Papers by Keyword: Redistribution

Abstract: Through the system reliability theory, the reliability of each subsystem of fully mechanized working face was got. The reliability of the working face was 0.82. By using the reliability of redistribution, the reliability of weak links of the system was improved to 0.966, so that the reliability of the working face was raised to 0.86. The reliability of the working face was enhanced and the mining production was stable.

Abstract: The machining deformations caused by the release and redistribution of original residual stresses were studied by the theoretical analysis and finite element method. The research results show that the release and redistribution of original residual stresses result in machining distortion of the plate part. There exists an optimal value of material removal amount according to original residual stresses. When the amount of the material removed exceeds the optimal value, the machining deformation can be controlled effectively.

Abstract: The paper presents results obtained during evaluation of dissimilar weld joints of creep-resistant steels. During high temperature exposure of dissimilar weld joints, alloying elements were redistributed across the weld interface. These diffusion effects can cause local changes of microstructure and have a direct effect on local mechanical properties in weld interface area. Carbon and nitrogen have the strongest influence on changes of mechanical properties of steels. . These local changes of mechanical properties have a strong influence on the reliability and the service live of the whole welded structures. The dissimilar joints of the austenitic steel/martenzitic steel type was studied. Laboratory weld joints were prepared and annealed at different temperatures for different time periods. Microhardness profiles across the weld interface were measured and the influence of long-term, high temperature exposure on the changes of local microhardness was evaluated. Results were compared with pseudo-binary phase diagrams and with the literature.

Abstract: In order to study the effect of the diffusers,there has been designed a variety of diffusers.If groove depth is large , the diffuser will become a high absorption coefficient, low-frequency sounds will reduce significantly. So we have spread the body size nested within each other, a small has been nested in a large body .The smaller parts expand of high-frequency sound, the larger parts for low-frequency sound, so over a wide frequency band can been spreading.

Abstract: The Diffusion and Solubility of B Implanted in δ-Ni₂Si and Nisi Layers Is Studied by SIMS. it Is Observed that both Diffusion and Solubility Are Higher in δ-Ni₂Si than Nisi. the Redistribution of B during Ni Silicidation Is Also Studied. the SIMS Profiles Show the Presence of Concentration Step in the Middle of the Final Nisi Layer. this Profile Shape Is Explained in Light of the Results Obtained in Preformed Silicides. the Proposed Model Is Supported by Redistribution Simulations that Can Reproduce the Main Features of the Profile.

Abstract: This paper is concerned with the deformation and the redistribution process of particles in SnO2/Ag particulate reinforced metal-matrix composites during micro-extrusion. The effects of the extrusion angle, the extrusion ratio and the ram speed on the deformation and redistribution of particles during the forming process were studied by finite element methods using Deform software. The deformation behavior and redistribution pattern are explained based on the non-uniform flow of the billet and the non-uniform stress distribution.

Abstract: The structural changes taking place in the dissimilar laboratory welds of 6CrMoV 8-3-2 (T25), being under development, and modified X12CrMoVNb 10-1 (P91) nitrided steels annealed at temperatures of 500 – 900 °C have been subject of study. Carbon and nitrogen redistribution measurement by the EPMA method was complemented with detailed structural analysis aimed at the phase profiles and chemical composition of coexisting carbides and carbonitrides in particular regions of the weld joint. Results of experimental work were compared with thermodynamic and kinetic modeling using the DICTRA software. A very good agreement between the modeling and the experiments was observed.

Abstract: In this paper three-dimensional welding simulations were carried out in FE software ANSYS in order to predict transient temperatures and the residual stresses in a three pass welded tubular joints. The thermal analysis and the moving heat source were verified with temperature measurements and the computed residual stresses were verified with hole drilling measurements. Then residual stress relaxation analyses were carried out on the tubular structure, with similar load cases as in earlier fatigue testing on the same tubular joint structures.

Abstract: Disastrous rock slope failures have been posing a hazard to people’s lives and causing enormous economic losses worldwide. Numerical simulation of rock slope failure can lead to improve the degree of understand of such phenomenon so as to predict and avoid the occurrence of these disastrous events. In order to simulate the global behaviors of rock slope failure under the high seepage pressure and the local behaviors of the occurrence of hydraulic fracture in the pre-existing rock joints effectively, a powerful finite element tools F-RFPA2D, is adopted. The simulation takes into account of the growth of existing fractures and the initiation of new fractures under various of hydraulic pressure in different heterogeneities medium. The behavior of fluid flow and damage evolution, and their coupling action are studied in small specimens that are subjected to both hydraulic and biaxial compressive loadings. The influence of the ratio (the initial horizontal stress to the initial vertical stress) and the distance between the two existing cracks on the fracture propagation behaviors are investigated. Moreover, based on the fundamental study of hydraulic fracture, the progressive failure of rock slope under the influence of the increase in hydraulic pressure was also studied in the paper.