Numerical Analysis on the Expanding Process of Expandable Casing and Contact Evaluation of its Threaded Connection

2013 ◽  
Vol 378 ◽  
pp. 632-638
Author(s):  
Xin Pu Shen ◽  
Guo Yang Shen
Keyword(s):  
Numerical Analysis ◽  
Driving Force ◽  
Equivalent Plastic Strain ◽  
Expansion Process ◽  
Accurate Analysis ◽  
Threaded Connection ◽  
Sealing Capacity ◽  
Maximum Value ◽  
Processing Accuracy ◽  
3D Finite Element Method

A detailed analysis of the expansion process will not only provide proper estimates for processing accuracy, but will also provide critical information needed to properly design the driving force required to perform the expansion process. Furthermore, accurate analysis of the contact of the threaded connection is necessary for estimating the sealing capacity of an expandable casing section after expansion. The 3D Finite Element Method has been used to numerically simulate the expansion process fora given expandable casing section. The principal results obtained from this numerical analysis include: 1) maximum value and distribution of equivalent plastic strain after expansion within the casing, 2) deformed casing shape, 3) maximum value and distribution of contact force at contact surface between pin thread and box thread, and 4) variation in values of the driving force of the mandrel cone during the expansion process.

scholarly journals Experimental and numerical analysis of an oil-flooded air screw expander

2021 ◽  
Vol 345 ◽  
pp. 00026
Author(s):  
Lukas Richter ◽  
Zdenka Rendlova ◽  
Stanislav Planicka ◽  
Jan Seeger ◽  
Marco Taschek ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Experimental Device ◽  
Screw Compressor ◽  
Geometric Description ◽  
Expansion Process ◽  
Energy Unit ◽  
Working Chamber ◽  
3D Scan ◽  
Real Machine

This article describes the results of a project whose task is to research and develop a screw expander through the inversion of a screw compressor. The article summarizes aspects of the construction of an experimental device that works with an oil-flooded air screw expander. The expander was subjected to experimental and numerical analysis, the results of which are presented in the article. Numerical analysis to examine the expansion process is performed both on the basis of the analytical geometric description of the working chamber of the expander and on the basis of the geometry obtained from a 3D scan of a real machine. The results of experimental and numerical analysis will be used to integrate an oil-flooded screw expander into an energy unit for the use of low-potential heat, for example in ORC systems.

Input-output relations of the feedback synapse between horizontal cells and cones in the tiger salamander retina

1991 ◽  
Vol 65 (5) ◽  
pp. 1197-1206 ◽  
Author(s):  
S. M. Wu
Keyword(s):  
Driving Force ◽  
Light Response ◽  
Horizontal Cells ◽  
Resting Potential ◽  
Voltage Gain ◽  
Input Output ◽  
Light Responses ◽  
Maximum Value ◽  
Truncated Cone ◽  
The Relationship

1. The input-output relation of the feedback synapse between horizontal cells (HCs) and cones was studied by simultaneously recording the light responses of the HCs and of cones the outer segments of which were truncated off. 2. The postsynaptic light response of the truncated cone was depolarizing and free of direct influence of photocurrents. These postsynaptic light responses were graded and sustained; their waveform resembled that of the HC light responses. 3. Input-output relation of the HC-cone feedback synapse was obtained by plotting the simultaneous voltage points of the HC and truncated cone light responses. At the resting potential of the cone (-40 mV), the voltage gain of the feedback synapse was about -0.33 when VHC = -20 mV and it was about -0.03 when VHC = -60 mV. 4. At more hyperpolarized cone voltages, the feedback signals in cones became smaller, and they reversed at about -67 mV. The voltage gain of the feedback synapse at VHC = -20 mV was about -0.23, -0.18, -0.07, and +0.2 when Vcone = -44.5, -52.5, -65, and -77.5 mV, respectively. 5. Light hyperpolarized the HC, which resulted in a conductance change (delta Gs) in cones. The cone conductance decreased progressively as the HCs were increasingly hyperpolarized, and delta Gs reached a maximum value of 0.93 nS when the HCs were hyperpolarized from -20 to -52 mV. 6. The peak light responses of intact cones were plotted against the peak HC light responses. This gives the relationship between the pre- and postsynaptic voltages of the cone-HC (forward) and HC-cone (feedback) synapses at any given light intensity. Combining this relationship with the input-output relations obtained at various voltages of the truncated cones allows the input-output relation of the feedback synapse for light-evoked signals to be obtained. 7. The input-output relation of the feedback synapse for light-evoked signals was bell-shaped, because the feedback light responses were controlled by two opposing factors: as the light became brighter, the postsynaptic conductance change increased, but the driving force decreased. 8. For light-evoked signals, the slope gain (slope of the input-output relation) of the HC-cone feedback synapse was negative (varied from -0.33 to 0) when VHC lay between -20 and -52 mV; and it was positive (0 to +0.8) when VHC lay between -52 and -72 mV. 9.(ABSTRACT TRUNCATED AT 400 WORDS)

Numerical Analysis of Fire Performance of a Spacial Pre-Stressed Steel Structure in Fire

2013 ◽  
Vol 790 ◽  
pp. 189-192
Author(s):  
Tian Hong Wang ◽  
Jin Can Xu ◽  
Hai Lun Tong ◽  
Xin Tang Wang
Keyword(s):  
Thermal Expansion ◽  
Numerical Analysis ◽  
Numerical Model ◽  
Stress Relaxation ◽  
Thermal Response ◽  
Structural Response ◽  
Steel Structure ◽  
Fire Performance ◽  
Maximum Value ◽  
In Fire

The numerical model of analysis of fire performance of a spatial pre-stressed steel structure with large span was established based on the software Marc. The thermal response and structural response of the pre-stressed steel structure was computed for some nodes of the structure in fire. The different fire scenes were considered for analysis of response temperature, displacements and stresses of the nodes of the pre-stressed steel structure.It is concluded that the temperature rise of the nodes of the structure is far behind that of air near the nodes, however they are quite close as the fire lasted for 3600s and almost the same after 7200s.The results show that the displacement of the node right above the inner cable is the maximum and the node above the outer cable has the smallest value of displacement and the maximum value is about two and half times as large as the minimum.The results show that the reason why the cables are out of work is that the equilibrium between the cables and the rods of the structure is lost, but not that the stress relaxation caused by thermal expansion make the cables out of work.

Effects on Plasticity and Structural Integrity of Tube Expansion

2012 ◽  
Author(s):  
Rashid Khan ◽  
Tasneem Pervez ◽  
Sayyad Zahid Qamar
Keyword(s):  
Mechanical Properties ◽  
Structural Integrity ◽  
Equivalent Plastic Strain ◽  
Cost Effective ◽  
Oil Well ◽  
Strain Rates ◽  
Expansion Process ◽  
Cold Expansion ◽  
Operational Conditions ◽  
Tube Expansion

This paper presents an investigation of the effects of cold expansion on plasticity and structural integrity of expandable tubulars. Down-hole tubular expansion has proven itself to be a vital technology in oil well applications. One of the challenges faced by researchers and field engineers in implementing and making down-hole tubular expansion technology cost effective is to conserve the structural integrity of tubular after the expansion process. Cold expansion affects the mechanical properties and induces residual stresses in the tubular, which could reduce its collapse, burst and fatigue ratings. Hence, a knowledge of variation of properties is required in correctly predicting the life span of tubular under given operational conditions. Cold expansion of tubulars under down-hole conditions is simulated at different strain rates using finite element method. The strain rates are varied by changing the velocity of mandrel used to expand the tubular. It is found that there are variations in contact pressure at tubular-mandrel interface, effective stress, equivalent plastic strain and thickness reduction during expansion process. These variations ultimately influence post-expansion properties of the tubular particularly the collapse and burst strengths, and hence its structural integrity. However, length shortening and surplus deformation have negligible effect on post-expansion properties of tubular.

scholarly journals The influence of river ice on spring runoff in the Lena river, Siberia

2005 ◽  
Vol 40 ◽  
pp. 123-127 ◽  
Author(s):  
Xieyao Ma ◽  
Tetsuzo Yasunari ◽  
Tetsuo Ohata ◽  
Yoshihiro Fukushima
Keyword(s):  
Numerical Analysis ◽  
The Arctic ◽  
Lena River ◽  
Spring Runoff ◽  
Maximum Value ◽  
The Arctic Ocean ◽  
Hydrological System ◽  
Break Up ◽  
The Difference ◽  
Spring Snowmelt

AbstractThe Lena river is one of the four largest rivers flowing into the Arctic Ocean. It has a complicated hydrological system that is affected not only by the amount of precipitation but also by the timing of ice break-up. To determine the mechanisms of runoff formation, a numerical analysis based on modeling was carried out for the period 1986–2000. The results show that (1) the timing of flood rise and peak can be modeled at Tabaga, which represents the upper and central portions of the Lena river; (2) river-freeze processes delay the spring, snowmelt-dominated flood by about 23 days; and (3) the difference between the break-up dates at Tabaga and Kirensk has ranged from several days to >2 months, and a maximum value of 69 days was recorded in spring 1998.

scholarly journals Study on Deep and Large Foundation Pit of a National First-Class Key Tomb Protection Project

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Jiagang Zhang ◽  
Zhimin Chen ◽  
Mingzhu Hu ◽  
Zhaoguo Wu
Keyword(s):  
Numerical Analysis ◽  
Large Range ◽  
Retaining Wall ◽  
Bending Moment ◽  
Foundation Pit ◽  
Reinforcement Scheme ◽  
Bored Pile ◽  
Maximum Value ◽  
The Stability ◽  
Support Engineering

For the support engineering of the deep and large foundation pit (DLFP) due to tomb protection, there are still no clear standards. The construction of DLFP will introduce large-range transverse and longitudinal disturbance on the stratum; therefore, it should be reinforced. In this paper, the reinforcement of the deep and large foundation pit of a national first-class key tomb protection project is studied. By comparing the existing supporting scheme and the stress conditions of the reinforced tomb, the combination reinforcement scheme by bored pile and pile slab retaining wall is found to be safe and feasible. Furthermore, according to the simulated bending moment, displacement, and axial force of the tomb by numerical analysis, an economic and reasonable mixed anchor support scheme is selected. In order to ensure the stability of the tomb during the supporting process of the foundation pit, a maximum value of 10 mm for the overall settlement of the tomb can be treated as the control benchmark based on the support and anchorage schemes in each specification and the in-site measured settlement values of the tomb. The determined support, anchorage schemes, and the control benchmark can provide certain technique guidance and research significance for the protection of similar ancient buildings in the future.

scholarly journals Experimental and Numerical Analysis of Expanded Pipe using Rigid Conical Shape

2018 ◽  
Vol 24 (8) ◽  
pp. 106
Author(s):  
Ahmed Ibrahim Razooqi
Keyword(s):  
Plastic Deformation ◽  
Finite Element ◽  
Numerical Analysis ◽  
Expansion Ratio ◽  
Large Plastic Deformation ◽  
Expansion Process ◽  
Finite Element Software ◽  
Conical Shape ◽  
Expansion Force ◽  
Good Agreement

The experimental and numerical analysis was performed on pipes suffering large plastic deformation through expanding them using rigid conical shaped mandrels, with three different cone angles (15◦, 25◦, 35◦) and diameters (15, 17, 20) mm. The experimental test for the strain results investigated the expanded areas. A numerical solution of the pipes expansion process was also investigated using the commercial finite element software ANSYS. The strains were measured for each case experimentally by stamping the mesh on the pipe after expanding, then compared with Ansys results. No cracks were generated during the process with the selected angles. It can be concluded that the strain decreased with greater angles of conical shape and an increase in expansion ratio results in an increase of expansion force and a decrease in the pipe thickness and length resulting in pipe thinning and shortening. Good agreement is evident between experimental and ANSYS results within discrepancy (16.90017%) in the X direction and (27.68698%) in the Y direction. Also, the stress distribution is investigated and it can be concluded that the case of Diameter (Do cone) = 35mm and (A) = α = 15° is the optimum.  

Two-Parameter Criteria for Ductile Crack Initiation and Propagation in High-Grade Line Pipes

2007 ◽  
Vol 348-349 ◽  
pp. 493-496
Author(s):  
Yoichi Kayamori ◽  
P.S.J. Crofton ◽  
Roderick A. Smith
Keyword(s):  
Crack Initiation ◽  
Plastic Strain ◽  
Driving Force ◽  
Equivalent Plastic Strain ◽  
Stress Triaxiality ◽  
High Grade ◽  
Ductile Crack ◽  
Force Curve ◽  
Crack Driving Force ◽  
The Relationship

Full-scale burst test data of high-grade line pipes for high-pressure gas pipelines were referred to, and 3-D elastic-plastic finite element analysis was carried out using the test data for the calculation of fracture parameters. Ductile crack initiation was evaluated by the intersection of a toughness locus and a crack driving force curve, where the toughness locus was indicated by the relationship between the critical equivalent plastic strain and the stress triaxiality, and the crack driving force curve was shown by a history of the equivalent plastic strain and the stress triaxiality at characteristic distance. In addition, ductile crack rapid propagation was assessed by the relationship between the critical CTOA and the global constraint factor, where the critical CTOA remained almost constant because of high constraint.

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