Finite Element Analysis and Mechanical Testing of External Fixator Designs

1994 ◽  
Vol 208 (2) ◽  
pp. 103-110 ◽  
Author(s):  
P J Prendergast ◽  
S J Toland ◽  
J P Corrigan
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Finite Element Models ◽  
Close Correspondence ◽  
Element Analysis ◽  
Modular Assembly ◽  
Shell Elements ◽  
Fixation Devices ◽  
Stress Patterns ◽  
Theoretical Stress

Experimental and theoretical stress analysis methods are used to evaluate the mechanical behaviour of external fixation devices as load-bearing structures. For the experimental part, a modular assembly was fabricated from which unilateral and bilateral fixators of different design configurations were assembled and tested under various loading conditions. A reflective photoelasticity technique was used to study the effect of frame configuration on the stress patterns generated around the pin-bone interface. Finite element models of each design were also generated using three-dimensional beam and shell elements. Spring elements were used to model the pin/sidebar clamp. It is shown that close correspondence between the experimental and theoretical methods of investigation is obtained when the flexibility of the pin/side-bar clamp is taken into account. It is also shown that a unilateral design, modified by attaching a second side-bar to the first and connecting them by means of a semicircular component, can achieve some of the structural advantages of bilateral fixators without the clinical disadvantage of transfixing pins.

Finite Element Analysis for a CAD of a Concrete Mixer Drum

1994 ◽  
Author(s):  
Hossam S. Badawi ◽  
Sherif A. Mourad ◽  
Sayed M. Metwalli
Keyword(s):  
Finite Element ◽  
Computer Aided Design ◽  
Three Dimensional ◽  
Plain Concrete ◽  
Element Analysis ◽  
Shell Elements ◽  
Bending Stresses ◽  
Loading Effects ◽  
Concrete Mixer ◽  
Aided Design

Abstract For a Computer Aided Design of a concrete truck mixer, a six cubic meter concrete mixer drum is analyzed using the finite element method. The complex mixer drum structure is subjected to pressure loading resulting from the plain concrete inside the drum, in addition to its own weight. The effect of deceleration of the vehicle and the rotational motion of the drum on the reactions and stresses are also considered. Equivalent static loads are used to represent the dynamic loading effects. Three-dimensional shell elements are used to model the drum, and frame elements are used to represent a ring stiffener around the shell. Membrane forces and bending stresses are obtained for different loading conditions. Results are also compared with approximate analysis. The CAD procedure directly used the available drafting and the results were used effectively in the design of the concrete mixer drum.

Finite Element Analysis of Elliptical Chord

2013 ◽  
Vol 3 (4) ◽  
pp. 44-61
Author(s):  
K. S. Narayana ◽  
R. T. Naik ◽  
R. C. Mouli ◽  
L. V. V. Gopala Rao ◽  
R. T. Babu Naik
Keyword(s):  
Finite Element ◽  
Natural Frequencies ◽  
Three Dimensional ◽  
Compressive Load ◽  
Dynamic Strength ◽  
Element Analysis ◽  
T Joints ◽  
Shell Elements ◽  
Tubular Joints ◽  
Plane Bending

The work presents the Finite element study of the effect of elliptical chords on the static and dynamic strength of tubular T-joints using ANSYS. Two different geometry configurations of the T-joints have been used, namely Type-1 and Type-2. An elastic analysis has been considered. The Static loading conditions used are: axial load, compressive load, In-plane bending (IPB) and Out-plane bending (OPB). The natural frequencies analysis (dynamic loading condition) has also been carried out. The geometry configurations of the T-joints have been used, vertical tubes are called brace and horizontal tubes are called chords. The joint consists of brace joined perpendicular to the circular chord. In this case the ends of the chord are held fixed. The material used is mild steel. Using ANSYS, finite element modeling and analysis of T-joint has been done under the aforementioned loading cases. It is one of the most powerful methods in use but in many cases it is an expensive analysis especially due to elastic–plastic and creep problems. Usually, three dimensional solid elements or shell elements or the combination of two types of elements are used for generating the tubular joints mesh. In tubular joints, usually the fluid induced vibrations cause the joint to fail under resonance. Therefore the natural frequencies analysis is also an important issue here. Generally the empirical results are required as guide or comparison tool for finite element investigation. It is an effective way to obtain confidence in the results derived. Shell elements have been used to model the assembled geometry. Finite element ANSYS results have been validated with the LUSAS FEA and experimental results, that is within the experimentation error limit of ten percentage.

The Effects of Mini Implant and Anterior Arch Hook Heights on En Masse Retraction: A Finite Element Analysis

2013 ◽  
Vol 461 ◽  
pp. 993-1001
Author(s):  
Wen Wen Deng ◽  
Fang Wang ◽  
Ferdinand M. Machibya ◽  
Shang Gao ◽  
Xiao Long Wang ◽  
...  
Keyword(s):  
Finite Element ◽  
Cone Beam Ct ◽  
Three Dimensional ◽  
Cone Beam ◽  
Finite Element Models ◽  
Treatment Results ◽  
Element Analysis ◽  
Anterior Teeth ◽  
Orofacial Region ◽  
En Masse Retraction

Introduction: An en-masse retraction with mini implant (MI) anchorage may be associated with unwanted intrusion/extrusion and uncontrolled tipping of anterior teeth. An optimum combination of MIs and hooks heights is required for proper treatment results. Materials and Methods: Maxillary finite element models were constructed from a cone beam CT scan of a patient’s orofacial region. The initial tooth displacement at 200g force with 0.019 × 0.025-in stainless steel working archwires engaged in 0.022 brackets slot was assessed. The three-dimensional displacement was examined at various MI and AAH heights. Results: The lower MI position caused extrusion of the central incisors, but the teeth were intruded at higher (6- and 8-mm) MI heights. While the shorter (2- and 4-mm) hooks extruded the central incisors, the higher (6- and 8-mm) intruded the teeth. The higher MI and hooks reduced the palatal tipping of central incisors. The distobucal cusp of the first molar was intruded, while the mesiobucal cusp was extruded in all models: Nonetheless, the shorter hooks and low MI had small molar tipping effects. Conclusions: The higher MIs caused intrusion and less palatal tipping of the central incisors crowns. The increase in hook height resulted into extrusion and reduction in palatal tipping of the central incisors crowns.

FINITE ELEMENT ANALYSIS OF THE THERMAL BEHAVIOUR OF SINGLE-DISC CLUTCHES DURING REPEATED ENGAGEMENTS

Tribologia ◽  
2016 ◽  
Vol 266 (2) ◽  
pp. 9-24 ◽  
Author(s):  
Oday I. ABDULLAH ◽  
Laith Abed SABRI ◽  
Wassan S. Abd Al-SAHB
Keyword(s):  
Finite Element ◽  
Thermal Behaviour ◽  
Thermal Stresses ◽  
Three Dimensional ◽  
Finite Element Models ◽  
Element Analysis ◽  
Premature Failure ◽  
Friction Clutch ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Most of the failures in the sliding systems occur due to the high thermal stresses, which generated at the interface between the contacting surfaces due to sliding between parts, such as friction clutches and brakes. In this paper, the thermal behaviour of a single-disc clutch is investigated. The surface temperatures of the friction clutch disc will be increased during repeated engagements, in some cases, will lead to premature failure of the clutch disc. In order to avoid this kind of failure, it the surface temperature should be calculated with high accuracy to know the maximum working temperature of the friction system. In this work, the temperature distributions are computed during four repeated engagements at regular intervals (5 s) for the same energy dissipation. Three-dimensional finite element models are used to simulate the typical friction clutch disc.

Analysis of load in ties in masonry veneer walls

2003 ◽  
Vol 30 (5) ◽  
pp. 850-860 ◽  
Author(s):  
Junyi Yi ◽  
David Laird ◽  
Bill McEwen ◽  
Nigel G Shrive
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Finite Element Models ◽  
Structural System ◽  
Shell Elements ◽  
Beam Elements ◽  
Load Distributions ◽  
Staggered Arrangement ◽  
Brick Veneer ◽  
Steel Stud

Masonry is frequently used as a veneer, tied to a backup structural system. In many cases, the structural system is steel studding. Very little research has been conducted to examine the effect of staggering the ties between the veneer and the backup on the load distributions in the ties and studs. This paper describes three-dimensional (3-D) finite element models developed for masonry veneer walls (brick veneer – steel stud) subjected to wind load. Various tie arrangements were analyzed. Shell elements were used to model the brick veneer, and beam elements were used to model the steel studs and ties. Cracking was introduced in a horizontal mortar joint through the use of gap elements (discrete cracking method). The loads in the ties for various tie arrangements were examined. It appears that staggering the ties does not overload them when a full row of ties is provided at the top or at both the top and the bottom. The load distribution in the ties in a staggered arrangement is close to that in the full-tie arrangement.Key words: masonry veneer walls, 3-D, finite element models, brick veneer, steel studs, ties.

An Investigation Into the Effects of Modelling Cylindrical Nozzle to Cylindrical Vessel Intersections Using 2D Axisymmetric Finite Element Models and a Proposed Method for Correcting the Results

2011 ◽  
Author(s):  
Daniel Sommerville ◽  
Matthew Walter
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Correction Factor ◽  
Three Dimensional ◽  
Wall Stress ◽  
Finite Element Models ◽  
Element Analysis ◽  
Cylindrical Pressure Vessel ◽  
Axisymmetric Modeling ◽  
Specific Correction

Two dimensional (2-D) axisymmetric finite element models (FEMs) are often used as a simplification to modeling cylindrical nozzles that intersect a cylindrical pressure vessel. However, an axisymmetric model has the effect of representing the vessel as a spherical shell rather than a cylindrical shell. Previous work has been done to determine 2-D axisymmetric to three dimensional (3-D) stress correction factors (CFs) for the total stress at the nozzle blend radius to account for this inconsistency. The present paper expands on that work to investigate the effects of the 2-D axisymmetric modeling simplification on the through wall stress distribution at the nozzle corner. The through-wall stress distribution is necessary for some fracture mechanics analyses performed for corner cracked nozzles and for using the simplified elastic-plastic analysis given in NB-3228.5. A simplified method is proposed which can be used to obtain a nozzle specific correction factor, rather than a bounding correction factor, that can be applied to 2-D finite element analysis stress results to correct for the inaccuracy introduced by modeling the intersection as an axisymmetric section.

Computer Graphics for 3-D Finite Element Models

1974 ◽  
Vol 96 (3) ◽  
pp. 200-206 ◽  
Author(s):  
L. W. Kirchhoff
Keyword(s):  
Finite Element ◽  
Computer Graphics ◽  
Three Dimensional ◽  
Analysis Data ◽  
Finite Element Models ◽  
Element Analysis ◽  
General Line ◽  
Dimensional Finite Element ◽  
Hidden Line ◽  
Three Dimensional Finite Element

A description is given of a computer graphics program for detecting errors in three-dimensional finite element models and reducing finite element analysis data to a usable form. An efficient hidden line algorithm for mixed sets of polygons and polyhedra is presented together with a general line classification scheme. They are used to produce the variety of plots necessary to detect errors in the model. They also provide an “uncluttered” surface for displaying stress, temperature, and displacement data.

scholarly journals A Computational Approach to Model Interfacial Effects on the Mechanical Behavior of Knitted Textiles

2018 ◽  
Vol 85 (4) ◽  
Author(s):  
Dani Liu ◽  
Bahareh Shakibajahromi ◽  
Genevieve Dion ◽  
David Breen ◽  
Antonios Kontsos
Keyword(s):  
Finite Element ◽  
Mechanical Behavior ◽  
Mechanical Performance ◽  
Computational Cost ◽  
Three Dimensional ◽  
Finite Element Models ◽  
Element Analysis ◽  
Reduced Order ◽  
Interfacial Effects ◽  
Relative Contribution

The mechanical behavior of knitted textiles is simulated using finite element analysis (FEA). Given the strong coupling between geometrical and physical aspects that affect the behavior of this type of engineering materials, there are several challenges associated with the development of computational tools capable of enabling physics-based predictions, while keeping the associated computational cost appropriate for use within design optimization processes. In this context, this paper investigates the relative contribution of a number of computational factors to both local and global mechanical behavior of knitted textiles. Specifically, different yarn-to-yarn interaction definitions in three-dimensional (3D) finite element models are compared to explore their relative influence on kinematic features of knitted textiles' mechanical behavior. The relative motion between yarns identified by direct numerical simulations (DNS) is then used to construct reduced order models (ROMs), which are shown to be computationally more efficient and providing comparable predictions of the mechanical performance of knitted textiles that include interfacial effects between yarns.

Sign in / Sign up

Export Citation Format

Share Document