Papers by Keyword: Infrared Camera

Abstract: The article presents the results of a study of use thermographic non-destructive testing to search for cracks in steel structures. Theoretical substantiation of thermal non-destructive method of control for detection of cracks in steel structures. A practical study proving the possibility of using thermal non-destructive testing to detect cracks in steel structures is described. The problems that arise during the thermal non-destructive method of control and possible ways to solve them. The authors conclude that the method of thermographic control can be used during the inspection of steel structures for qualitative assessment of cracks.

Abstract: Understanding and predicting relationships between laser welding process parameters, such as laser power and welding speed, and molten pool have been studied widely in order to critically control and improve laser welding. The laser welding processes are difficult to monitor in real time because of high temperature and rapid heating characteristics. In this study, infrared camera was set to collect data and provide real time monitoring system to determine the molten pool characteristics and weld quality. This study carried out a laser welding of SS400 low carbon steel and analyzed real-time image of the welding process to determine the average temperature of molten pool and calculate the size of molten pool. By varying the laser power and the welding speed, the infrared camera and imaging processing technique can monitor change of molten pool temperature in a range of 1000 C to 15000 C with about 1% temperature fluctuation. In addition, the size of molten pool can be calculated from the temperature profile of the welding zone. The calculated molten pool size was about 95% accurate compared to the measured size from microscope imaging.

Abstract: Tests were performed on two Carbon-Manganese steels (A42 and A48 steels, French standard) in the gigacycle fatigue domain thanks to a piezoelectric fatigue machine working at 20000Hz. During the tests, temperature recordings were achieved by an infrared camera for various stress amplitudes. The main difference between the two steels compositions was the aluminum content (0.045% for the A42 steel and 0.004% for the A48 steel), and the carbon content (0.140% for the A 42 steel and 0.198% for the A48 steel). In the A48 steel, the few aluminum content induces a higher free content of solute nitrogen in the lattice. Mechanical spectroscopy tests were performed and gave qualitative results on the solute contents repartition in the lattice. The temperature increase recorded during the fatigue tests for the two steels are different at the beginning of the tests. The differences can be explained by the different repartition of the solute atoms which induces a different dislocation gliding between the two materials. At the end of the tests, the thermal recordings are similar and attributed to the evolution of the solute atoms repartition and the dislocation structure.

Abstract: The tensile failure behavior of railway wheelset materials was studied with the aid of infrared thermography technology. The tensile specimens were prepared from the actual railway vehicle parts, which were used for over 20 years. Generally, the Lüders bands are appeared and observed in annealed soft steel like low-carbon steel, during yield point phenomenon due to the unbalance of strain. During the tensile testing, a high-speed infrared camera was employed to monitor surface temperature changes in specimen. During the tensile testing, the formation of Lüders bands was clearly observed. Moreover, the propagation of bands along the 45 degree direction of loading axis was also observed. In this investigation, the yield point phenomenon with Lüders band in railway wheelset materials was introduced, and the interpretation of tensile behavior was also discussed.

Abstract: . The minimum cost and high productivity of the recent industrial renaissance are its main challengers. Selecting the optimum cutting parameters play a significant role in achieving these aims. Heat generated in the cutting zone area is an important factor affecting workpiece and cutting tool properties. The surface finish quality specifies product success and integrity. In this paper, the temperature generated in the cutting zone (shear zone and chip-tool interface zone) and workpiece surface roughness is optimized using an artificial immune system (AIS) intelligent algorithm. A mild steel type (S45C) workpiece and a tungsten insert cutting tool type (SPG 422) is subjected to dry CNC turning operation are used in experiments. Optimum cutting parameters (cutting velocity, depth of cut, and feed rate) calculated by the (AIS) algorithm are used to obtain the simulated and ideal cutting temperature and surface roughness. An infrared camera type (Flir E60) is used for temperature measurement, and a portable surface roughness device is used for roughness measurement. Experimental results show that the ideal cutting temperature (110°C) and surface roughness (0.49 μm) occur at (0.3 mm) cut depth, (0.06 mm) feed rate, and (60 m/min) cutting velocity. The AIS accuracy rates in finding the ideal cutting temperature and surface roughness are (91.70 %) and (90.37 %) respectively. Analysis shows that the predicted results are close to the experimental ones, indicating that this intelligent system can be used to estimate cutting temperature and surface roughness during the turning operation of mild steel.

Abstract: The fiber is considered the most important element in fiber reinforced composite materials, as it generally occupies the largest volume in a composite material; further, delivers the heaviest loads. therefore, it is important to select types, quantity and proper stacking angles of the fiber. In this study, the fiber directions were arranged in different orientation angles, i.e. in symmetric (0°/0°,15°/15°,30°/30°,45°/45°,90°/90°) and asymmetric (0°/15°,0°/30°,0°/45°,0°/90°), to analyze the tensile strengths depending on the fiber orientation angles through the tensile test. In addition, a thermal imaging camera was used to investigate the thermal characteristics of the test specimens generated during the tensile test. the tensile strength showed a tendency of decreasing while the orientation angle increased. the maximum temperature generated when the fracture occurred increased at the fiber orientation angle of 30°, and showed a tendency of decreasing as the orientation angle increased.

Abstract: It is a very difficult task to land on aircraft carrier, because of limits of the carrier runway during rough sea. In this article, a new algorithm of aircraft carrier landing is proposed utilizing airborne infrared camera/inertial integrated system, which can provide the relative positions and orientation of the aircraft with respect to the carrier so as to help aircrafts semi-auto or auto landing. The mathematic relationship between guidance parameters and imaging information was modeled, and then the relative position and attitude information between the carrier and the aircraft were estimated through Newton iteration method. From that information, the pitching, rolling and heave movement of the carrier were estimated and compensated, so the touchdown point could be predicted and provided to the pilot so as to control aircraft landing. On the ground of the theoretic research, the field verification tests were carried out, which adopted the minification scheme to simulate the process of aircraft carrier landing. In the experiments, the runway simulator simulated the motion of the carrier runway and the land vehicle was used as the aircraft. The results verify the landing guidance system scheme is feasible and effective, and lay the technical foundation for the flight test, improving its safety.

Abstract: In this paper, through theoretical analysis, find out the cause of formation of the infrared camera critical flicker problem and the relations of the internal switch structure, and through the circuit structure, the ways and specific measures are presented to solve the infrared camera critical flicker problem.

Abstract: The problem of transverse crack formation in continuously cast steel has been an issue for over 30 years. The crack susceptibility depends not only to the steel composition, but also to the temperature history during casting. To improve the surface quality, two key solutions have been suggested; adjusting the straightening stage to an appropriate temperature range, out of hot ductility trough, and/or alloy modification. These solutions have certain limitations and difficulties still exist for grades such as peritectic steels containing Nb or V. In this article, the hot ductility of a peritectic steel grade with Nb has been studied under direct cast conditions. This was performed using a Gleeble 3800 thermo-mechanical simulator under two critical strain rates. In addition, the transverse crack formation and appearance, as well as the application of infrared camera to study the surface temperature profile of the slabs is presented.

Abstract: It is well known those two popular methods of testing; destructive testing based on fracture mechanics and non-destructive testing (NDT) which does not make any damage in the specimen. NDT was first used for military purpose but nowadays it is used widely in many fields such as composite materials, medical purposes, fire safety, laser welding, food safety and quality and characterization of materials. The aim of this paper is to review the recent advancement of thermography non-destructive methods especially in testing a quality of bio-composites materials. The review reveals the advantages and disadvantages of pursuing any of the available methods in NDT on bio composite materials.