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.

The Uneven Settlement Cause and Settlement Prediction of Xi Ying Sluice

2015 ◽  
Vol 733 ◽  
pp. 116-119
Author(s):  
Qing Yuan Zhu ◽  
Li Ting Qiu ◽  
Ting Jiang
Keyword(s):  
Three Dimensional ◽  
Normal Operation ◽  
Wall Structure ◽  
Construction Period ◽  
Settlement Prediction ◽  
Concrete Pile ◽  
Operation Period ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Design Construction

Xi Ying sluice built in Xishi River, Changzhou City, is a single span sluice with width of 6m. The chamber is pier wall structure of depressed reinforced concrete floor, when the chamber had a filling and discharging water during construction period, we found that the chamber appeared large uneven subsidence. According to the design, construction and other specific circumstances of Xi Ying sluice, by using three-dimensional finite element method to calculate and analyzed the settlement of the sluice, we studied on the genesis of the uneven settlement and predicted the settlement after the running. Analysis shows that the chamber of the uneven settlement is due to the jacking effect of concrete pile. The settlement has been basically completed caused by chamber weight, there will not be a substantial settlement; In the case of blocking water during operation period, chamber’s settlement increment outside the river side and inside the river side are respectively 0.3mm and 0.4mm; through processing, the settlement of chamber won’t affect the normal operation of sluice.

Channel Strain Analysis in Damascene-gate pMOSFETs on Si (100) and (110) Substrate by Conventional and Cross-sectional Raman Spectroscopy

2009 ◽  
Vol 1194 ◽  
Author(s):  
Munehisa Takei ◽  
Daisuke Kosemura ◽  
Kohki Nagata ◽  
Hiroaki Akamatsu ◽  
Satoru Mayuzumi ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Compressive Stress ◽  
Measurement Data ◽  
Strain Analysis ◽  
Channel Length ◽  
Laser Exposure ◽  
Strain Component ◽  
Gate Stack ◽  
Cross Sectional ◽  
Channel Center

AbstractChannel strain in damascene gate pMOSFETs with compressive stress liner (c-SL) and embedded SiGe (eSiGe) were studied by micro-Raman spectroscopy with a quasi-line-shape UV excitation (λ=363.8nm). The channel strain profiles were obtained by the conventional mea-surement from the surface after dummy gate removal. The compressive strains at the channel edges were larger than that at the channel center for the relatively long gate length (Lgate). As the Lgate became smaller, although it became hard to recognize the strain profile, the compres-sive strain at the channel center increased by the superposition of the strain at the channel edges. However, channel strain disappeared in the measurement data for the channel length less than 160 nm. Thus, we extended the laser exposure time from 10 to 40 minutes to extract the channel strain component from obtained Raman spectra. The Raman peaks consisted of two or three peaks for the Lgate less than 160 nm. By multi peak fitting, we have succeeded in measuring the extremely large stress of - 2.4 GPa in the channel of Lgate = 30 nm pMOSFET. We also per-formed the cross-sectional measurements for the samples before and after metal-gate/high-k gate stack formation. Channel strain profiles were obtained similar to those by the conventional mea-surement. Extremely high device performance can be clearly explained by the compressive stress derived from the Raman measurements both in the Lgate dependence and eSiGe effect. We also demonstrated that Raman spectroscopy using cross-sectional measurement can evaluate the channel strain even in the MOSFETs after gate stack formation.

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.

Mechanical Properties of the Ecological Filling Blocks of the New Composite Wall Based on the Unified Strength Theory

2011 ◽  
Vol 250-253 ◽  
pp. 843-848
Author(s):  
Wei Huang ◽  
Hao Zhen Wu ◽  
Guo Xin Chen ◽  
Yin Zhang ◽  
Jun Yuan Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Stress ◽  
Lightweight Concrete ◽  
Yield Criterion ◽  
Testing Machine ◽  
Wall Structure ◽  
Strength Theory ◽  
Stress Strain ◽  
Unified Strength Theory ◽  
Composite Wall

In order to make the new composite wall structure the group developed to adapt different regional natural conditions, and along with the demand of gradually in-depth study the damage characteristics of the new composite wall, need to research the mechanical properties of the wall filling materials. In this paper, the ZG-CSS Electronic Universal Testing Machine was used on the uniaxial compressive test of the three blocks(the mud billet block, the cotton stalk block, the recycled EPS lightweight concrete block), to analyze the failure characteristics of the blocks and the other mechanical properties, such as Poisson’s ratio, elastic modulus, then the full compressive stress-strain curves are given, and at last fitting the mathematical expression of the uniaxial compressive stress - strain curves. And this paper also gives the yield criterion based on the unified strength theory of the three ecological filling blocks.

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.

Computational Fluid Dynamics Guided Investigation for Reducing Emissions and Increasing Exergy of the Pyroscrubber in a Petcoke Calcining Facility

2012 ◽  
Vol 4 (1) ◽  
Author(s):  
Zhao Lei ◽  
Wang Ting
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Measurement Data ◽  
Energy Output ◽  
Pollutant Emission ◽  
Wall Structure ◽  
Strong Mixing ◽  
Nox Emissions ◽  
Gas Temperature ◽  
Reduce Emissions

A pyroscrubber is a device used in the petroleum coke calcining industry to oxidize the carbonaceous contents, including hydrocarbon volatiles of the exhaust gas from the calcination kiln, so as to recover energy to produce electricity and leave no more than small traces of unburned volatiles, solid carbon, ash, or emission (e.g., CO, NOx, and SOx) in the flue gas discharged. Motivated by the need to maximize the energy recovery and reduce the pollutant emission from the pyroscrubber, a 3D computational model is developed to simulate the combustion and thermal-flow phenomena inside a pyroscrubber to guide an investigation of the means to reduce emissions and increase exergy output for downstream power generation. Computational fluid dynamics model validation is achieved by comparing the baseline case results with the plant measurement data of the temperature at three different locations, high bay, middle of the chamber, and exit, as well as NOx emissions at the exit. The simulation results show that the specially designed high-bay wall structure generates a strong mixing zone, forcing combustion to happen at an earlier stage and helping to efficiently utilize the main chamber space. A well-balanced amount of excess air is favorable in generating more energy output and lowering NOx emissions. Incomplete combustion with substoichiometric air cuts NOx emissions, but leads to less total energy output, lowers gas temperature, and increases CO emissions. A multistage burning strategy is introduced and studied and results show that it successfully cuts emission without compromising energy (electricity power) output.

scholarly journals Model for the analysis of thermal conductivity of composite material of natural origin

2019 ◽  
Vol 23 (6 Part A) ◽  
pp. 3513-3523
Author(s):  
Ilija Milicic ◽  
Radomir Folic ◽  
Aleksandar Prokic ◽  
Arpad Ceh
Keyword(s):  
Thermal Conductivity ◽  
Mathematical Model ◽  
Composite Material ◽  
Measurement Data ◽  
Experimental Tests ◽  
Wall Structure ◽  
Passive House ◽  
Average Value ◽  
Passive Houses ◽  
The Continuum

Thermal properties of the wall structure elements made from gel and straw (?Ethno-eco-passive houses?) have been investigated. The gel was made from a mixture of clay, lime, and water. A 1-D mathematical model based on the continuum mechanics, for predicting the thermal conductivity, is proposed. The results obtained by applying the proposed mathematical model were compared with the measurement data of experimental tests, using the Isomet 2114 instrument. The program envisages the measurement of thermal conductivity of three specimens, 5-year-old, comprising three series within 365 days. In the theoretical analysis, the same parameters of thermal stability were treated as in the experiment. The average value of the material thermal conductivity is 0.0990 W/mK, so it can be concluded that, the composite material intended for the envelope of the proposed constructive system ?Ethno-eco-passive house? is verified as thermally suitable.

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