scholarly journals The influence of stiffness coefficient of steel support on supporting effect and its optimization

2021 ◽  
Vol 714 (3) ◽  
pp. 032044
Author(s):  
Jie Zhang ◽  
Yue Li ◽  
Xinyue Zhao ◽  
Shenyue Shi ◽  
Wenxia Liu ◽  
...  
Keyword(s):  
Stiffness Coefficient ◽  
Supporting Effect

Numerical and Experimental Research on the Fluid-Induced Forces of Clearance Flow in Canned Motor Reactor Coolant Pump

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Rui Xu ◽  
Yun Long ◽  
Yaoyu Hu ◽  
Junlian Yin ◽  
Dezhong Wang
Keyword(s):  
Large Mass ◽  
Stiffness Coefficient ◽  
Pressurized Water ◽  
Coolant Pump ◽  
Reactor Coolant ◽  
Various Boundary Conditions ◽  
Clearance Flow ◽  
Mass Coefficient ◽  
Cfd Method ◽  
Canned Motor

Reactor coolant pump (RCP) is one of the most important equipment of the coolant loop in a pressurized water reactor system. Its safety relies on the characteristics of the rotordynamic system. For a canned motor RCP, the liquid coolant fills up the clearance between the metal shields of the rotor and stator inside the canned motor, forming a long clearance flow. The fluid-induced forces of the clearance flow in canned motor RCP and their effects on the rotordynamic characteristics of the pump are numerically and experimentally analyzed in this work. A transient computational fluid dynamics (CFD) method has been used to investigate the fluid-induced force of the clearance. A vertical experiment rig has also been established for the purpose of measuring the fluid-induced forces. Fluid-induced forces of clearance flow with various whirl frequencies and various boundary conditions are obtained through the CFD method and the experiment. Results show that clearance flow brings large mass coefficient into the rotordynamic system and the direct stiffness coefficient is negative under the normal operating condition. The rotordynamic stability of canned motor RCP does not deteriorate despite the existence of significant cross-coupled stiffness coefficient from the fluid-induced forces of the clearance flow.

scholarly journals Cell-derived Extracellular Matrix as maintaining Biomaterial for adipogenic differentiation

2020 ◽  
Vol 6 (3) ◽  
pp. 410-413
Author(s):  
Petra J. Kluger ◽  
Svenja Nellinger ◽  
Simon Heine ◽  
Ann-Cathrin Volz
Keyword(s):  
Tissue Engineering ◽  
Extracellular Matrix ◽  
Adipogenic Differentiation ◽  
Cellular Activity ◽  
Adipose Tissue Engineering ◽  
Physical Support ◽  
Supporting Effect ◽  
Brdu Assay ◽  
The Impact

AbstractThe extracellular matrix (ECM) naturally surrounds cells in humans, and therefore represents the ideal biomaterial for tissue engineering. ECM from different tissues exhibit different composition and physical characteristics. Thus, ECM provides not only physical support but also contains crucial biochemical signals that influence cell adhesion, morphology, proliferation and differentiation. Next to native ECM from mature tissue, ECM can also be obtained from the in vitro culture of cells. In this study, we aimed to highlight the supporting effect of cell-derived- ECM (cdECM) on adipogenic differentiation. ASCs were seeded on top of cdECM from ASCs (scdECM) or pre-adipocytes (acdECM). The impact of ECM on cellular activity was determined by LDH assay, WST I assay and BrdU assay. A supporting effect of cdECM substrates on adipogenic differentiation was determined by oil red O staining and subsequent quantification. Results revealed no effect of cdECM substrates on cellular activity. Regarding adipogenic differentiation a supporting effect of cdECM substrates was obtained compared to control. With these results, we confirm cdECM as a promising biomaterial for adipose tissue engineering.

scholarly journals Research and Implementation of an Automatic Reset Force of a Force Feedback Handle

2020 ◽  
Vol 316 ◽  
pp. 01003
Author(s):  
Xin An Qiu ◽  
Shi Jia Wang ◽  
Dong Tao Ma
Keyword(s):  
Force Feedback ◽  
High Accuracy ◽  
Damping Coefficient ◽  
Robotic Arm ◽  
Force Model ◽  
Stiffness Coefficient ◽  
Application Field ◽  
New Development

Take the force feedback handle applied to the teleoperation of space robotic arm as a requirement. In order to improve users’ experience, we studied the automatic reset force of the handle. This paper proposes a springdamping model and applies it to the torque output of the motor to achieve a good reset of the handle, which is a new development of the application field of the automatic reset force model of the force feedback device. The experiment shows that the automatic reset force model has high accuracy when the handle returns to zero. In addition, through dynamic and reasonable adjustment of the stiffness coefficient and damping coefficient, it can meet the needs of different users for the automatic reset force of the force feedback handle.

Buckling of Double Layer Grid Edge Members

1997 ◽  
Vol 12 (2) ◽  
pp. 81-87
Author(s):  
Erling Murtha-Smith ◽  
Thuyen P. Nguyen
Keyword(s):  
Double Layer ◽  
External Load ◽  
Stiffness Matrix ◽  
Diagonal Matrix ◽  
Moment Of Inertia ◽  
Effective Length ◽  
Stiffness Coefficient ◽  
Stability Functions

Stability equations are developed for edge joints for Double Layer Grids. Translations are neglected and rotations at each joint are related. Hence, the stiffness matrix reduces to a diagonal matrix of unit bandwidth so each joint becomes an independent substructure. Instability of an edge joint occurs when the minimum principal stiffness coefficient of the joint goes to zero. Using stability functions and the regular geometric relationships of DLG topology, the buckling forces in the members and hence the external load on the system are determined. A simple example in which the members were all of the same length, material and moment of inertia, gives effective length factors for the edge members of between 0.77 to 0.81.

The Rationality of Compiling a Forest Resource Balance Sheet

2021 ◽  
Vol 71 (4) ◽  
pp. 309-321
Author(s):  
Lijun Jin ◽  
Meng Lin ◽  
Guoshuang Tian
Keyword(s):  
Balance Sheet ◽  
Forest Products ◽  
Theory And Practice ◽  
Practical Significance ◽  
Accounting System ◽  
Forest Resource ◽  
Balance Sheets ◽  
Service Value ◽  
Supporting Effect ◽  
Resource Accounting

Abstract The existing forest resource accounting system is limited to the valuation of wood and forest products; the service value of the forest resource ecosystem is not yet included. This study adopts an empirical approach to studying the rationality and influencing factors of compiling a forest resource balance sheet (FRBS). An FRBS can systematically reflect the contribution of forest resources to the economy, ecology, and society in terms of both physical quantity and value quantity. A questionnaire survey was used to collect the data. We found that the determination and measurement of forest resource assets and liabilities and the calculation of the service value of the ecosystem had a supporting effect on the rationality of compiling an FRBS. This study expands the field and scope of forest resource accounting, facilitates the compilation of natural resources and government balance sheets, and presents the practical significance for the theory and practice behind the development of an FRBS.

scholarly journals INFLUENCE OF INCONSTANT DISTRIBUTION OF DEADWOOD BEARING STIFFNESS COEFFICIENTON NATURAL FREQUENCY OF THE SHAFT TRANSVERSE VIBRATIONS

2019 ◽  
pp. 89-96
Author(s):  
Guriy Kushner ◽  
Victor Andreevich Mamontov
Keyword(s):  
Differential Equation ◽  
Distribution Function ◽  
Uniform Distribution ◽  
Natural Frequency ◽  
Stiffness Coefficient ◽  
Propeller Shaft ◽  
Shaft Length ◽  
Slide Bearing ◽  
Transverse Vibrations ◽  
Stiffness Distribution

One of the most significant factors affecting the natural frequency of transverse vibrations of shaft-slide bearing systems is the stiffness coefficient of the slide bearing. The need to consider the influence of heterogeneity of stiffness coefficient of the bearing on its natural frequency is caused by the fact that when the bearing is worn, the modulus of longitudinal elasticity of the material changes, and since the bearing wears unevenly, the non-uniform distribution of the stiffness coefficient occurs. The problem of determining the natural frequency of transverse vibrations of a ship propeller shaft based on the foundation with a variable stiffness coefficient along the length has been studied. The differential equation of the propeller shaft vibrations written taking into account the stiffness coefficient variable along the shaft length is considered. It has been noted that, in the general case, this equation is a fourth-order partial differential equation and cannot be integrated in quadratures for an arbitrary stiffness distribution function along the shaft length. A numerical-analytical method for determining the natural frequency of a system based on approximation of the stiffness distribution function by a piecewise-linear function is proposed. The method is applied to calculate the natural frequencies of the pipeline section taking into account the functions describing the change in the stiffness coefficient. The proposed method allows to consider the section of the shafting enclosed in the stern bearing, subject to the non-uniform distribution of the stiffness coefficient of the bearing, and is the basis for improving the accuracy of finding the true natural frequency of transverse vibrations of the shafting.

scholarly journals Tunnel Squeezing Deformation Control and the Use of Yielding Elements in Shotcrete Linings: A Review

Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 391
Author(s):  
Xiaomeng Zheng ◽  
Kui Wu ◽  
Zhushan Shao ◽  
Bo Yuan ◽  
Nannan Zhao
Keyword(s):  
High Resistance ◽  
Review Paper ◽  
State Of The Art ◽  
Squeezing Ground ◽  
Deformation Control ◽  
Development History ◽  
Ground Conditions ◽  
Supporting Effect ◽  
Mechanical Performances ◽  
Shotcrete Lining

Shotcrete lining shows high resistance but extremely low deformability. The utilization of yielding elements in shotcrete lining, which leads to the so-called ductile lining, provides a good solution to cope with tunnel squeezing deformations. Although ductile lining exhibits great advantages regarding tunnel squeezing deformation control, little information has been comprehensively and systematically available for its mechanism and design. This is a review paper for the purpose of summarizing the development history and discussing the state of the art of ductile lining. It begins by providing a brief introduction of ductile lining and an explanation of the importance of studying this issue. A following summary of supporting mechanism and benefits of ductile lining used in tunnels excavated in squeezing ground conditions is provided. Then, it summarizes the four main types of yielding elements applied in shotcrete lining and introduces their basic structures and mechanical performances. The influences of parameters of yielding elements on the supporting effect are discussed and the design methods for ductile lining are reviewed as well. Furthermore, recommendations for further research in ductile lining are proposed. Finally, a brief summary is presented.

Effect of Stress-Free Edges in Plane Shear of a Rectangular Orthotropic Region

1978 ◽  
Vol 45 (2) ◽  
pp. 307-312 ◽  
Author(s):  
S. Nair
Keyword(s):  
Lower Bounds ◽  
Elastic Problem ◽  
Upper And Lower Bounds ◽  
Tangential Displacement ◽  
Stiffness Coefficient ◽  
Shearing Force ◽  
Plane Shear ◽  
Zero Stresses ◽  
Plane Elastic Problem ◽  
Free Edges

The plane elastic problem of a rectangular orthotropic region is considered; subject to the boundary conditions of prescribed equal and opposite tangential displacements and zero normal displacements on the upper and lower edges and zero stresses on the remaining edges. The effect of the stress-free edges on the stiffness coefficient relating the tangential displacement and the corresponding shearing force is estimated in the form of upper and lower bounds for this coefficient.

Research on Supporting Countermeasure of B103W01 Transport Roadway in Shajihai Coal Mine

2013 ◽  
Vol 401-403 ◽  
pp. 2221-2225
Author(s):  
Shu Jiang Zhao
Keyword(s):  
Coal Mine ◽  
Deformation Mechanism ◽  
Soft Rock ◽  
Single Type ◽  
Engineering Practice ◽  
Deformation And Failure ◽  
Constant Resistance ◽  
Supporting Effect ◽  
Deformation Mechanics ◽  
Coupling Support

For the soft rock roadwaysupporting problems, using the conventional methods cannot effectively controlthe deformation and failure. This paper took B103W01 transport gateway projectin Shajihai coal mine as example and analyzed its deformation failure reasonand deformation mechanism and determined the specific measures of transformingcompound mechanism of deformation mechanics into a single type. In the end, weput forward coupling support technology of constant resistance and largedeformation bolt + hollow grouting anchor + corner grouting steel pipe, whichhad been applied to engineering practice. The monitoring results showed thatthe supporting effect was good. So it can be used for reference for the similarconditions of roadway supporting.

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