Stiffening Effect of Motor Core Webs for Torsional Rotordynamics

2012 ◽  
Author(s):  
Chris D. Kulhanek ◽  
Stephen M. James ◽  
Justin R. Hollingsworth
Keyword(s):  
Torsional Stiffness ◽  
Poor Agreement ◽  
Motor Shaft ◽  
Element Analysis ◽  
Resonance Frequencies ◽  
Cooling Air Flow ◽  
Cooling Air ◽  
Sufficient Space ◽  
Stiffening Effect ◽  
Good Agreement

Longitudinal webs or spider bars are often placed mid-span of a motor shaft and are primarily used to support the windings or rotor laminations while allowing sufficient space for cooling air flow. When subject to a torque, the radial webs experience a loading configuration that includes bending and torsion while the base shaft experiences pure torsion. A webbed cross-section has a higher torsional stiffness as compared to the torsional stiffness of just the circular portion of the shaft section. This influences the torsional critical speeds and can become important for torsional systems that operate with minimal separation margins from resonance frequencies. This work presents various approaches to calculate the stiffening effect. The approaches include empirical and analytical methods described by Nestorides and API 684. An additional method uses a solid model of the motor core and a commercial Finite Element Analysis (FEA) solver to predict steady-state deflection under a torsional load. This in turn allows for a torsional stiffness calculation. Motor core configurations with various shaft diameters, number of spider bars, and spider bar geometries are considered. Good agreement is shown between the FEA results and the Griffith and Taylor method described by Nestorides. The other methods considered, including the calculation method described in API 684, show generally poor agreement with the FEA torsional stiffness results for the webbed shaft geometries studied.

An Improved Unified Solution for a Vibration Equation of Tension-Stiffening Beam Using Extended Rayleigh Energy Method

2019 ◽  
Author(s):  
Zhijun Yang ◽  
Ruiqi Li ◽  
Youdun Bai
Keyword(s):  
Boundary Conditions ◽  
Analytical Solutions ◽  
Energy Method ◽  
Physical Science ◽  
Element Analysis ◽  
Tension Stiffening ◽  
Design And Optimization ◽  
Micro Motion ◽  
Stiffening Effect ◽  
Good Agreement

Abstract The tension-stiffening effect is very important for physical science, which has been widely used in MEMS, sensors and micro-motion stages. The analytical solutions of the tension-stiffening beam are extremely significant, in consideration of the inefficiency of finite element analysis (FEA) for the design and optimization. Commonly, there are three typical types of boundary conditions for tension-stiffening (or stress-induced) beams, i.e., clamped-clamped, clamped-hinged, and hinged-hinged. But only the hinged-hinged beam has an analytical solution. Therefore, a method based on extended Rayleigh energy method is proposed in this paper to deduce the analytical solutions of three boundary conditions. The predictions are verified to be in good agreement with FEA and experiment results.

The Prediction of Flow Through Leading Edge Holes in a Film Cooled Airfoil With and Without Inserts

1985 ◽  
Vol 107 (1) ◽  
pp. 92-98 ◽  
Author(s):  
E. S. Tillman ◽  
E. O. Hartel ◽  
H. F. Jen
Keyword(s):  
Leading Edge ◽  
Flow Rates ◽  
Cooling Flow ◽  
Internal Loss ◽  
Measured Flow ◽  
Flow Through ◽  
Loss Coefficients ◽  
Cooling Air Flow ◽  
Cooling Air ◽  
Good Agreement

A method for predicting cooling air flow rates using tests on cylindrical models of typical turbine blade leading edges has been extended to include blades with inserts and blades with reversed-angled holes. When an insert is used, the pressure loss across the insert can be determined from flow tests and added to other losses in the flow path to determine cooling flow rates. Calculated and experimentally determined flow rates are compared with good agreement. The second experiment was performed to determine internal loss coefficients for reverse-angled holes oriented so the flow makes a reverse turn to enter the holes. The reversed flow case produced significantly greater internal loss coefficients than when the same holes were oriented in the direction of flow. These results were used to predict flow from arrays of reverse- angled holes and from a cylinder containing both reverse-angled holes and nonreversed holes. In all cases, good agreement was found between predicted and measured flow rates.

Rim Seal Experiments and Analysis of a Rotor-Stator System With Nonaxisymmetric Main Flow

1992 ◽  
Author(s):  
K. Hamabe ◽  
K. Ishida
Keyword(s):  
Static Pressure ◽  
Main Flow ◽  
Test Results ◽  
Gas Concentration ◽  
Static Pressure Distribution ◽  
Precise Prediction ◽  
Cooling Air Flow ◽  
Shrouded Rotor ◽  
Cooling Air ◽  
Good Agreement

To examine the simplified model to predict the ingress flow rate which was formerly proposed by the authors, the scaling characteristics of a shrouded rotor-stator system with a nonaxisymmetric main flow is studied using gas concentration measurements in the wheel-space. The predicted value for the sealing effectiveness as well as the minimum cooling air flow ratio necessary to prevent ingress is shown to be relatively in good agreement with the test results. It is also found that for the precise prediction of the sealing effectiveness, the circumferential static pressure distribution in the annulus is needed.

Computer Modeling of a Tire under Cornering Loads

1989 ◽  
Vol 17 (2) ◽  
pp. 86-99 ◽  
Author(s):  
I. Gardner ◽  
M. Theves
Keyword(s):  
Finite Element Analysis ◽  
Geometric Approach ◽  
Lateral Force ◽  
Slip Angle ◽  
Element Analysis ◽  
Pressure Distributions ◽  
Slip Effects ◽  
Improved Accuracy ◽  
Nonlinear Geometric ◽  
Good Agreement

Abstract During a cornering maneuver by a vehicle, high forces are exerted on the tire's footprint and in the contact zone between the tire and the rim. To optimize the design of these components, a method is presented whereby the forces at the tire-rim interface and between the tire and roadway may be predicted using finite element analysis. The cornering tire is modeled quasi-statically using a nonlinear geometric approach, with a lateral force and a slip angle applied to the spindle of the wheel to simulate the cornering loads. These values were obtained experimentally from a force and moment machine. This procedure avoids the need for a costly dynamic analysis. Good agreement was obtained with experimental results for self-aligning torque, giving confidence in the results obtained in the tire footprint and at the rim. The model allows prediction of the geometry and of the pressure distributions in the footprint, since friction and slip effects in this area were considered. The model lends itself to further refinement for improved accuracy and additional applications.

Torsional Analysis of a Steel Cord-Rubber Tire Belt Structure

1996 ◽  
Vol 24 (4) ◽  
pp. 339-348 ◽  
Author(s):  
R. M. V. Pidaparti
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Composite Structures ◽  
Three Dimensional ◽  
Element Model ◽  
Torsional Stiffness ◽  
Element Analysis ◽  
Rubber Belt ◽  
Steel Cord ◽  
Torsional Analysis

Abstract A three-dimensional (3D) beam finite element model was developed to investigate the torsional stiffness of a twisted steel-reinforced cord-rubber belt structure. The present 3D beam element takes into account the coupled extension, bending, and twisting deformations characteristic of the complex behavior of cord-rubber composite structures. The extension-twisting coupling due to the twisted nature of the cords was also considered in the finite element model. The results of torsional stiffness obtained from the finite element analysis for twisted cords and the two-ply steel cord-rubber belt structure are compared to the experimental data and other alternate solutions available in the literature. The effects of cord orientation, anisotropy, and rubber core surrounding the twisted cords on the torsional stiffness properties are presented and discussed.

A PARADIGM SHIFT FOR TORSIONAL STIFFNESS OF NICKEL-TITANIUM ROTARY INSTRUMENTS: A FINITE ELEMENT ANALYSIS.

2021 ◽  
Author(s):  
Zanza Alessio ◽  
Seracchiani Marco ◽  
Di Nardo Dario ◽  
Reda Rodolfo ◽  
Gambarini Gianluca ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Paradigm Shift ◽  
Nickel Titanium ◽  
Torsional Stiffness ◽  
Element Analysis ◽  
Rotary Instruments

scholarly journals Design and analysis of concrete-filled tubular flange girders under combined loading

2021 ◽  
pp. 136943322110015
Author(s):  
Rana Al-Dujele ◽  
Katherine Ann Cashell
Keyword(s):  
Finite Element ◽  
Axial Force ◽  
Failure Modes ◽  
Numerical Study ◽  
Combined Loading ◽  
Torsional Stiffness ◽  
Fe Model ◽  
Combined Effects ◽  
Element Analysis ◽  
Hollow Section

This paper is concerned with the behaviour of concrete-filled tubular flange girders (CFTFGs) under the combination of bending and tensile axial force. CFTFG is a relatively new structural solution comprising a steel beam in which the compression flange plate is replaced with a concrete-filled hollow section to create an efficient and effective load-carrying solution. These members have very high torsional stiffness and lateral torsional buckling strength in comparison with conventional steel I-girders of similar depth, width and steel weight and are there-fore capable of carrying very heavy loads over long spans. Current design codes do not explicitly include guidance for the design of these members, which are asymmetric in nature under the combined effects of tension and bending. The current paper presents a numerical study into the behaviour of CFTFGs under the combined effects of positive bending and axial tension. The study includes different loading combinations and the associated failure modes are identified and discussed. To facilitate this study, a finite element (FE) model is developed using the ABAQUS software which is capable of capturing both the geometric and material nonlinearities of the behaviour. Based on the results of finite element analysis, the moment–axial force interaction relationship is presented and a simplified equation is proposed for the design of CFTFGs under combined bending and tensile axial force.

Thermo-Mechanical Modeling and Analysis of Equal Channel Angular Pressing

2005 ◽  
Vol 23 ◽  
pp. 263-266 ◽  
Author(s):  
Qing Xiang Pei ◽  
B.H. Hu ◽  
C. Lu
Keyword(s):  
Equal Channel Angular Pressing ◽  
Temperature Rise ◽  
Flow Behavior ◽  
Material Model ◽  
Workpiece Material ◽  
Element Analysis ◽  
Modeling And Analysis ◽  
Die Geometry ◽  
Angular Pressing ◽  
Good Agreement

Thermo-mechanical finite element analysis was carried out to study the deformation behavior and temperature distribution during equal channel angular pressing (ECAP). The material model used is the Johnson-Cook constitution model that can consider the multiplication effect of strain, strain rate, and temperature on the flow stress. The effects of pressing speed, pressing temperature, workpiece material and die geometry on the temperature rise and flow behavior during ECAP process were investigated. The simulated temperature rise due to deformation heating was compared with published experimental results and a good agreement was obtained. Among the various die geometries studied, the two-turn die with 0° round corner generates the highest and most uniform plastic strain in the workpiece.

Experimental and theoretical study of sandwich composites with Z-pins under quasi-static compression loading

2021 ◽  
pp. 136943322110073
Author(s):  
Erdem Selver ◽  
Gaye Kaya ◽  
Hussein Dalfi
Keyword(s):  
Vinyl Ester ◽  
Failure Modes ◽  
Critical Role ◽  
Sandwich Composites ◽  
Test Results ◽  
Compressive Properties ◽  
Element Analysis ◽  
Static Compression ◽  
Quasi Static Compression ◽  
Good Agreement

This study aims to enhance the compressive properties of sandwich composites containing extruded polystyrene (XPS) foam core and glass or carbon face materials by using carbon/vinyl ester and glass/vinyl ester composite Z-pins. The composite pins were inserted into foam cores at two different densities (15 and 30 mm). Compression test results showed that compressive strength, modulus and loads of the sandwich composites significantly increased after using composite Z-pins. Sandwich composites with 15 mm pin densities exhibited higher compressive properties than that of 30 mm pin densities. The pin type played a critical role whilst carbon pin reinforced sandwich composites had higher compressive properties compared to glass pin reinforced sandwich composites. Finite element analysis (FE) using Abaqus software has been established in this study to verify the experimental results. Experimental and numerical results based on the capabilities of the sandwich composites to capture the mechanical behaviour and the damage failure modes were conducted and showed a good agreement between them.

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