scholarly journals Modeling of longitudinal welded pipe forming in open rolling pass unit of electric weld pipe mill

2019 ◽  
Vol 62 (7) ◽  
pp. 531-538
Author(s):  
S. V. Samusev ◽  
V. A. Fadeev
Keyword(s):  
Geometric Parameters ◽  
Roll Forming ◽  
Geometrical Parameters ◽  
Forming Process ◽  
Molding Process ◽  
Left Edge ◽  
Working Zone ◽  
Technical Parameters ◽  
Rolling Pass ◽  
The Third

The results of theoretical and physical modeling of pipes forming process are described. Experiments on strip billets forming were carried out on 10-50 pipe-welding mill for a pipe 50 mm in diameter with 1mm wall. Forming of pipe billets was carried out at unit of forming horizontal and vertical stands with estimation of geometrical parameters. Roll drafting is one-radial. Energy-power parameters of the process that affect quality of billet geometry were determined and measured. Analysis of geometric parameters of resulting billet has revealed defects of buckling type on the billet’s right edge between the second edger and the third molding stand. Similar defect was detected at the left edge of the billet at a distance of the third molding and edger stands. To eliminate defects in forming section, shaping stands were rebuilt so that forces on drive cells were identical. Energy-force parameters of the process were sequentially determined: pulling forces of drive stands, resistance to strip movement and vertical molding forces. Calculations for determining energy-force parameters were performed taking into account the main technical parameters using two methods. The first technique takes into account geometric parameters of molded billet and parameters of working zone with the zone of non-contact deformation. The second method is based on consideration of contact interaction between the billet and shaped instrument along the deformation section. Discrepancy between calculated and experimental data was 8  –  12  %. After adjusting technical parameters of the molding process and the passes re-adjusting, a defect-free pipe billet was formed. Comparative analysis of calculated and experimental edge trajectories along the height and width of the cages showed discrepancy in results in range of 6  –  9  %. While studying geometric parameters of the focus of deformation, contact and non-contact zones of working zone and area of sprinkling were taken into account. Parameters of the pipe billet shaping in monotonous and roll forming centers have been calculated. Analysis of the results has shown that change in billet’s geometry in shaping stand corresponds to the accepted statements of billet’s geometry changes in rolling pass.

scholarly journals Investigation of interactions in Lewis pairs between phosphines and boranes by analyzing crystal structures from the Cambridge Structural Database

2018 ◽  
Vol 74 (3) ◽  
pp. 255-263 ◽  
Author(s):  
Milan R. Milovanović ◽  
Jelena M. Andrić ◽  
Vesna B. Medaković ◽  
Jean-Pierre Djukic ◽  
Snežana D. Zarić
Keyword(s):  
Crystal Structures ◽  
Boron Atom ◽  
Geometric Parameters ◽  
Cambridge Structural Database ◽  
Geometrical Parameters ◽  
Frustrated Lewis Pairs ◽  
Hydrogen Atoms ◽  
The Third ◽  
Structural Database ◽  
Lewis Pairs

The interactions between phosphines and boranes in crystal structures have been investigated by analyzing data from the Cambridge Structural Database (CSD). The interactions between phosphines and boranes were classified into three types; two types depend on groups on the boron atom, whereas the third one involves frustrated Lewis pairs (FLPs). The data enabled geometric parameters in structures to be compared with phosphine–borane FLPs with classical Lewis pairs. Most of the crystal structures (78.1%) contain BH3as the borane group. In these systems, the boron–phosphorus distance is shorter than systems where the boron atom is surrounded by groups other than hydrogen atoms. The analysis of the CSD data has shown that FLPs have a tendency for the longest boron–phosphorus distance among all phosphine–borane pairs, as well as different other geometrical parameters. The results show that most of the frustrated phosphine–borane pairs found in crystal structures are bridged ones. The minority of non-bridged FLP structures contain, beside phosphorus and boron atoms, other heteroatoms (O, N, S for instance).

Study of the process of forming a hole for a thread at manufacturing a high nut

2020 ◽  
Vol 76 (8) ◽  
pp. 841-846
Author(s):  
I. G. Shubin ◽  
A. A. Kurkin
Keyword(s):  
Metal Flow ◽  
Nonlinear Dependence ◽  
Geometrical Parameters ◽  
Relative Height ◽  
Forming Process ◽  
Normal Height ◽  
Accuracy Class ◽  
Limit Values ◽  
Program Complex ◽  
Class B

During manufacturing nuts of increased height, a problem of obtaining correct cylindrical form of the hole for thread and overall geometrical parameters arises. To solve the problem it is necessary to know regularity of the blank forming process. Results of the study of a technological process of high hexahedral nuts forming presented. The nuts were M18 of 22 mm height, M16 of 19 mm height and M12 of normal height 10 mm according to GOST 5915–70, accuracy class B, steel grade 10 according to GOST 10702–78. The volumetric stamping was accomplished at the five-position automatic presses of АА1822 type. It was determined, that unevenness of the metal flow in the process of plastic deformation of blanks of increased height nuts was caused by different stress conditions by their sections. To simulate the mode of deformation, the program complex QForm-3D was chosen. The complex ensured to forecast with necessary accuracy the metal flow in a blank, as well as to define the deformation force and arising stress in the working instrument. The simulation showed the presence of regularity between preliminary formed buffle and deviation of dimensions and form of a blank wall after its finishing piercing, which can be expressed by a nonlinear dependence. The limit values of the relative height of the buffle С/D = 0.56–0.588 defined, exceeding which will result in rejection of the finished product. Accounting the limit values of the relative height of the buffle will enable to correct a mode of technological operations and technological instruments at stamping of high hexahedral nuts.

Genetic algorithm application for optimization of geometry of synchronous electric motor with permanent magnets by criterion of electromagnetic torque

2019 ◽  
pp. 56-62
Author(s):  
I. N. Belezyakov ◽  
K. G. Arakancev
Keyword(s):  
Genetic Algorithm ◽  
Electric Motor ◽  
Permanent Magnets ◽  
Evolutionary Optimization ◽  
Electric Machines ◽  
Geometric Parameters ◽  
Geometrical Parameters ◽  
Electromagnetic Torque ◽  
Automatic Control Systems ◽  
Optimization Of Geometry

At present time there is a need to develop a methodology for electric motors design which will ensure the optimality of their geometrical parameters according to one or a set of criterias. With the growth of computer calculating power it becomes possible to develop methods based on numerical methods for electric machines computing. The article describes method of a singlecriterion evolutionary optimization of synchronous electric machines with permanent magnets taking into account the given restrictions on the overall dimensions and characteristics of structural materials. The described approach is based on applying of a genetic algorithm for carrying out evolutionary optimization of geometric parameters of a given configuration of electric motor. Optimization criteria may be different, but in automatic control systems high requirements are imposed to electromagnetic torque electric machine produces. During genetic algorithm work it optimizes given geometric parameters of the electric motor according to the criterion of its torque value, which is being calculated using finite element method.

Analysis of Crimping of Large Diameter Welding Pipe

2014 ◽  
Vol 997 ◽  
pp. 517-521
Author(s):  
Li Feng Fan ◽  
Ying Gao ◽  
Jian Bin Yun ◽  
Lin Feng Dong
Keyword(s):  
Analytical Model ◽  
Large Diameter ◽  
Forming Process ◽  
Technical Parameters ◽  
Polynomial Curve ◽  
Welding Pipe ◽  
X80 Steel ◽  
Polynomial Curve Fitting ◽  
Effective Path ◽  
Submerged Arc

Crimping is widely used in production of large diameter submerged-arc welding pipes. Traditionally, the designers obtain the technical parameters for crimping from experience or trial-errors by experiments. To tackle this problem, a theoretical analytical model is proposed to analysis crimping forming process. In this paper, taking the crimping of X80 steel Φ1219mm×22mm×12000mm welding pipe for instance, the theoretical analytical model is constructed by quadratic polynomial curve fitting technique and mechanics theory. And it is verified by a comparison with experiment results. Thus, the presented model of this research provides an effective path to design crimping parameters.

Stress Analysis of Sheet Metal Vibration Incremental Forming

2010 ◽  
Vol 154-155 ◽  
pp. 166-170
Author(s):  
Gai Pin Cai ◽  
Ning Yuan Zhu ◽  
Na Wen
Keyword(s):  
Sheet Metal ◽  
Incremental Forming ◽  
Low Frequency ◽  
Forming Process ◽  
Technical Parameters ◽  
Vibration Technique ◽  
Low Frequency Vibration ◽  
Metal Deformation ◽  
Angle Effect ◽  
Forming Angle

As a non-homogenous force stresses during incremental forming, sheet metal easily tended to instability, and some defects, such as deposition, wrinkle and fracture, would appear. If the vibration technique was combined the incremental forming process, its deformation mechanism would be different from that of the old process, and sheet metal deformation quality was also risen. Then some mechanical equations were built by force analyzed on element in local contact zone of die head forcing down. According to reasonable hypothesis and simplified, the equations were solved. Some stress-time curves of the element were obtained by given process parameters, vibrational parameters and time parameters. It is shown from analysis that stress variety of the element is closely related to amplitude, frequency and forming angle, effect of sheet metal vibration incremental forming with high frequency vibration is more superior than that of with low frequency vibration; only when vibrational parameters are reasonably matching technical parameters, the effective vibration incremental forming can be obtained.

Effect of Geometric Parameters of New Semisubmersible Platform on Stability and Hydrodynamic Performance

2021 ◽  
Author(s):  
Tianying Wang ◽  
Yanjun Zhou ◽  
Honglin Tang ◽  
Shihua Zhang ◽  
Haiqing Tian
Keyword(s):  
Geometric Parameters ◽  
Hydrodynamic Performance ◽  
Geometrical Parameters ◽  
Main Body ◽  
Floating Bodies ◽  
Full Picture ◽  
New Type ◽  
Design Plan ◽  
The Stability ◽  
Shape Characteristics

Abstract The JCSM concept (short for Jackup Combined Semisubmersible Multifunction Platform) is a new type of semisubmersible platform presented by the first author, which overcomes the shortcomings of the available semisubmersible platforms, and combines the advantages of the traditional semisubmersible platform, the Jackup platform and the new FPSO concept - IQFP. Due to the complicated interaction between stability and hydrodynamic performance, it is necessary to explore the effect of geometrical parameters of the main body on the stability and hydrodynamic performance in order to obtain the optimal design plan of a JCSM platform. Firstly, the structure components and innovations of the JCSM were briefly reviewed in order to facilitate readers to understand its full picture. Then, six independent geometric parameters were selected by carefully studying the shape characteristics of the initial design plan of a JCSM study case. Furthermore, the stability heights and motion responses of various floating bodies of the JCSM case with different geometric parameters in wave were calculated using boundary element method based on potential flow theory. Lastly, effect of the shape parameters on stability and hydrodynamic performance of the JCSM was qualitatively evaluated. The research would shed lights on the shape design of the JCSM main body.

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