Papers by Keyword: Stress Distribution

Abstract: Extensive research on X80 pipeline steel has been conducted, while there is little research on X60 pipeline steel. In this study, FEM (Finite Element Method) on the double defect pipeline model of the outer and inner walls is conducted using ANSYS Workbench software. The research object is the X60 pipeline with rectangular double corrosion defect. Firstly, the stress distribution is examined; Secondly, by changing the geometric factors of the double defects on the outer and inner walls, the influence law on the failure pressure is examined; Finally, based on the FEM results, the failure pressure calculation formula for X60 pipeline with double corrosion defects on the outer and inner walls was fitted by MATLAB software, and whether the fitting formula was accurate and applicable was examined. The stress cloud map of double defect pipeline has two areas: The area near the defect and that far away from the defect, with the former belonging to the danger zone and the latter belonging to the safe zone, Specific to the double defect pipeline model with inner and outer walls, the failure pressure presents a sharp reduction as the defect depth elevates, and its impact on the failure pressure becomes increasingly significant with the narrowing axial distance between the two defects; the increasing defect length increases is related to decreasing failure pressure. In line with the significantly increased defect length, its impact on pipeline failure pressure gradually weakens; the width variation of double defect impacts pipeline failure pressure very slightly; The MATLAB fitting formula possesses a high fitting degree, and the FEM calculation data is basically distributed on the fitting curve, which can better fit the curve of the limit load variation law; The inner wall double defect model performs better in pressure ratio and error analysis. The conclusions drawn have specific reference significance for the safety assessment of oil and gas pipelines.

Abstract: The adhesive lap joints are extensively used in various engineering fields. Various methods were proposed to increase the strength of the lap joint. This paper presents the lap joint's characterization by applying three grades of adhesives in different material properties along the bond line. The stiffest adhesive is employed in the middle bond line, then gradually, those with a lower modulus of elasticity are placed at the ends of the lap joint. This technique reduces the stress concentration at the joining ends, so the stress distribution becomes smoother. Finite element analysis is used to model this problem in two dimensions. One of the adherent edges is applied to the fixed support, and the other end is subjected to tension. The analysis results show that the use of tri-adhesive changes the shear stress distribution along the bond line flatter and increases the strength of tri-adhesive lap joints compared to those single type adhesive applied individually.

Abstract: In the present study, A functionally graded cylinder subjected to internal pressure has been analyzed using the finite element method based software ANSYS. The variations of properties of the functionally graded material are considered based on a power-law function. The inner and outer surfaces of the cylinder are made of alumina and C45 steel respectively. The continuous composition of the two materials has been considered in the form of varying elastic modulus and Poisson’s ratio along the radial direction as the power-law function. The result of present approach is compared with analytical result of available literature. The comparison represents good coincidence between analytical and numerical results and confirms the accuracy of solutions presented in the present approach for cylinder made up of FGM. Further the stress distribution of FGM made cylindrical shell for given pressure load conditions have analyzed. Stress distributions along the radial direction are studied. The obtained result shows that the property of FGMs has a significant influence to the deformation and stress distribution along the radial direction. Numerical results presented are useful for engineer to design a cylinder made of FGMs

Abstract: This work emphasize on utilization of fly ash in to novel aluminium alloy (Al-2024). The Al-2024 alloy and composites (≈10%flyash) prepared by stir casting technique. The composites is cold forged and identified properties (mechanical, structural and stress distribution in component). Upset tests at room temperature, during the deformation process, provide representative behaviour. The metallographic structure of alloy revelled dendritic and composites shows fine spherical prime segment split and regularly dispersed intermetallic compounds. The stress intensity and distribution of temperature were examined in depth at different input combinations. Compression tests were conducted on Ø 12 mm cylindrical specimens at an H/D ratio of 1.0 and 1.5 for alloy and fly ash composites (2, 6 and 10 wt %). In determining the forging load, the upset ratio defined as the mainly important factor. The strain in composites increased with increasing % of reduction in size and decreased with % of fly ash.

Abstract: The design of an implant thread plays a fundamental role in the osseointegration process, particularly in low-density bone. It has been postulated that design features that maximize the surface area available for contact may improve mechanical anchorage and stability in cancellous bone. The primary stability of a dental implant is determined by the mechanical engagement between the implant and bone at the time of implant insertion. The contact area of implant-bone interfaces and the concentrated stresses on the marginal bones are principal concerns of implant designers. Numerous factors influence load transfer at the bone-implant interface, for example, the type of loading, surface structure, amount of surrounding bone, material properties of the implant and implant design. The purpose of this study was to investigate the effects of the impact two different projectile of implant threads on stress distribution in the jawbone using three-dimensional finite element analysis.

Abstract: Friction stir spot welding process is a solid state joining process which has attracted great attention due to its ability to join low melting point light weight alloys such as aluminium and magnesium with high efficiency. In order to understand the complex thermo-mechanical joining process involved with friction stir spot welding, a numerical simulation study was done using ABAQUS finite element software. The simulation primarily aims to interpret the effect of a set of process parameters and tool geometry on the workpiece plates. Johnson-Cook damage criteria model was used to obtain the stress and strain distribution on the workpiece consisting of aluminium 6061 and magnesium AZ-31B placed in a lap configuration. Temperature distribution of the workpiece was obtained by simulating a penalty based frictional contact between the tool and the plate. The thermal results showed that the maximum temperatures attained were significantly lower than the melting points of the base materials indicating that the material mixing and joining occurred as a result of superplastic deformation process instead of melting. Change in material flow behaviour was also observed by the model as pin and shoulder geometries changed.

Abstract: In this work various methods of glass plate hardening are considered. These plates are used to protect defense devices. As a glass was used system R₂O-B₂O₃-SiO₂. The method of thermal hardening was considered. Technological disadvantages of this method were discovered by analyzing Newton's rings and a polarizing plate. The use of chemical hardening has shown its advantages over the thermal method. The essence of the method is the ion exchange of alkali metals between glass plates and the chemical mixture melt. The operating principle of the chemical hardening equipment and its technology were considered. As a result, hardened glass plates with preservation of planar geometry were obtained.

Abstract: The ultrasonic mold was designed for the ceramic powder compression. CAD and CAE were used in the design to analyze the mold strength and its natural frequency. The study of stress distribution and compression in upper and lower punch, mold body and waveguide comparison of stresses was analyzed by FEA experiments under maximum compression at 50,000 N to validate the results of both methods and the mold natural frequency. The difference between FEA and experimental analysis was 3-7%, acceptable. The redesign results in a cylindrical mold body with the outer diameter of 80 mm, the height of 100 mm, and the upper punch of 125 mm in length. The six sides are 26 mm of the high waveguide with 100 mm height. The internal and external diameters are 80 and 110 mm, respectively. The mold has been redesigned and can support the maximum compression force of 1,500 kN. with the bearing steel, AISI 52100, obtainable hardness 65 HRC, the stress concentration occurs at the neck of the upper punch using the ultrasonic at 12.00 to 12.45 kHz.

Abstract: Advanced materials such as aluminum alloys and composites offer great potential for weight reduction applications in automotive and aerospace vehicles construction. In order to investigate the feasibility of using such materials in the form of laminates, sheet bulging with single-layer aluminum and the aluminum/Composite laminate with the carbon cloth as the middle layer is investigated under uniform liquid pressure conditions. The aluminum sheet stress-strain, wall thickness distribution, carbon fiber radius stress-strain distribution and the effect of die entrance radius etc. are discussed and compared in details. FE results validate that the numerical method can predict the same fracture regions for bulging-blank as observed in experimental tests. Furthermore, the study validates that multi-layer sheet hydro-bulging process with composite fiber as a middle layer is not feasible to form laminates due to rupture of composite fibers near edge regions. Further study is needed to improve the methodology.

Abstract: In this paper the authors present the results of a study of plasticity and deformation resistance of the number of structural steels at temperatures of hot rolling. The patterns of changes in the studied characteristics of steels in the range of rolling temperatures are determined. In order to improve the quality of rolled products, we developed and substantiated recommendations for optimizing temperature of rolling ingot of the studied steels. The proposed recommendations have been verified by computer simulation of rolling high billets in flat rolls after heating up to 1100 and 1200 °C. For example, we showed the distribution of strains and stresses throughout the volume of the rolled product from steel grade 38KhS (State Standard GOST 4543-71).