Effectiveness of Wear Plate at the Saddle Support

1992 ◽  
Vol 114 (1) ◽  
pp. 12-18 ◽  
Author(s):  
Ong Lin Seng
Keyword(s):  
Cylindrical Shell ◽  
Contact Stress ◽  
Stress Reduction ◽  
Reduction Factor ◽  
Optimum Thickness ◽  
Simply Supported ◽  
Parametric Data ◽  
Cylindrical Pressure Vessel ◽  
Definition Of ◽  
Wear Plate

A theory is presented to analyze the effectiveness of incorporating a wear plate at the saddle support of a cylindrical pressure vessel. The wear plate can be either welded to the vessel or of loose fitting. The theory is based on a contact stress formulation together with the use of a cylindrical shell bending theory for simply supported cylinder. The effectiveness of the wear plate in reducing the peak circumferential saddle-horn stress is quantified by definition of a stress reduction factor. Parametric data are carried out for the saddle angle of 120 deg. From the study, the optimum thickness of the wear plate for three different angular extensions, are obtained.

Local loads on a toroidal shell

1992 ◽  
Vol 27 (2) ◽  
pp. 59-66 ◽  
Author(s):  
D Redekop ◽  
F Zhang
Keyword(s):  
Cylindrical Shell ◽  
Shell Theory ◽  
Elastic Shell ◽  
Toroidal Shell ◽  
Pipe Bend ◽  
Local Loads ◽  
Simply Supported ◽  
Linear Elastic ◽  
Wide Range ◽  
Theory Solution

In this study the effect of local loads applied on a sectorial toroidal shell (pipe bend) is considered. A linear elastic shell theory solution for local loads is first outlined. The solution corresponds to the case of a shell simply supported at the two ends. Detailed displacement and stress results are then given for a specific shell with loadings centred at three positions; the crown circles, the extrados, and the intrados. These results are compared with results for a corresponding cylindrical shell. The paper concludes with a table summarizing results for characteristic displacements and stresses in a number of shells, covering a wide range of geometric parameters.

Cylindrical Shells Under Line Load

1957 ◽  
Vol 24 (4) ◽  
pp. 553-558
Author(s):  
R. M. Cooper
Keyword(s):  
Cylindrical Shell ◽  
Radial Displacement ◽  
Circular Cylindrical Shell ◽  
Transverse Shear Deformation ◽  
System Of Equations ◽  
Principle Of Superposition ◽  
Line Load ◽  
Simply Supported ◽  
Shell Equations ◽  
Shell Geometry

Abstract The problem of a line load along a segment of a generator of a simply supported circular cylindrical shell is treated using shallow cylindrical shell equations which include the effect of transverse-shear deformation. The line load is first treated as a sinusoidally-varying edge load over the length of the shell, with boundary conditions prescribed along the loaded generator such that the continuity of the shell is maintained. The solution for the problem of a uniform line load over a segment of a generator is obtained from the preceding solution, using the principle of superposition. By means of a numerical example it is shown that the results predicted by the Donnell equations for the stresses are in excellent agreement with those obtained from the system of equations employed here. However, the radial displacement predicted by the Donnell equations is in error by as much as 20 per cent in the range of shell geometry considered.

Frequency manipulation of a light-activated shape-memory polymer-laminated cylindrical shell

2021 ◽  
pp. 095440892110632
Author(s):  
Tao He ◽  
Pengpeng Zhu ◽  
Xiangmin Zhang
Keyword(s):  
Cylindrical Shell ◽  
Shape Memory ◽  
Natural Frequency ◽  
Frequency Control ◽  
Shape Memory Polymer ◽  
Control Effect ◽  
Optimal Scheme ◽  
Simply Supported ◽  
Control Capability ◽  
Laminated Cylindrical Shell

A light-activated shape-memory polymer is a novel smart material that exhibits a dynamic Young's modulus when exposed to light. The non-contact actuation feature facilitates the lamination of a light-activated shape-memory polymer on host structures for realising frequency control. In this study, we investigated the natural frequency of a simply supported cylindrical shell coupled with light-activated shape-memory polymer patches located arbitrarily on the shell. Initially, we compared the natural frequency of a completely laminated cylindrical shell using two different approaches. Further, we analysed the effect of changes in the length and location of the light-activated shape-memory polymer patch pair on the natural frequency of the cylindrical shell. Based on the experimental results, we propose an optimal scheme, wherein several light-activated shape-memory polymer patch pairs are distributed on the surface of the shell, and the frequency control capability of the proposed scheme is evaluated comprehensively. The results verify that the optimal scheme has an adequate control effect on the natural frequency of the cylindrical shell.

Surface instability of imperfectly bonded multi-layered curved films under van der Waals forces

2017 ◽  
Vol 82 (5) ◽  
pp. 1088-1103
Author(s):  
Xu Wang ◽  
Peter Schiavone
Keyword(s):  
Cylindrical Shell ◽  
Stability Analysis ◽  
Analytical Solutions ◽  
Van Der Waals ◽  
Van Der Waals Forces ◽  
Imperfect Interface ◽  
Surface Instability ◽  
Simply Supported ◽  
Linear Spring ◽  
Interface Parameters

Abstract Using a linear stability analysis and the transfer matrix method, we investigate the surface instability of an imperfectly bonded multi-layered curved film interacting with a curved rigid contactor, another imperfectly bonded multi-layered curved film or an imperfectly bonded multi-layered simply-supported cylindrical shell in each case through the action of attractive van der Waals forces. The imperfect interface is modelled as a linear spring layer with vanishing thickness characterized by normal and tangential imperfect interface parameters. Detailed numerical results are presented to demonstrate the resulting analytical solutions.

Contact Stress Reduction Mechanisms for the CAM-Based Infinitely Variable Transmission

2007 ◽  
Author(s):  
Derek F. Lahr ◽  
Dennis W. Hong
Keyword(s):  
Contact Stress ◽  
Stress Reduction ◽  
Kinematic Model ◽  
Three Dimensional ◽  
Speed Ratio ◽  
Cam Mechanism ◽  
Expected Performance ◽  
Differential Mechanism ◽  
Variable Transmission ◽  
Infinitely Variable Transmission

The Cam-based Infinitely Variable Transmission (IVT) is a new type of ratcheting IVT based on a three dimensional cam and follower system which provides unique characteristics such as generating specific functional speed ratio outputs including dwells, for a constant velocity input. This paper presents several mechanisms and design approaches used to improve the torque and speed capacity of this unique transmission. A compact, lightweight, and capable differential mechanism based on a cord and pulley system is developed to double the number of followers in contact with the cam at any time, thereby reducing the contact stress between the followers and the cam surface considerably. A kinematic model governing the motion of this differential is developed and a few experimental results from the prototype are presented, showing an overall increase in performance including a smooth output, a wide gear range, and the ability to shift under load. Plans for future improvements to the design, including an inverted external cam mechanism, is also presented along with the expected performance gains.

scholarly journals Well-Being Workshops in Eating Disorder Wards and Their Perceived Benefits to Patients and the Multi-Disciplinary Team: A Pilot Study

2019 ◽  
Vol 9 (10) ◽  
pp. 247
Author(s):  
Katherine Smith ◽  
Yasemin Dandil ◽  
Claire Baillie ◽  
Kate Tchanturia
Keyword(s):  
Eating Disorder ◽  
Thematic Analysis ◽  
Stress Reduction ◽  
Self Care ◽  
Well Being ◽  
Content Structure ◽  
Self Compassion ◽  
Staff Burnout ◽  
Definition Of ◽  
Multi Disciplinary Team

A more holistic definition of patients’ recovery from eating disorders (EDs) highlights that well-being interventions linked to self-compassion are under-researched and under-utilised. Staff burnout is also common in ED units (EDUs), linked to difficult relationships with patients and poor self-care, and is not well addressed. Therefore we piloted a series of joint well-being workshops to target these issues. Joint workshops were offered to patients (n = 55) and the multi-disciplinary team MDT (n = 34) in adult ED wards over two years. Experiences were evaluated quantitively and qualitatively. Mood post-workshops increased significantly for both groups (patients: p < 0.001, r = 0.49; MDT: z = 3.043, p = 0.002, r = 0.41), with the feeling that they deserved to take time for self-care (patients: z = 2.419, p = 0.016, r = 0.31); MDT: z = 2.814, p = 0.005, r = 0.38). Workshops were found to be enjoyable and highly relevant to well-being, but less useful by patients. Thematic analysis identified six themes: Enjoyment, recovery and well-being, relationships, content, structure and future ideas. Both groups experienced improved mood and increased enjoyment and awareness of well-being. Patient isolation was addressed, and the staff experienced stress reduction and increased productivity. Both groups experienced improved relationships.

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