Influence of Internal Defects of Basic Metal of the Equipment on Its Operational Properties

The paper deals with the issue of safe operation of technological equipment with a defect in the base metal of the delamination type. Mathematical modeling of the stress-strain state in the defect zone by the finite element method in ANSYS software package is carried out. The article presents and analyzes the obtained graphs of the distribution of stress intensity factors. Based on the analysis of the obtained dependences, it is shown that stratification of the base metal does not have a significant effect on the performance of the process equipment.

Numerical Simulation of Mechanical Characteristics of Roadway Surrounding Rock under Dynamic and Static Loading

Mechanical characteristics of roadway surrounding rock under different stress wave disturbances are the key to design roadway supporting scheme. In this study, the 2802 transportation roadway in Zhangcun Coal Mine is selected as the engineering background. The distribution of stress, displacement, and plastic zone in surrounding rock under the impact of different stress waves is studied. Results show that the stress and displacement of the roof, floor, and coal walls present fluctuating change with time during the stress wave loading process. With the increase of disturbing intensity of stress wave, the resistance ability for stress wave disturbance of the roof is lower than that of the floor, while the resistance ability of two sides is the same. The volume of plastic zone in roadway surrounding rock was calculated by the self-compiled FISH code. The relationship between the plastic zone volume and the stress wave disturbing intensity in different states is explored. The cubic polynomial relationship between the volume and the disturbing intensity in the state of shear_past and tension_past is obtained. Under the simulated condition, the disturbing intensity of stress wave has the greatest influence on the increase of shear_past volume when it equals 11 MPa. While the disturbing intensity of stress wave has the greatest influence on the increase of tension_past volume, it equals 7 MPa. Meanwhile, the relation between stress wave disturbing intensity and surrounding rock stress and displacement is obtained respectively. The achievements provide a theoretical base for roadway surrounding rock support under dynamic and static loading.

About biological hip joint prostheses and the biomechanical behavior of implanted femur

Biofidel femur Models with finite elements were developed using a specific segmentation combination with computed tomography and solid modeling tools capable of representing bone physiology and structural behavior. These biofidel Finite Element Models (FEM) are used to evaluate the change in the physiological distribution of stress in the prosthesis femur and to evaluate the new design criteria for biopsy biopsy biopsy biopsy. The proposed belief patterns allowed us to adequately take into account the non-isotropic features of the proximal femoral epiphysis and isotropic behavior in diaphysis to explain the critical changes in stress distribution in a femur resected after the implantation of a traditional articular prosthesis. It has been shown that a wide range of femoral diaphyses is completely protected by rigid prostheses that significantly alter the physiological distribution of stress, which should guarantee healthy growth and bone regeneration.

Finite Element Method for Ship Composite-Based on Aluminum

The structure and construction of ships made of aluminum alloy, generally of the type of wrought aluminum alloy, when experiencing fatigue failure caused by cracking of the ship structure, is a serious problem. Judging from the ‘weaknesses’ of aluminum material for ships, this chapter will explain the use of alternative materials for ship building, namely aluminum-based composite material which is an aluminum alloy AlSi10Mg (b) ship building material based on the European Nation (EN) Aluminum Casting (AC) - 43,100, with silicon carbide (SiC) reinforcement which has been treated with an optimum composition of 15%, so that the composite material is written with EN AC-43100 (AlSi10Mg (b) + SiC * / 15p. Composite ship model using ANSYS (ANalysis SYStem) software to determine the distribution of stress. The overall result of the voltage distribution has a value that does not exceed the allowable stress (sigma 0.2) and has a factor of safety above the minimum allowable limit, so it is safe to use. The reduction in plate thickness on the EN AC-43100 (AlSi10Mg (b)) + SiC * /15p composite vessel is significant enough to reduce the ship’s weight, so it will increase the speed of the ship.

Study on Counter-Roller Spinning Technology of Large Diameter Aluminum Alloy Cylindrical Parts

Counter-roller spinning is an optimal process for forming large diameter cylindrical parts. In this paper, the finite element model of large diameter aluminum alloy cylindrical parts Counter-roller spinning is established, the regularities of distribution of stress and strain of each pass of the workpiece is obtained, as well as the influence of the roller feed ratio and fillet radius on the forming quality is obtained. The process parameters were optimized by grey correlation analysis. In this paper, for large diameter aluminum alloy cylindrical parts, the optimal spinning parameters are obtained as follows: the feed ratio is 1.0mm/r, the rotary roller fillet radius is 8mm. The results of numerical simulation are consistent with those of process test. The technological parameters can be used to guide the actual production of such large diameter cylindrical parts.

Kinematic and dynamic analysis and distribution of stress for seven-item mechanism by means of the SolidWorks program

This paper presents a kinematic and dynamic analysis and distribution of the stress for seven-item planar mechanism by means of the SolidWorks software. The authors of the introduced paper deal with the kinematic analysis of planar mechanisms as well as with the implementation of the vector method into the SolidWorks software program in order to determine the kinematic variables (quantities) of the individual bodies in the whole complex system. The dynamic analysis is performed on the basis of the kinematic analysis. Dynamic analysis allows us to design a system of bodies correctly and it is with the respect to the dynamic loading. For the interpretation of the introduced analysis, the seven-item planar mechanism was selected. Graphic dependence of kinematic and dynamic magnitudes of some points is given in dependence on the angle of rotation of the driving item and in dependence on time. In relation to the kinematic and dynamic analysis and subsequent simulation of the planar as well as spatial mechanisms, it is perfect solution to use SolidWorks software program. The considerable advantage of this mentioned program is based on its simplicity from the aspect of modeling and moreover, it is important to point out that utilisation of the mentioned program leads to results which are precise and accurate in the case of the numerical solution of the equations in the whole magnitude referring to motion of mechanism while the given results are obtained in the graphic form.

Kinematic and dynamic analysis and distribution of stress for six-item mechanism by means of the SolidWorks program

This paper presents a kinematic and dynamic analysis and distribution of the stress for six-item planar mechanism by means of the SolidWorks software. The main purpose of the investigation is connected with the kinematic analysis of planar mechanisms as well as with the implementation of the vector method into the SolidWorks software program in order to determine the kinematic variables of the individual bodies in the whole investigated system. The process of the dynamic analysis is based on the kinematic analysis. The dynamic analysis makes possible to design a system of bodies correctly and it is with the respect to the dynamic loading. For the interpretation of the introduced analysis, the six-item planar mechanism was used as example (representative). Graphic dependence of kinematic and dynamic magnitudes of some points is given in dependence on the angle of rotation of the driving item and in dependence on time. In relation to the kinematic and dynamic analysis and subsequent simulation of the planar as well as spatial mechanisms, it is great solution to use SolidWorks software program. The considerable advantage of this mentioned program is based on its simplicity from the aspect of modeling and moreover, it is important to point out that utilisation of the mentioned program leads to results which are precise and accurate in the case of the numerical solution of the equations in the whole magnitude referring to motion of mechanism while the given results are obtained in the graphic form.

Analytical Limit Load Procedure for The Axial Complex Shaped Defect in a Pressurized Pipe

The paper is devoted to elaboration of the analytical O-procedure for limit load analysis of complex shaped axial defect in a pressurized pipe. It is based on the classical lower bound theorem of the theory of plasticity, and consists in construction of the statically admissible solution, where distribution of stress satisfies to the equilibrium equations and strength conditions. O-procedure is an optimization process to get the most favorable stress distribution for providing the maximal pressure. It allows to explicitly account for the variable geometrical and physical parameters. Contrary to other approaches, the derived formula for rectangular defect is only a particular case of the general procedure application. Four different methods for the complex defects are compared. They are: first, ASME, A-, rectangular defect formula combined with RSTRENG, R-, procedure, i.e., A-R approach; second, PCORRC, P-, formula with R-procedure, P-R approach; third, Orynyak's, O-, formula with R-procedure, O-R approach; and fourth, our universal O-procedure. The verification begins for rectangular defects where both theoretical and experimental comparison is performed for A-, P-, and O- formulas. The difference between them is small, provided that all three employ the same characteristic of material, here the ultimate strength. Then theoretical comparison for A-R, P-R, O-R approaches and O-procedure is performed for the artificial complex defects, for two symmetrical rectangular defects, for triangular defect. Experimental comparison between four methods is made based on the well-known University of Waterloo full scale tests.

Experimental Centrifuge Study of the Effects of Valley Topography on the Behavior of a Concrete Face Rockfill Dam

The recent focus on water conservancy projects globally has resulted in the construction of increased numbers of concrete face rockfill dams in narrow valleys. However, valley topography impacts the deformation of a dam and further influences the distribution of stress and position of cracks on the face slab. This study conducted two centrifuge experiments to study the influence of the valley topography on the behavior of a concrete face rockfill dam from construction to impoundment. Experimental models of concrete face slab sand-gravel dams with “U”-type and “V”-type valley topographies were established. The settlement of the dam crest, the displacement of the upstream slope of the dam, and the stress on both sides of the face slab were observed. The experiment also represented the cracking of the face slab during impoundment. The results showed that the “V”-type valley topography effectively reduced the progression of dam crest settlement and influenced stress on the slab resulting from impounded water pressure. Furthermore, the flexural form of the face slab in the “U”-type valley topography took on a “D” shape and cracks progressively developed on the face slab with increased water load. The flexural form of the face slab in the “V”-type valley topography showed a “B” shape, and cracks occurred under a particular water impoundment pressure.

Identification for Abutment Stress by Drilling Cuttings

The concentration of abutment pressure acting on coal seams induced by mining is a key factor to trigger rock burst. Understanding of abutment pressure or stress concentration is fundamental in preventing and controlling rock burst. The influence on abutment pressure fluctuation caused by the inhomogeneity of coal seams needs to be considered, but it is difficult to obtain by the present usual ways such as acoustic transmission, electromagnetic wave transmission, etc. In this article, the relationship between the amount of cuttings drilled in a coal seam and stress level was analyzed by considering the effect of drilling cutting expansion, and the drilling cutting test was carried out in Xinglongzhuang Coal Mine, Shandong Energy Ltd. It is found that the amount of cuttings drilled is positively related to the degree of stress concentration in both the plastic fracture zone and elastic zone. The amount of drilling cuttings is closely related to the roof weighting. In addition, the irregular fluctuation of drilling cuttings is an approximate map of distribution of stress concentration because of the non-uniformity of cracks and other defects in the coal seam. In order to meet the need of rock burst prevention by accurate pressure relief in high-stress zones, enough boreholes are needed.