Wall thickness uniformity in plastic pipes: Computer simulations of the effectiveness of die mandrel offsetting and pipe rotation in combatting sag

1995 ◽  
Vol 35 (11) ◽  
pp. 921-928 ◽  
Author(s):  
J. F. T. Pittman ◽  
G. P. Whitham ◽  
I. A. Farah
Keyword(s):  
Computer Simulations ◽  
Wall Thickness ◽  
Thickness Uniformity ◽  
Plastic Pipes ◽  
Pipe Rotation

scholarly journals Effect of Aneurysm and Patient Characteristics on Intracranial Aneurysm Wall Thickness

2021 ◽  
Vol 8 ◽  
Author(s):  
Jason M. Acosta ◽  
Anne F. Cayron ◽  
Nicolas Dupuy ◽  
Graziano Pelli ◽  
Bernard Foglia ◽  
...  
Keyword(s):  
Intracranial Aneurysm ◽  
Wall Thickness ◽  
Positive Family History ◽  
Patient Characteristics ◽  
Western World ◽  
University Hospitals ◽  
Thickness Uniformity ◽  
Neck Size ◽  
Aneurysm Wall

Background: The circle of Willis is a network of arteries allowing blood supply to the brain. Bulging of these arteries leads to formation of intracranial aneurysm (IA). Subarachnoid hemorrhage (SAH) due to IA rupture is among the leading causes of disability in the western world. The formation and rupture of IAs is a complex pathological process not completely understood. In the present study, we have precisely measured aneurysmal wall thickness and its uniformity on histological sections and investigated for associations between IA wall thickness/uniformity and commonly admitted risk factors for IA rupture.Methods: Fifty-five aneurysm domes were obtained at the Geneva University Hospitals during microsurgery after clipping of the IA neck. Samples were embedded in paraffin, sectioned and stained with hematoxylin-eosin to measure IA wall thickness. The mean, minimum, and maximum wall thickness as well as thickness uniformity was measured for each IA. Clinical data related to IA characteristics (ruptured or unruptured, vascular location, maximum dome diameter, neck size, bottleneck factor, aspect and morphology), and patient characteristics [age, smoking, hypertension, sex, ethnicity, previous SAH, positive family history for IA/SAH, presence of multiple IAs and diagnosis of polycystic kidney disease (PKD)] were collected.Results: We found positive correlations between maximum dome diameter or neck size and IA wall thickness and thickness uniformity. PKD patients had thinner IA walls. No associations were found between smoking, hypertension, sex, IA multiplicity, rupture status or vascular location, and IA wall thickness. No correlation was found between patient age and IA wall thickness. The group of IAs with non-uniform wall thickness contained more ruptured IAs, women and patients harboring multiple IAs. Finally, PHASES and ELAPSS scores were positively correlated with higher IA wall heterogeneity.Conclusion: Among our patient and aneurysm characteristics of interest, maximum dome diameter, neck size and PKD were the three factors having the most significant impact on IA wall thickness and thickness uniformity. Moreover, wall thickness heterogeneity was more observed in ruptured IAs, in women and in patients with multiple IAs. Advanced medical imaging allowing in vivo measurement of IA wall thickness would certainly improve personalized management of the disease and patient care.

Characterization of sphericity and wall thickness uniformity of thick-walled hollow microspheres

2014 ◽  
Vol 26 (2) ◽  
pp. 22017 ◽  
Author(s):  
刘梅芳 Liu Meifang ◽  
陈素芬 Chen Sufen ◽  
刘一杨 Liu Yiyang ◽  
苏琳 Su Lin ◽  
史瑞廷 Shi Ruiting ◽  
...  
Keyword(s):  
Wall Thickness ◽  
Hollow Microspheres ◽  
Thickness Uniformity

Cooling and Wall Thickness Uniformity in Plastic Pipe Manufacture

1994 ◽  
Vol 9 (2) ◽  
pp. 130-140 ◽  
Author(s):  
J. F. T. Pittman ◽  
G. P. Whitham ◽  
S. Beech ◽  
D. Gwynn
Keyword(s):  
Wall Thickness ◽  
Thickness Uniformity ◽  
Plastic Pipe ◽  
Pipe Manufacture

A Study on the Large-Diameter Seamless Gas Cylinder Dimensional Accuracy of Rotary Expanding Process with Finite Element Analysis

2011 ◽  
Vol 328-330 ◽  
pp. 136-142
Author(s):  
Shun Yao Jin ◽  
Zhong Guo Huang ◽  
Zong Ke Shao ◽  
Ming Xiang Li ◽  
Hui Lai Sun ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Wall Thickness ◽  
Large Diameter ◽  
Dimensional Accuracy ◽  
Steel Tube ◽  
Element Analysis ◽  
Thickness Uniformity ◽  
Gas Cylinder ◽  
Roll Gap

This paper expounds the application of rotary expanding process to manufacture the large-diameter hot-rolled seamless gas cylinder. Through analytic geometry method, an equation is established among the tail roll gap, roll distance and the plug protrusion distance. 3D drawing software CATIA-V5 is applied to build 3d models of steel tube and rolling tools. The rolling process is simulated by MSC.Marc FEA (finite element analysis) software. Marc’s second development function and FORTRAN software’s extracting finite element node coordinates function are applied to calculate the wall thickness uniformity. A novel method to calculate the wall thickness uniformity after finite element analysis is proposed. The wall thickness uniformity of steel tube after rolling is well simulated and compared by MSC.Marc FEA software, which can help the technologist to predict and choose the best rolling parameter. For gas cylinder rolling, the tail roll gap should be set to 17mm. The roller distance and the plug protrusion distance should be set as 342mm and 78mm separately.

scholarly journals A Precision Grinding Technology for Zirconium Alloy Tubes Based on Ultrasonic Wall Thickness Automatic Measurement System

2021 ◽  
Author(s):  
Lai Zou ◽  
Heng Li ◽  
Wenxi WANG ◽  
Yun Huang ◽  
Yutong Li
Keyword(s):  
Wall Thickness ◽  
Measurement System ◽  
Zirconium Alloy ◽  
Thickness Distribution ◽  
Performance Testing ◽  
Numerical Control ◽  
Measuring System ◽  
Combination Method ◽  
New Combination ◽  
Thickness Uniformity

Abstract To ensure the safety and long-term performance of nuclear fuel cladding zirconium tubes, the wall thickness uniformity of each cross section is strictly needed. Therefore, this paper presents comprehensive investigations on development of an automatic ultrasonic wall thickness measurement system for detecting the nuclear zirconium tubes. Based on the determination of overall scheme, optimization of key mechanical structures and design of control system, a series of performance testing analyses of this developed auto-measuring system were performed from aspects of measuring accuracy, measuring efficiency, stability and practicability. The results revealed that it could accurately obtain the wall thickness distribution and effectively guide the subsequent grinding process by automatically generated deviation correcting procedures to achieve the requirement of the wall thickness uniformity. The new combination method of ultrasonic auto-measuring and numerical control grinding proposed in this work would have a great significance for the development and application of nuclear reaction zirconium alloy container.

Process Parameter Analysis of Higher D/T Ratio Tube Formed From Sheet Hydroforming

2017 ◽  
Author(s):  
Duanyang Tian ◽  
Xuedao Shu ◽  
Yilun Wei ◽  
Yu Wang
Keyword(s):  
Wall Thickness ◽  
Large Diameter ◽  
Hydraulic Pressure ◽  
Blank Holder Force ◽  
Blank Holder ◽  
Forming Quality ◽  
Sheet Hydroforming ◽  
Thickness Uniformity ◽  
Thin Walled Tube ◽  
Thin Walled

As a core part of the aero engine casing, the thin-walled tube with large diameter usually formed by sheet hydroforming presents high forming precision and forming quality. In this paper, the appropriate hydraulic pressure and blank holder force should be identified to control the wall thickness uniformity of N08811 alloy tube with large diameter. Firstly, the stress-strain curve of this material at room temperature is obtained from deep drawing tests. Subsequently, within the allowable range of springback and wrinkling errors, finite element simulation and the uniform test design are performed to investigate the effect of the multi-level process parameters on the thickness uniformity of the higher D/t ratio tube. Results show that the blank holder force and the hydraulic pressure produce significant effects on the wall thickness uniformity. Finally, the regression analysis is further carried out for the computational results from uniform experimental design experiments. The optimized process parameters are then obtained and the wall thickness uniformity of the tube is improved. These results provide a theoretical reference for improving the forming quality of thin-walled tube with large diameter.

Evaluation of the Resistance of X120 Pipe to Mechanical Damage

2006 ◽  
Author(s):  
Antonio Lucci ◽  
Gianluca Mannucci ◽  
Giuliano Malatesta ◽  
Nicholas E. Biery
Keyword(s):  
High Pressure ◽  
Computer Simulations ◽  
Test Data ◽  
Wall Thickness ◽  
Mechanical Damage ◽  
High Strength ◽  
Lower Grade ◽  
Common Causes ◽  
Pipeline Failure ◽  
Linepipe Steels

High strength linepipe steels are being considered for several upcoming projects due to their potential to offer substantial savings through reduced wall thickness, particularly for high pressure designs. It is well known that mechanical damage from excavation activities is one of the most common causes of pipeline failure, however, little test data are available for higher grade steels. This paper presents the results of simulated excavator impacts on X120 pipe, and compares the results to those obtained on lower grade materials and to those predicted by computer simulations.

Improvement of wall thickness uniformity of thick-walled polystyrene shells by density matching

2014 ◽  
Vol 241 ◽  
pp. 466-476 ◽  
Author(s):  
Meifang Liu ◽  
Sufen Chen ◽  
Xiao bo Qi ◽  
Bo Li ◽  
Ruiting Shi ◽  
...  
Keyword(s):  
Wall Thickness ◽  
Thickness Uniformity

Fabrication of thick-walled polyacrylonitrile (PAN) with high uniformity by an easily assembled double-T droplet generator

RSC Advances ◽  
2015 ◽  
Vol 5 (120) ◽  
pp. 98892-98899 ◽  
Author(s):  
Hao Peng ◽  
Meifang Liu ◽  
Jing Li ◽  
Sufen Chen ◽  
Zhanwen Zhang ◽  
...  
Keyword(s):  
Wall Thickness ◽  
Droplet Generator ◽  
Thickness Uniformity ◽  
High Uniformity

Thick-walled PAN microspheres with good wall thickness uniformity and sphericity were obtained by adjusting the solidifying temperature and the viscosity of O2phase.

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