Dynamic stress analysis of rotating twisted and tapered blades

1980 ◽  
Vol 15 (3) ◽  
pp. 117-126 ◽  
Author(s):  
V Ramamurti ◽  
S Sreenivasamurthy
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress Analysis ◽  
Dynamic Stress ◽  
Three Dimensional ◽  
The Finite Element Method ◽  
Extensive Analysis ◽  
Dynamic Stress Analysis ◽  
Skew Angles ◽  
Good Agreement

In this paper the finite element method has been used to determine the stresses and deformations of pre-twisted and tapered blades. Three-dimensional, twenty-noded isoparametric elements have been used for the analysis. Extensive analysis has been done for various pre-twist angles, skew angles, breadth to length ratios, and breadth to thickness ratios of the blades. Experiments were carried out to determine the stresses for the verification of the numerical results and they were found to be in good agreement.

540 Dynamic Stress Analysis of Artificial Hip Joint by Finite Element Method

2006 ◽  
Vol 2006.5 (0) ◽  
pp. 135-136
Author(s):  
Mitsugu TODO ◽  
Seiichiro TOKUNAGA ◽  
Masaaki MAWATARI ◽  
Takao HOTOKEBUCHI
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress Analysis ◽  
Hip Joint ◽  
Dynamic Stress ◽  
Artificial Hip Joint ◽  
Artificial Hip ◽  
Dynamic Stress Analysis ◽  
Element Method

An Evaluation of ASME’s “Design by Analysis” Guidelines

2013 ◽  
Author(s):  
Kotur S. Raghavan
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress Analysis ◽  
Three Dimensional ◽  
Limit Load ◽  
Point Of View ◽  
Elastic Analysis ◽  
The Finite Element Method ◽  
Elastic Stresses ◽  
Element Method

ASME’s Boiler and Pressure Vessel Codes have a history of over one hundred years. The codes have been evolving over time with continuous revisions, improvements and refinements. A major milestone has been the incorporation of “Design by Analysis (DBA)” guidelines about fifty years back (for instance Sec. VIII, Division 2). These were introduced as it was recognized that the prevailing Design by Rules (Section VIII, Division 1) tended to be somewhat over-conservative. The essence of DBA guidelines consists of evaluating the elastic stresses at critical locations and checking the same against the allowable. The allowable happen to functions of the nature of stress distribution and the nature of load. A given stress could be of membrane, bending or peak category and also be either primary or secondary. At the time of appearance of the DBA guidelines, the state of the art of stress analysis was not well advanced and the finite element method was just getting developed. As of today, however, the finite element method has reached a high level of maturity and is very widely used. The latest edition (2010) has recognized this and it contains modeling and post-processing guidelines applicable to FE analysis. This edition also recommends the use of one of three possible approaches. The first is the elastic analysis and classification and categorization of stresses with guidelines regarding how to deal with two- and three-dimensional situations. The other two options are provided to take care of situations wherein the categorization process may lead to either uncertainty or ambiguity. These involve nonlinear analysis either by way of Limit-Load method or Elastic-Plastic Stress Analysis. In either approach the analyst will look for the loads at which there is an onset of gross plastic flow. In the present paper an attempt is made to evaluate the latest DBA guidelines from design application point of view. The purpose is to assess the limitations of the elastic analysis approach. Studies are undertaken to focus typically on the following aspects: 1. Two dimensional problems involving symmetry or axisymmetry. There are situations in which the “bending” stresses are liable to be misinterpreted. 2. Three dimensional problems with emphasis on the assessment of bending stress as categorization in 3D situations is a real challenge 3. General situations involving the secondary stresses. The allowable stress limit for secondary stress is somewhat arbitrary and perhaps very conservative. The studies tend to suggest that the nonlinear route is to be adopted as it is reliable and accounts for many uncertainties associated with the elastic approach.

Comparison of Conventional and Pontic Fixed Partial Dentures Over Implants Using the Finite Element Method: Three-Dimensional Analysis of Cortical and Medullary Bone Stress

2020 ◽  
Vol 46 (3) ◽  
pp. 175-181
Author(s):  
Marcelo Bighetti Toniollo ◽  
Mikaelly dos Santos Sá ◽  
Fernanda Pereira Silva ◽  
Giselle Rodrigues Reis ◽  
Ana Paula Macedo ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Three Dimensional ◽  
The Finite Element Method ◽  
Medullary Bone ◽  
Principal Stresses ◽  
Bone Stress ◽  
Bone Damage ◽  
Rehabilitation System ◽  
Minimum Requirements

Rehabilitation with implant prostheses in posterior areas requires the maximum number of possible implants due to the greater masticatory load of the region. However, the necessary minimum requirements are not always present in full. This project analyzed the minimum principal stresses (TMiP, representative of the compressive stress) to the friable structures, specifically the vestibular face of the cortical bone and the vestibular and internal/lingual face of the medullary bone. The experimental groups were as follows: the regular splinted group (GR), with a conventional infrastructure on 3 regular-length Morse taper implants (4 × 11 mm); and the regular pontic group (GP), with a pontic infrastructure on 2 regular-length Morse taper implants (4 × 11 mm). The results showed that the TMiP of the cortical and medullary bones were greater for the GP in regions surrounding the implants (especially in the cervical and apical areas of the same region) but they did not reach bone damage levels, at least under the loads applied in this study. It was concluded that greater stress observed in the GP demonstrates greater fragility with this modality of rehabilitation; this should draw the professional's attention to possible biomechanical implications. Whenever possible, professionals should give preference to use of a greater number of implants in the rehabilitation system, with a focus on preserving the supporting tissue with the generation of less intense stresses.

Towards Predicting Relative Belt Edge Endurance With the Finite Element Method

1990 ◽  
Vol 18 (4) ◽  
pp. 216-235 ◽  
Author(s):  
J. De Eskinazi ◽  
K. Ishihara ◽  
H. Volk ◽  
T. C. Warholic
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Three Dimensional ◽  
The Finite Element Method ◽  
Shear Deformations ◽  
Element Analysis ◽  
Vertical Loading ◽  
Predicted Values ◽  
Element Method

Abstract The paper describes the intention of the authors to determine whether it is possible to predict relative belt edge endurance for radial passenger car tires using the finite element method. Three groups of tires with different belt edge configurations were tested on a fleet test in an attempt to validate predictions from the finite element results. A two-dimensional, axisymmetric finite element analysis was first used to determine if the results from such an analysis, with emphasis on the shear deformations between the belts, could be used to predict a relative ranking for belt edge endurance. It is shown that such an analysis can lead to erroneous conclusions. A three-dimensional analysis in which tires are modeled under free rotation and static vertical loading was performed next. This approach resulted in an improvement in the quality of the correlations. The differences in the predicted values of various stress analysis parameters for the three belt edge configurations are studied and their implication on predicting belt edge endurance is discussed.

Analysis of the Contact Deformation of Tread Blocks

1992 ◽  
Vol 20 (4) ◽  
pp. 230-253 ◽  
Author(s):  
T. Akasaka ◽  
K. Kabe ◽  
M. Koishi ◽  
M. Kuwashima
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Deformation Behavior ◽  
Contact Deformation ◽  
The Finite Element Method ◽  
The Road ◽  
Loss Of Contact ◽  
Tread Rubber ◽  
Good Agreement ◽  
Rubber Block

Abstract The deformation behavior of a tire in contact with the roadway is complicated, in particular, under the traction and braking conditions. A tread rubber block in contact with the road undergoes compression and shearing forces. These forces may cause the loss of contact at the edges of the block. Theoretical analysis based on the energy method is presented on the contact deformation of a tread rubber block subjected to compressive and shearing forces. Experimental work and numerical calculation by means of the finite element method are conducted to verify the predicted results. Good agreement is obtained among these analytical, numerical, and experimental results.

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