An Innovative Procedure for High Speed Weighing in Motion of Railway Vehicles

2015 ◽  
Author(s):  
Enrico Meli ◽  
Pierluca D’Adamio ◽  
Alice Innocenti ◽  
Lorenzo Marini ◽  
Luca Pugi ◽  
...  
Keyword(s):  
Experimental Data ◽  
High Speed ◽  
Estimation Algorithm ◽  
Operating Conditions ◽  
Least Square ◽  
Accurate Estimation ◽  
Research Activity ◽  
Multibody Model ◽  
Weigh In Motion ◽  
Numerical Noise

In the present work the authors propose an innovative estimation algorithm for Weigh-in-motion (WIM) applications with the aim of estimating the axle or wheel loads of a generic train composition, starting from indirect track measurements. The WIM algorithm elaborates the set of experimental physical quantities chosen as track inputs, making use of estimation procedures based on least square minimization techniques. To perform an accurate estimation, the algorithm uses a flexible multibody model of the track and the vehicle. The novelty of the proposed solution is the general approach that allows to manage different kinds of measurement station and signal inputs (both experimental data and simulated ones) and the good robustness against numerical noise. The algorithm has been tested under any operating conditions through a wide simulation campaign, obtaining good results. Future developments will be based on the experimental data provided by Ansaldo STS and ECM SpA that supported the research activity.

Aerodynamic Damping Predictions Using a Linearized Navier-Stokes Analysis

1999 ◽  
Author(s):  
Daniel Hoyniak ◽  
William S. Clark
Keyword(s):  
Experimental Data ◽  
High Speed ◽  
Operating Conditions ◽  
The Other ◽  
Navier Stokes ◽  
Turbine Cascade ◽  
Blade Loading ◽  
Operating Condition ◽  
Linear Cascade ◽  
Aerodynamic Damping

A recently developed two dimensional, linearized Navier-Stokes algorithm, capable of modeling the unsteady flows encountered in turbomachinery applications, has been benchmarked and validated for use in the prediction of the aerodynamic damping. Benchmarking was accomplished by comparing numerical simulations with experimental data for two geometries. The first geometry investigated is a high turning turbine cascade. For this configuration, two different steady operating conditions were considered. The exit flow for one operating condition is subsonic whereas the exit flow for the other operating condition is supersonic. The second geometry investigated is a tip section from a high speed fan. Again, two separate steady operating conditions were examined. For this fan geometry, one operating condition falls within an experimentally observed flutter region whereas the other operating condition was observed experimentally to be flutter free. For both geometries considered, experimental measurements of the unsteady blade surface pressures were acquired for a linear cascade subjected to small amplitude torsional vibrations. Comparisons between the numerical calculations and the experimental data demonstrate the ability of the present computational model to predict accurately the steady and unsteady blade loading, and hence the aerodynamic damping, for each configuration presented.

The Output Filter Identification of Three-Phase PWM Converter Using Weighted Least Square Method

2015 ◽  
Vol 734 ◽  
pp. 877-886
Author(s):  
Yi Long Zhang ◽  
Xue Guang Zhang
Keyword(s):  
Control Strategies ◽  
Least Square Method ◽  
Operating Conditions ◽  
Least Square ◽  
Accurate Estimation ◽  
Pwm Converter ◽  
Weighted Least Square ◽  
Three Phase ◽  
Mathematical Techniques ◽  
Output Filter

This paper proposed the Weighted Least Square method (WLS method) to identify the output filter of three-phase PWM converter, which incorporates the signal processing as well as mathematical techniques into conventional Least Square method. It sets different weights to different measurements according to the phase where it locates, based on the discovery of the correlation between accuracy and phase of current. The algorithm is tested in both simulation and experimental environment, and the results validate that proposed method gives accurate estimation in steady state, and can response within 10ms in when grid voltage drops. This method can work under both balanced and unbalanced operating conditions, therefore provides a powerful tool for various control strategies to better understand the operating conditions. Compared with the invasive method, which intentionally inject a series of white noise in the system, proposed WLS method does not bring any turbulence, while compared with conventional Least Square method, it possesses better stability as well as higher accuracy.

Dynamic Modeling of a Dual Clearance Squeeze Film Damper: Part III

2005 ◽  
Author(s):  
L. Moraru ◽  
F. Dimofte ◽  
S. Cioc ◽  
T. G. Keith ◽  
D. P. Fleming
Keyword(s):  
Experimental Data ◽  
High Speed ◽  
Rotating Machinery ◽  
Operating Conditions ◽  
Squeeze Film ◽  
Squeeze Film Damper ◽  
Squirrel Cage ◽  
Squeeze Film Dampers ◽  
Abnormal Operating Conditions ◽  
Oil Films

Squeeze film dampers (SFD) are devices utilized to control vibrations of the shafts of high-speed rotating machinery. A dual squeeze film damper (DSFD) consists of two squeeze film bearings that are separated by a sleeve, which is released when the rotor experiences abnormal operating conditions. In this part of our study of DSFD we analyze the case when both the inner and the outer oil films are active and the separating sleeve is supported by a squirrel cage. Numerical results are compared with the experimental data.

scholarly journals Measurement of Windage Losses and Temperature Distribution for a High Speed Composite Rotor in a Stator Assembly at Low Air Pressures

2003 ◽  
Author(s):  
Jonathan Hahne ◽  
Mike Werst ◽  
Charles Penney ◽  
Hsing-Pang Liu ◽  
Jeremy O’Rarden ◽  
...  
Keyword(s):  
Experimental Data ◽  
Temperature Distribution ◽  
Thermal Effects ◽  
High Speed ◽  
Operating Conditions ◽  
Heat Distribution ◽  
Loss Analysis ◽  
Thermal Distribution ◽  
Specific Geometry ◽  
Proper Design

With the advancements in composite technology several innovative applications present themselves that involve high-speed composite rotors spinning in a stator assembly. As rotational speeds and rotor tip speeds increase, these rotors must operate in low air pressure environments to minimize windage losses and thermal effects of being at high speed for long durations. Accurately predicting this windage loss for a specific geometry and operating conditions is very important for a proper design. It is also very important to know the relative heat distribution that is seen by the rotor and stator from this windage loss. Analysis tools to date do not have a coupled link that calculates windage loss and a resultant thermal distribution to the rotor and stator surfaces. This paper presents the design and fabrication of a test setup to measure the total windage loss and temperature distribution from a high-speed composite rotor in a stator structure. Rotor speeds up to 40,000 rpm and rotor tip speeds up to 900 m/s with pressure ranges from 0.1 torr to 10 torr were operating parameters during the testing. The paper will also present experimental data obtained during the testing. Experimental data obtained during the testing will be used to evaluate new analysis methods for predicting the windage loss and thermal distribution in new high-speed rotor applications.

Evaluation of Parameters in a Fluid Cutting Equation

1990 ◽  
Vol 112 (3) ◽  
pp. 240-244 ◽  
Author(s):  
C. E. Whiting ◽  
E. E. Graham ◽  
B. Ghorashi
Keyword(s):  
Experimental Data ◽  
Material Properties ◽  
High Speed ◽  
Solid Material ◽  
Operating Conditions ◽  
Depth Of Cut ◽  
Solid Materials ◽  
Evaluation Of Parameters ◽  
Extensive Experimental Data ◽  
General Method

The application of a high speed jet of water for cutting solid materials has gained general industrial acceptance, but as yet no method exists for prediction of the depth of cut based on documented material properties. Extensive experimental data for the cutting of woods, plastics, and lead have been obtained and applied to equations developed by Hashish and duPlessis [1], [2] resulting in correlations for two key parameters in Hashish’s equations; the coherent core length and the damping coefficient. This has led to a general method for predicting the depth of a water jet cut that requires no prior experimental data. Using only basic physical properties of a solid material, the depth of cut can be predicted for a given set of operating conditions including feed rate, nozzle diameter, standoff distance, and pressure.

A Useful Curve Fitting Method for Concrete Uniaxial Compressive Experiment Data

2011 ◽  
Vol 291-294 ◽  
pp. 1015-1020 ◽  
Author(s):  
Chong Jin ◽  
Hong Wang ◽  
Xiao Zhou Xia
Keyword(s):  
Experimental Data ◽  
Orthogonal Polynomial ◽  
Least Square ◽  
Base Function ◽  
Concrete Material ◽  
Fitting Method ◽  
Orthogonal Base ◽  
The Matrix ◽  
Uniform Function ◽  
Curve Fitting Method

Based on the superiority avoiding the matrix equation to be morbid for those fitting functions constructed by orthogonal base, the Legendre orthogonal polynomial is adopted to fit the experimental data of concrete uniaxial compression stress-strain curves under the frame of least-square. With the help of FORTRAN programming, 3 series of experimental data is fitted. And the fitting effect is very satisfactory when the item number of orthogonal base is not less than 5. What’s more, compared with those piecewise fitting functions, the Legendre orthogonal polynomial fitting function obtained can be introduced into the nonlinear harden-soften character of concrete constitute law more convenient because of its uniform function form and continuous derived feature. And the fitting idea by orthogonal base function will provide a widely road for studying the constitute law of concrete material.

Fast and Accurate Estimation of Statistical Eye Diagram for Nonlinear High-Speed Links

2021 ◽  
pp. 1-9
Author(s):  
Xiuqin Chu ◽  
Wenting Guo ◽  
Jun Wang ◽  
Feng Wu ◽  
Yuhuan Luo ◽  
...  
Keyword(s):  
High Speed ◽  
Accurate Estimation ◽  
Eye Diagram

Identification of Bearing Coefficients of Flexible Rotor-Bearing Systems

2000 ◽  
Author(s):  
Tachung Yang ◽  
Wei-Ching Chaung
Keyword(s):  
Industrial Applications ◽  
Operating Conditions ◽  
Least Square ◽  
Flexible Rotor ◽  
Fem Modeling ◽  
Identification Method ◽  
Reaction Forces ◽  
Manufacturing Assembly ◽  
Stiffness And Damping

The accuracy of stiffness and damping coefficients of bearings is critical for the rotordynamic analysis of rotating machinery. However, the influence of bearings depends on the design, manufacturing, assembly, and operating conditions of the bearings. Uncertainties occur quite often in manufacturing and assembly, which causes the inaccuracy of bearing predictions. An accurate and reliable in-situ identification method for the bearing coefficients is valuable to both analyses and industrial applications. The identification method developed in this research used the receptance matrices of flexible shafts from FEM modeling and the unbalance forces of trial masses to derive the displacements and reaction forces at bearing locations. Eight bearing coefficients are identified through a Total Least Square (TLS) procedure, which can handle noise effectively. A special feature of this method is that it can identify bearing coefficients at a specific operating speed, which make it suitable for the measurement of speed-dependent bearings, like hydrodynamic bearings. Numerical validation of this method is presented. The configurations of unbalance mass arrangements are discussed.

Development and Validation of a Three-Dimensional Multiphase Flow CFD Analysis for Journal Bearings in Steam and Heavy Duty Gas Turbines

2012 ◽  
Author(s):  
Stephan Uhkoetter ◽  
Stefan aus der Wiesche ◽  
Michael Kursch ◽  
Christian Beck
Keyword(s):  
Experimental Data ◽  
Multiphase Flow ◽  
Gas Turbines ◽  
High Speed ◽  
Three Dimensional ◽  
Air Entrainment ◽  
Journal Bearings ◽  
Heavy Duty ◽  
Present Contribution ◽  
Two Phase

The traditional method for hydrodynamic journal bearing analysis usually applies the lubrication theory based on the Reynolds equation and suitable empirical modifications to cover turbulence, heat transfer, and cavitation. In cases of complex bearing geometries for steam and heavy-duty gas turbines this approach has its obvious restrictions in regard to detail flow recirculation, mixing, mass balance, and filling level phenomena. These limitations could be circumvented by applying a computational fluid dynamics (CFD) approach resting closer to the fundamental physical laws. The present contribution reports about the state of the art of such a fully three-dimensional multiphase-flow CFD approach including cavitation and air entrainment for high-speed turbo-machinery journal bearings. It has been developed and validated using experimental data. Due to the high ambient shear rates in bearings, the multiphase-flow model for journal bearings requires substantial modifications in comparison to common two-phase flow simulations. Based on experimental data, it is found, that particular cavitation phenomena are essential for the understanding of steam and heavy-duty type gas turbine journal bearings.

scholarly journals Material parameter identification using finite elements with time-adaptive higher-order time integration and experimental full-field strain information

2021 ◽  
Author(s):  
Stefan Hartmann ◽  
Rose Rogin Gilbert
Keyword(s):  
Experimental Data ◽  
Finite Elements ◽  
Parameter Identification ◽  
Material Parameter ◽  
Measurement Data ◽  
Least Square ◽  
Image Correlation ◽  
Field Strain ◽  
Material Parameter Identification ◽  
Full Field

AbstractIn this article, we follow a thorough matrix presentation of material parameter identification using a least-square approach, where the model is given by non-linear finite elements, and the experimental data is provided by both force data as well as full-field strain measurement data based on digital image correlation. First, the rigorous concept of semi-discretization for the direct problem is chosen, where—in the first step—the spatial discretization yields a large system of differential-algebraic equation (DAE-system). This is solved using a time-adaptive, high-order, singly diagonally-implicit Runge–Kutta method. Second, to study the fully analytical versus fully numerical determination of the sensitivities, required in a gradient-based optimization scheme, the force determination using the Lagrange-multiplier method and the strain computation must be provided explicitly. The consideration of the strains is necessary to circumvent the influence of rigid body motions occurring in the experimental data. This is done by applying an external strain determination tool which is based on the nodal displacements of the finite element program. Third, we apply the concept of local identifiability on the entire parameter identification procedure and show its influence on the choice of the parameters of the rate-type constitutive model. As a test example, a finite strain viscoelasticity model and biaxial tensile tests applied to a rubber-like material are chosen.

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