scholarly journals Simulating sauropod manus-only trackway formation using finite-element analysis

2010 ◽  
Vol 7 (1) ◽  
pp. 142-145 ◽  
Author(s):  
P. L. Falkingham ◽  
K. T. Bates ◽  
L. Margetts ◽  
P. L. Manning
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Surface Area ◽  
Fossil Record ◽  
Temporal Correlation ◽  
Finite Element Analyses ◽  
Centre Of Mass ◽  
Element Analysis ◽  
Mass Distributions ◽  
Track Formation

The occurrence of sauropod manus-only trackways in the fossil record is poorly understood, limiting their potential for understanding locomotor mechanics and behaviour. To elucidate possible causative mechanisms for these traces, finite-element analyses were conducted to model the indentation of substrate by the feet of Diplodocus and Brachiosaurus . Loading was accomplished by applying mass, centre of mass and foot surface area predictions to a range of substrates to model track formation. Experimental results show that when pressure differs between manus and pes, as determined by the distribution of weight and size of respective autopodia, there is a range of substrate shear strengths for which only the manus (or pes) produce enough pressure to deform the substrate, generating a track. If existing reconstructions of sauropod feet and mass distributions are correct, then different taxa will produce either manus- or pes-only trackways in specific substrates. As a result of this work, it is predicted that the occurrence of manus- or pes-only trackways may show geo-temporal correlation with the occurrence of body fossils of specific taxa.

Application of ASME Code Section XI Appendix L Using 3-D Finite Element Analyses

2020 ◽  
Author(s):  
Charles Fourcade ◽  
Minji Fong ◽  
James Axline ◽  
Do Jun Shim ◽  
Chris Lohse ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Crack Growth ◽  
Cyclic Stress ◽  
Finite Element Analyses ◽  
Element Analysis ◽  
Aspect Ratios ◽  
Flaw Tolerance ◽  
Asme Code ◽  
Stress Ratios

Abstract As part of a fatigue management program for subsequent license renewal, a flaw tolerance evaluation based on ASME Code, Section XI, Appendix L may be performed. The current ASME Code, Section XI, Appendix L flaw tolerance methodology requires determination of the flaw aspect ratio for initial flaw size calculation. The flaw aspect ratios listed in ASME Section XI, Appendix L, Table L-3210-2, for austenitic piping for example, are listed as a function of the membrane-to-gradient cyclic stress ratio. The Code does not explicitly describe how to determine the ratio, especially when utilizing complex finite element analyses (FEA), involving different loading conditions (i.e. thermal transients, piping loads, pressure, etc.). The intent of the paper is to describe the methods being employed to determine the membrane-to-gradient cyclic stress ratios, and the corresponding flaw aspect ratios (a/l) listed in Table L-3210-2, when using finite element analysis methodology. Included will be a sample Appendix L evaluation, using finite element analysis of a pressurized water reactor (PWR) pressurizer surge line, including crack growth calculations for circumferential flaws in stainless steel piping. Based on this example, it has been demonstrated that, unless correctly separated, the membrane-to-gradient cyclic stress ratios can result in extremely long initial flaw lengths, and correspondingly short crack growth durations.

Finite Element Analysis in Orthopaedics

1987 ◽  
Vol 110 ◽  
Author(s):  
James B. Koeneman
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Beam Theory ◽  
Stress Distributions ◽  
Finite Element Analyses ◽  
Element Analysis ◽  
Bone Changes ◽  
Joint Implants ◽  
Bone Structures

AbstractPredicting the stress state in bones is important to the understanding of bone remodeling and the long-term reliability of total joint implants. Beam theory, 2-D and 3-D finite element analysis have been used to calculate stress distributions. These finite element analyses of bone structures are progressing from crude models for which the clinical relevance has been questioned to an important tool which is necessary to understand stress related bone changes.

Finite Element Analysis of a Steel Spiral Staircase with Multiple Supports

2011 ◽  
Vol 255-260 ◽  
pp. 1964-1967
Author(s):  
Tao Chen ◽  
Hua Dong He
Keyword(s):  
Finite Element Method ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Mode Analysis ◽  
Complex Geometries ◽  
Finite Element Analyses ◽  
Element Analysis ◽  
Linear Elastic ◽  
Moment Distribution ◽  
Spiral Staircase

This paper presents finite element analyses of a steel spiral staircase with multiple supports. The complex geometries were modeled using commercial finite element method (FEM) software. Linear elastic analyses were carried out to investigate its deformation and moment distribution. Besides these, mode analysis was also performed to explore its pedestrian comfort. Finally the reliability of the structure is proved.

Bounded Elastic Moduli Multiplier Technique for Limit Loads: Part 1 - Theory

2022 ◽  
Author(s):  
Sathya Prasad Mangalaramanan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Lower Bound ◽  
Power Law ◽  
Elastic Moduli ◽  
Stress Distributions ◽  
Finite Element Analyses ◽  
Element Analysis ◽  
Limit Loads ◽  
Reduced Modulus

Abstract Statically admissible stress distributions are necessary to evaluate lower bound limit loads. Over the last three decades, several methods have been postulated to obtain these distributions using iterative elastic finite element analyses. Some of the pioneering techniques are the reduced modulus, r-node, elastic compensation, and linear matching methods, to mention a few. A new method, called the Bounded Elastic Moduli Multiplier Technique (BEMMT), is proposed and the theoretical underpinnings thereof are explained in this paper. BEMMT demonstrates greater robustness, more generality, and better stress distributions, consistently leading to lower-bound limit loads that are closer to elastoplastic finite element analysis estimates. BEMMT also questions the validity of the prevailing power law based stationary stress distributions. An accompanying research offers several case studies to validate this claim.

Analysis of a Hemispherical Head With Nozzle and Local Thin Area

2004 ◽  
Author(s):  
Michael W. Guillot ◽  
Jack E. Helms
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Pressure Vessels ◽  
Structural Defects ◽  
Finite Element Models ◽  
Finite Element Analyses ◽  
Element Analysis

The ability to analyze the behavior of pressure vessels with structural defects has been greatly improved by the general availability of PC based finite element analysis programs. In this study a hemispherical head with a nozzle and a local thin area is analyzed using finite element models. The requirement to apply a 15 % stress adjustment is also examined in light of the results of the finite element analyses.

scholarly journals Preliminary Finite Element Analysis of Locomotive Crashworthy Components

2011 ◽  
Author(s):  
Patricia Llana ◽  
Richard Stringfellow
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Energy Management ◽  
New Technologies ◽  
The Other ◽  
Finite Element Models ◽  
Finite Element Analyses ◽  
Element Analysis ◽  
Passenger Trains ◽  
Deformation Modes

The Office of Research and Development of the Federal Railroad Administration (FRA) and the Volpe Center are continuing to evaluate new technologies for increasing the safety of passengers and operators in rail equipment. In recognition of the importance of override prevention in train-to-train collisions in which one of the vehicles is a locomotive, and in light of the success of crash energy management technologies in cab car-led passenger trains, the Volpe Center seeks to evaluate the effectiveness of components that could be integrated into the end structure of a locomotive that are specifically designed to mitigate the effects of a collision and, in particular, to prevent override of one of the lead vehicles onto the other. A research program is being conducted that aims to develop, fabricate and test two crashworthy components for the forward end of a locomotive: (1) a deformable anti-climber, and (2) a push-back coupler. Preliminary designs for these components have been developed. This paper provides details on the finite element models of the crashworthy components and how the component designs behave in the finite element analyses. The component designs will be evaluated to determine if the requirements have been met, such as the energy absorption capability, deformation modes, and force/crush characteristics.

scholarly journals Influence of the geometry of ceramic specimens on biaxial flexural strength: experimental testing and finite element analysis

Cerâmica ◽  
2018 ◽  
Vol 64 (369) ◽  
pp. 120-125 ◽  
Author(s):  
J. da S. Ramos ◽  
S. Fraga ◽  
G. F. Vogel ◽  
L. G. May
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Flexural Strength ◽  
Principal Stress ◽  
Surface Area ◽  
Element Analysis ◽  
Biaxial Flexural Strength ◽  
Square Plate ◽  
Tensile Surface

Abstract This study evaluated the influence of the geometry of ceramic specimens (disc vs. square plate) on the biaxial flexural strength (BFS) using an experimental set and finite element analysis (FEA). Leucite glass-ceramic blocks were used in the preparation of disc (D; n=14) and square plate (S; n=13) specimens with the same lower (tensile) surface area. The specimens were subjected to a piston-on-three-ball flexural test (ISO 6872:2008). To calculate the BFS of the S group, the specimen radius, indicated by the ISO 6872:2008 formula for discs, was replaced by half of the side length. FEA compared the pattern of stress distribution and the first principal stress between D and S specimens having the same and different lower (tensile) surface area. Student’s t-test showed no difference (p=0.85) in the BFS between D (95.0±9.6 MPa) and S (84.3±10.3 MPa). FEA indicated a similar pattern of stress distribution, with almost no difference in the first principal stress of discs and square plates with the same lower (tensile) surface area. In the experimental condition investigated, square plate ceramic specimens can be used in piston-on-three-ball tests. For the calculation of the BFS, the specimen radius may be replaced by half side length of the square specimen.

Things to Concern for Finite Element Analyses

2015 ◽  
Author(s):  
Yasumasa Shoji
Keyword(s):  
Finite Element Method ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Functional Limitation ◽  
Finite Element Analyses ◽  
Element Analysis ◽  
Trouble Shooting ◽  
User Friendly ◽  
Physical Phenomena

Recently FEA (Finite Element Analysis) is used in various engineering fields such as for design, verification, validation trouble-shooting and other applications. As the more users are treating FEA, the quality of analyses has become the larger issue. Finite Element Method (FEM) is just a calculation method to reproduce physical phenomena, and it has functional limitation in nature. As the software becomes more and more user-friendly, the limitation is hidden in the operation. However, as the limitation still exists in principle, users must be aware of it when using the FEA software. This paper will address about the issues that we are easily trapped in modeling, such as element selection, boundary conditions and other conditions.

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