scholarly journals Spatial Distribution of Mass and Speed on Movement of Two Shrapnel Discs of Variable Thickness in Explosive Load

2020 ◽  
Vol 70 (5) ◽  
pp. 479-485
Author(s):  
Yuryi M. Sydorenko ◽  
Bohdan Jo Semon ◽  
Vadim V. Yakovenko ◽  
Yevhen V. Ryzhov ◽  
Eugene G. Ivanyk
Keyword(s):  
Computer Simulation ◽  
High Speed ◽  
Three Dimensional ◽  
Axial Flow ◽  
Element Model ◽  
Computer Design ◽  
Numerical Studies ◽  
Explosive Expansion ◽  
Continuous Formulation ◽  
Different Thickness

Results of studies of the explosive expansion of a set of shrapnel discs of natural crushing are described in the article. Set consisted of two disks of different thickness, but of a fixed total mass. The studies were carried out by computer simulation of shock-wave processes in a continuous formulation using the ANSYS/LS-DYNA program. The program of computer design foresees development of three-dimensional certainly-element model including, in accordance with symmetry of the examined system fourth part of the examined explosive system of casting block, with imposed on its knots of the proper scopes terms concerted with taken mixed Lagrangian-Eulerian approach within the framework of the continuum model. The effect of the order of installing disks of different thickness on the distribution of their mass and its velocity in the middle of the meridional angle of expansion is established. The analysis of the computer simulation presented on the basis of numerical studies on the distribution of the mass of the disks and its velocity of motion suggests that to create a narrow high-speed uniformly filled fragmentary mass of the axial flow, it is necessary to change the geometric shape of the disc so that in the central angular zones of the disks. This allows the velocity of the fragment mass to be aligned along the radius of the discs and to fill the first angular zones with the required mass of fragments.

Experimental and numerical studies of bolted joints subjected to torsional excitation

2018 ◽  
Vol 32 (34n36) ◽  
pp. 1840083 ◽  
Author(s):  
Xuetong Liu ◽  
Jianhua Liu ◽  
Huajiang Ouyang ◽  
Zhenbing Cai ◽  
Jinfang Peng ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Hysteresis Loops ◽  
Element Model ◽  
Bolted Joints ◽  
Torsional Angle ◽  
Numerical Studies ◽  
Dimensional Finite Element ◽  
Torsional Excitation ◽  
Three Dimensional Finite Element ◽  
Angular Amplitude

The dynamic response of bolted joints subjected to torsional excitation is investigated experimentally and numerically. First, the effects of the initial preload and the angular amplitude on axial force loss of the bolt were studied. Second, the change of hysteresis loops with the increasing number of loading cycles was found under a larger torsional angle. At last, a fine-meshed three-dimensional finite element model was built to simulate the bolted joint under torsional excitation, from which the hysteresis loops were obtained under varying angular amplitudes. The results of numerical analysis are in good agreement with those of experiments.

The Effect of Concrete Containing Recycled Concrete Aggregate and Crushed Clay Bricks on Slab under Dynamic Loading

2014 ◽  
Vol 629-630 ◽  
pp. 330-336
Author(s):  
Mohammad Ali Yazdi ◽  
Saeid Motaghi ◽  
Jian Yang
Keyword(s):  
Three Dimensional ◽  
Blast Loading ◽  
Element Model ◽  
Recycled Concrete ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Clay Bricks ◽  
Numerical Studies ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

This paper investigates a set of nonlinear numerical studies slab subjected to blast loading. A three-dimensional finite element model is developed using ABAQUS by emphasizing on using concrete with recycled concrete aggregate and crushed clay bricks (RCA and CCB) to promote the strength of slab against blast loading. Different charge weights of 0.2–0.55 kg equivalent weight of TNT at a 0.4 m standoff above the slabs were considered as variables in order to evaluate damage levels and define the relations among these variables with respect to the residual strength of slab after blast. The maximum deflection and spalling ratio of the specimens were verified with the experimental data. The results corroborate that using recycled concrete aggregate and crushed clay bricks improve the strength of slabs against blast loading. In addition, the best fraction of this type of materials has been illustrated.

scholarly journals Vibration Response Characteristics of the Cross Tunnel Structure

2016 ◽  
Vol 2016 ◽  
pp. 1-16 ◽  
Author(s):  
Jinxing Lai ◽  
Kaiyun Wang ◽  
Junling Qiu ◽  
Fangyuan Niu ◽  
Junbao Wang ◽  
...  
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Time History ◽  
Element Model ◽  
Vibration Response ◽  
Shield Tunnel ◽  
Tunnel Structure ◽  
Response Characteristics ◽  
Vehicle Load ◽  
Metro Tunnel

It is well known that the tunnel structure will lose its function under the long-term repeated function of the vibration effect. A prime example is the Xi’an cross tunnel structure (CTS) of Metro Line 2 and the Yongningmen tunnel, where the vibration response of the tunnel vehicle load and metro train load to the structure of shield tunnel was analyzed by applying the three-dimensional (3D) dynamic finite element model. The effect of the train running was simulated by applying the time-history curves of vibration force of the track induced by wheel axles, using the fitted formulas for vehicle and train vibration load. The characteristics and the spreading rules of vibration response of metro tunnel structure were researched from the perspectives of acceleration, velocity, displacement, and stress. It was found that vehicle load only affects the metro tunnel within 14 m from the centre, and the influence decreases gradually from vault to spandrel, haunch, and springing. The high-speed driving effect of the train can be divided into the close period, the rising period, the stable period, the declining period, and the leaving period. The stress at haunch should be carefully considered. The research results presented for this case study provide theoretical support for the safety of vibration response of Metro Line 2 structure.

Thermal Analysis and Optimization Design on Spindle Bearing of GSCK200A CNC Lathe

2011 ◽  
Vol 314-316 ◽  
pp. 1760-1763
Author(s):  
Le Ping Liu ◽  
Guo Hong Deng
Keyword(s):  
High Speed ◽  
Thermal Deformation ◽  
Optimization Design ◽  
Three Dimensional ◽  
Element Model ◽  
Radial Clearance ◽  
Spindle Bearing ◽  
Heat Transfer Theory ◽  
Cnc Lathe ◽  
Three Dimensional Finite Element

Establish the three-dimensional finite element model of GSCK200A type High-speed & high-precision CNC Lathe spindle bearing, based on tribology and heat transfer theory, using ANSYS to analyze the corresponding temperature field and thermal deformation of spindle bearing in steady working state, according to this thermal deformation to obtain decrease volume of radial clearance, and the installation clearance optimization scheme is putted forward.

Three-Dimensional Relief in Turbomachinery Blading

1990 ◽  
Vol 112 (4) ◽  
pp. 587-596 ◽  
Author(s):  
A. R. Wadia ◽  
B. F. Beacher
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Axial Flow ◽  
Leading Edge ◽  
Two Dimensional ◽  
Suction Surface ◽  
Airfoil Surface ◽  
Flow Angle ◽  
Edge Loading ◽  
Cascade Analysis

The leading edge region of turbomachinery blading in the vicinity of the endwalls is typically characterized by an abrupt increase in the inlet flow angle and a reduction in total pressure associated with endwall boundary layer flow. Conventional two-dimensional cascade analysis of the airfoil sections at the endwalls indicates large leading edge loadings, which are apparently detrimental to the performance. However, experimental data exist that suggest that cascade leading edge loading conditions are not nearly as severe as those indicated by a two-dimensional cascade analysis. This discrepancy between two-dimensional cascade analyses and experimental measurements has generally been attributed to inviscid three-dimensional effects. This article reports on two and three-dimensional calculations of the flow within two axial-flow compressor stators operating near their design points. The computational results of the three-dimensional analysis reveal a significant three-dimensional relief near the casing endwall that is absent in the two-dimensional calculations. The calculated inviscid three-dimensional relief at the endwall is substantiated by airfoil surface static pressure measurements on low-speed research compressor blading designed to model the flow in the high-speed compressor. A strong spanwise flow toward the endwall along the leading edge on the suction surface of the airfoil is responsible for the relief in the leading edge loading at the endwall. This radial migration of flow results in a more uniform spanwise loading compared to that predicted by two-dimensional calculations.

A Study of Thermohydrodynamic Features of Multi Wound Foil Bearing Using Lobatto Point Quadrature

2008 ◽  
Author(s):  
Kai Feng ◽  
Shigehiko Kaneko
Keyword(s):  
High Speed ◽  
Reynolds Equation ◽  
Energy Equation ◽  
Three Dimensional ◽  
Iteration Process ◽  
Element Model ◽  
Air Bearings ◽  
Foil Bearing ◽  
Deformation Equation ◽  
Wide Range

The applications of foil air bearings, which are recognized to be the best choice for oil free applications, have been extended for use in a wide range of turbo-miachineries with high speed and high temperature. Lubricant temperature becomes an important factor in the performance of foil air bearings, especially at high rotational speeds and high loads or at high ambient temperature. However, most of the published foil air bearing models were based on the isothermal assumption. This study presents a thermohydrodynamic analysis (THD) of Multi Wound Foil Bearing (MWFB), in which the Reynolds’ equation is solved with the gas viscosity as a function of temperature that is obtained from the energy equation. Lobatto point quadrature, which was proposed by Elrod and Brewe and introduced into compressible calculation by Moraru and Keith, is utilized to accelerate the iteration process with a sparse mesh across film thickness. A finite element model of the foil is used to describe the foil elasticity. An iterative procedure is performed between the Reynolds’ equation, the foil elastic deformation equation and the energy equation, until the convergence is achieved. A three-dimensional temperature prediction of air film is presented and a comparison of THD to isothermal results is made to emphasize the importance of thermal effects. Finally, published experimental data are used to validate this numerical solution.

Electromagnetic torque and strength analysis of combination rotor in high speed PMSM

2020 ◽  
Vol 64 (1-4) ◽  
pp. 1019-1027
Author(s):  
Hao Lin ◽  
Haipeng Geng ◽  
Lie Yu ◽  
Hao Li ◽  
Sheng Feng ◽  
...  
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Permanent Magnet Synchronous Motor ◽  
Three Dimensional ◽  
Analytical Calculation ◽  
Element Model ◽  
Strength Analysis ◽  
Electromagnetic Torque ◽  
Foil Bearings ◽  
Three Dimensional Finite Element

For a high-speed permanent magnet synchronous motor supported by air foil bearings, analyzing the influence of the electromagnetic torque on the strength of the combination rotor was necessary. In this study, the electromagnetic torque was obtained using the analytical calculation and the finite element simulation. The contact interface stress analytical equation affected by the electromagnetic torque was elaborated. A three-dimensional finite element model simulating the combination rotor was constructed, and the stress calculations were performed. The strength of the combination rotor met the design requirement. It properly reflected the characteristics of the electromechanical analysis in the combination rotor. The operation experiments were realized to verify the electromagnetic performance and the strength of the combination rotor. The simulation and experimental results were significant for the electromechanical design and analysis of the combination rotor.

Development and numerical validation of a finite element model of the muscle standardized femur

2003 ◽  
Vol 217 (3) ◽  
pp. 165-172 ◽  
Author(s):  
K Polgar ◽  
H S Gill ◽  
M Viceconti ◽  
D W Murray ◽  
J J O'Connor
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Data Sets ◽  
Fe Model ◽  
Fe Method ◽  
Human Femur ◽  
Numerical Studies ◽  
Physiological Loading ◽  
Physiological Load

The human femur is one of the parts of the musculo-skeletal system most frequently analysed by means of the finite element (FE) method. Most FE studies of the human femur are based on computed tomography data sets of a particular femur. Since the geometry of the chosen sample anatomy influences the computed results, direct comparison across various models is often difficult or impossible. The aim of the present work was to develop and validate a novel three-dimensional FE model of the human femur based on the muscle standardized femur (MuscleSF) geometry. In the new MuscleSF FE model, the femoral attachment of each muscle was meshed separately on the external bone surface. The model was tested under simple load configurations and the results showed good agreement with the converged solution of a former study. In the future, using the validated MuscleSF FE model for numerical studies of the human femur will provide the following benefits: (a) the numerical accuracy of the model is known; (b) muscle attachment areas are incorporated in the model, therefore physiological loading conditions can be easily defined; (c) analyses of the femur under physiological load cases will be replicable; (d) results based on different load configurations could be compared across various studies.

An Experimental Arrangement for the Measurement of the Pressure Distribution on High Speed Rotating Blade Rows

1956 ◽  
Author(s):  
K. Leist
Keyword(s):  
Experimental Investigation ◽  
Pressure Distribution ◽  
High Speed ◽  
Three Dimensional ◽  
Axial Flow ◽  
Three Dimensional Flow ◽  
Research Staff ◽  
Rotating Blade ◽  
Flow Through ◽  
Turbine Blading

For several years past, the research staff of the Institute for Turbomachines of the Aachen Technical University has carried out measurements on rotating turbine blading. This program is part of a comprehensive effort directed toward the experimental investigation of the three-dimensional flow through axial-flow turbomachines.

The Influence of Shrouded Stator Cavity Flows on the Aerodynamic Performance of a High-Speed Multistage Axial-Flow Compressor

2011 ◽  
Author(s):  
Dai Kato ◽  
Mai Yamagami ◽  
Naoki Tsuchiya ◽  
Hidekazu Kodama
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Axial Flow ◽  
Main Flow ◽  
Navier Stokes ◽  
Cavity Flows ◽  
Axial Flow Compressor ◽  
First Case ◽  
Flow Compressor ◽  
Unsteady Effects

This paper investigates numerically the effects of shrouded stator seal cavity flows on a high-speed, six-stage, advanced axial-flow compressor performance. Two cases of fully three-dimensional unsteady Reynolds-averaged Navier-Stokes simulations are performed. The first case includes only the main flow path without cavities, while the second case takes into account the effect of cavities by fully meshing and solving the seal cavity flows under each of the stator vanes. Both simulations included rotor blade tip clearances. The latter case showed 1.7 point degradation in efficiency from the first case. Contributors to the overall performance degradation, such as windage heating, mixing loss due to seal leakage flow with the main flow, and additional loss of the rotors and stators due to alteration in velocity triangles, are identified by comparing the two simulation results. Compared to theoretical or semi-empirical leakage and windage models, higher loss production and temperature rise are found especially in mid to rear stages. Unsteady effects for such differences are discussed.

Sign in / Sign up

Export Citation Format

Share Document