scholarly journals Numerical Simulation and Experimental Confirmation of a Bimetallic Pipe Forming Process

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3561
Author(s):  
Zhiqiang Dong ◽  
Zhenzhen Xu ◽  
Wenke Wang ◽  
Zongyue Bi ◽  
Jianxun Zhang
Keyword(s):  
Stress Distribution ◽  
Three Dimensional ◽  
Good Choice ◽  
Image Correlation ◽  
Residual Tensile Stress ◽  
Three Dimensional Model ◽  
Forming Process ◽  
Corrosion Failure ◽  
Cold Forming ◽  
Bimetallic Pipe

Most oil and gas is transported by pipeline, and corrosion causes a great threat to the service life of the pipeline; bimetallic pipe, which combines the advantages of good mechanical properties, good corrosion resistance, and relatively low price, is a good choice for high-pressure and corrosion-resistant pipe, but its manufacturing process and stress distribution are more complex than single metal pipe. JCO is a widely used cold forming method for pipes which is named by the shape of the plate in the forming process, i.e. J-shape, C-shape and O-shape, and the forming process is an important parameter that determines the level of imperfections and residual stresses in a pipe, and residual tensile stress will accelerate corrosion failure of the pipe. In this study, the three-dimensional (3D) finite element method (FEM) is used to simulate the pre-bending and JCO forming process of a 2205/X65 bimetallic pipe. The model and the simulated results are validated by digital image correlation (DIC) experimental and the opening width of the formed pipe billet, respectively. The influence factors of the stresses are studied. Further, a two-dimensional (2D) model is established to study the characteristics of bimetallic plate bending and the stress distribution at the interface of different materials, and the results are compared with that of three-dimensional model.

Numerical and experimental analysis on cold-forming and spring-back of hull plate

2018 ◽  
Vol 233 (3) ◽  
pp. 561-569 ◽  
Author(s):  
Wei Shen ◽  
Renjun Yan ◽  
Shuangying Li
Keyword(s):  
Three Dimensional ◽  
Dimensional Accuracy ◽  
Ship Hull ◽  
Laser Forming ◽  
Successive Approximation Method ◽  
Spring Back ◽  
Forming Process ◽  
Cold Forming ◽  
Thick Plates ◽  
Forming Mechanism

Ship hull structures are fabricated by curved thick plates before they are welded together. There are traditional methods such as, line heating and laser-forming methods for plate bending. However, it is recognized that the hot-forming technology causes a series of troubles on doubly or multiple curved plates. Multi-point forming mechanism with square press heads is a new forming process for three-dimensional ship hull plate. Cold-forming has a high dimensional accuracy but results in spring-back. The spring-back process of curved thick plates in the finite element method is analyzed and the predicted results are compared with the test results in the present paper. To ensure the forming precision, the successive approximation method is also developed and verified to control the spring-back.

scholarly journals Stress analysis of a second stage gas turbine blade under asymmetric thermal gradient

2019 ◽  
Vol 20 (6) ◽  
pp. 607
Author(s):  
Javad Rahimi ◽  
Esmaeil Poursaeidi ◽  
Ehsan Khavasi
Keyword(s):  
Stress Distribution ◽  
Turbine Blade ◽  
Three Dimensional ◽  
Element Model ◽  
The State ◽  
Three Dimensional Model ◽  
Cooling Mode ◽  
Cooling Channels ◽  
Second Stage ◽  
Main Factor

In this study the main causes of the failure of a GE-F9 second stage turbine blade were investigated. The stress distribution of the blade which has 6 cooling vents in three modes (with full cooling, closure of half of the cooling channels, and without cooling) was studied. A three dimensional model of the blade was built and the fluid flow on the blade was studied using the FVM method. The stress distribution due to centrifugal forces applied to the blade, temperature gradients and aerodynamic forces on the blade surface was calculated by the finite element model. The results show that the highest temperature gradient and as a result the highest stress value occurs for the semi-cooling state at the areas near the blade root and this status is true for the full cooling mode for the regions far from the root. However, the field observations showed that the failure occurred for the blade with the semi-cooling state (due to closure of some of the channels) at areas far from the root. It is discussed that the main factor of the failure is not the stress values being maximum because in the state of full cooling mode (the state with the maximum stress values) the temperature of the blade is the lowest state and as a result the material properties of the blade show a better resistance to phenomena like hot corrosion and creep.

Influence of the TMJ Implant Geometry on Stress Distribution

2012 ◽  
Vol 488-489 ◽  
pp. 991-995 ◽  
Author(s):  
Zohreh Arabshahi ◽  
Jamal Kashani ◽  
Mohammed Rafiq Abdul Kadir ◽  
Abbas Azari
Keyword(s):  
Stress Distribution ◽  
Temporomandibular Joint ◽  
Contact Surface ◽  
Equivalent Stress ◽  
Three Dimensional ◽  
Surface Region ◽  
Implant Design ◽  
Three Dimensional Model ◽  
Element Analysis ◽  
Applied Loading

The purpose of this study was to investigate the influence of Temporomandibular Joint implant geometry on stress distribution in total reconstruction of temporomandibular joint. A three dimensional model of a lower jaw of a patient was developed from a Computed Tomography scan images. Anatomical curvature and flat contact surface of implant design and fixation screws were modeled. Two implanted mandibles were then compared by means of finite element analysis. The muscle forces for incisal clenching were applied. The equivalent stress resulted in contact surface region of the bone and implant and in fixation screw holes were investigated to evaluate the designs. In applied loading condition, The results showed that anatomical design of implant was more preferred and it will lead to long-term success of implant.

A Three Dimensional Finite Element of Anterior Cruciate Ligament Model

2012 ◽  
Vol 626 ◽  
pp. 896-901
Author(s):  
A.H. Alafiah ◽  
M. Normahira ◽  
M.N. Anas
Keyword(s):  
Finite Element ◽  
Anterior Cruciate Ligament ◽  
Stress Distribution ◽  
Contact Pressure ◽  
Cruciate Ligament ◽  
Three Dimensional ◽  
Three Dimensional Model ◽  
Knee Ligament ◽  
Suitable Material ◽  
Anterior Cruciate

Anterior Cruciate Ligament (ACL) is of the major knee ligament. A three dimensional model that reflects the geometric characteristics of the human ACL developed to explore and analyze finite element parameters such as contact pressure and stress distribution on ACL in response to complex loading conditions. Moreover, various cases studied such as cases involving and uninvolving ligament in order to obtain and analyze the stress and contact pressure relationship between ACL, meniscus and cartilage. It is known that the contact and friction caused by the ACL wrapping around the bone during knee motion played the role of transferring the force from the ACL to the bone, and had a direct effect on the stress distribution of the ACL. Thus, the project lead to better understand the mechanism of injury, to improve the design of ACL reconstruction using suitable material and optimizing rehabilitation protocols by investigation of contact pressure with and without ACL.

scholarly journals Comparative analysis of stress distribution in one-piece and two-piece implants with narrow and extra-narrow diameters: A finite element study

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0245800
Author(s):  
Fabricia Teixeira Barbosa ◽  
Luiz Carlos Silveira Zanatta ◽  
Edélcio de Souza Rendohl ◽  
Sergio Alexandre Gehrke
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Three Dimensional ◽  
In Vitro Study ◽  
Von Mises Stress ◽  
Axial Loads ◽  
Three Dimensional Model ◽  
The One ◽  
Von Mises

Objectives The aim of this in vitro study was to evaluate the stress distribution on three implant models with narrow and extra-narrow diameters using the finite element method (FEA). Materials and methods Dental implants of extra-narrow diameter of 2.5 mm for a one-piece implant (group G1), a narrow diameter of 3.0 mm for a one-piece implant (group G2) and a narrow diameter of 3.5 mm for a two-piece implant with a Morse taper connection (group G3). A three-dimensional model was designed with cortical and cancellous bone, a crown and an implant/abutment set of each group. Axial and angled (30°) loads of 150 N was applied. The equivalent von Mises stress was used for the implants and peri-implant bone plus the Mohr-Coulomb analysis to confirm the data of the peri-implant bone. Results In the axial load, the maximum stress value of the cortical bone for the group G1 was 22.35% higher than that the group G2 and 321.23% than the group G3. Whereas in angled load, the groups G1 and G2 showing a similar value (# 3.5%) and a highest difference for the group G3 (391.8%). In the implant structure, the group G1 showed a value of 2188MPa, 93.6% higher than the limit. Conclusions The results of this study show that the extra-narrow one-piece implant should be used with great caution, especially in areas of non-axial loads, whereas the one- and two-piece narrow-diameter implants show adequate behavior in both directions of the applied load.

scholarly journals A Finite Element Analysis to Compare Stress Distribution on Extra-Short Implants with Two Different Internal Connections

2019 ◽  
Vol 8 (8) ◽  
pp. 1103 ◽  
Author(s):  
García-Braz ◽  
Prados-Privado ◽  
Zanatta ◽  
Calvo-Guirado ◽  
Prados-Frutos ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Axial Load ◽  
Three Dimensional ◽  
Dimensional Model ◽  
Stress Concentrations ◽  
Three Dimensional Model ◽  
Element Analysis ◽  
Short Implants

Background: The goal of this study was to analyze the stress distribution on two types of extra-short dental implants with 5 mm of length: An internal hexagon (IH) and morse taper connection (MT). Methods: The three-dimensional model was composed of trabecular and cortical bone, a crown, an extra-short dental implant and their components. An axial load of 150 N was applied and another inclined 30° with the same magnitude. Results: Stress concentrations on the IH implant are observed in the region of the first threads for the screw. However, in the MT implant the highest stress occurs at the edges of the upper implant platform. Conclusions: In view of the results obtained in this study the two types of prosthetic fittings present a good stress distribution. The Morse taper connections presented better behavior than the internal in both loading configurations.

Nonlinear Finite Element Analysis of Spring-Back Characteristics in the Cold-Forming Process of Three-Dimensionally Curved Thick Metal Plates

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Jeom Kee Paik ◽  
Jeong Hwan Kim ◽  
Bong Ju Kim ◽  
Chang Hyo Tak
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Steel Plates ◽  
Research Centre ◽  
Spring Back ◽  
Forming Process ◽  
Element Analysis ◽  
Cold Forming ◽  
Metal Plates ◽  
National University

The present paper is part of the study to develop the advanced computer aided manufacture (CAM) system called the changeable die system (CDS) that applies the cold-forming technique to produce curved thick metal plates with complex, three-dimensional geometry [Paik et al., 2009, “Development of the Changeable Die System for the Cold-Forming of Three-Dimensionally Curved Metal Plates,” The Lloyd's Register Educational Trust Research Centre of Excellence, Pusan National University, Korea]. This paper focuses on the procedure of predicting the spring-back characteristics using elastic-plastic large deflection finite element method, which is a key technical element within the framework of the CDS process. The validity of the procedure is confirmed by comparison with experimental results obtained by the CDS machine in the cold-forming process of curved steel plates.

Numerical and Experimental Analysis for Large Radius Deformation of Stainless Steels by Laser Forming Process

2005 ◽  
Author(s):  
J. Pennuto ◽  
J. Choi
Keyword(s):  
Experimental Data ◽  
Phase Transformation ◽  
Experimental Testing ◽  
Three Dimensional ◽  
Laser Forming ◽  
Bend Angle ◽  
Large Radius ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Forming Process

In an effort to develop a process free of dedicated tooling, this research seeks to study large radius deformation by laser forming. Experimental testing was conducted to determine how the laser parameters affect the single pass output bend angle as well as the additive bend angle from successive parallel, evenly spaced laser irradiations. As an extension of the previous developments, this work seeks to develop a three-dimensional model to simulate the multi-scan laser process. It is of interest to determine how sophisticated a three-dimensional case is required for sufficient agreement to experimental data. The simulated results of bending angle are compared with experimental data and suggestions for future study include the implementation of phase transformation and microstructure data within the model to account for stress development resulting from phase transformation and grain growth.

scholarly journals Stress Distribution of CF/EP Laminated Composites under Supercritical Conditions

2015 ◽  
Vol 2015 ◽  
pp. 1-8
Author(s):  
Haihong Huang ◽  
Zhenwen Li ◽  
Huanbo Cheng ◽  
Yanzhen Yin
Keyword(s):  
Shear Stress ◽  
Stress Distribution ◽  
Maximum Shear Stress ◽  
Three Dimensional ◽  
Transfer Model ◽  
Three Dimensional Model ◽  
Interfacial Layers ◽  
Temperature And Pressure ◽  
Carbon Fiber Epoxy ◽  
Supercritical Temperature

Enormous amounts of wastes have been produced due to extensive use of carbon fiber/epoxy resin (CF/EP) composites. The fact that the supercritical fluid can be used to recycle these composites efficiently has attracted widespread concerns. A three-dimensional model of CF/EP laminates considering the interfacial layers was established. The internal stress distribution of laminates was simulated based on a heat transfer model; and the change of shear stress with supercritical temperature and pressure was investigated. The results show that the shear stress concentration was located in the interfacial layers; the maximum shear stress can be expressed by a curve of convex parabola to the temperature; and the most serious damage occurred in interfacial layers when temperature approached the glass-transition temperature of resin.

Numerical Investigation on Laser-Assisted Flow Forming Process

2014 ◽  
Vol 620 ◽  
pp. 29-34
Author(s):  
Ling Yan Sun ◽  
Chao Yang
Keyword(s):  
Laser Beam ◽  
Three Dimensional ◽  
Reduction Rate ◽  
Intense Laser ◽  
Material Strength ◽  
Three Dimensional Model ◽  
Forming Process ◽  
Flow Forming ◽  
Heating Source ◽  
Heating And Cooling

Recent years laser-assisted manufacturing techniques are increasingly the focus of the automotive and aerospace industry due to cost price, low energy efficiency and safety. Among these techniques is laser-assisted flow forming process that combines laser beam technology with conventional flow forming process. During forming the material undergoes a rapidly heating and cooling cycles with the irradiative action of the laser beam, which is quite different from the traditional process. A transient three-dimensional model was developed to investigate the influence of laser irradiation on the forming process, in which a user-defined function was created to overcome the problem of a moving Gaussian heating source. The result indicates that a ring-shaped temperature field is acquired when the heating source scans workpiece along a thread; the deformation area on the workpiece during forming is extensively and continuously heated by intense laser radiation and the thermally induced loss of material strength significantly increases the formability concerning the achievable material reduction rate and tool service life; the possibility of accuracy improvement by laser assistance has been investigated and an accuracy error decreases 10%-28.5%.

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