Effects of Increasing Allowable Compressive Stress at Prestress Transfer

2010 ◽  
Vol 107 (01) ◽  
Keyword(s):  
Compressive Stress ◽  
Allowable Compressive Stress

scholarly journals Inversion analysis and safety evaluation of deformation of cutoff wall in Daning Reservoir

2021 ◽  
Vol 276 ◽  
pp. 01035
Author(s):  
Hong-hu Yuan ◽  
Liao Kun ◽  
Wang Yu
Keyword(s):  
Compressive Stress ◽  
Stress Condition ◽  
Measurement Data ◽  
Safety Evaluation ◽  
Wall Structure ◽  
Cutoff Wall ◽  
Construction Period ◽  
Deformation Law ◽  
Allowable Compressive Stress ◽  
Inversion Analysis

There is a large amount of backfilled earth on both sides of the wall and the top of the lower wall of the Daning Reservoir’s cutoff wall, which is greatly disturbed by the project, and the safety of the cutoff wall needs to be evaluated. Based on the deformation law and stress condition of rigid cutoff wall during construction, according to the connection characteristics of rigid cutoff wall and plastic cutoff wall structure, the stress analysis of rigid cutoff wall is carried out by using field measurement data, so as to deduce the deformation law of plastic cutoff wall underneath, and evaluate the safety of plastic cutoff wall. The results show that the plastic cutoff wall is mainly affected by compressive stress, and the maximum compressive stress is far less than the allowable compressive stress, which indicates that the plastic cutoff wall is safe and stable during the whole construction period, although it is affected by construction and rigid cutoff wall.

scholarly journals Allowable Compressive Stress Rules in the ASME Boiler and Pressure Vessel Code, Section VIII, in the Creep Regime

2018 ◽  
Author(s):  
Maan Jawad
Keyword(s):  
Compressive Stress ◽  
Pressure Vessel ◽  
Time Dependent ◽  
Asme Code ◽  
Section Viii ◽  
Allowable Compressive Stress ◽  
Creep Regime

This paper outlines several procedures for developing allowable compressive stress rules in the creep regime (time dependent regime). The rules are intended for the ASME Boiler and Pressure Vessel codes (Sections I and VIII). The proposed rules extend the methodology presently outlined in Sections I, II-D, and VIII of the ASME code for temperatures below the creep regime into temperatures where creep is a consideration.

Non-Linear Creep-Buckling Analysis: An Approach Based on WRC-443 for Development of Allowable Compressive Stresses in Coke Drums

2010 ◽  
Author(s):  
M. Sohel M. Panwala ◽  
S. L. Mehta
Keyword(s):  
Compressive Stress ◽  
Temperature Limit ◽  
Buckling Analysis ◽  
Part D ◽  
Compressive Stresses ◽  
Creep Buckling ◽  
Linear Creep ◽  
Non Linear ◽  
Temperature And Pressure ◽  
Allowable Compressive Stress

Coke Drums are critical equipment in refineries due to variable temperature and pressure. The temperature is also very high and coke drums works in the creep range for some duration of one full cycle. In the present study, a coke drum is subjected to pressure–temperature reversal with each cycle of 48 hours duration. Temperature and pressure varies from 65 to 495 °C and 1.72 to 4.62 bar, respectively. Design temperature of 510 °C and total Operating Weight of coke drum is 2500 tons. The skirt is to be check against the operating weight, operating pressure & wind load/earthquake load at high temperature which causes the compressive stresses in skirt. The phenomenon of creep along with buckling plays a very crucial role in failure of skirt of coke drums. In addition to this, the skirt is provided with slots at specific pitch all around circumference to induce flexibility for fatigue which weakens the skirt for compressive loading. The material of construction is 1.25Cr-0.5Mo. The temperature limit of 1.25Cr-0.5Mo is 482 °C as per external pressure chart & Appendix-3 of ASME Section II, Part D. Design temperature of coke drum is 510 °C & as design temperature is exceeding the temperature limit, allowable compressive stress from ASME Section II, Part D, Subpart 3 can not be used for design. Thus, an allowable compressive stress for 1 Hr and 100,000 Hr has been developed using Non-linear creep-buckling analysis with WRC-443 to check the skirt against induced compressive stresses. The isochronous curve including accumulated creep strain has been developed for 1 Hr & 100,000 Hr using API 579-1/ASME FFS-1 2007. Non-linear creep buckling analysis at 1 Hr & 100,000 Hr has been carried out in ANSYS using isochronous stress-strain curve as material properties. An induced stress in skirt obtained from analysis has been used in WRC-443 for calculation allowable compressive stress in skirt. An allowable compressive stress works out to be 227.8 MPa & 86.8 MPa at 1 Hr and 100,000 Hr, respectively.

Closed-Form Solutions for Code Case 2286 Allowable Compressive Stresses Analogous to Vacuum Chart Method

2012 ◽  
Author(s):  
Harsh Kumar Baid ◽  
Donald LaBounty ◽  
Amiya Chatterjee
Keyword(s):  
Closed Form ◽  
Compressive Stress ◽  
Pressure Vessels ◽  
Closed Form Solutions ◽  
Compressive Stresses ◽  
Division 1 ◽  
Section Viii ◽  
Allowable Compressive Stress ◽  
User Friendly

The allowable compressive stresses in pressure vessels can be calculated either from ASME Section VIII Division 1, Paragraph UG-28 vacuum chart method [2] or Code Case 2286 [1]. Code Case 2286 has been incorporated into ASME Section VIII Division 2, Part 5. For Division 1 vessels, the vacuum chart method is a user-friendly tool for determining allowable compressive stress. In this paper, the authors present the development of allowable compressive stress data based on closed-form solutions of Code Case 2286. These closed-form solutions yield exact allowable compressive stress values which are not influenced by any kind of sensitivity. The development presented in the paper is also user-friendly, similar to the vacuum chart, for the determination of allowable compressive stresses. These designs, based on Code Case 2286, are economical without any compromise in the safety of the pressure vessel. Examples are included to demonstrate the results.

scholarly journals Allowable Compressive Stress of Pre-Tensioned Members with Tee or Inverted Tee Sections at Transfer

2011 ◽  
Vol 23 (3) ◽  
pp. 353-364
Author(s):  
Deuck-Hang Lee ◽  
Jeong-Yeon Lee ◽  
Joo-Hyuk Lim ◽  
Kang-Su Kim
Keyword(s):  
Compressive Stress ◽  
Allowable Compressive Stress

Stability Design Criterion for Vessels Subjected to Concurrent External Pressure and Longitudinal Compressive Loads

1979 ◽  
Vol 101 (2) ◽  
pp. 178-181
Author(s):  
N. Gilbert ◽  
J. R. Polani
Keyword(s):  
Compressive Stress ◽  
Design Procedure ◽  
Elastic Stability ◽  
External Pressure ◽  
Design Criterion ◽  
Buckling Loads ◽  
Compressive Loads ◽  
Section Viii ◽  
Stability Data ◽  
Allowable Compressive Stress

This paper presents a design procedure for determining the maximum allowable compressive stress and the maximum allowable external pressure for cylindrical vessels subjected to loadings which produce both longitudinal and circumferential stresses simultaneously. Although the ASME Pressure Vessel Code Section VIII [1] mentions the combinations of loadings as a factor in determining the thickness of vessels, the Code procedures (UG-23) for longitudinal compressive stress and (UG-28) for external pressure do not consider the interaction of these two buckling loads when acting concurrently. Calculations of typical vessels subjected to these conditions reveal that adherence to the Code rules without inclusion of these effects may yield results which fall below the safe design limits established by the Code. The design procedure developed herein extends the existing Code formulations as applicable; and incorporates established elastic stability data as necessary.

The Case for MACA: The Optimization of Corrosion Allowance

2016 ◽  
Author(s):  
Jaan Taagepera
Keyword(s):  
Tensile Stress ◽  
Compressive Stress ◽  
Pressure Vessel ◽  
Cylindrical Shells ◽  
Pressure Vessels ◽  
Degradation Mechanisms ◽  
Working Pressure ◽  
Exothermic Reactions ◽  
Allowable Compressive Stress ◽  
Original Edition

Engineers are taught to optimize. In the case of pressure vessel design, one means of optimizing the steel which is used is to increase the rated pressure capacity of the vessel beyond the design needs. This optimized pressure is formally known by the term MAWP or Maximum Allowable Working Pressure. Of historical interest, this concept has existed for over 100 years, with the MAWP formula for cylindrical shells being tracable back to the original edition of the Boiler Code. However, other variables in vessel design can also be optimized. In addition to pressure, consideration can be given to temperature or corrosion allowance. Increasing the temperature has the effect of reducing the basic allowable tensile stress as well as the allowable compressive stress and flange ratings. In the case of some specialty vessels such as reactors with exothermic reactions adding a few degrees to the design temperature may be very beneficial. But virtually all vessels degrade in some manner, most often corrosion but sometimes via erosion or other degradation mechanisms. Significant amounts of time and effort are spent with unnecessary shutdowns, repairs, and / or fitness for service (FFS) evaluations all of which might have been avoided or deferred for years had the vessel originally been optimized for corrosion allowance. The term Maximum Allowable Corrosion Allowance or MACA is used to describe this approach. This paper presents some arguments in favor of optimizing the corrosion allowance of pressure vessels, using a MACA based optimization for the design of new vessels rather than a pressure optimization or MAWP philosophy.

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