An experimental—numerical investigation of a metal spinning process

2010 ◽  
Vol 225 (3) ◽  
pp. 509-519 ◽  
Author(s):  
H R Beni ◽  
Y T Beni ◽  
F R Biglari
Keyword(s):  
Strain Distribution ◽  
Theoretical Calculations ◽  
Three Dimensional ◽  
Experimental Tests ◽  
Experimental Results ◽  
Explicit Finite Element ◽  
Wide Range ◽  
Spinning Process ◽  
Metal Spinning ◽  
Drawing Method

Spinning process is an advanced plastic working method, which is frequently used for manufacturing of axisymmetric shapes, especially those that cannot be easily produced with deep drawing method. In this article, a three-dimensional explicit finite-element (FE) analysis is employed to simulate the spinning process of an aluminium circular sheet. To achieve a wide range of strain distribution in different directions, a hemispherical cup has been chosen as the final product shape. In addition, a theoretical shear forming as well as a conventional model has been employed to estimate strain distribution in the spinning hemispherical cup. Experimental tests are carried out using a spinning machine and a hemispherical mandrel. Finally, FE and theoretical calculations are compared with the experimental results. A good agreement has been demonstrated between numerical and experimental results but a relative agreement with theoretical calculations.

Non-Linear Dynamic Magneto Electric Effects in Ferromagnetic-Ferroelectric Layered Composites

2013 ◽  
Author(s):  
Satenik Harutyunyan ◽  
Davresh Hasanyan
Keyword(s):  
Vibration Frequency ◽  
Strain Distribution ◽  
Longitudinal Vibration ◽  
Three Dimensional ◽  
Low Frequency ◽  
Structure Design ◽  
Experimental Results ◽  
Physical Parameters ◽  
Wide Range ◽  
Non Linear

A non-linear theoretical model including bending and longitudinal vibration effects was developed for predicting the magneto electric (ME) effects in a laminate bar composite structure consisting of magnetostrictive and piezoelectric multi-layers. If the magnitude of the applied field increases, the deflection rapidly increases and the difference between experimental results and linear predictions becomes large. However, the nonlinear predictions based on the present model well agree with the experimental results within a wide range of applied electric field. The results of the analysis are believed to be useful for materials selection and actuator structure design of actuator in actuator fabrication. It is shown that the problem for bars of symmetrical structure is not divided into a plane problem and a bending problem. A way of simplifying the solution of the problem is found by an asymptotic method. After solving the problem for a laminated bar, formula that enable one to change from one-dimensional required quantities to three dimensional quantities are obtained. The derived analytical expression for ME coefficients depend on vibration frequency and other geometrical and physical parameters of laminated composites. Parametric studies are presented to evaluate the influences of material properties and geometries on strain distribution and the ME coefficient. Analytical expressions indicate that the vibration frequency strongly influences the strain distribution in the laminates, and that these effects strongly influence the ME coefficients. It is shown that for certain values of vibration frequency (resonance frequency), the ME coefficient becomes infinity; as a particular case, low frequency ME coefficient were derived as well.

Investigations of the Effect of Annulus Taper on Transonic Turbine Cascade Flow

1986 ◽  
Vol 108 (2) ◽  
pp. 285-292 ◽  
Author(s):  
W. Bra¨unling ◽  
F. Lehthaus
Keyword(s):  
Surface Pressure ◽  
Theoretical Calculations ◽  
Three Dimensional ◽  
Computer Code ◽  
Numerical Results ◽  
Test Facility ◽  
Turbine Cascade ◽  
Pressure Distributions ◽  
Aspect Ratios ◽  
Wide Range

In a test facility for rotating annular cascades with three conical test sections of different taper angles (0, 30, 45 deg), experiments are conducted for two geometrically different turbine cascade configurations, a hub section cascade with high deflection and a tip section cascade with low deflection. The evaluation of time-averaged data derived from conventional probe measurements upstream and downstream of the test wheel in the machine-fixed absolute system is based on the assumption of axisymmetric stream surfaces. The cascade characteristics, i.e., mass flow, deflection, and losses, for a wide range of inlet flow angles and outlet Mach numbers are provided in the blade-fixed relative system with respect to the influence of annulus taper. Some of the results are compared with simple theoretical calculations. To obtain some information about the spatial structure of the flow within the cascade passages, surface pressure distributions on the profiles of the rotating test wheels are measured at three different radial blade sections. For some examples those distributions are compared with numerical results on plane cascades of the same sweep and dihedral angles and the same aspect ratios. The computer code used is based on a three-dimensional time-marching finite-volume method solving the Euler equations. Both experimental and numerical results show a fairly good qualitative agreement in the three-dimensional blade surface pressure distributions. This work will be continued with detailed investigations on the spatial flow structure.

scholarly journals Investigations of the Effect of Annulus Taper on Transonic Turbine Cascade Flow

1985 ◽  
Author(s):  
W. Bräunling ◽  
F. Lehthaus
Keyword(s):  
Surface Pressure ◽  
Theoretical Calculations ◽  
Three Dimensional ◽  
Computer Code ◽  
Numerical Results ◽  
Test Facility ◽  
Turbine Cascade ◽  
Pressure Distributions ◽  
Aspect Ratios ◽  
Wide Range

In a test facility for rotating annular cascades with three conical test sections of different taper angles (0°, 30°, 45°), experiments are conducted for two geometrically different turbine cascade configurations, a hub section cascade with high deflection and a tip section cascade with low deflection. The evaluation of time averaged data derived from conventional probe measurements upstream and downstream of the test wheel in the machine-fixed absolute system is based on the assumption of axisymmetric stream surfaces. The cascade characteristics, i.e. mass flow, deflection and losses, for a wide range of inlet flow angles and outlet Mach numbers are provided in the blade-fixed relative system with respect to the influence of annulus taper. Some of the results are compared with simple theoretical calculations. To obtain some informations about the spatial structure of the flow within the cascade passages, surface pressure distributions on the profiles of the rotating test wheels are measured at three different radial blade sections. For some examples those distributions are compared with numerical results on plane cascades of the same sweep and dihedral angles and the same aspect ratios. The computer code used is based on a three-dimensional time-marching finite-volume method solving the Euler equations. Both experimental and numerical results show a fairly good qualitative agreement in the three-dimensional blade surface pressure distributions. This work will be continued with detailed investigations on the spatial flow structure.

scholarly journals Three-Dimensional Resistive Metamaterial Absorber Loaded with Metallic Resonators for the Enhancement of Lower-Frequency Absorption

2017 ◽  
Author(s):  
Yang Shen ◽  
Jie Qiu Zhang ◽  
Yong Qiang Pang ◽  
Lin Zheng ◽  
Jia Fu Wang ◽  
...  
Keyword(s):  
Absorption Band ◽  
Three Dimensional ◽  
Areal Density ◽  
Metamaterial Absorber ◽  
Experimental Results ◽  
Broadband Absorption ◽  
Three Samples ◽  
Wide Range ◽  
Metamaterial Absorbers

Resistive patch array incorporating with metallic backplane provided an effective way to the achievement of broadband metamaterial absorbers(MAs). When loading metallic metamaterial to resistive MA, the outstanding construction helps realize more flexible and diversified forms of broadband absorption. In this paper, we attempted to load metallic resonators(MRs) to resistive MA in the three-dimensional construction, which benefits further enhancement of lower-frequency absorption. Simulation showed that the partial absorption band was separated to lower frequency, while the rest of broadband absorption was unaffected. Meanwhile, after combining multi-unit of the proposed MAs, the stair-stepping broadband absorption was also achieved. At last, three samples were fabricated. The agreements between simulations and experimental results demonstrated that resistive MA loaded with MRs provided an effective way for further enhancement of lower-frequency absorption with almost no change of the absorbing structure and areal density. Thus, it is worthy to expect a wide range of applications to emerge inspired from the proposed attempt.

Prediction of Snow/Tire Interaction Using Explicit FEM and FVM

2003 ◽  
Vol 31 (3) ◽  
pp. 173-188 ◽  
Author(s):  
E. Seta ◽  
T. Kamegawa ◽  
Y. Nakajima
Keyword(s):  
Plastic Material ◽  
Three Dimensional ◽  
Yield Model ◽  
Explicit Finite Element ◽  
Eulerian Formulation ◽  
Single Function ◽  
Wide Range ◽  
Volume Method ◽  
Contact Pressures ◽  
Cam Clay

Abstract A three-dimensional prediction model has been developed in which the interaction between snow and a rolling tire with tread pattern is considered. An explicit finite element method (FEM) and a finite volume method (FVM) are used to model tire and snow respectively. Snow deformation is calculated by the Eulerian formulation to solve the complex interaction between snow and tire tread pattern. Coupling between a tire and snow is automatically computed by the coupling element. Numerical modeling of snow is essential to the tire performance prediction on snow. In this study, snow is assumed to be homogeneous and considered to be an elasto-plastic material. The Mohr-Coulomb yield model, in which the yield stress is a single function of pressure, is adopted. This function is investigated by tire traction tests under a wide range of tire contact pressures using several tires with different inflation pressures and patterns. The predicted results using the Mohr-Coulomb yield model are compared with those using the Capped Drucker-Pragger and the Cam-Clay yield models. Snow traction of a tire featuring different tread patterns is simulated by this technology. Results are shown to be in good qualitative agreement with experimental data.

Steel-Concrete Bond Deterioration under Repeated Loading for Different Confinement Levels

2012 ◽  
Vol 217-219 ◽  
pp. 188-191 ◽  
Author(s):  
Marco Valente
Keyword(s):  
Cyclic Loading ◽  
Bond Strength ◽  
Three Dimensional ◽  
Experimental Tests ◽  
Experimental Results ◽  
Numerical Analyses ◽  
Repeated Loading ◽  
Loading History ◽  
Steel Rebar ◽  
Bond Deterioration

This paper presents the results of experimental tests and numerical analyses concerning the influence of repeated cyclic loading and reinforcement confinement on bond between steel rebar and concrete. Experimental tests of push-pull type were carried out at the Politecnico di Milano on concrete specimens provided with a steel cage of longitudinal bars and stirrups, and reinforced with a single steel rebar. The experimental tests were conducted under monotonic and repeated loading history. Bond strength degradation was observed due to repeated cyclic loading. Detailed three-dimensional finite element models of the specimens were developed to reproduce laboratory tests and parametric analyses were performed to provide a better understanding of the experimental results. The numerical analyses showed good agreement with the experimental results and confirmed that the applied repeated loading history caused significant bond deterioration. High values of reinforcement confinement enhanced bond strength and delayed the onset of bond deterioration.

Analysis of Radial Strain Distribution in the Metal Spinning Process by Taguchi Approach

2012 ◽  
Vol 472-475 ◽  
pp. 719-722
Author(s):  
Peter Šugár ◽  
Jana Šugárová ◽  
Peter Zemko
Keyword(s):  
Strain Distribution ◽  
Radial Strain ◽  
Taguchi Approach ◽  
Analysis Method ◽  
Anova Analysis ◽  
Planar Anisotropy ◽  
Factors Affecting ◽  
Grid Analysis ◽  
Spinning Process ◽  
Metal Spinning

The paper presents the results of radial strain distribution measurement throughout the part after multi-pass conventional metal spinning by the circle grid analysis method. The influence of the mandrel speed, workpiece geometry and planar anisotropy of material on the radial strain was studied. For experiment design, an orthogonal array L27 was used and ANOVA (Analysis of Variance) was carried out. Based on the results it is determined that the sequence of factors affecting radial strain corresponds to geometry of spun part, mandrel speed, planar anisotropy of the sheet. In particular, it is found that the workpiece geometry (specific areas of spun part: mandrel/workpiece radius, conical area, cylindrical area) is the most important factor which influences the radial strain of the spun part.

Application of computational fluid dynamics to predict hydrodynamic downpull on high head gates

2017 ◽  
Vol 34 (4) ◽  
pp. 1191-1203 ◽  
Author(s):  
Mete Koken ◽  
Ismail Aydin ◽  
Akis Sahin
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Numerical Models ◽  
Separation Bubble ◽  
Three Dimensional ◽  
Experimental Models ◽  
Experimental Results ◽  
Content Type ◽  
Wide Range ◽  
High Head

Purpose High head gates are commonly used in hydropower plants for flow regulation and emergence closure. Hydrodynamic downpull can be a critical parameter in design of the lifting mechanism. The purpose of this paper is to show that a simplified two-dimensional (2D) computational fluid dynamics solution can be used in the prediction of the downpull force on the gate lip by comparison of computed results to experimentally measured data. Design/methodology/approach In this study, ANSYS FLUENT CFD software was used to obtain 2D numerical solution for the flow field around a generic gate model located in a power intake structure which was previously used in an experimental study. Description of the flow domain, computational grid resolution, requirements on setting appropriate boundary conditions and methodology in describing downpull coefficient are discussed. Total number of 245 simulations for variable gate lip geometry and gate openings were run. The downpull coefficient evaluated from the computed pressure field as function of gate opening and lip angle are compared with the experimental results. Findings The computed downpull coefficient agrees well with the previous experimental results, except one gate with small lip angle where a separation bubble forms along the lip, which is responsible from this deviation. It is observed that three-dimensional (3D) effects are confined to the large gate openings where downpull is minimum or even reversed. Research limitations/implications In large gate openings, three dimensionality of the flow around gate slots plays an important role and departure from 2D solutions become more pronounced. In that case, one might need to perform a 3D solution instead. Practical implications This paper presents a very fast and accurate way to predict downpull force on high head gates in the absence of experimental data. Originality/value An extensive amount of simulations are run within the scope of this study. It is shown that knowing its limitations, 2D numerical models can be used to calculate downpull for a wide range of gate openings without the need of expensive experimental models.

scholarly journals A Virtual Testing Strategy to Determine Macroscopic Properties of Elasto-Plastic Heterogeneous Composite Materials

2021 ◽  
Author(s):  
◽  
Mahshid Ranjbarestalkhjani
Keyword(s):  
Finite Element ◽  
Composite Materials ◽  
Three Dimensional ◽  
Analytical Models ◽  
Testing Strategy ◽  
Virtual Testing ◽  
Explicit Finite Element ◽  
Yield Criteria ◽  
Representative Volume ◽  
Wide Range

The objective of this work is to determine an e˙ective yield criteria for porous pressure sensitive solids and investigate the anisotropic yield behavior by employing a virtual testing strategy. The work is concerned with the pressure sensitivity typically displayed by geometarials, such as sandstone and composite materials consisting of a series of parallel layers, such as sedimentary rock and underground salt.Virtual testing strategy is based on computational homogenization approach for the definition of the elasto-plastic transition. Representative volume elements (RVEs) containing single-centered and distributed ellipsoidal voids are analyzed using three-dimensional finite element models under both small and finite strains. Yield curves are obtained following a unified variational formulation, which provides bounds on the e˙ective material properties for a given choice of the Representative Volume Element (RVE).In order to estimate the e˙ective properties of porous solid, the constitutive behavior of the continuum matrix is assumed to follow the standard Drucker-Prager elasto-plastic model. The computationally generated e˙ective yield criteria are compared against the recently proposed analytical estimates for Drucker-Prager type solids and the SR4 constitutive model for soft rocks. The developed computational approach is applied to estimate the e˙ective properties of a realistic rock sample. To illustrate a wide range of potential engineering applications, the computationally e˙ective yield surface are also obtained under the explicit finite element method.Finally, based on the simulated yield stress point of composite materials, the pa-rameters for proposed analytical models are acquired with ellipse fit by Taubin’s method.

scholarly journals WAVE PROPAGATION ON A FLUME: NUMERICAL SIMULATION

2015 ◽  
Vol 14 (1) ◽  
pp. 95
Author(s):  
J. M. P. Conde ◽  
P. T. S. Roberto ◽  
C. J. E. M. Fortes
Keyword(s):  
Time Series ◽  
Water Column ◽  
Wave Height ◽  
Stokes Equations ◽  
National Laboratory ◽  
Three Dimensional ◽  
Experimental Tests ◽  
Numerical Code ◽  
Wave Transformation ◽  
Wide Range

This paper presents the numerical simulations done by using the waves2Foam, an OpenFOAM® library, to simulate the propagation of regular waves without breaking in a three-dimensional flume. The numerical code solves the unsteady Navier-Stokes equations and uses a Volume-of-Fluid (VoF) method to identify the free-surface. A regular incident wave with a 1.5s period and 0.1m wave height was considered. This is one of the conditions, from the wide range of wave flume tests conducted at the National Laboratory for Civil Engineering (LNEC), whose objective was to analyze the hydrodynamics of wave transformation and wave breaking for different incident conditions over a variable bathymetry. Comparisons are made between the numerical and the experimental results. These comparisons include time-series of wave-gauges records at several locations along the flume and the corresponding amplitude spectra; significant wave height and average period evolution along the flume; time-series of the velocity components at one section of the flume, measured at the middle of the water column; and hodograph representation of the velocity components, in the middle of the water column, in the xy, xz, and yz planes, along the flume. It was found that the numerical results obtained are close to the experimental data. The observed differences are attributable to numerical inaccuracies as well as the differences between the wave generation method in the numerical and experimental tests.

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