Comparison on Mechanical Behavior of Bolted Flanges Per Old and New Section VIII Division 2

2011 ◽  
Author(s):  
Susumu Terada ◽  
Tatsuo Nishihara ◽  
Tomohiro Suzuki
Keyword(s):  
Stress Level ◽  
Contact Stress ◽  
Outer Edge ◽  
Main Concern ◽  
Symmetric Model ◽  
Large Size ◽  
Sealing Performance ◽  
Internal Fluid ◽  
Section Viii ◽  
As Stress

The allowable stress for 2.25Cr 1Mo 0.25V steel per ASME Section VIII Div.2 2007 edition (hereinafter called New Div2) becomes higher than that per old Div.2. Therefore the thickness of flange can be thinner than that per old Div.2. The internal fluid leakage is main concern as well as stress level especially for large size flanges per New Div.2. In this paper the analysis method using axi-symmetric model are investigated and the numerical analyses using axi-symmetric models for two types of flange design are performed in order to compare the flange rotation, gasket contact stress and stress level of flange and bolts. The contact stress of New Div.2 flange was lower than that of Old Div.2 flange totally. However the maximum gasket contact stress of New Div.2 flange which occurred at outer edge of the gasket is almost same as that of Old Div.2. Therefore it is expected that the sealing performance of flange connections per both Old Div.2 and New Div.2 is almost same.

Factors contributing to burnout among perfusionists in the United States

Perfusion ◽  
2011 ◽  
Vol 26 (6) ◽  
pp. 461-466 ◽  
Author(s):  
J Bui ◽  
A Hodge ◽  
A Shackelford ◽  
J Acsell
Keyword(s):  
Stress Level ◽  
Employee Turnover ◽  
Electronic Mail ◽  
Maslach Burnout Inventory ◽  
The United States ◽  
Current Level ◽  
Professional Burnout ◽  
Turnover Rates ◽  
Job Demand ◽  
As Stress

Introduction: As the job climate continues to change, many perfusionists are faced with high employee turnover rates, working longer hours, and increased stress related to more complex surgeries. Understanding the sources of professional burnout and stress may allow the formulation of a strategy to help prevent such negative outcomes. The purpose of this study was to determine the current level of stress and burnout among perfusionists. Methods: A questionnaire was constructed with the use of SurveyMonkey®. Invitations requesting participation in the survey were distributed by electronic mail to members of PerfList and PerfMail. To assess burnout, components of the well-established Maslach Burnout Inventory (MBI) tool were used. Results: At p<0.05, job demand variables such as stress level, conflict, call duties, hours worked, and case load were all shown to have a statistically significant relationship to burnout. Conclusion: The study found that, among the various factors, job demands were the most likely culprit contributing to burnout. Stress level and conflict, in particular, had the strongest association to burnout.

Analysis of Packer Rubber Mechanics Properties

2014 ◽  
Vol 971-973 ◽  
pp. 380-389
Author(s):  
Jian Ning Wang ◽  
Gang Wu ◽  
Wei Yi Xie ◽  
Xin De Han ◽  
Ming Chao Gang
Keyword(s):  
Finite Element ◽  
Elastic Modulus ◽  
Constitutive Model ◽  
Contact Stress ◽  
Theoretical Basis ◽  
Element Model ◽  
Rubber Material ◽  
Bottom Hole ◽  
Sealing Performance ◽  
The Finite Element Model

Abstract: The packer rubber stress in the bottom hole is more complex. Based on constitutive model of the packer rubber material, this paper determines such parameters as model constants, Poisson's ratio of rubber materials and elastic modulus by using experimental method, to build up the finite element model of center tube-rubber cylinder-casing for the purpose of stress analysis. Finally, the distribution regularity of rubber cylinder-casing contact stress and packer setting travel distance with varying loads is concluded. The results can provide the theoretical basis for further analysis of packer rubber sealing performance.

scholarly journals HUBUNGAN ANTARA TINGKAT STRES DENGAN KUALITAS TIDUR PADA WARGA BINAAN DI LEMBAGA PEMASYARAKATAN KLAS IIA YOGYAKARTA

2018 ◽  
Vol 7 (1) ◽  
pp. 28-33
Author(s):  
Dheska Arthyka Palifiana ◽  
Ratih Kumorojati
Keyword(s):  
Sleep Quality ◽  
Stress Level ◽  
Sampling Technique ◽  
Class Ii ◽  
Women Prisoners ◽  
P Value ◽  
Chi Square ◽  
Cross Sectional ◽  
As Stress

Background: To have rest or to sleep is basic need that needed by everyone.  To have enough rest or sleep will make body functioned optimally. By sleeping people can restore or to rest the physical after whole day activities, it can reduce stress and anxiety. It also improve concentration and improve ability when doing daily activities. Factors that affect quality and quantity of sleep include ill, fatigue, environment, lifestyle, emotional stress, diet, smoking, stimulant, alcohol, and motivation. The stress level on assisted citizen of woman’s prisoner will be more severe than who are not in prison so as stress can be overcome then the quality of sleep becomes better. Objective:To know the correlation between stress levels and sleep quality on assisted people in woman Penitentiary class II A Yogyakarta. Methods: The research was conducted at women's prison class II A Yogyakarta.  Research population was 117 women prisoners. The sample was 50 women prisoners. Type of the research was descriptive analytic research with cross sectional design. Statistical analysis used chi square. The sampling technique used purposive sampling. Results: The stress level was mostly in high category as many as 17 respondents experienced stress (34%). Sleep quality of the respondents were mostly in bad category as many as 38 respondents (76%). There is a correlation between stress level and sleep quality on women prisoners in Penitentiary class II A Yogyakarta with p-value (0.033). Conclusion: There is a correlation between stress level and sleep quality on women prisoners in Penitentiary class II A Yogyakarta.   Keywords:Stress level, sleep quality, assisted people, penitentiary

Tubing String Thread Sealing Surfaces Damage Evaluation Based on Acoustic Elasticity Theory

2019 ◽  
Vol 944 ◽  
pp. 828-834 ◽  
Author(s):  
Jian Jun Wang ◽  
Jian Hua Sun ◽  
Shang Yu Yang ◽  
Yao Rong Feng ◽  
Kai Lin
Keyword(s):  
Surface Roughness ◽  
Elasticity Theory ◽  
Contact Stress ◽  
Surface Characterization ◽  
Surface Damage ◽  
Center Frequency ◽  
Sealing Performance ◽  
Tubing String ◽  
Acoustic Elasticity

During the processing of tubing premium threaded made up, the degree of the thread sealing surface intactness will directly affect the sealing performance of the string. Nevertheless, there are some difficulties to detect the damage of the engaged sealing surface effectively. In the present study the sealing surface damage was judged by the sealing surface contact stress’s relative changes according to the acoustic elasticity theory,. At the same time, the wear defects generated at the tubing sealing surface, during the tubing made up, contrasted with the wear and unworn surface roughness of coupling ultrasonic detected about the sealing surface. The results showed that with the acoustic amplitude evaluated the sealing contact stress was susceptible to the influence of surface roughness of coupling. But the reflection wave with the center frequency on the sealing surface characterization of the contact stress could avoid this problem effectively.

FEM Stress Analysis and the Sealing Performance Evaluation in Stainless Steel Elbow and Tee Fittings Under Internal Pressure: Case Where Internal Fluid is Liquid

2004 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Hideaki Shimazu
Keyword(s):  
Stainless Steel ◽  
Internal Pressure ◽  
Stress Analysis ◽  
Chemical Plants ◽  
Three Dimension ◽  
Sealing Performance ◽  
Internal Fluid ◽  
Calculated Stress ◽  
Stress States ◽  
Screw Threads

Stainless steel fittings such as elbows, tees, nipples and so on have been widely used in mechanical structures and chemical plants, it is well known that the leakage in the fittings used sealing tapes is less than that without the sealing tapes. In a practical design, it is necessary to examine the stress states and the leakage in the fittings under internal pressure and external loads such as tensile loads, bending moments and so on. This paper deals with the FEM stress analysis of the fittings subjected to internal pressure. In the FEM calculations, the engaged screw threads are taken into consideration as helical threads in the three-dimension. The leakage tests for the fittings under internal pressure were also conducted by using liquid (oil). Using the results of the leakage tests and the calculated stress states in the fittings, the sealing performance of the fittings under internal pressure was evaluated and the effect of the tightening torque was clarified on the sealing performance. In addition, the numerical results were compared with the experimental results. As the result, the effects of the sealing tapes on the contact stress distributions were also clarified.

FLANGED JOINT ANALYSIS: A SIMPLIFIED METHOD BASED ON ELASTIC INTERACTION

1993 ◽  
Vol 17 (2) ◽  
pp. 181-196 ◽  
Author(s):  
A. Bouzid ◽  
A. Chaaban
Keyword(s):  
Fluid Pressure ◽  
Elastic Interaction ◽  
Bolted Joints ◽  
Joint Analysis ◽  
Simple Analytical Model ◽  
Good Design ◽  
Sealing Performance ◽  
Internal Fluid ◽  
Simplified Method ◽  
Joint Behaviour

Structurally sound bolted joints often fail due to loss of tightness. This is because the clamping load is affected by the application of the internal fluid pressure. A good design technique should therefore encompass most aspects of joint behaviour and produce efficient sealing performance within the clearly defined limits of the method used. This paper presents a simple analytical model based on an extension of the Taylor Forge approach taking into account flange rotation, flexibility of both the gasket and the bolts and, when applicable, the stiffness of the end closure. Examples will be discussed based on experimentally determined gasket properties.

502 Relationship between sealing performance and gasket contact stress of pipe flange connections

2004 ◽  
Vol 2004 (0) ◽  
pp. 127-128
Author(s):  
Kouji SATOU ◽  
Tomohiro TAKAKI ◽  
Yuki YAMANAKA ◽  
Toshimichi FUKUOKA
Keyword(s):  
Contact Stress ◽  
Sealing Performance

On the Effect of External Bending Loads in Bolted Flange Joints

2007 ◽  
Author(s):  
Abdel-Hakim Bouzid ◽  
Yves Birembaut ◽  
Hubert Lejeune
Keyword(s):  
Analytical Model ◽  
Contact Stress ◽  
Analytical Approach ◽  
Bolted Joint ◽  
Acceptable Solution ◽  
Sealing Performance ◽  
Circumferential Distribution ◽  
Bending Loads ◽  
Minimum Stress ◽  
Bolted Flange

Most current flange design methods use an equivalent pressure to treat bolted flange connections subjected to external bending loads. This oversimplified approach together with the lack of a proper assessment of the actual affected tightness make these methods inadequate for modern flange design. The substitution of the external applied moment by an equivalent pressure is excessively conservative and not realistic since it assumes that the achieved tightness is that of a gasket unloaded entirely to a minimum stress whereas in reality only a small section of it is, the rest of it is actually at a much higher stress. The successfulness of a valid analytical approach in yielding to an acceptable solution resides in its ability to account for the circumferential distribution of the gasket contact stress and its effect on leakage. This paper presents an analytical model based on the flexibility of the flange to treat flanges subjected to bending loads such as those produced by external moments and misalignments and capable of integrating leakage around the gasket circumference. The bolted joint sealing performance in the presence of such loads is evaluated using the new PVRC gasket constants Gb, a and Gs obtained from ROTT tests. The analytical results including leakage predictions are validated by comparison to those obtained numerically by FEA and experimentally on different size flanges. The over-conservatism of the equivalent pressure is demonstrated.

scholarly journals TERAPI MURATTAL SURAT AR-RAHMAN MENURUNKAN STRES KEHAMILAN

2019 ◽  
Vol 4 (1) ◽  
pp. 38-41
Author(s):  
Anni Annisa ◽  
Emdat Suprayitno
Keyword(s):  
Pregnant Women ◽  
Stress Level ◽  
Test Design ◽  
Mild Stress ◽  
Severe Stress ◽  
Career Women ◽  
Post Test ◽  
Sample Technique ◽  
As Stress ◽  
Moderate Stress

Pregnancy is a life process that women will experience after marriage. But not all women have the chance to get pregnant, it is very natural for many women who consider pregnancy to be an extraordinary period so that women focus on filling their pregnancy with activities that make the fetus grow healthy. Spikologis reactions such as stress in pregnant women caused a non-smooth process and the risks experienced by pregnant women, so not all women have a smooth pregnancy. This type of research uses quasy-experiment using one group pre-post test design test. Therapy is measured by the stress level of pregnant women for 15 minutes after Qs therapy. The beneficent. Murattal Audio Qs. Ar-Rahman and the DASS (Depression Anxiety Stress Scales) questionnaire. In this study, researchers used the sample technique in an incidental manner. The sample used as many as 56 pregnant women, consisting of 28 pregnant women who work as career women and 28 people who work as housewives After the Murattal therapy of Qs Ar-Rahman in 56 respondents there was a decrease in the stress level of pregnant women. 35 respondents of pregnant women experienced mild stress with a percentage of 62.5%, with moderate stress as many as 15 pregnant women with a percentage of 26.8%. While for severe stress 6 pregnant women with a percentage of 10.7%.

An Analysis of Circular Bolted Flanged Joints on Solid Round Bars Subjected to External Bending Moments

2000 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Tsuneshi Morohoshi ◽  
Akihiro Shimizu
Keyword(s):  
Stress Distribution ◽  
Contact Stress ◽  
Three Dimensional ◽  
Bending Moment ◽  
Theory Of Elasticity ◽  
Load Factor ◽  
Bending Moments ◽  
Sealing Performance ◽  
Contact Stress Distribution ◽  
Good Agreement

Abstract In designing bolted joints, it is important to know the contact stress distribution which governs the clamping effect or the sealing performance and to estimate the load factor (the ratio of an increment in axial bolt force to an external load) from bolt design standpoint. The clamping force by bolts and the external bending moment are axi-asymmetrical loads and not many investigations have seen reported which treat axi-asymmetrical. In this paper, the clamping effect, and the load factor for the case of solid round bars with circular flanges, subjected to external bending moments, are analyzed as an axi-asymmetrical problem using the three-dimensional theory of elasticity. Experiments were carried out concerning the contact stress distribution, and the load factor for the external bending moment (a relationship between an increment in axial bolt force, and external bending moment). The analytical results were in fairly good agreement with the experimental ones.

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