scholarly journals Three-dimensional computer simulations of feeding behaviour in red and giant pandas relate skull biomechanics with dietary niche partitioning

2014 ◽  
Vol 10 (4) ◽  
pp. 20140196 ◽  
Author(s):  
Borja Figueirido ◽  
Zhijie Jack Tseng ◽  
Francisco J. Serrano-Alarcón ◽  
Alberto Martín-Serra ◽  
Juan F. Pastor
Keyword(s):  
Niche Partitioning ◽  
Three Dimensional ◽  
Mechanical Efficiency ◽  
Ailuropoda Melanoleuca ◽  
Stress Distributions ◽  
Foraging Mode ◽  
Element Analysis ◽  
Giant Pandas ◽  
Energy Profiles ◽  
Dietary Niche

The red ( Ailurus fulgens ) and giant ( Ailuropoda melanoleuca ) pandas are mammalian carnivores convergently adapted to a bamboo feeding diet. However, whereas Ailurus forages almost entirely on younger leaves, fruits and tender trunks, Ailuropoda relies more on trunks and stems. Such difference in foraging mode is considered a strategy for resource partitioning where they are sympatric. Here, we use finite-element analysis to test for mechanical differences and similarities in skull performance between Ailurus and Ailuropoda related to diet. Feeding simulations suggest that the two panda species have similar ranges of mechanical efficiency and strain energy profiles across the dentition, reflecting their durophagous diet. However, the stress distributions and peaks in the skulls of Ailurus and Ailuropoda are remarkably different for biting at all tooth locations. Although the skull of Ailuropoda is capable of resisting higher stresses than the skull of Ailurus , the latter is able to distribute stresses more evenly throughout the skull. These differences in skull biomechanics reflect their distinct bamboo feeding preferences. Ailurus uses repetitive chewing in an extended mastication to feed on soft leaves, and Ailuropoda exhibits shorter and more discrete periods of chomp-and-swallow feeding to break down hard bamboo trunks.

scholarly journals Comparison of Tooth- and Bone-Borne Appliances on the Stress Distributions and Displacement Patterns in the Facial Skeleton in Surgically Assisted Rapid Maxillary Expansion—A Finite Element Analysis (FEA) Study

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1152
Author(s):  
Rafał Nowak ◽  
Anna Olejnik ◽  
Hanna Gerber ◽  
Roman Frątczak ◽  
Ewa Zawiślak
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Rapid Maxillary Expansion ◽  
Stress Distributions ◽  
Maxillary Expansion ◽  
Facial Skeleton ◽  
Element Analysis ◽  
Maxillary Constriction

The aim of this study was to compare the reduced stresses according to Huber’s hypothesis and the displacement pattern in the region of the facial skeleton using a tooth- or bone-borne appliance in surgically assisted rapid maxillary expansion (SARME). In the current literature, the lack of updated reports about biomechanical effects in bone-borne appliances used in SARME is noticeable. Finite element analysis (FEA) was used for this study. Six facial skeleton models were created, five with various variants of osteotomy and one without osteotomy. Two different appliances for maxillary expansion were used for each model. The three-dimensional (3D) model of the facial skeleton was created on the basis of spiral computed tomography (CT) scans of a 32-year-old patient with maxillary constriction. The finite element model was built using ANSYS 15.0 software, in which the computations were carried out. Stress distributions and displacement values along the 3D axes were found for each osteotomy variant with the expansion of the tooth- and the bone-borne devices at a level of 0.5 mm. The investigation showed that in the case of a full osteotomy of the maxilla, as described by Bell and Epker in 1976, the method of fixing the appliance for maxillary expansion had no impact on the distribution of the reduced stresses according to Huber’s hypothesis in the facial skeleton. In the case of the bone-borne appliance, the load on the teeth, which may lead to periodontal and orthodontic complications, was eliminated. In the case of a full osteotomy of the maxilla, displacements in the buccolingual direction for all the variables of the bone-borne appliance were slightly bigger than for the tooth-borne appliance.

Finite Element Analysis of Poor Distal Contact of the Femoral Component of a Cementless Hip Endoprosthesis

1993 ◽  
Vol 207 (4) ◽  
pp. 255-261 ◽  
Author(s):  
M Taylor ◽  
E W Abel
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Influencing Factor ◽  
Three Dimensional ◽  
Stress Distributions ◽  
Element Analysis ◽  
Hip Endoprosthesis ◽  
Applied Loading ◽  
Femoral Geometry ◽  
Contact Models

The difficulty of achieving good distal contact between a cementless hip endoprosthesis and the femur is well established. This finite element study investigates the effect on the stress distribution within the femur due to varying lengths of distal gap. Three-dimensional anatomical models of two different sized femurs were generated, based upon computer tomograph scans of two cadaveric specimens. A further six models were derived from each original model, with distal gaps varying from 10 to 60 mm in length. The resulting stress distributions within these were compared to the uniform contact models. The extent to which femoral geometry was an influencing factor on the stress distribution within the bone was also studied. Lack of distal contact with the prosthesis was found not to affect the proximal stress distribution within the femur, for distal gap lengths of up to 60 mm. In the region of no distal contact, the stress within the femur was at normal physiological levels associated with the applied loading and boundary conditions. The femoral geometry was found to have little influence on the stress distribution within the cortical bone. Although localized variations were noted, both femurs exhibited the same general stress distribution pattern.

Effect of Adhesive Behavior on Normal Stress Distributions in the Single-Lap Adhesive Joints

2015 ◽  
Vol 1088 ◽  
pp. 769-773
Author(s):  
Xiao Cong He
Keyword(s):  
Finite Element ◽  
Normal Stress ◽  
Three Dimensional ◽  
Adhesive Layer ◽  
Elastic Stiffness ◽  
Adhesive Joints ◽  
Stress Distributions ◽  
Element Analysis ◽  
Element Technique ◽  
Three Dimensional Finite Element

The effect of adhesives behavior on the normal stress distributions of single-lap adhesive joints is investigated using the three-dimensional finite element technique. Numerical examples are provided to show the influence on the normal stresses of the joints using adhesives of different characteristics which encompass the entire spectrum of elastic stiffness behaviour. finite element analysis solutions of the normal stress distributions in the adhesive layer have been obtained for four typical characteristics of adhesives. The results indicate that Young’s modulus and Poisson’s ratios of adhesives strongly affect the normal stress distributions of the joints.

Influence of Mechanical Properties of Adhesives on Stress Distributions in Lap Joints

Volume 1 ◽  
2004 ◽  
Author(s):  
Xiaocong He ◽  
S. Olutunde Oyadiji
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Three Dimensional ◽  
Lap Joints ◽  
Stress Distributions ◽  
Element Analysis ◽  
Linear Elastic ◽  
Cantilevered Beam ◽  
Cantilevered Beams ◽  
Different Characteristics

This paper deals with stress analysis of a single lap-jointed cantilevered beam using the three dimensional linear elastic finite element analysis (FEA) technique. Numerical examples are provided to show the influence on the stresses of the single lap-jointed cantilevered beams using adhesives of different characteristics which encompass the entire spectrum of viscoelastic behaviour. The results indicate that the stress distributions of a single-lap jointed cantilevered beam are strongly affected by both Young’s modulus and Poisson’s ratios. The maximum stress ratio was used to determine maximum values of Young’s Modulus required in order that the static stresses of an adhesively bonded cantilevered beam will not be more than given value of that of the equivalent homogeneous structure, that is a geometrically similar beam but without a joint. The analysis results also show that by choosing suitable adhesives, the maximum stresses can be reduced and the strength can be improved.

Three-dimensional deformations in a single-lap joint

1994 ◽  
Vol 29 (2) ◽  
pp. 137-145 ◽  
Author(s):  
M Y Tsai ◽  
J Morton
Keyword(s):  
Three Dimensional ◽  
Two Dimensional ◽  
Stress Distributions ◽  
Lap Joint ◽  
Displacement Fields ◽  
Element Analysis ◽  
Linear Elastic ◽  
Non Linear ◽  
Linear Effects ◽  
Peel Stress

The three-dimensional nature of the state of deformation in a single-lap test specimen is investigated in a linear elastic finite element analysis in which the boundary conditions account for the geometrically non-linear effects. The validity of the model is demonstrated by comparing the resulting displacement fields with those obtained from a moiré inteferometry experiment. The three-dimensional adherend and adhesive stress distributions are calculated and compared with those from a two-dimensional non-linear numerical analysis, Goland and Reissner's solution, and experimental measurements. The nature of the three-dimensional mechanics is described and discussed in detail. It is shown that three-dimensional regions exists in the specimen, where the adherend and adhesive stress distributions in the overlap near (and especially on) the free surface are quite different from those occurring in the interior. It is also shown that the adhesive peel stress is extremely sensitive to this three-dimensional effect, but the adhesive shear is not. It is also observed that the maximum value of the peel stress occurs at the end of the overlap in the central two-dimensional core region, rather than at the corners where the three-dimensional effects are found. The extent of three-dimensional regions is also quantified.

Elastic Damage Analysis of Interlaminar Stress Distributions in Symmetrical Composite Laminates with Edge Delamination Cracks

1994 ◽  
Vol 208 (1) ◽  
pp. 1-11 ◽  
Author(s):  
C L Chow ◽  
F Yang
Keyword(s):  
Composite Laminates ◽  
Three Dimensional ◽  
Tensile Load ◽  
Uniaxial Tensile ◽  
Stress Distributions ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Edge Delamination ◽  
Delamination Cracks

This paper is intended to present a study of elastic-damaged behaviour of symmetrical composite laminates with edge delamination cracks subjected to uniformly applied uniaxial tensile load. The response of composite laminates is investigated by a quasi-three-dimensional finite element analysis including the damage characterization of constituent plies. Of principal concern are the effects of edge delamination cracks as well as the influence of damage on stress distributions in graphite/epoxy [0/90°]s, [90/0°]s and [±45°], laminates. The computed results between the behaviours of laminates with stiffness damage consideration and those of geometrically similar laminates without stiffness damage are compared and the significance of damage in stress analysis of fibre-reinforced composite materials is elucidated.

A Comparison of Analysis Flywheel Stress Distributions Based on Different Material

2014 ◽  
Vol 536-537 ◽  
pp. 1291-1294 ◽  
Author(s):  
Hong Liang Chen ◽  
Chang Sheng Zhu ◽  
Peng Ye
Keyword(s):  
Finite Element Analysis ◽  
Energy Storage ◽  
Three Dimensional ◽  
Stress Distributions ◽  
High Output Power ◽  
Element Analysis ◽  
Composite Flywheel ◽  
Storage And Retrieval ◽  
Storage Technologies ◽  
High Output

Flywheels serve as kinetic energy storage and retrieval devices with the ability to deliver high output power at high rotational speeds as being one of the emerging energy storage technologies available today in various stages of development. This article analyzes the three-dimensional stress distribution of flywheel in Finite-element analysis. It is compared flywheel made of different material to meet the design of reasonable safety composite flywheel.

Finite Element Analysis of Perforated Plates Containing Triangular Penetration Patterns of 5 and 10 Percent Ligament Efficiency

1975 ◽  
Vol 97 (3) ◽  
pp. 199-205 ◽  
Author(s):  
D. P. Jones
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Peak Stress ◽  
Stress Distributions ◽  
Element Analysis ◽  
Perforated Plates ◽  
Vessel Closure ◽  
Asme Code ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Two- and three-dimensional finite element models were used to determine elastic stress distributions in plate ligaments for various in-plane, bending, and thermal loadings. Plates containing triangular penetration patterns of 5 and 10 percent ligament efficiency were analyzed as well as the example of a circular plate containing a single centrally placed hole subjected to step change in temperature on one surface. Detailed descriptions of boundary conditions are given with the results presented in terms of stresses important in tubesheet and vessel closure design considerations. Results show that the minimum ligament section of the perforated region need not be the critically stressed cross section as is currently assumed in the ASME Boiler and Pressure Vessel Code. Further, a thermal shock ΔT applied to the surface of a perforated region will result in a maximum peak stress of EαΔT/(1−ν) and may be significantly lower than the thermal skin stress calculated by the ASME Code procedures.

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