Non-Destructive Determination of Welding Residual Stress
Development of a Non-Destructive Method and Equipment for Determination of Welding Residual Stress on the Basis of Coherent Photonics and Computer Modeling
Tech Area / Field
- PHY-OPL/Optics and Lasers/Physics
- FIR-MOD/Modelling/Fission Reactors
- INF-SOF/Software/Information and Communications
- INS-MEA/Measuring Instruments/Instrumentation
8 Project completed
Senior Project Manager
Latynin K V
MIFI, Russia, Moscow
- Kurchatov Research Center / Institute of Reactor Technologies and Materials, Russia, Moscow
- Institut National de Sciences Appliquees de Strasbourg, France, Strasbourg\nUniversity of New Mexico, USA, NM, Albuquerque
Project summaryThe purpose of the Project is development of non-destructive numerically-experimental methods and inventories for determination of residual stress in construction units of Nuclear Power Stations by indentation of indentor of the special shape. As the result, most up-to-date physical and mathematical methods of diagnostic of residual stress will be implemented and, consequently, safety of pipelines and devices of atomic stations will be increased.
The urgency of the project is bound that the effective stresses in constructive elements are results of superimposition of stresses caused by external forces on technological residual stresses. In this connection, the reliable experimental determination of values and sign of residual stress are important not only for prediction of a state of nuclear plants with exhausted resource but also for ensuring of designed resource.
At present time for determination of values and signs of principal residual stress the method of probing holes (reach-through or part-through holes), as a rule, is used. This method is destroying even if holes are small in diameter. This method is in common practice in laboratory conditions for improvement of different master schedules, for example, welding. Only in USA there is the standard for residual stress measuring by the method of probing holes and resistive-strain sensors. The method of probing holes based on holographic interferometry and finite elements, developed in the framework of the ISTC project #0774, has essentially increased the reliability of determination of principal residual stress, although it is also destructive. The elasto-plastic indentation of indentors of different shape would be an expedient of determination of residual stress on the operative equipment minimally effecting on an explored body. For example, now indentors of the spherical shape are widely used on the operative equipment of atomic stations for hardness test. Thus, the shared use of indentors of the different shape with methods of holographic interferometry, electronic speckle interferometry and finite elements enables to elaborate almost nondestructive method and inventory for principal residual stresses measuring.
Within the framework of the tendered project for determination of residual stress in weld zone by the nondestructive method the following items are proposed for development:
- holographic interferometer for residual displacement measuring in the zone of indentor indentation;
- electronic speckle interferometer for measuring of separate components of residual displacements in the zone of indentor indentation;
- technique for measuring of a contact spot of indentor with an explored body;
- prototype of electronic speckle interferometer;
- automated system of interference fringe patterns processing;
- algorithms and software for solution of a nonlinear contact problem in three-dimensional statement at the different diagrams of material deformation;
- methods of residual stress determination on the basis of measured residual and calculated displacements;
- a device for indentor indenting (and its manufacturing);
- testing of a designed procedure of residual stress determination in conditions of monoaxial and biaxial tension;
- study of residual stress by the method of impression of indentor on welded pipeline of DU-300 of atomic stations and also on specimens presented by the collaborators.
The organizations - performers in the aggregate have unique scientific and industrial potential, sufficient for solving of proposed complex problem.
Sharing of numerical methods and data of interference measurements will allow to create a procedure for reliable determination of values of components of residual stress by the method of indentor impression.
The project fulfillment presumes a active role of the foreign partners having experience in the field of a laser holography, computer speckle interferometry and mathematical numerical modeling of deformation processes, in the form of joint seminars and working conferences, joint publications and reports on conferences, mutual exchange of technological information, advertising, international certification, application and commercialization of obtained results.
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