5/19/2023 0 Comments Residual stressesBut when the changes of residual stresses during the contact rolling fatigue process are to be analyzed, it is clear that this antagonism rises only virtually because there exists a real tri-axial stress condition, which tolerates a two axial distressing of the material. The three dimensional materials distressing within the roller-bearing component on the one hand and the two dimensionally originating of the WEA on the other seem to be an antagonism. All these white etching areas, regarding their morphological structure and the etching conditions, are commonly originated by two axial distressing. Structural alterations of the rolling contact fatigue process are shown by means of metallography as followed: by dark etching areas (DEA), and by white etching areas (WEA) showing bands, which are positioned beneath the contact area at an angle of 30° (30°WEB) and for instance at 80° (80°WEB), and furthermore by so called butterfly structures (butterflies with “white etched” flanks). The progressive plastically deformations accompanying the growing fatigue procedure cause perpetually alterations in the distress- conditions of the material. These are superimposed to the operational -loading –stresses which change the distressing conditions of the material. During the fatigue period, the microstructure will be changed by micro- and macro- plastically deformation. The materials strengthening can be described by the hypothesis of alteration of shape. A HERTZian load stress will be accumulated over an elliptical contact area and within and beneath this contact area three dimensional stresses are acting. A lubricant film inhibits the metallic contact of the revolved bearing components. Following these conceptions simplifying quasi-static conditions are drawn. But by means of simplified considerations an approach to the rolling contact fatigue process can be obtained. Widely unknown is therefore, how the materials conditions are influenced by these processes. The loading cycle runs within extremely short rates and structural alterations occur under high hydrostatic pressure. Because the loading conditions during the elastic- hydro- dynamical contact are not clearly described. The mechanism can only be described by speculative considerations. Consequences of residual stresses: fatigue, crack propagation, damage, chemical reactivity, stress corrosion, physical properties of solids.Rolling contact fatigue is a very complex process.Residual stresses in devices, components and structures: distortion engineering, stress relaxation methods, MEMS, electronic devices, residual stresses in geological materials and structures, residual stresses in biological systems….Residual stresses, Internal stresses and microstructures: phase transformations, phase stresses, intergranular/intragranular stresses, dislocations…. Residual stresses in advanced materials: polymer based composites, metal and/or ceramic composites, glass and amorphous materials, functionally graded materials, nanocrystallised/nanostructured materials, thin films, coatings, multilayers….Residual stresses in manufacturing processes: heat treatments, surface treatments (mechanical, thermochemical…), casting, additive technologies, machining, cutting, coating technologies, welding and other assembling methods….Residual stress management and control: design, engineering, product life cycle management, stress monitoring, standards, quality control, metrological aspects.Modelling methods: at different scales (nano, micro, macroscales), multiscale modelling….Measurement methods: diffraction methods, line profile analysis, magnetic methods, acoustic methods, photomechanical methods, mechanical and micromechanical methods….Special attention is paid to method development and burning issues of great current interest, as, for example, stresses in nanosized systems, stress analysis using synchrotron radiation, multiscale approaches. The conference provides a key forum for scientists, students, and engineers interested in the prediction, evaluation, control, and application of residual stresses.Įqual emphasis is given to the measurement, modelling, and utilization of residual stress/strain data.īoth the scientific and engineering aspects of these topics, such as the influence of residual stress fields on distortion, material response to loading, damage initiation and propagation, component performance, life and failure, will be addressed.
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