Determination of Residual Stresses in Coatings and Coated Parts: Extended variant with additional information
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The methods of experimental residual stress analysis in coatings available at present are indirect. A distinct deformation parameter of a substrate or a coating should always be measured, from which the values of residual stresses can be calculated. At the same time, distinction should be made between layer-growing (nondestructive) and layer-removing (destructive) measurement methods. In the case of growing methods, a deformation parameter is measured by applying a coating a coating to the substrate, while in the case of layer-removing methods, by removing it from the substrate. G. Stoney was the first to use a layer-growing method for determination of residual stress in galvanic coatings. By using his method (proposed in 1909), residual stress in a coating is calculated by the curvature measured during the unilateral coating of a free straight strip substrate assuming a one-dimensional state of stress. In the course of time various layer-growing methods have been developed for determination of residual stresses in coatings. Still, layer-removing methods are also applied for determination of residual stresses in coatings. It has been established that layer-growing and layer-removing methods can be described by a single algorithm. Algorithms of this kind have been developed by the author of this thesis for a free plate with a unilateral coating, for a hollow cylinder and for a hollow sphere with an outer coating. This thesis summarizes the research conducted by the author and the coauthors in the field of experimental mechanics of residual stresses in coatings and coated parts between 1965 and 1994. The thesis contains the following sections: 1. Determination of residual stresses in coated parts: general algorithm; 2. Determination of residual stresses in bars, plates, cylinders and spheres with a thick coating; 3. Methods for determination of initial stress; 4. Thermal stresses in coated parts; 5. Some results of the experiments; Conclusions; Bibliography (Main publications on the subject of the thesis; Abstracts of main reports on the subject of the thesis; References); Appendix: Examples of application. In the form of an additional information list of titles and copies of the main publications on the subject of the thesis, as well as information about the defence of the thesis and a copy of the issued doctoral diploma are submitted.TITLES OF THE MAIN PUBLICATIONS ON THE SUBJECT OF THE THESIS IN ENGLISH: 1. Eigenstresses in thin electrodeposits. 2. Determination of eigenstresses in electrodeposits by deformation of a thin-walled tube cathode. 3. Determination of residual stresses in bars and plates using the strain measurement method. 4. On calculation of electrocrystallization stresses by deformation of a band cathode. 5. Investigation of residual stresses in electrodeposits by strain measurement of a thin-walled tubular cathode. 6. Once again about the force and deformation methods for determination of residual stresses in clamped bars and plates with coatings. 7. Boundary effect in the case of deposition of the coating on a free edged thin-walled tube. 8. Determination of residual stresses in coatings of rigidly clamped rods and plates by measuring strain. 9. On the method for determining residual stresses in hollow spheres. 10. On determination of residual stresses in coatings. 11. Determination of residual stresses in cylinders with coatings. 12. Thermal stresses in plates, cylinders and spheres with coatings. 13. On determination of residual stresses in non-homogeneous hollow cylinders. 14. A problem of thermoelasticity for a free nonhomogeneous plate with temperature variation through thickness. 15. Determination of residual stresses in the coatings of plates using the curvature measurement method. 16. On the determination of residual stresses in the deposits applied by brush plating. 17. On the determination of residual stresses in fibers using the axial strain measurement method. 18. On the determination of surface stresses in coatings by means of axial strain measurement method of flat-sheet substrate. 19. Modelling of the bending of a coated straight strip substrate. 20. Determination of residual stresses in deposits by measuring the deformation of a thin-walled ring-shaped substrate. 21. The application of the method of holographic interferometry by modelling the bending of a straight strip substrate with the deposit. 22. On determination of residual stresses in deposits by measuring the bending of a thin-walled substrate in the form of a curvilinear strip. 23. Study of deformations of thermobimetallic straight strips under heating by the holographic interferometry method. 24. Determination of residual stresses in the coat deposited by brush plating. 25. Modelling of residual stresses by photoelastic method during the coating deposition.Väitekirjas käsitletakse eksperimentaalsete meetodite väljatöötamist ja täiustamist jääkpingete ja deformatsioonide määramiseks pinnetes ja pindega detailides. Esitatakse üldine algoritm, mis võimaldab määrata jääkpinged kas pinde kasvamisel (pindamisel) või kahanemisel (eemaldamisel) aluse vabal pinnal või pinde liikuval pinnal mõõdetud deformatsiooniparameetrite järgi. On koostatud algoritmid jääkpingete määramiseks paksu mitmekihilise pindega mitmekihilistes ristkülikvarrastes, plaatides, silindrites ja kerades. Täpsustatakse algpingete arvutust sirge ribaaluse, ümartraatalause, õhukeseseinalise torualuse ja lahtise rõnga kujulise aluse deformatsiooniparameetrite järgi. Esitatakse õhukeseseinalise torualuse ja lahtise rõnga kujulise aluse deformatsiooniparameetirte mõõtmise meetodid algpingete määramiseks vastavalt galvaanilistes ja tampoongalvaanilistes pinnetes. Fotoelastsumeetodiga on kontrollitud jääkpingete jaotust sirge varrasaluse ühepoolses pindes. Termobimetallanaloogiat kasutades on näidatud, et ühepoolse pinde kasvamisel või kahanemisel paindub riba- või plaatalus sfääriliselt. Eksperimentaalselt on kontrollitud ühepoolse pindega kruvijoonelise ribaaluse puhta painde teooriat. On uuritud jääkpingeid paksudes galvaanilistes teraspinnetes.