Ugine & Alz to simulate such thermal and mechanical conditions. The examination of failed specimens indicates that cracks could be generally attributed to out-of-phase TMF. However, in specific cases, in-phase TMF may be dominant. For instance, manifolds made of austenitic stainless steel grades usually fail by in-phase TMF. Based on finite element calculation of the V-shape test, a damage criterion is proposed for out-of-phase TMF, which correlates the amplitude of the viscoplastic strain, the maximal temperature, the dwell time during the thermal cycle and the number of cycles to failure.
Chinouilh, G., Santacreu, P. O., Herbelin, J. M.
Advanced Systems for Monitoring Underwater SoundsTBMG-13433/1/2007
The term “Passive Acoustic Monitoring System” (PAMS) describes a developmental sensing and data-acquisition system for recording underwater sounds. The sounds (more precisely, digitized and preprocessed versions from acoustic transducers) are subsequently analyzed by a combination of data processing and interpretation to identify and/or, in some cases, to locate the sources of those sounds. PAMS was originally designed to locate the sources such as fish of species that one knows or seeks to identify. The PAMS unit could also be used to locate other sources, for example, marine life, human divers, and/or vessels.
Test Methods and Equipment for Lighting Devices and Components for Use on Vehicles Less than 2032 mm in Overall WidthJ575_200611 (Historical)11/21/2006
This SAE Recommended Practice provides standardized laboratory tests, test methods, and requirements applicable to many of the lighting devices and components covered by SAE Recommended Practices and Standards and is intended for reference for devices used on vehicles less than 2032 mm in width, regardless of length, or 7620 mm in length regardless of width. Tests for vehicles larger than 2032 mm in overall width are covered in J2139.
Test Methods and Equipment Stds Committee
Performance Improvement in Loop Heat Pipe Using Primary Wick with Circumferential Grooves2006-01-21727/17/2006
This paper presents an investigation of LHPs that operate with acetone as working fluid, for maximum operational heat loads of 80 W, where the results of tests performed in laboratory conditions are presented. Two identical LHPs were tested, where one presents the capillary evaporator primary wick with axial grooves, while the other presents the design of circumferential grooves and both evaporators present microgrooves in their internal diameter. For the same active length, there has been a gain of 20% on the contact area when using circumferential grooves on the primary wick, which resulted in better thermal performance. When the LHP operates at its maximum operational heat load, the heat source temperature for the evaporator with the primary wick with circumferential grooves is kept at levels 50% lower then when using the one with axial grooves. Besides the fact the an increase on the contact area has been achieved, other factors related to the design of the capillary evaporator
Riehl, Roger R., Santos, Nadjara dos
Dielectric Heaters for Testing Spacecraft Nuclear ReactorsTBMG-4052/1/2006
Like the electrical-resistance heaters used heretofore for such testing, the dielectric heaters would be inserted in the reactors in place of nuclear fuel rods. A typical heater according to the proposal would consist of a rod of lossy dielectric material sized and shaped like a fuel rod and containing an electrically conductive rod along its center line. Exploiting the dielectric loss mechanism that is usually considered a nuisance in other applications, an RF signal, typically at a frequency =50 MHz and an amplitude between 2 and 5 kV, would be applied to the central conductor to heat the dielectric material. The main advantage of the proposal is that the wiring needed for the RF dielectric heating would be simpler and easier to fabricate than is the wiring needed for resistance heating. In some applications, it might be possible to eliminate all heater wiring and, instead, beam the RF heating power into the dielectric rods from external antennas.
Flight Tests Telemetry Link for Small and Medium Aircrafts2005-01-413711/22/2005
It is common at the great aerospace companies or research centers to perform flight tests in facilities deployed for aircrafts and systems evaluation. These resources require high planning and investments comprising telemetry system, airborne and terrestrial equipments, calibration labs and specialized staff. It proposes in flight data acquisition means for support tests programs of aircrafts and airborne systems of low complexity in new developments. Also, it can be used as an optimization tool by introducing the telemetry efficiency concept applied to the development of new aircrafts where there are at least two prototypes read to fly.
Rodrigues, Tiago Giglio, Góes, Luiz Carlos Sandoval, Leite, Nelson Paiva Oliveira, Marins, Carlos Nazareth Motta
Thin-Film Resistance Heat-Flux SensorsTBMG-291757/1/2005
Thin-film heat-flux sensors of a proposed type would offer advantages over currently available thin-film heat flux sensors. Like a currently available thin-film heat-flux sensor, a sensor according to the proposal would be based on measurement of voltages related to the temperatures of thin metal films on the hotter and colder faces of a layer of an electrically insulating and moderately thermally conductive material. The heat flux through such a device is proportional to the difference between the temperatures and to the thermal conductivity of the layer. The advantages of the proposed sensors over the commercial ones would arise from the manner in which the temperature-related voltages would be generated and measured.
Improved Thermal Matching of Materials for Hermetic Optical WindowsTBMG-64297/1/2005
A family of iron-nickel and ironnickel- cobalt alloys made using metal injection technology (MIT) has been designed to match the coefficient of thermal expansion (CTE) of select optical glass materials more closely than commonly available wrought alloys of similar composition. Using these glass and metal combinations, custom windows can be developed with improved optical properties, greater hermeticity levels, and lower residual stress.
Mars Exploration Rover Thermal Test Program Overview2004-01-23107/19/2004
In January 2004, two Mars Exploration Rovers (MER) landed on the surface of Mars to begin their mission as robotic geologists. A year prior to these historic landings, both rovers and the spacecraft that delivered them to Mars, were completing a series of environmental tests in facilities at the Jet Propulsion Laboratory. This paper describes the test program undertaken to validate the thermal design and verify the workmanship integrity of both rovers and the spacecraft. The spacecraft, which contained the rover within the aeroshell, were tested in a 7.5 m diameter thermal vacuum chamber. Thermal balance was performed for the near earth (hot case) condition and for the near Mars (cold case) condition. A solar simulator was used to provide the solar boundary condition on the solar array. IR lamps were used to simulate the solar heat load on the aeroshell for the off-sun attitudes experienced by the spacecraft during its cruise to Mars. Each rover was tested separately in a 3.0 m
Pauken, M. T., Kinsella, G. M., Novak, K. S., Tsuyuki, G. T., Phillips, C. J.
Factors Affecting Severity of Oven Shock Test for Ceramic Substrates2003-01-307410/27/2003
The oven shock test is an accelerated test which is often used to quantify the thermal durability of both coated and uncoated ceramic substrates. The test calls for heating the substrate for 30 minutes in an oven, which is preheated to specified temperature, and then cooling it in ambient environment for 30 minutes. Such a cycle induces axial and tangential stresses, during cooling, in the skin region whose magnitude depends on physical properties, oven temperature, radial temperature gradient and the aspect ratio of substrate. In addition, these stresses vary with time; their maximum values occur as soon as the substrate is taken out of the oven. This paper evaluates the severity of thermal stresses as function of above factors and estimates the probability and mode of failure during cooling using thermocouple data. Methods to reduce these stresses are discussed. The relative severity of the oven shock test is compared with the Maremont thermal cycling test which is an industry
Gulati, S. T., Widjaja, S., Hampton, L. E., Roe, T. A.
A Thermal Model for the Human Ensemble System2003-01-22106/17/2003
Numerous thermal models have been developed for the human body. Most of them are only for the nude person. Without applying clothing, the human thermal models have very limited uses. In this paper, a comprehensive numerical model was developed for the coupled transport of energy and mass through the human ensemble system. In the development, not only has attention been paid to the theoretical relations between heat and moisture in the ensemble system, special attention has also been paid to the integration between the human and clothing thermal models. The model was developed such that clothing can be easily applied to the human thermal model the way people put their clothing on. Since the model is integrated with a human thermal model it is applicable in a wide range of real life applications. Model predictions and experimental results were compared for a variety of transient environmental exposures. The results, which show substantial agreement, indicate that the model can be used to
Fu, George, Jones, Byron
Thermal Load Sensors for Automotive ApplicationsTBMG-293926/1/2003
Next-generation thermal load sensors, or combo sensors, optimize climate control and lighting in "intelligent automobiles," thereby enhancing the comfort and safety of drivers and passengers. The sensors combine performance and quality with customized design to exceed the rigorous requirements of auto manufacturers. Several prominent auto manufacturers currently use these sensors in a variety of vehicles.
A Study on Creep Analysis of Automobile Instrumental Panel2003-01-11733/3/2003
The operating temperature of IP (Instrument panel) of passenger vehicles usually ranges from under freezing temperature to over glass transition temperature. The varying temperature induces thermal expansion of IP. Coupled with constraint condition, thermal expansion causes thermal deformation, which sometimes turns into unwanted permanent deformation. In this study, non-linear finite element method has been introduced to study the deformation behavior of IP in thermal cycle test. The time-dependent deformation behavior of IP has been investigated using creep material model. To quantify the creep behavior of polymer material which has been applied to IP, flexural creep test has been performed on various stress, temperature condition. The test result has been fitted into a time-hardening type creep constitutive equation. The coefficient of creep equation has been validated with the comparison of test result and FEM simulation result. In view of short-term thermal loading case, such as
Yeo, Tae-Jung, Kim, Soo Sang, Park, Soon Jo, Kim, Chul Soo, Park, Yune-Seo, Lee, Shi-Ho
Floating Probe Assembly for Measuring Temperature of WaterTBMG-13953/1/2003
A floating apparatus denoted a temperature probe aquatic suspension system (TPASS) has been developed for measuring the temperature of an ocean, lake, or other natural body of water at predetermined depths. These types of measurements are used in computer models to relate remotely sensed water-surface temperature to bulk- water temperature. Prior instruments built for the same purpose were found to give inaccurate readings because the apparatuses themselves significantly affected the temperatures of the water in their vicinities. The design of the TPASS is intended to satisfy a requirement to minimize the perturbation of the temperatures to be measured.
Thermography Using YVO₄:Dy³⁺TBMG-2942811/1/2002
A proposed thermographic technique would exploit the unique fluorescence characteristics of yttrium vanadate doped with dysprosium (YVO4:Dy3+). The particular aspect of the fluorescence characteristics that would be exploited in this technique is the relative intensity of emitted light as a function of the temperature and of the wavelength of the light used to excite the fluorescence (see figure).
Items per page:
1 – 50 of 89