Nonlocal Continuum Theory Based Modeling of Carbon Nanotube Composites

2008 ◽  
Author(s):  
Ali Alavinasab ◽  
Goodarz Ahmadi ◽  
Ratneshwar Jha
Keyword(s):  
Finite Element ◽  
Carbon Nanotube ◽  
Continuum Theory ◽  
Nonlocal Theory ◽  
Total Force ◽  
Stress Distributions ◽  
Nonlocal Continuum ◽  
Element Analysis ◽  
Nonlocal Continuum Theory ◽  
Nanotube Composites

Analytical modeling of Carbon Nanotube (CNT) composite based on the nonlocal continuum theory is investigated. This approach accounts for nonlocal stress-strain relationships, that is, stress at any point in a structure is a function of strain in the entire structure. Finite element analysis of a representative volume element (RVE) of CNT composite is used to evaluate unknown constant in the nonlocal theory based solution. Stress distributions are obtained from finite element method (FEM), nonlocal theory, and standard (local) elasticity. Nonlocal theory and FEM stress distributions yield the same total force and first moment, whereas standard elasticity gives less accurate results.

scholarly journals ON MULTISCALE DAMAGE MODELLING OF HETEROGENEOUS MATERIALS USING NONLOCAL CONTINUUM THEORY

Brodogradnja ◽  
2021 ◽  
Vol 72 (4) ◽  
pp. 121-139
Author(s):  
Jurica Sorić ◽  
◽  
Tomislav Lesičar ◽  
Filip Putar ◽  
Zdenko Tonković ◽  
...  
Keyword(s):  
Finite Element ◽  
Equivalent Plastic Strain ◽  
Continuum Theory ◽  
Material Point ◽  
Ductile Damage ◽  
Element Formulation ◽  
State Variables ◽  
Nonlocal Continuum ◽  
Element Discretization ◽  
Nonlocal Continuum Theory

An overview of the modelling of quasi-brittle as well as ductile damage is given. The multiscale procedure employing the nonlocal continuum theory is described in more detail. The softening is introduced at the microlevel in the microstructural volume element and after that the homogenization procedure state variables are mapped at the macrolevel material point via the scale transition approach. In the case of quasi-brittle softening the C1 continuous finite element discretization is applied at both micro- and macrolevel. At the modelling of ductile damage response, the macrolevel is also discretized by the C1 finite element formulation, while the microscale utilizes quadrilateral mixed finite elements employing the nonlocal equivalent plastic strain and gradient-enhanced elastoplasticity. All approaches presented are verified in the standard examples.

Finite Element Analysis of Tire/Rim Interface Forces Under Braking and Cornering Loads

1992 ◽  
Vol 20 (2) ◽  
pp. 83-105 ◽  
Author(s):  
J. P. Jeusette ◽  
M. Theves
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Contact Pressure ◽  
Element Model ◽  
Shear Stresses ◽  
Detailed Knowledge ◽  
Stress Distributions ◽  
Element Analysis ◽  
Plane Shear ◽  
Normal Contact

Abstract During vehicle braking and cornering, the tire's footprint region may see high normal contact pressures and in-plane shear stresses. The corresponding resultant forces and moments are transferred to the wheel. The optimal design of the tire bead area and the wheel requires a detailed knowledge of the contact pressure and shear stress distributions at the tire/rim interface. In this study, the forces and moments obtained from the simulation of a vehicle in stationary braking/cornering conditions are applied to a quasi-static braking/cornering tire finite element model. Detailed contact pressure and shear stress distributions at the tire/rim interface are computed for heavy braking and cornering maneuvers.

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.

Finite Element Analysis of Temperature and Stress Distributions on Touching Area of Freight Train Wheel

2011 ◽  
Vol 120 ◽  
pp. 56-60
Author(s):  
Han Wu Liu ◽  
Zhi Qiang Li ◽  
Yun Hui Du ◽  
Peng Zhang
Keyword(s):  
Finite Element ◽  
Development Trend ◽  
Stress Distributions ◽  
Railway Transportation ◽  
Element Analysis ◽  
Work Condition ◽  
Freight Train ◽  
The Development Trend ◽  
The Relationship ◽  
Wheel Track

With the development trend of constant speeding and heavy loading of the railway transportation, the freight train wheels which take the way of touching area breaking are in the bad conditions of strong friction, fever load and big wheel track forces. After many times’ repeated breaking, the wheels will come to be thermal fatigue, then, result in expired puncture. In this article, according to the actual work condition of the freight train wheel, its temperature and stress fields in the process of an urgently breaking when the wheel speed is 120 km/h with the 21 tons shaft weight were analyzed and simulated by Finite Element Method. The relationship between the injury occurring on the touching area of freight wheel and the fields of the temperature and stress was also studied. The research results showed that the maximum values of the temperature and thermal stress lied in the breaking process all locate in the touching friction area between the breaking and the wheel, and the temperature rises continuously with the breaking process going on. When the value of the temperature gets to the crest value, it slowly descends. The wheel temperature reduces from the touching area to the wheel shaft, and the nearer of the distance to wheel shaft, the lower of the temperature and stress values. After the end of the breaking process, the temperature into the wheel is higher than that on the touching area, and the maximum stress exists under the wheel touching area.

Investigation on stress distribution and pressure capacity of two-layer split high-pressure die based on finite element analysis

2019 ◽  
Vol 233 (14) ◽  
pp. 5048-5055
Author(s):  
Z Yi ◽  
WZ Fu ◽  
MZ Li
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
High Pressure ◽  
Stress State ◽  
Von Mises Stress ◽  
Stress Distributions ◽  
Element Analysis ◽  
Round Cylinder ◽  
Von Mises ◽  
Supporting Ring

In order to obtain a higher pressure capacity for the high-pressure die with a larger sample cavity, two types of two-layer split dies with a round cylinder and a quadrate cylinder were designed based on the conventional belt-type die. Finite element analysis was performed to investigate the stress distributions and pressure capacities of the high-pressure dies using a derived Mohr–Coulomb criterion and the von Mises criterion for the cylinder and supporting rings, respectively. As predicted by the finite element analysis results, in the two-layer split dies with a round cylinder, the stress state of the cylinder can be only slightly improved; and the von Mises stress of the first layer supporting ring can be hardly decreased. However, in the two-layer split dies with a quadrate cylinder and sample cavity, the stress state of the cylinder can be remarkably improved. Simultaneously, the von Mises stress of the supporting rings, especially for the first-layer supporting ring, can be also effectively decreased. The pressure capacities of the two-layer split dies with a round cylinder and a quadrate cylinder are 16.5% and 63.9% higher with respect to the conventional belt-type die.

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