Papers by Keyword: Stress Deformation

Abstract: With the aim of enhancing the precision and quality of turning processes, this study investigated cutting stress and thermal deformation induced by friction between the tool and chip of a Wolfram carbide (WC) tool cutting AISI-1045 carbon steel. Analysis of cutting stress and thermal deformation using COMSOL Multiphysics software is useful for evaluating the compensation for machining errors and reducing tool wear. Three cutting loads were adopted for the simulation of the thermal conduction, and changes in temperature and the stress field. Simulation results show that thermal deformation in the tool tip is proportional to cutting speed and time. As long as the temperature of the tool remains below the quasi-steady-state temperature, the amount of deformation does not change significantly. An understanding of the thermo-mechanical coupling effect during turning can help to improve the accuracy of compensation for thermal deformation in turning tools.

Abstract: Taking a new subway going through under the existing subway station as the engineering background, based on geological exploration data in the field, the deformation influence for the station structure of the existing subway when the main structure station constructs could be studied. It constructed a three dimensional calculation model by Ansys software to simulate the transverse and vertical deformation and the stress variation of new building line station's main structure, Through the analysis of the results,it put forward the predictive analysis to control the risk. To ensure the safety in construction process through adjust the construction scheme timely. It provided the corresponding reference for the such subway building project.

Abstract: The three-dimentional finite element analysis is adopted to simulate and cauculate the stresses and deformations of a certain core rockfill dam on narrow velley, with Duncan-Chang E-ν model during its completion and operation periods by incremental loading. The results show that the stresses and deformations of core rockfill dam on narrow velley are allowble and the design proposal is reasonable, which provides the theoretical basis for similar engineering.

Abstract: The cement-base composite formwork reinforced by FRP is developed to act as permanent construction formwork. Considering such properties as the minor stiffness out of the plain and the smaller bending resistance of the formwork, the matched cross support device is designed which can be recycled. In this paper, components of the support device and the corresponding functions are introduced, the technological process is described. By means of finite element program, the appropriate support distances of formwork during concrete placement are calculated, the stress and deformation performances are also analyzed. In the end, economic benefit and environment efficiency of the permanent formwork system are discussed. The above research results indicate the feasibility and economy of the support system, which present a gist for investigation and application of the permanent FRP cement composite formwork.

Abstract: This paper describes the calculation analysis of joint open, and the research has been carried up on Portland cement concrete pavement and rubberized concrete pavement with the consideration of hogging distortion caused by temperature, expansion deformation and drying shrinkage. Finally ,it were observed that joint open of 6m contraction joint spacing for rubberized concrete pavement is the same as 4.5m contraction joint spacing for Portland cement concrete pavement. The above analysis provides the possibility of 6-meter contraction joint spacing for rubberized concrete pavement which give theoretical basis for engineering application.

Abstract: Many thin-walled aero-parts have complex structure, and high machining accuracy is required. But because of their poor rigidity, it is easy to bring machining deformation caused by the existence of the clamping residual stress, and influences machining accuracy of workpiece. At the present time it is a focal point how to reduce the deformation the machined surface. Present studies mainly focus on the influences of clamping points, clamping order and clamping force on residual stresses. It is few studied for clamping schemes how to influence the residual stresses and the fatigue resistance of the machined parts. To reflect the relationship between clamping schemes and residual stresses and fatigue resistance, finite element models with different clamping schemes were built and the clamping process was simulated. A conclusion is obtained that it is advisable to adopt even and symmetry distributed clamps and multi-point clamps to reduce the workpiece distortion of aero-multi-frame components due to the clamping. This study conclusion has been validated by the actual production.

Abstract: The behaviour of the core of rockfill dam with slanting clay core was investigated with the Jebba main dam, Nigeria as a case study. The stress-deformation behavior of the dam was studied using the finite element mathematical modeling technique. The actual fill properties were utilized and two loading scenarios-no water and full reservoir operations-were investigated. At full reservoir, the actual seepage line, as recorded over the years was used. The linear total stress analysis using the finite element method of analysis was employed to analyze the dam section. Following the finite element mathematical modeling and computer simulations of the models, deformations and stresses distributions were determined. The results showed that the observed longitudinal cracks at the Jebba main dam crest are as a result of potential cracks in the dam core section. The cracks observed at the crest, from analysis, commenced from the dam’s core upstream face, downstream face and core crest. This may have resulted from probable hydraulic fracturing and tensile stresses developments in these regions. The results also showed likely loss of integrity of core due to cracks. However, total collapse may not be experienced but dam performance may be impaired and alarming visible cracks may not be ruled out over time.