Papers by Keyword: Stress Field

Abstract: In order to study the distribution of the stress field in the high-speed intermittent cutting process, finite element model of high-speed intermittent cutting is established. Exponential material model of the constitutive equation and adaptive grid technology are applied in the finite element analysis software AdvantEdge. The material processing is simulated under certain cutting conditions with FEM ( Finite Element Method ) and the distribution of cutting force, stress field, and temperature field are received. A periodic variation to the cutting force and temperature is showed in the simulation of high-speed intermittent cutting. Highest value of the milling temperature appears in front contacting area of the knife -the chip.and maximum stress occurs at the tip of tool or the vicinity of the main cutting edge. The analysis of stress and strain fields in-depth is of great significance to improve tool design and durability of tool.

Abstract: In this paper, micro-Raman characterizations and Finite element modeling (FEM) of microstructures (cantilever, bridge, planar rotating probe) realized on single-crystal (100) 3C-SiC/Si films are performed. Transverse optical (TO) Raman mode analysis reveals the stress relaxation on the free standing structure (796.5 cm-1) respect to the stressed unreleased region (795.7 cm-1). The TO Raman mode exhibits an intense shift, up to 2 cm-1, located on the undercut region, where the Silicon substrate starts to be released. Such effect is ascribed to the modification of the Raman stress tensor that makes the generalized axial regime, described by diagonal components of the Raman stress tensor, unsuitable to describe the stress status on this region. Raman maps analysis and FEM simulations show the “activation” of the shear stress, i.e. non-diagonal components of the stress tensor. The aim of future works will be to minimize the stress field generation and the defects density within the epitaxial layer.

Abstract: In this paper, a representative volume element (RVE) model of composites with different fiber volume fraction is established by ANSYS finite element software. The stiffness matrix of the RVE model can be calculated by studying its stress field, and then the elastic properties of composites could be obtained. By comparing with the results from NASA empirical equation, the reliability of the method can be proved. This is a new way to predict the elastic properties of composites.

Abstract: To precisely describe the fracture opening and extending during the process of refracturing, in this paper the actual mechanical characteristics of the reservoir before the refracturing has been considered, according to the principle of conservation of energy, the calculation model of the damage stress of the rock around the borehole before the refracturing has been established, and at the same time the calculation model of the fracture veer has been established , then the well A in Jilin Oilfield has been chosen to calculate and analyze, the calculation results demonstrate that the corrigendum between the actual results and the calculation results is 0.2%, which are very anastomosing.

Abstract: Shipboard service environment of solid rocket motor (SRM) was monitored. Based on the monitored temperature and vibration data, the effects of temperature and low frequency vibration load on the stress and strain of SRM were analyzed by ABAQUS. It was shown by the results that the stress and strain of gain fluctuated near the initial thermal stress and strain with the low frequency vibration load. It was also found that the variations in stress and strain of the bonding interface were larger than that of the slot.

Abstract: With the increasing integration of electronic products, the heat flux density is increasing. Research on the heat dissipation of the PCB attracts more attention. Temperature field of the electronic products always changes a lot, usually leading to a transient stress field in the PCB. Due to the transient temperature field and transient stress field, the PCB’s modal changed. In this paper, the temperature field and the stress field are obtained to explain the reason of the change. The influence on PCB’s modal caused by the temperature field and the stress field are analyzed, on the basis of PCB’s thermal modal analysis, which provide a reference for the PCB design and modal analysis in the future.

Abstract: The indirect coupled modeling of the metal base disrepair has been carried out by software ANSYS. Results show that diagonal tensile stress is the main factor of crack, crack easily take place in the lower surface, where obviously exist a region of stress concentration in 45°direction. It should make symmetrical and uniform distribution as much as possible

Abstract: Multi-parameter description of crack behavior in quasi-brittle materials offers still enough space for investigations. Several studies have been carried out by the authors in this field [1-3]. One part of the publications by the authors (this work included) contain analyses of the accuracy, convergence and/or tuning of the over-deterministic method that enables determination of the coefficients of the higher-order terms in Williams expansion approximating the stress and displacement fields in a cracked body without any complicated FE formulations. These intermediate studies should bring together a list of recommendations how to use the ODM as effectively as possible and obtain reliable enough values of coefficients of the higher-order terms. Thus, the stress/displacement field can be determined precisely even in a larger distance from the crack tip, which is crucial for assessment of the fracture occurring in quasi-brittle materials.

Abstract: Amending the normal stress over the slip surface based on the stress field by numerical analysis, applying the three-dimensional global limit equilibrium method to the stability analysis of tension-slackened rock mass in the right bank of Yagen hydropower station. Stability analysis shows that if do not take any measures, the loose rock mass stability can cater to the Specification demand, but some small sliders is in the limit state under the water and earthquake condition, if use the cutting slope and unloading scheme, the whole loose rock mass and the all small sliders can meet the Specification standard stability requirements.

Abstract: Boiler failure is the main power plant boiler operation fault. And boiler superheater tube is one of the important reasons for boiler failure, which affects the safe and stable operation of power generation equipment. Structure design and calculation of boiler superheater has important influence on performance and life of boiler, so three-dimensional structural model of boiler superheater is built in this paper. Based on the finite element method boiler superheater in temperature and stress coupled field are analyzed. The highest temperature, maximum stress, and distribution characteristics of stress and temperature couple field of boiler superheater including straight and elbow section are computed. The date on the actual operation of a power plant was used in the process of analysis. And thermal physics and mechanical properties of the boiler superheater tube were taken full consideration. It provides a reliable basis for reasonable design and safety evaluation of the boiler superheater.