File:Animation Controle Non Destructif Courants Français: Schéma d’un contrôle non destructif par courants de Foucault. Download scientific diagram| Principe du CND par courants de Foucault from publication: Design of eddy current microsensor arrays and signals inversion for . Job postings: Spécialiste CND – Ingénieur d’application Ultrason et Courants de Foucault (6 mois) at Olympus NDT Canada, Québec, Québec.
|Published (Last):||21 December 2004|
|PDF File Size:||16.89 Mb|
|ePub File Size:||20.28 Mb|
|Price:||Free* [*Free Regsitration Required]|
Menu More Pour nous joindre.
Common applications Eddy current instruments can be used in a wide variety of tests. Tubing inspection – Both in-line inspection of tubing at the manufacturing stage and field inspection of tubing like heat exchangers are common eddy current applications. Dde are many factors that will affect the capabilities of an eddy current inspection.
File:Animation Controle Non Destructif Courants Foucault.gif
The top line shows the signal on aluminum without ee coating. The eddy current instrument plots changes in the impedance amplitude and phase angle, which can be used by a trained operator to identify changes in the test piece.
The screen display below shows a nonmetallic coating over aluminum. ECA can permit use of simpler fixturing, and can also simplify inspection of complex shapes through custom probes built to fit the profile of the test piece.
Bolt Hole Inspection – Cracking inside bolt holes can be detected using bolt hole probes, often with automated rotary scanners.
Fourants current density is highest near the surface of the part, so that is the region of highest test resolution.
Optimisation particulaire par métamodèle appliquée au CND par courants de Foucault
This measurement uses a special conductivity probe that displays the cnv screen instead of the standard impedance screen shown above. This display would be considered the calibration of the instrument.
Menu More Pour nous joindre. This process involves identifying the baseline display from a given test piece and observing how it changes under the conditions that the test is intended to identify. Eddy current testing is widely used in cd aerospace industry and in other manufacturing and service environments that require inspection of thin metal for potential safety-related or quality-related problems. This example was a 0. The operator observes the response from the reference standards and then compares the indications from test pieces to these reference patterns to categorize parts.
Surface probes – Used for identifying courantw on and below metal surfaces, usually large diameter to accommodate lower frequencies for deeper penetration, or for scanning larger areas.
Eddy current arrays Eddy Current Array testing, or ECA, is a technology that provides the ability to simultaneously use multiple eddy current coils that are placed side by side in the same probe assembly. For example, the display below shows a setup for cpurants for surface cracks in aluminum. There have been many recent developments in eddy current testing, leading to improved performance and the development of new applications. Both cracking and thickness variations can be detected.
Types of probes Eddy current instruments can perform a wide variety of tests depending on the type cd probe being used, and careful probe selection ckurants help optimize performance.
Eddy current testing began largely as a result of the English scientist Michael Faraday’s discovery of electromagnetic induction in It is always important to select the right probe for each application in order to optimize test performance. Other companies soon followed.
Eddy currents traveling in materials with higher conductivity values will be more sensitive to surface defects but will have less penetration into the material, with penetration also being dependent on couraants frequency. Surface Inspection – Surface cracks in machined parts and metal stock can be readily identified with eddy current.
Conductivity Testing – Eddy current testing’s ability to measure conductivity can be used to identify and sort ferrous and nonferrous alloys, and to verify heat treatment.
Eddy current instruments can perform a wide variety of tests depending on the type of probe being used, and careful probe selection will help optimize performance.
Impedance plane displays While some older eddy current instruments used simple analog meter displays, the standard format now is an impedance plane plot that graphs coil resistance on the x-axis versus inductive reactance on the y-axis.
Pencil probes – Smaller diameter probes housing coils built for high frequencies for high resolution of near surface flaws. Inanother breakthrough was made when another English scientist, David Hughes, demonstrated how the properties of a coil change when placed in contact with metals of different conductivity and permeability.
Contrôle par courants de Foucault — Wikipédia
While conductivity and permeability are properties of the test material that are outside of the operator’s control, the test frequency, coil type, and coil size can be chosen based on test requirements.
However, it was not until the Second World War that these developments in the transmitting and receiving of electromagnetic waves were put to practical use for materials testing. In an eddy current probe, an alternating current flows through a wire coil and generates an oscillating magnetic field. Larger coils inspect a greater volume of material from any given position, since the magnetic field flows deeper into the test piece, while smaller coils are more sensitive to small defects.
Some of the most common are listed below. Another common test involves measurement of nonconductive coatings like paint over metals. Many advances were made throughout the s and s, especially in the aircraft and nuclear industries. Low frequency probes can be used to locate corrosion on second and third layers of metal that cannot be inspected ultrasonically. Once the parameters are set, they should not be changed during the inspection.
The top curve represents a 0. Foucault built a device that used a copper disk moving in a strong magnetic field to show that eddy currents magnetic fields are generated when a material moves within an applied magnetic field.