Contact Stresses in Dovetail Attachments: Physical Modeling

2002 ◽  
Vol 124 (2) ◽  
pp. 325-331 ◽  
Author(s):  
G. B. Sinclair ◽  
N. G. Cormier
Keyword(s):  
Finite Element ◽  
Physical Modeling ◽  
Physical Models ◽  
Shear Stresses ◽  
Major Contributor ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Large Fluctuations ◽  
Hoop Stresses ◽  
Good Agreement

Simple physical models for the stresses in dovetail attachments are developed. These models address: to slip or not to slip, nominal stresses during loading up, peak contact and shear stresses during loading up, hoop stresses during loading up, peak contact and shear stresses during unloading, and hoop stresses during unloading. Comparisons are made with a previous paper on companion finite element modeling. Generally there is good agreement between the simple physical models and the finite element analysis. Together the two identify a pinching mechanism as leading to large fluctuations in hoop stresses at the edges of contact. These fluctuating hoop stresses can be expected to be a major contributor to the fatigue of dovetail attachments.

Contact Stresses in Dovetail Attachments: Physical Modeling

2000 ◽  
Author(s):  
G. B. Sinclair ◽  
N. G. Cormier
Keyword(s):  
Finite Element ◽  
Physical Modeling ◽  
Physical Models ◽  
Shear Stresses ◽  
Major Contributor ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Large Fluctuations ◽  
Hoop Stresses ◽  
Good Agreement

Simple physical models for the stresses in dovetail attachments are developed. These models address: to slip or not to slip, nominal stresses during loading up, peak contact and shear stresses during loading up, hoop stresses during loading up, peak contact and shear stresses during unloading, and hoop stresses during unloading. Comparisons are made with a previous paper on companion finite element modeling. Generally there is good agreement between the simple physical models and the finite element analysis. Together the two identify a pinching mechanism as leading to large fluctuations in hoop stresses at the edges of contact. These fluctuating hoop stresses can be expected to be a major contributor to the fatigue of dovetail attachments.

Contact Stresses in Dovetail Attachments: Alleviation via Precision Crowning

2003 ◽  
Vol 125 (4) ◽  
pp. 1033-1041 ◽  
Author(s):  
G. B. Sinclair ◽  
N. G. Cormier
Keyword(s):  
Finite Element ◽  
Contact Stresses ◽  
Physical Models ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Large Fluctuations ◽  
Dimensional Finite Element ◽  
Hoop Stresses ◽  
Good Agreement ◽  
Made In

Previous studies of contact stresses in dovetail attachments provide verified finite element stresses as well as some simple physical models of such stresses. Generally there is good agreement between the finite element analysis and the simple physical models. Together the two identify a pinching mechanism as leading to large fluctuations in hoop stresses at the edges of contact. These fluctuating hoop stresses can be expected to be a major contributor to the fatigue of dovetail attachments. The present study investigates a method of alleviating the fluctuating hoop stresses. This method entails crowning of the contacting flat on a blade. Such crowning is in two orthogonal directions on the blade flat. Two-dimensional finite element analyses are made in both directions. These analyses indicate that significant reductions in fluctuating hoop stresses can be achieved by the method, provided the crowning is controlled sufficiently precisely.

Contact Stresses in Dovetail Attachments: Alleviation via Precision Crowning

2001 ◽  
Author(s):  
G. B. Sinclair ◽  
N. G. Cormier
Keyword(s):  
Finite Element ◽  
Contact Stresses ◽  
Physical Models ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Large Fluctuations ◽  
Dimensional Finite Element ◽  
Hoop Stresses ◽  
Good Agreement ◽  
Made In

Previous studies of contact stresses in dovetail attachments provide verified finite element stresses as well as some simple physical models of such stresses. Generally there is good agreement between the finite element analysis and the simple physical models. Together the two identify a pinching mechanism as leading to large fluctuations in hoop stresses at the edges of contact. These fluctuating hoop stresses can be expected to be a major contributor to the fatigue of dovetail attachments. The present study investigates a method of alleviating the fluctuating hoop stresses. This method entails crowning of the contacting flat on a blade. Such crowning is in two orthogonal directions on the blade flat. Two-dimensional finite element analyses are made in both directions. These analyses indicate that significant reductions in fluctuating hoop stresses can be achieved by the method, provided the crowning is controlled sufficiently precisely.

Life Assessment of Turbine Components Through Experimental and Numerical Investigations

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
Dianyin Hu ◽  
Rongqiao Wang ◽  
Guicang Hou
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fatigue Life ◽  
Life Prediction ◽  
Life Assessment ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Creep Fatigue ◽  
Turbine Component ◽  
Good Agreement

A new lifetime criterion for withdrawal of turbine components from service is developed in this paper based on finite element (FE) analysis and experimental results. Finite element analysis is used to determine stresses in the turbine component during the imposed cyclic loads and analytically predict a fatigue life. Based on the finite element analysis, the critical section is then subjected to a creep-fatigue test, using three groups of full scale turbine components, attached to an actual turbine disc conducted at 750 °C. The experimental data and life prediction results were in good agreement. The creep-fatigue life of this type of turbine component at a 99.87% survival rate is 30 h.

Static Analysis of Thin Film Piezoelectric Micro-Accelerometer Using Analytical and Finite Element Modeling

2003 ◽  
Author(s):  
Zhaochun Yang ◽  
Qing-Ming Wang ◽  
Patrick Smolinski ◽  
Hongbo Yang
Keyword(s):  
Finite Element ◽  
High Sensitivity ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Beam Thickness ◽  
Input Acceleration ◽  
On Chip ◽  
Micro Accelerometer ◽  
Fixed Beam ◽  
Good Agreement

On-chip microaccelerometers using piezoelectric thin films has attracted much interest due to their simple structure and potentially high sensitivity. However, the relationships between the structure of the microaccelerometer and its performance still need to be further developed in more details. In this paper we present a theoretical model for a microaccelerometer with four suspended flexural PZT/silicon beams and a central proof mass configuration. The model takes into account the effect of device geometry and elastic properties of the piezoelectric film, and is supported by the finite element analysis. The good agreement of the results demonstrates the validity of the modeling assumptions. This study shows that the accelerometer sensitivity decreases with increasing the width and thickness of the bilayer beams, and elastic modulus of the mechanical microstructure, while increasing the length of the beam, increases sensitivity. For a fixed beam thickness, a maximum sensitivity exists for appropriate PZT/Si thickness. In addition, it is found that the sensitivity is also proportional to the magnitude of the input acceleration. The results of this study can be readily applied to for on-chip piezoelectric microaccelerometer design and its structural optimization.

The Effect of the Die Temperature on the Solidification Behaviour of the Al/SiCp Metal Matrix Composite: A Comparative Study of Experimental and Finite Element Analysis

2014 ◽  
Vol 893 ◽  
pp. 314-319
Author(s):  
P. Gurusamy ◽  
S. Balasivanandha Prabu ◽  
R. Paskaramoorthy
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Time History ◽  
Cooling Curves ◽  
Element Analysis ◽  
Solidification Behaviour ◽  
The Finite Element Analysis ◽  
Die Temperature ◽  
Temperature Time ◽  
Good Agreement

This paper discusses the influence of die temperature on the solidification behaviour of A356/SiCp composites fabricated by squeeze casting method. Information on the solidification studies of squeeze cast composites is somewhat scarce. Experiments were carried out by varying the die temperatures for cylindrical shaped composite castings K-type thermocouples were interfaced to the die and the temperature-time history was recorded to construct the cooling curves. The cooling curves are also predicted from the finite element analysis (FEA) software ANSYS 13. The experimental and predicted cooling curves are not in good agreement. In addition to, the experimental and theoretical solidification times are studied. It was understood that the increase in the die temperature decreases the cooling rate.

Deep Drawing of Square-Shaped Sheet Metal Parts, Part 1: Finite Element Analysis

1993 ◽  
Vol 115 (1) ◽  
pp. 102-109 ◽  
Author(s):  
S. A. Majlessi ◽  
D. Lee
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Membrane Properties ◽  
Computationally Efficient ◽  
Element Analysis ◽  
Sheet Metal Parts ◽  
Part Geometry ◽  
Analysis Technique ◽  
The Finite Element Analysis ◽  
Good Agreement

The process of square-cup drawing is modeled employing a simplified finite element analysis technique. In order to make the algorithm computationally efficient, the deformation (total strain) theory of plasticity is adopted. The solution scheme is comprised of specifying a mesh of two-dimensional finite elements with membrane properties over the deformed configuration of the final part geometry. The initial positions of these elements are then computed by minimization of the potential energy, and therefore the strain distributions are determined. In order to verify predictions made by the finite element analysis method, a drawing apparatus is built and various drawing experiments are carried out. A number of circular and square cups are drawn and strain distributions measured. It is observed that there is generally a good agreement between computed and measured results for both axisymmetric and nonaxisymmetric cases.

Experimental and finite element investigation of a local dent on a pressurized pipe

1992 ◽  
Vol 27 (3) ◽  
pp. 177-185 ◽  
Author(s):  
L S Ong ◽  
A K Soh ◽  
J H Ong
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Surface Defect ◽  
Peak Stress ◽  
Plastic Collapse ◽  
Hoop Strain ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Local Dent ◽  
Good Agreement

The problem of a local dent on a pressurized pipe is studied in this paper. Two case problems of dent are considered - a plain local dent (a smooth local dent without a surface defect), and a local dent associated with a loss of thickness defect. The strain gauging test and the finite element analysis on the plain local dent showed that the strain distributions in the local dent are different from those of a long and continuous dent. The maximum hoop strain in the local dent is located at the flank of the dent, along the dent axial axis, whereas in the case of the long dent, it is located at the root of the dent. In addition, the peak stress in the local dent is generally lower than that in the long dent. To estimate the stress concentration in the local dent using the analysis for the long dent would be grossly overestimated. The burst pipe tests on 17 dented pipes showed that the pipe failures were generally insensitive to the existence of the local dents. The pipe failures were found to be due to the loss-of-thickness defect. The comparison of results between the burst pipe tests and the plastic collapse formula shows reasonably good agreement.

Nonlinear Finite Element Analysis of Steel-Encased Composite Continuous Beams with High Strength Materials

2013 ◽  
Vol 648 ◽  
pp. 59-62
Author(s):  
Qi Yin Shi ◽  
Yi Tao Ge ◽  
Li Lin Cao ◽  
Zhao Chang Zhang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Error Control ◽  
High Strength ◽  
Element Model ◽  
Test Results ◽  
Element Analysis ◽  
Continuous Beams ◽  
The Finite Element Analysis ◽  
Good Agreement

In this study, based on the test of the high strength materials of steel-encased concrete composite continuous beam, the ultimate flexural capacity of 8 composite continuous beams are analyzed by using the finite element analysis software ABAQUS. Numerical results show that it is a very good agreement for the load-deflection curves which obtained by finite element method (FEM) and those by the test results, and the error control is less than 8.5%. When selecting and utilizing appropriate cyclic constitutive model, element model and failure criterion of high strength steel and high strength concrete, the accuracy of the calculation can be improved better.

Finite element analysis for precision cold forging of helical gear using recurrent boundary conditions

1998 ◽  
Vol 212 (3) ◽  
pp. 231-240 ◽  
Author(s):  
Y B Park ◽  
D Y Yang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Boundary Conditions ◽  
Three Dimensional ◽  
Helical Gear ◽  
Cold Forging ◽  
Rigid Plastic ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Good Agreement

In metal forming, there are problems with recurrent geometric characteristics without explicitly prescribed boundary conditions. In such problems, so-called recurrent boundary conditions must be introduced. In this paper, as a practical application of the proposed method, the precision cold forging of a helical gear (which is industrially useful and geometrically complicated) has been simulated by a three-dimensional rigid-plastic finite element method and compared with the experiment. The application of recurrent boundary conditions to helical gear forging analysis is proved to be effective and valid. The three-dimensional deformed pattern by the finite element analysis is shown, and the forging load is compared with the experimental load. The profiles of the free surface of the workpiece show good agreement between the computation and the experiment.

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