Investigation of the influence of distribution of defections along the axial direction on eternal ultimate strength of titanium alloy pressure hulls of long barrel shape

2021 ◽  
pp. 095440542110406
Author(s):  
Xiangyu Yu ◽  
Hao Zhang ◽  
Hongtao Ji ◽  
Dongkai Xu
Keyword(s):  
Titanium Alloy ◽  
Numerical Simulations ◽  
Ultimate Strength ◽  
Axial Direction ◽  
Processing Method ◽  
Dimensional Error ◽  
Average Ratio ◽  
Plastic Processing ◽  
Strength Based ◽  
Von Mises

During the fabrication of pressure hulls, plastic processing is indispensable, which is an environmental, highly effective, and economical processing method. However dimensional error is also induced during plastic processing. This kind of error is one type of defection, which makes the hulls in danger, especially when the hulls suffer eternal pressure. Von Mises theory is an effective approach to study failure of pressure hulls. In this paper, numerical simulations are performed to investigate influence of distribution of defections along the axial direction on the ultimate strengths of titanium alloy pressure hulls of long barrel shape with two vessel heads using ABAQUS. The results of numerical simulations show that the ultimate strengths of pressure hulls with defections are relative to the location and distribution of defections, and they are decreasing with reduction of the average ratio and standard deviation when the hull suffers eternal pressure. The method of evaluating degradation of ultimate strength based on simulations can be employed to check the safety of pressure hulls.

Stresses in Teeth and Overlying Crowns

2012 ◽  
Vol 457-458 ◽  
pp. 567-571
Author(s):  
Liliana Sandu ◽  
Florin Topală ◽  
Sorin Porojan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Numerical Simulations ◽  
Experimental Model ◽  
3D Scanning ◽  
Analysis Software ◽  
Element Analysis ◽  
Equivalent Stresses ◽  
Von Mises

A complete cast crown allows the operator to modify axial tooth contour. The margin should be smooth and distinct and its width has to allow adequate bulk of metal at the margin. The objective of this study was to evaluate, by finite element analysis, the influence of different degree of taper and marginal designs for cast crown preparations, on the stress distribution in teeth and crowns. As experimental model an upper first molar was used. The geometry of the intact tooth were obtained by 3D scanning. The tooth preparations and the complete cast crowns were designed. Models were exported in a finite element analysis software for structural simulations. Von Mises equivalent stresses were calculated and their distribution was plotted graphically. Numerical simulations provide a biomechanical explanation for stress distribution in prepared teeth and overlying crowns.

scholarly journals An Improved Abrasive Flow Processing Method for Complex Geometric Surfaces of Titanium Alloy Artificial Joints

2018 ◽  
Vol 8 (7) ◽  
pp. 1037 ◽  
Author(s):  
Li Zhang ◽  
Zhimin Yuan ◽  
Dapeng Tan ◽  
Yi Huang
Keyword(s):  
Titanium Alloy ◽  
Processing Method ◽  
Artificial Joints

Comparative Analysis of Forging Rolling and Cross-Wedge Rolling of Forgings from Titanium Alloy Ti6Al4V

2016 ◽  
Vol 687 ◽  
pp. 141-148 ◽  
Author(s):  
Arkadiusz Tofil ◽  
Janusz Tomczak ◽  
Tomasz Bulzak
Keyword(s):  
Titanium Alloy ◽  
Numerical Simulations ◽  
Complex Analysis ◽  
Stable Process ◽  
Rolling Process ◽  
Optimal Parameters ◽  
Cross Wedge Rolling ◽  
Theoretical Assumptions ◽  
Titanium Alloy Ti6al4v

Theoretical-experimental results of forging rolling and cross-wedge rolling of stepped shafts forgings from titanium alloy Ti6Al4V are presented in this paper. Theoretical assumptions were based on the results of numerical simulations conducted by means of finite element method with the application of software Simufact Forming. During numerical simulations optimal parameters of the rolling processes were determined in view to possibility of obtaining forgings of assumed quality and stable process course. Experimental verification was conducted in universal forging rolling mill of own design, which allows for realization of such processes as splitting without waste, forging rolling and cross as well as cross-wedge rolling processes. During conducted research influence of the way of rolling on the obtained parts quality and the process force parameters were determined. Complex analysis of the chosen rolling parameters impact on the rolling process course and quality of finished products was made. Conducted research showed that it is possible to roll axi-symmetrical forgings of stepped shafts both in transverse and longitudinal arrangement. However, forgings rolled crosswise are characterized by larger precision than in comparison with semi-finished products in longitudinal arrangement.

scholarly journals Evaluation of Stress Distribution and Force in External Hexagonal Implant: A 3-D Finite Element Analysis

2021 ◽  
Vol 18 (19) ◽  
pp. 10266
Author(s):  
Vinod Bandela ◽  
Ram Basany ◽  
Anil Kumar Nagarajappa ◽  
Sakeenabi Basha ◽  
Saraswathi Kanaparthi ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Maximum Stress ◽  
Axial Direction ◽  
Von Mises Stress ◽  
P Value ◽  
Implant Surface ◽  
Element Analysis ◽  
Von Mises

Purpose: To analyze the stress distribution and the direction of force in external hexagonal implant with crown in three different angulations. Materials and Methods: A total of 60 samples of geometric models were used to analyze von Mises stress and direction of force with 0-, 5-, and 10-degree lingual tilt. Von Mises stress and force distribution were evaluated at nodes of hard bone, and finite element analysis was performed using ANSYS 12.1 software. For calculating stress distribution and force, we categorized and labeled the groups as Implant A1, Implant A2, and Implant A3, and Implant B1, Implant B2, and Implant B3 with 0-, 5-, and 10-degree lingual inclinations, respectively. Inter- and intra-group comparisons were performed using ANOVA test. A p-value of ≤0.05 was considered statistically significant. Results: In all the three models, overall maximum stress was found in implant model A3 on the implant surface (86.61), and minimum was found on model A1 in hard bone (26.21). In all the three models, the direction of force along three planes was maximum in DX (0.01025) and minimum along DZ (0.002) direction with model B1. Conclusion: Maximum von Mises stress and the direction of force in axial direction was found at the maximum with the implant of 10 degrees angulation. Thus, it was evident that tilting of an implant influences the stress concentration and force in external hex implants.

The prediction of stress rupture life of notched specimens in the beta-processed titanium alloy Ti5331s

1987 ◽  
Vol 22 (3) ◽  
pp. 145-153 ◽  
Author(s):  
P S Webster ◽  
A C Pickard
Keyword(s):  
Titanium Alloy ◽  
Notch Root ◽  
Rupture Life ◽  
Equivalent Stress ◽  
Stress Rupture ◽  
High Rate ◽  
Stress Rupture Life ◽  
Notched Specimen ◽  
Notched Specimens ◽  
Von Mises

Methods of predicting notched bar stress rupture behaviour are reviewed. Two very different types of notched specimens are analysed using the finite element method; one being a circumferentially V-notched test piece, the other having two semi-circular notches in a plane section. A prediction based on the Von Mises equivalent stress distribution is proposed. Predictions using this method are compared with notched specimen test results in a commercially available titanium alloy, Ti5331s, tested at 600°C. The correlation is good for the semi-circular notched specimen and for the V-notched specimen at low stress, long life and can be improved at high stresses by making allowance for time independent plasticity and for the initial high rate of creep strain accumulation at the notch root.

Failure Pressure in Corroded Pipelines Based on Equivalent Solutions for Undamaged Pipe

2010 ◽  
Vol 132 (5) ◽  
Author(s):  
M. Bony ◽  
J. L. Alamilla ◽  
R. Vai ◽  
E. Flores
Keyword(s):  
Shear Stress ◽  
Numerical Simulations ◽  
Wall Thickness ◽  
Yield Criteria ◽  
Failure Pressure ◽  
Average Shear Stress ◽  
Average Shear ◽  
Thin Walled ◽  
Von Mises

Simple and accurate approaches to predict failure pressures in corroded pipelines are outlined in this work. It is shown that failure pressures for corroded pipelines can be predicted from the solution for undamaged pipelines using an equivalent wall thickness. Three different yield criteria (Tresca, ASSY (average shear stress yield), and von Mises) are reviewed in the light of reported experimental burst pressures. At first, failure pressures for cylindrical vessels with an infinitely long groove are studied by means of numerical simulations. The effect of groove size (depth and width) over the pipeline performance is quantified through a model. Finally, the scheme is extended to estimate the failure pressure of thin walled vessels with irregular finite defects.

Development of Axially Splitting Method for the Pipe Materials with the Cutting Tool

2014 ◽  
Vol 1017 ◽  
pp. 350-354
Author(s):  
Eitoku Nakanishi ◽  
Masayuki Hyono ◽  
Seijiro Maki
Keyword(s):  
Stainless Steel ◽  
Cutting Tool ◽  
Splitting Method ◽  
Axial Direction ◽  
Processing Method ◽  
The Other ◽  
Wall Surface ◽  
Steel Pipes ◽  
Simple Processing ◽  
Pipe Materials

A simple processing method for splitting pipes in the axial direction using a cutting tool was investigated. The special tool developed in this study was pressed into the pipes in the axial direction, and the pipes were split very smoothly without any lubricant. This cutting method did not form fine chips, did not produce a significant heat effect on the inner wall surface. The splitting experiment was carried out with pipes constructed of aluminum and stainless steel. The outer diameters of the pipes were approximately 50 mm, and the thicknesses of the wall varied from 1 to 3 mm. The aluminum pipes were split very smooth by the tool, and curled strip-shaped chips were created by the splitting. On the other hand, the stainless pipes were greatly deformed, making them difficult to cut. Therefore, it was necessary to prevent deformation of the pipe by attaching an outer tool. The outer tool made it possible to cut stainless steel pipes.

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