scholarly journals Nonlinear Elastic Deformation of Mindlin Torus

2021 ◽  
Author(s):  
Bohua Sun
Keyword(s):  
Numerical Simulations ◽  
Stress Analysis ◽  
Elastic Deformation ◽  
Nonlinear Deformation ◽  
Good Accuracy ◽  
Gauss Curvature ◽  
Numerical Investigations ◽  
Complicated Topology ◽  
Nonlinear Elastic ◽  
Maple Code

The nonlinear deformation and stress analysis of a circular torus is a difficult undertaking due to its complicated topology and the variation of the Gauss curvature. A nonlinear deformation (only one term in strain is omitted) of Mindlin torus was formulated in terms of the generalized displacement, and a general Maple code was written for numerical simulations. Numerical investigations show that the results obtained by nonlinear Mindlin, linear Mindlin, nonlinear Kirchhoff-Love, and linear Kirchhoff-Love models are close to each other. The study further reveals that the linear Kirchhoff-Love modeling of the circular torus gives good accuracy and provides assurance that the nonlinear deformation and stress analysis (not dynamics) of a Mindlin torus can be replaced by a simpler formulation, such as a linear Kirchhoff-Love theory of the torus, which has not been reported in the literature.

Pneumatic pulsator design as an example of numerical simulations in engineering applications

2012 ◽  
Vol 2 (1) ◽  
Author(s):  
Krzysztof Wołosz ◽  
Jacek Wernik
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Cast Iron ◽  
Numerical Simulations ◽  
Stress Analysis ◽  
Aluminium Alloy ◽  
Loose Material ◽  
Engineering Applications ◽  
Pressure Losses ◽  
Pneumatic Impact

AbstractThe paper presents the part of the investigation that has been carried out in order to develop the pneumatic pulsator which is to be employed as an unblocking device at lose material silo outlets. The part of numerical simulation is reported. The fluid dynamics issues have been outlined which are present during supersonic airflow thought the head of the pulsator. These issues describe the pneumatic impact phenomenon onto the loose material bed present in the silo to which walls the pulsator is assembled. The investigation presented in the paper are industrial applicable and the result is the working prototype of the industrial pneumatic pulsator. The numerical simulation has led to change the piston shape which is moving inside the head of the pulsator, and therefore, to reduce the pressure losses during the airflow. A stress analysis of the pulsator controller body has been carried out while the numerical simulation investigation part of the whole project. The analysis has made possible the change of the controller body material from cast iron to aluminium alloy.

scholarly journals Evaluation of Stiffness and Dynamic Properties of a Mine Shaft Steelwork Structure through In Situ Tests and Numerical Simulations

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 664
Author(s):  
Jacek Jakubowski ◽  
Przemysław Fiołek
Keyword(s):  
Numerical Simulations ◽  
Dynamic Properties ◽  
Vertical Motion ◽  
Load Test ◽  
Mode Shapes ◽  
Dynamic Amplification Factor ◽  
In Situ Tests ◽  
Mine Shaft ◽  
Numerical Investigations

A mine shaft steelwork is a three-dimensional frame that directs the vertical motion of conveyances in mine shafts. Here, we conduct field and numerical investigations on the stiffness and dynamic properties of these structures. Based on the design documentation of the shaft, materials data, and site inspection, the steelwork’s finite element model, featuring material and geometric non-linearities, was developed in Abaqus. Static load tests of steelwork were carried out in an underground mine shaft. Numerical simulations reflecting the load test conditions showed strong agreement with the in situ measurements. The validated numerical model was used to assess the dynamic characteristics of the structure. Dynamic linear and non-linear analyses delivered the natural frequencies, mode shapes, and structural response to dynamic loads. The current practices and regulations regarding shaft steelwork design and maintenance do not account for the stiffness of guide-to-bunton connections and disregard dynamic factors. Our experimental and numerical investigations show that these connections provide considerable stiffness, which leads to the redistribution and reduction in bending moments and increased stiffness of the construction. The results also show a high dynamic amplification factor. The omission of these features implicates an incorrect assessment of the design loads and can lead to over- or under-sized structures and ultimately to shortened design working life or failure.

Trailing Edge Filings and a Modified Stodola’s Slip Factor for Centrifugal Impeller

2015 ◽  
Author(s):  
Guang Xi ◽  
Huijing Zhao ◽  
Zhiheng Wang
Keyword(s):  
Numerical Simulations ◽  
Good Accuracy ◽  
Centrifugal Impeller ◽  
Pressure Side ◽  
Compressor Stage ◽  
Trailing Edge ◽  
Obvious Effect ◽  
Quantitative Calculation ◽  
Slip Factor ◽  
Stage Efficiency

The paper investigates the effect of trailing edge filing in the impeller on the performances of impeller and compressor stage. The 3D viscous numerical simulations are carried out under different positions, thicknesses and lengths of filing. The results show that, the filing on the trailing edge has an obvious effect on the pressure ratios of impeller and compressor stage. The trailing edge filing has little effect on the impeller efficiency while the filing on the pressure side is favorable to improving the stage efficiency. Then, through correcting the blade angles at the suction and pressure sides, considering the viscosity and 3D characteristics of the flow, a modified slip factor formula is proposed for the centrifugal impeller with a trailing edge filing. The validation to the proposed formula shows that the proposed formula can be used to predict the slip factors of different filing cases with a good accuracy. It can provide a theoretical guidance for the quantitative calculation when using the filing technology to improve the performance of centrifugal impeller as well as the stage.

scholarly journals Application of Piecewise Successive Linearization Method for the Solutions of the Chen Chaotic System

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
S. S. Motsa ◽  
Y. Khan ◽  
S. Shateyi
Keyword(s):  
Dynamical Systems ◽  
Numerical Simulations ◽  
Chaotic System ◽  
Good Accuracy ◽  
Linearization Method ◽  
Chen System ◽  
Successive Linearization Method ◽  
Runge Kutta

This paper centres on the application of the new piecewise successive linearization method (PSLM) in solving the chaotic and nonchaotic Chen system. Numerical simulations are presented graphically and comparison is made between the PSLM and Runge-Kutta-based methods. The work shows that the proposed method provides good accuracy and can be easily extended to other dynamical systems including those that are chaotic in nature.

scholarly journals Structural Design for a 10-GWh SMES Vacuum Vessel

1978 ◽  
Vol 100 (3) ◽  
pp. 263-270
Author(s):  
J. G. Bennett ◽  
C. A. Anderson
Keyword(s):  
Cylindrical Shell ◽  
Approximate Solution ◽  
Elastic Deformation ◽  
Material Properties ◽  
Structural Design ◽  
Shell Thickness ◽  
Construction Cost ◽  
Vacuum Vessel ◽  
Nonlinear Elastic

An approximate solution to the problem of the nonlinear elastic deformation of a periodically point-supported cylindrical shell is obtained. This solution is used to investigate the structural design of the vacuum vesssel for the large underground SMES concept. Vacuum vessel designs are evaluated by varying such parameters as shell thickness, support, spacing, material properties and physical configuration to keep the amount of material used and construction cost to a minimum.

Experimental Study on a Motion of “Underwater Platform” Including Hydro-Elastic Deformation in Waves

2015 ◽  
Author(s):  
Motohiko Murai ◽  
Ken Haneda ◽  
Jun Yamanoi ◽  
Yuta Abe
Keyword(s):  
Numerical Simulations ◽  
Elastic Deformation ◽  
Large Scale ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Wind Condition ◽  
Small Motion ◽  
Small Water ◽  
Motion Characteristics ◽  
Plane Area

A new type of floater for floating offshore wind turbine (FOWT) was proposed. The floater, named an “underwater platform”, aims at high economic efficiency of energy generation of floating wind farm. The underwater platform is a large scale submerged structure which has small water plane area and can support several wind turbines. It is expected that the platform has small motion characteristics in waves because of its small water plane area, and it contributes for FOWT to generate energy safety. In this study, the feasibility and usefulness study about the platform was carried out through experiments and numerical simulations. The first experiment was conducted with partial rigid model of the platform to verify the feasibility. From the experiment, it was confirmed that the model has small motion characteristics in waves. The experimental results were compared with numerical simulations of potential theory and they were well matched. Besides, the coupling analysis with aero-hydro dynamics was also carried out and it was confirmed that the stability of the platform was enough in steady wind condition. The second experiment was conducted with elastic body model to study the elastic deformation of the platform in waves. From the experiment, it was confirmed that the deformation is small when the draft was 250mm (50m in the actual model).

Low-cycle fatigue properties of a titanium alloy exhibiting nonlinear elastic deformation behavior

2011 ◽  
Vol 59 (11) ◽  
pp. 4690-4699 ◽  
Author(s):  
S.Q. Zhang ◽  
S.J. Li ◽  
M.T. Jia ◽  
F. Prima ◽  
L.J. Chen ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Elastic Deformation ◽  
Deformation Behavior ◽  
Low Cycle Fatigue ◽  
Fatigue Properties ◽  
Cycle Fatigue ◽  
Nonlinear Elastic

Evaluation of Stress-Controlled Permeability of Coal Fractures - A Laboratory Study

2013 ◽  
Vol 734-737 ◽  
pp. 703-708
Author(s):  
Yi Dong Cai ◽  
Da Meng Liu ◽  
Yan Bin Yao ◽  
Bai Ren Zhang ◽  
Jun Qian Li ◽  
...  
Keyword(s):  
Elastic Deformation ◽  
Axial Stress ◽  
Fractal Dimensions ◽  
Confining Pressure ◽  
Control Factor ◽  
Type I ◽  
Permeability Characteristics ◽  
Linear Elastic ◽  
Variable Permeability ◽  
Nonlinear Elastic

Experiments on coal permeability with saturated water under tri-axial stress were conducted. The relationship between stress and permeability under tri-axial stress was analyzed on the rock mechanical experimental rig (GAW-2000). After the experiments on permeability, the fracture characteristics were researched by X-ray computerized tomography, which shows that the bituminous coal normally has high fractal dimensions (generally over 1.8) and wide aperture. The results for permeability reveal that bituminous coals always have variable permeability characteristics under incremental axial stress due to its inherent fracture features. It can be divided into two types: type I, at the linear and nonlinear elastic deformation and peak stage, the permeability keeps rising, which is represented by FYGY8 #. The main control factor of permeability should be related to coal microfractures and coal compositions. Type II, which is represented by sample YCLZ2#, in the initial linear elastic stage, there is a decrease trend in the permeability performance, and then permeability gradually rise when it comes into the stage of nonlinear elastic deformation. The permeability will keep go down after coal becomes soften under the action of confining pressure, compaction.

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