Application of Plastic Region Bolt Tightening to Flange Joint Assembly: Behavior of Compact Flanged Joint Subjected to Thermal Load

2010 ◽  
Author(s):  
Shinobu Kaneda ◽  
Yoshiyasu Shimizu ◽  
Satoshi Nagata ◽  
Hirokazu Tsuji
Keyword(s):  
Thermal Load ◽  
Plastic Region ◽  
Load Factor ◽  
Past Study ◽  
Flange Joint ◽  
Allowable Limit ◽  
The Past ◽  
Internal Fluid ◽  
Assembly Behavior ◽  
Yield Force

In the past study the plastic region tightening has been applied to the compact flange joint and its advantages have been demonstrated. However, behavior of the compact flange joint subjected to the thermal load is not investigated. There are reduction of the gasket stiffness, the flange rotation, and difference in the thermal expansion among the members making up the flange joint. It is well known that these problems cause the change in axial bolt force. The present paper describes the behavior of the compact flange joint subjected to the thermal load under the plastic region tightening. Since there is a difference in temperature between the compact flange joint and the bolts, the axial bolt force increases as the temperature of the internal fluid increases. The additional axial bolt force is positive when the thermal loads are applied to the compact flange joint. However, the additional axial bolt force was approximately 3% of the bolt yield force at maximum and the bolt had a sufficient margin for the allowable limit. Additionally, the load factor depends on the change in the elastic modulus due to change in temperature of the internal fluid.

Application of Plastic Region Bolt Tightening to Flange Joint Assembly: Behavior of Large Diameter Flange

2009 ◽  
Author(s):  
Shinobu Kaneda ◽  
Hirokazu Tsuji
Keyword(s):  
Internal Pressure ◽  
Large Diameter ◽  
Plastic Region ◽  
Load Factor ◽  
Past Study ◽  
Flange Joint ◽  
The Past ◽  
Sealing Performance ◽  
Assembly Behavior ◽  
Bolted Flange

In the past study the plastic region tightening has been applied to the bolted flange joint with smaller nominal diameter and its advantages have been demonstrated, however, behavior of the bolted flange joint with larger diameter is not investigated. Flange rotation of the bolted flange joint with large diameter increases when the internal pressure is applied. Gasket stress is not uniform and it may cause leak accident. So, it is necessary to investigate the behavior of the larger diameter flange. The present paper describes the behavior of bolted flange joint with large diameter under plastic region tightening. Firstly, API 20-inch flange joint tightened to the plastic region by bolt with a smaller diameter and superiority in the uniformity of the axial bolt force is demonstrated. And then the internal pressure is applied to the bolted flange joint and the behavior of the additional axial bolt force is demonstrated. The axial bolt force decreases with increasing the internal pressure, and the load factor is negative due to increasing of the flange rotation. However, the load factor of the bolted flange joint tightened to the plastic region by using the bolt with the smaller diameter approached zero. Using the bolts with smaller diameter is advantageous to the flange joint with the larger diamter, whose load factor is negative, to prevent the leakage. Additionally, the leak rate from the bolted flange joint is measured and the sufficient sealing performance is obtained.

Application of Plastic Region Tightening Bolt to Flange Joint Assembly: Downsizing of Flange Joint and Behavior of Bolt Force Under Internal Pressure

2008 ◽  
Author(s):  
Shinobu Kaneda ◽  
Hirokazu Tsuji
Keyword(s):  
Internal Pressure ◽  
Plastic Region ◽  
Load Factor ◽  
Outer Diameter ◽  
Flange Joint ◽  
Allowable Limit ◽  
Graphite Sheet ◽  
And Behavior ◽  
Yield Force ◽  
Bolt Spacing

The present paper describes the behavior of plastic region tightening of a bolt in a downsized flange joint subjected to internal pressure. An API 4-inch flange joint is downsized for plastic region tightening. The bolt is reduced from M16 to M8, and the bolt pitch circle diameter and the outer diameter of the flange are decreased by 11%. The flange rigidity and the stresses of the compact flange joint are calculated and are superior to the original API flange joint. The bolt spacing is also examined, and the correction factor for bolt spacing is acceptable. Internal pressure is applied to a compact flange joint, and the behavior of additional bolt force is demonstrated. Load factor depends on the type of gasket, such that the load factor is positive for a flexible graphite sheet gasket. The load factor is in agreement with the value calculated by the Load Factor Method (LFM). When the external force is applied to the bolted joint under plastic region tightening, the allowable limit of the additional bolt force is approximately 10% of the bolt yield force. In the present experiment, the additional bolt force is as small as 1% of the bolt yield force. Therefore, the additional bolt force has sufficient margin for the allowable limit.

Application of Plastic Region Tightening Bolt to Flange Joint Assembly: Behavior of Bolt Preload in Flange Joint Subjected to Internal Pressure

2007 ◽  
Author(s):  
Shinobu Kaneda ◽  
Hirokazu Tsuji
Keyword(s):  
Internal Pressure ◽  
Axial Force ◽  
Control Method ◽  
Plastic Region ◽  
Torque Control ◽  
Flange Joint ◽  
Allowable Limit ◽  
Torque Wrench ◽  
Assembly Behavior ◽  
Joint Assembly

Elastic region tightening by means of the torque control method is a conventional method to tighten bolts. The bolt axial force is controlled by a torque wrench; however, it is not easy to achieve constant bolt axial force. When the torque control method is applied to the flange joint assembly, the scatter of the bolt axial force is significant with respect to the joint reliability, such that it may cause leakage of the internal fluid from the flange joint. Recently, plastic region tightening has received considerable attention, which provides good uniformity in the bolt axial force. In a previous study, plastic region tightening was applied to a flange joint assembly, and the superior uniformity of the bolt axial force was demonstrated. The present paper describes the behavior of the plastic region tightening bolt in a flange joint subjected to internal pressure. First, the flange joint is tightened to the plastic region using a downsized bolt. The internal pressure is then applied to the flange joint, and the behavior of the additional bolt axial force is investigated. Application of plastic region tightening to the flange joint assembly is found to be effective for obtaining leak-free joints and for downsizing of the nominal diameter of the bolt. The behavior of the bolt axial force in a flange joint subjected to internal pressure was clarified. The additional bolt axial force has a sufficient margin for the allowable limit.

scholarly journals Looking at the Nudibranch Family Myrrhinidae (Gastropoda, Heterobranchia) from a Mitochondrial ‘2D Folding Structure’ Point of View

Life ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 583
Author(s):  
Giulia Furfaro ◽  
Paolo Mariottini
Keyword(s):  
16S Rrna ◽  
Phylogenetic Analyses ◽  
Integrative Taxonomy ◽  
Point Of View ◽  
Past Study ◽  
Mitochondrial Coi ◽  
The Past ◽  
Combining Data ◽  
Folding Structure ◽  
Comparison Of The Results

Integrative taxonomy is an evolving field of multidisciplinary studies often utilised to elucidate phylogenetic reconstructions that were poorly understood in the past. The systematics of many taxa have been resolved by combining data from different research approaches, i.e., molecular, ecological, behavioural, morphological and chemical. Regarding molecular analysis, there is currently a search for new genetic markers that could be diagnostic at different taxonomic levels and that can be added to the canonical ones. In marine Heterobranchia, the most widely used mitochondrial markers, COI and 16S, are usually analysed by comparing the primary sequence. The 16S rRNA molecule can be folded into a 2D secondary structure that has been poorly exploited in the past study of heterobranchs, despite 2D molecular analyses being sources of possible diagnostic characters. Comparison of the results from the phylogenetic analyses of a concatenated (the nuclear H3 and the mitochondrial COI and 16S markers) dataset (including 30 species belonging to eight accepted genera) and from the 2D folding structure analyses of the 16S rRNA from the type species of the genera investigated demonstrated the diagnostic power of this RNA molecule to reveal the systematics of four genera belonging to the family Myrrhinidae (Gastropoda, Heterobranchia). The “molecular morphological” approach to the 16S rRNA revealed to be a powerful tool to delimit at both species and genus taxonomic levels and to be a useful way of recovering information that is usually lost in phylogenetic analyses. While the validity of the genera Godiva, Hermissenda and Phyllodesmium are confirmed, a new genus is necessary and introduced for Dondice banyulensis, Nemesis gen. nov. and the monospecific genus Nanuca is here synonymised with Dondice, with Nanuca sebastiani transferred into Dondice as Dondice sebastiani comb. nov.

Comfort-energy nexus in naturally ventilated affordable mass housing with alternative constructions in the developing world

2021 ◽  
Author(s):  
Roshmi Sen ◽  
Shankha Pratim Bhattacharya ◽  
Subrata Chattopadhyay
Keyword(s):  
Energy Efficiency ◽  
Thermal Comfort ◽  
Thermal Load ◽  
Mixed Mode ◽  
Developing World ◽  
Assessment Model ◽  
Strong Positive Correlation ◽  
Mass Housing ◽  
The Past ◽  
Comfort Indices

<p>There is a strong positive correlation between thermal comfort quality experienced inside a building and its energy efficiency. This is more obvious in case of mechanically ventilated spaces where the energy gains are directly related to the thermal load, as compared to free running or naturally ventilated spaces. Current state of arts assess the energy efficiency of building envelops in terms of the cumulative thermal load in the operating phase of the building that are catered by mechanical ventilations. Our study aims at addressing this gap of research in assessing the thermal comfort quality of naturally ventilated residential living spaces. Our study is designed in a warm-humid climate setting and in the context of affordable mass housing in the developing world where mechanical ventilation is unaffordable or affordable only for a definite period of the day and during peak summer seasons; such buildings are said to be operating in temporal mixed mode.</p><p>Affordable mass housing constitutes 95% housing demand in the residential sector in India. Various alternative materials and composite roofing and walling envelops have been envisioned in the past decade for such constructions, however, their effectiveness in terms of comfort quality has not been assessed for naturally ventilated envelops. Our study introduces a model to assess the thermal performance of naturally ventilated bedrooms constructed with alternate building envelop configurations. We attempt to review  and compare alternative walling technologies and the currently emerging mass housing construction systems in India with the base case housing envelop constructions commonly in practice in India that use ordinary burnt clay brick walls and reinforced concrete roofs. We compare the thermal comfort purveyed in the indoor bedroom spaces using the adaptive thermal comfort model in EN15251 as thermal neutrality temperature. We assess and compare alternative envelop performance using two measuring thermal comfort indices suited for naturally ventilated scenarios - the discomfort hours index and the cooling indoor degree hours index. Discomfort hours measures the number of hours of discomfort experienced during the summer solstice and spring equinox months whereas the cooling indoor degree hours measures the cumulative average temperature elevation from the comfort temperature in the hours marked as discomfort hours. In our study, light gauge steel framed structure with foam concrete filling records the minimum number of discomfort hours, however purveys maximum cooling indoor degree hours.</p><p>The above two comfort indices have not been compared in the past to assess the thermal comfort quality in naturally ventilated or temporal mixed mode buildings. Our study frames a thermal comfort assessment model for naturally ventilated envelops and thereby offers a paradigm shift from life cycle cooling load minimization models which are appropriate for mechanically conditioned spaces. Our observations are also important for mass housing envelop selection and in the context of the current policy frameworks in the developing world, aimed at minimizing the projected demand for residential space cooling and future energy footprints in the housing sector.</p>

Using the Explicit Dynamic Method to Simulate Pile Dynamical Driving Process

2010 ◽  
Vol 163-167 ◽  
pp. 366-371
Author(s):  
Jian Bing Lv ◽  
He Lin Fu ◽  
Hua Zhi Li ◽  
Zhe Liu
Keyword(s):  
Method Development ◽  
Elastic Solid ◽  
Computational Method ◽  
Dynamical Analysis ◽  
Pile Driving ◽  
Past Study ◽  
Analysis Method ◽  
The Past ◽  
Explicit Dynamic ◽  
Dynamical Stress

The dynamic pile driving process is so complex that till now the analysis on the process had been focusing on the filed test or laboratory test. However, the past study about the dynamic process is a time consuming one; with the computational method development, the numerical simulation on this process is possible. In this paper, explicit dynamical analysis method is adopted, the pile is simulated using the elastic solid element, two computational cases are considered and finally the pile driving process dynamical stress is studied.

Development and Validation of Evaluation Method on Hypothetical Total Instantaneous Flow Blockage in Sodium-Cooled Fast Reactors and its Application to a Middle Size SFR

2017 ◽  
Author(s):  
Yoshitaka Fukano
Keyword(s):  
Control System ◽  
Power Control ◽  
Evaluation Method ◽  
Safety Evaluation ◽  
Past Study ◽  
Fast Reactors ◽  
Instantaneous Flow ◽  
The Past ◽  
Power Control System ◽  
Flow Blockage

Local faults (LFs) have been considered to be of greater importance in safety evaluation in sodium-cooled fast reactors (SFRs) because fuel elements were generally densely arranged in the subassemblies (SAs) in this type of reactors, and because power densities were higher compared with those in light water reactors. A hypothetical total instantaneous flow blockage at the coolant inlet of an SA (HTIB) gives most severe consequences among a variety of flow blockages. Although an evaluation on the consequences of HTIB using SAS4A code was also performed in the past study, SAS4A code was further developed by implementing analytical model of power control system in this study. An evaluation on the consequences of HTIB in Monju by this developed SAS4A code was performed in this study. Furthermore SAS4A code was newly validated using an in-pile experiment which simulated HTIB events. The validity of SAS4A application to safety evaluation on the consequence of HTIB was further enhanced in this study. It was clarified by the analyses considering power control system that the reactor would be safely shut down by the PPS triggered by either of 116% over power or DND trip signals. Therefore the conclusion in the past study that the consequences of HTIB would be much less severe than that of ULOF was strongly supported by this study.

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