scholarly journals Numerical study of inelastic buckling behavior of rectangular steel plates with circular openings under shear forces

2019 ◽  
Vol 258 ◽  
pp. 05026
Author(s):  
Rajawali M Akbar ◽  
Bambang Suryoatmono
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Steel Plates ◽  
Steel Beam ◽  
Circular Opening ◽  
Finite Element Analyses ◽  
Shear Forces ◽  
Inelastic Buckling ◽  
Buckling Behavior ◽  
Von Mises

Cellular steel beam is flanged steel beam with circular openings of uniform diameter and distance between each opening. The main benefit of such beam is to reduce the structural weight without reducing the strength significantly. A rectangular steel plate with circular opening is frequently used as a model of a web panel of such beam with vertical web stiffeners. The dimension of the plate is the dimension of the web bounded by top and bottom flanges and two adjacent vertical stiffeners. In this research, finite element method is utilized to perform inelastic buckling analyses of rectangular steel plates with circular openings under shear forces along all four edges assuming steel as elastic-perfectly-plastic material with yield stress of 250 MPa. Both nonlinear geometry and nonlinear material are considered in the analyses. The objective of this research is to study buckling behavior of the plate in terms of buckling mode, critical load, and Von Mises (effective) stress distribution. The buckling shear loads of the plates of various length-to-width ratios of the plate (1.0, 1.25, and 1.50) and various opening-diameter-to-plate-width ratios (0.00, 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50) have been obtained from the analyses. The deformation and Von Mises stress distribution at every load level have been obtained as well from the finite element analyses. Equation to predict inelastic buckling shear force of a rectangular steel plates with circular opening under shear forces is proposed in this study. Verification of the method has been performed by comparing shear buckling loads resulted from finite element analyses with the analytical results in the elastic range.

scholarly journals Biomechanical Tests and Finite Element Analyses of Pelvic Stability using Bilateral Single Iliac Screw with Different Channels in Lumbo-iliac Fixation

2021 ◽  
Author(s):  
Yangyang Sun ◽  
Ying Fu ◽  
Fanxiao Liu ◽  
Huanzhi Ma ◽  
Wen Zhang ◽  
...  
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Pubic Symphysis ◽  
Von Mises Stress ◽  
Finite Element Analyses ◽  
Iliac Screw ◽  
Von Mises ◽  
Iliac Fixation ◽  
Biomechanical Tests ◽  
Posterior Ring

Abstract Background: In lumbo-iliac fixation, the iliac screw can be placed in a number of locations and directions, and multiple screws can be placed to enhance the fixation effect. At present, there is no uniform standard for the placement of single iliac screw. Biomechanical tests and finite element analyses were used to compare the effect of bilateral single iliac screw with three channels on pelvic stability in lumbo-iliac fixation, so as to provide a basis for determining the best single iliac screw channel.Methods: Five adult embalmed cadaver pelvic specimens were selected. Unstable Tile C1 pelvic injury model (pubic symphysis separation and left sacral Denis II fracture) was established. The pubic symphysis was fixed with five-hole reconstruction plate. Lumbo-iliac fixation for the treatment of pelvic posterior ring injury: three channels of bilateral single iliac screw (channel A from PSIS to AIIS, channel B from 1 cm medial and 1 cm caudal of PSIS to AIIS, channel C from 2 cm below PSIS to AIIS). At the same time, the finite element model of unstable pelvic posterior ring injury treated with lumbo-iliac fixation was established, which were used to analyze and explore the effect of bilateral single iliac screw with three channels on the biomechanical stability of the pelvis, including the stress distribution and the maximum Von Mises stress of internal fixation, vertebral body and ilium.Results: Biomechanical tests revealed that under vertical compression load, the compressive stiffness of pelvic specimens fixed with three channels of bilateral single iliac screw was lower than that of complete pelvic specimens (P < 0.05). The vertical displacement fixed by channel B was smaller than that fixed by channel A and channel C; however, there was no significant difference between channel B and channel A (P > 0.05). The compressive stiffness fixed by channel B was better than that fixed by channel A and channel C. Under torsional load, the torsional stiffness fixed by channel B was stronger than that fixed by channel A and channel C. Finite element analyses conformed that the maximum Von Mises stress of the internal fixator fixed in channel B under the conditions of vertical, forward bending, backward extension, left bending, left rotating and right bending were significantly lower than that fixed in channel A and channel C. Under various working conditions, the maximum Von Mises stress of the internal fixture of channel B was less than that of channel A. In terms of the maximum Von Mises stress of the vertebral body and iliac, compared with the other two iliac screw channels, the overall stress distribution fixed by channel B was more reasonable.Conclusions: Bilateral single iliac screw with three channels in lumbo-iliac fixation could effectively restore pelvic stability. The construct stiffness of the channel from 1cm medial and 1cm caudal of PSIS to AIIS is better than that of the other two channels. This channel has the advantages of good biomechanical stability, reasonable stress distribution, small maximum Von Mises stress of internal fixation, strong fatigue resistance and not easy to break screws and robs.

scholarly journals Biomechanical assessment of different fixation methods in mandibular high sagittal oblique osteotomy using a three-dimensional finite element analysis model

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Charles Savoldelli ◽  
Elodie Ehrmann ◽  
Yannick Tillier
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Three Dimensional ◽  
Von Mises Stress ◽  
Analysis Model ◽  
Element Analysis ◽  
Fixation Methods ◽  
Oblique Osteotomy ◽  
Von Mises

AbstractWith modern-day technical advances, high sagittal oblique osteotomy (HSOO) of the mandible was recently described as an alternative to bilateral sagittal split osteotomy for the correction of mandibular skeletal deformities. However, neither in vitro nor numerical biomechanical assessments have evaluated the performance of fixation methods in HSOO. The aim of this study was to compare the biomechanical characteristics and stress distribution in bone and osteosynthesis fixations when using different designs and placing configurations, in order to determine a favourable plating method. We established two finite element models of HSOO with advancement (T1) and set-back (T2) movements of the mandible. Six different configurations of fixation of the ramus, progressively loaded by a constant force, were assessed for each model. The von Mises stress distribution in fixations and in bone, and bony segment displacement, were analysed. The lowest mechanical stresses and minimal gradient of displacement between the proximal and distal bony segments were detected in the combined one-third anterior- and posterior-positioned double mini-plate T1 and T2 models. This suggests that the appropriate method to correct mandibular deformities in HSOO surgery is with use of double mini-plates positioned in the anterior one-third and posterior one-third between the bony segments of the ramus.

Thermo-Elastoviscoplastic Buckling Behavior of Plates

1994 ◽  
Vol 61 (1) ◽  
pp. 169-175 ◽  
Author(s):  
G. J. Simitses ◽  
Y. Song
Keyword(s):  
Finite Element ◽  
Constitutive Equations ◽  
Material Models ◽  
Inelastic Buckling ◽  
Finite Element Approach ◽  
Numerical Examples ◽  
Initial Imperfections ◽  
Rate Dependent ◽  
Buckling Behavior ◽  
Element Approach

The thermo-elastoviscoplastic buckling behavior of plates is investigated. The analysis is based on nonlinear kinematic relations and nonlinear rate-dependent unified constitutive equations which include both Bodner-Partom’s and Walker’s material models. A finite element approach is employed to predict the inelastic buckling behavior. Numerical examples are given to demonstrate the effects of several parameters, which include temperature, small initial imperfections, and the thickness of the plate. Comparisons of buckling responses for the two models, Bodner-Partom’s and Walker’s, are also presented.

scholarly journals Effect of Fiber Posts on Stress Distribution of Endodontically Treated Upper Premolars: Finite Element Analysis

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1708 ◽  
Author(s):  
Maciej Zarow ◽  
Mirco Vadini ◽  
Agnieszka Chojnacka-Brozek ◽  
Katarzyna Szczeklik ◽  
Grzegorz Milewski ◽  
...  
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Resin Composite ◽  
Von Mises Stress ◽  
Stress Distributions ◽  
Stress Concentrations ◽  
Element Analysis ◽  
Endodontically Treated Tooth ◽  
Maxillary Premolars ◽  
Von Mises

By means of a finite element method (FEM), the present study evaluated the effect of fiber post (FP) placement on the stress distribution occurring in endodontically treated upper first premolars (UFPs) with mesial–occlusal–distal (MOD) nanohybrid composite restorations under subcritical static load. FEM models were created to simulate four different clinical situations involving endodontically treated UFPs with MOD cavities restored with one of the following: composite resin; composite and one FP in the palatal root; composite and one FP in the buccal root; or composite and two FPs. As control, the model of an intact UFP was included. A simulated load of 150 N was applied. Stress distribution was observed on each model surface, on the mid buccal–palatal plane, and on two horizontal planes (at cervical and root-furcation levels); the maximum Von Mises stress values were calculated. All analyses were replicated three times, using the mechanical parameters from three different nanohybrid resin composite restorative materials. In the presence of FPs, the maximum stress values recorded on dentin (in cervical and root-furcation areas) appeared slightly reduced, compared to the endodontically treated tooth restored with no post; in the same areas, the overall Von Mises maps revealed more favorable stress distributions. FPs in maxillary premolars with MOD cavities can lead to a positive redistribution of potentially dangerous stress concentrations away from the cervical and the root-furcation dentin.

The function(s) of bone ornamentation in the crocodylomorph osteoderms: a biomechanical model based on a finite element analysis

Paleobiology ◽  
2019 ◽  
Vol 45 (1) ◽  
pp. 182-200 ◽  
Author(s):  
François Clarac ◽  
Florent Goussard ◽  
Vivian de Buffrénil ◽  
Vittorio Sansalone
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Von Mises Stress ◽  
Late Triassic ◽  
Mechanical Resistance ◽  
Apical Surface ◽  
Element Analysis ◽  
Physiological Functions ◽  
Von Mises

AbstractThis paper aims at assessing the influence of the bone ornamentation and, specifically, the associated loss of bone mass on the mechanical response of the crocodylomorph osteoderms. To this end, we have performed three-dimensional (3D) modeling and a finite element analysis on a sample that includes both extant dry bones and well-preserved fossils tracing back to the Late Triassic. We simulated an external attack under various angles on the apical surface of each osteoderm and further repeated the simulation on an equivalent set of smoothed 3D-modeled osteoderms. The comparative results indicated that the presence of an apical sculpture has no significant influence on the von Mises stress distribution in the osteoderm volume, although it produces a slight increase in its numerical score. Moreover, performing parametric analyses, we showed that the Young's modulus of the osteoderm, which may vary depending on the bone porosity, the collagen fiber orientation, or the calcification density, has no impact on the von Mises stress distribution inside the osteoderm volume. As the crocodylomorph bone ornamentation is continuously remodeled by pit resorption and secondary bone deposition, we assume that the apical sculpture may be the outcome of a trade-off between the bone mechanical resistance and the involvement in physiological functions. These physiological functions are indeed based on the setup of a bone superficial vessel network and/or the recurrent release of mineral elements into the plasma: heat transfers during basking and respiratory acidosis buffering during prolonged apnea in neosuchians and teleosaurids; compensatory homeostasis in response to general calcium deficiencies. On a general morphological basis, the osteoderm geometric variability within our sample leads us to assess that the global osteoderm geometry (whether square or rectangular) does not influence the von Mises stress, whereas the presence of a dorsal keel would somewhat reduce the stress along the vertical axis.

scholarly journals A three - dimensional finite element study on the stress distribution pattern of two prosthetic abutments for external hexagon implants

2013 ◽  
Vol 07 (04) ◽  
pp. 484-491 ◽  
Author(s):  
Wagner Moreira ◽  
Caio Hermann ◽  
Jucélio Tomás Pereira ◽  
Jean Anacleto Balbinoti ◽  
Rodrigo Tiossi
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Three Dimensional ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
3D Fea ◽  
The One ◽  
Von Mises ◽  
Three Dimensional Finite Element

ABSTRACT Objective: The purpose of this study was to evaluate the mechanical behavior of two different straight prosthetic abutments (one- and two-piece) for external hex butt-joint connection implants using three-dimensional finite element analysis (3D-FEA). Materials and Methods: Two 3D-FEA models were designed, one for the two-piece prosthetic abutment (2 mm in height, two-piece mini-conical abutment, Neodent) and another one for the one-piece abutment (2 mm in height, Slim Fit one-piece mini-conical abutment, Neodent), with their corresponding screws and implants (Titamax Ti, 3.75 diameter by 13 mm in length, Neodent). The model simulated the single restoration of a lower premolar using data from a computerized tomography of a mandible. The preload (20 N) after torque application for installation of the abutment and an occlusal loading were simulated. The occlusal load was simulated using average physiological bite force and direction (114.6 N in the axial direction, 17.1 N in the lingual direction and 23.4 N toward the mesial at an angle of 75° to the occlusal plan). Results: The regions with the highest von Mises stress results were at the bottom of the initial two threads of both prosthetic abutments that were tested. The one-piece prosthetic abutment presented a more homogeneous behavior of stress distribution when compared with the two-piece abutment. Conclusions: Under the simulated chewing loads, the von Mises stresses for both tested prosthetic-abutments were within the tensile strength values of the materials analyzed which thus supports the clinical use of both prosthetic abutments.

Stresses in Teeth and Overlying Crowns

2012 ◽  
Vol 457-458 ◽  
pp. 567-571
Author(s):  
Liliana Sandu ◽  
Florin Topală ◽  
Sorin Porojan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Numerical Simulations ◽  
Experimental Model ◽  
3D Scanning ◽  
Analysis Software ◽  
Element Analysis ◽  
Equivalent Stresses ◽  
Von Mises

A complete cast crown allows the operator to modify axial tooth contour. The margin should be smooth and distinct and its width has to allow adequate bulk of metal at the margin. The objective of this study was to evaluate, by finite element analysis, the influence of different degree of taper and marginal designs for cast crown preparations, on the stress distribution in teeth and crowns. As experimental model an upper first molar was used. The geometry of the intact tooth were obtained by 3D scanning. The tooth preparations and the complete cast crowns were designed. Models were exported in a finite element analysis software for structural simulations. Von Mises equivalent stresses were calculated and their distribution was plotted graphically. Numerical simulations provide a biomechanical explanation for stress distribution in prepared teeth and overlying crowns.

Finite Element Analysis of Materials and Processing of Composite Flywheel Rotor

2014 ◽  
Vol 529 ◽  
pp. 92-96 ◽  
Author(s):  
Song Yi Guo ◽  
Chong Li ◽  
Wen Yi Li
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Storage System ◽  
Equivalent Stress ◽  
Energy Storage System ◽  
Element Analysis ◽  
Composite Flywheel ◽  
Flywheel Energy Storage System ◽  
Von Mises ◽  
Flywheel Rotor

Flywheel rotor is the very important component in the flywheel energy storage system (FESS). The key factors of rotor, such as rotor materials, geometry and fabrication process, have directly influence on the performance of FESS. At present, press-assembling the rotor with shrink-fit is used usually to increase strength of composite flywheel rotors filament wound in the radial direction. This paper is concerned that the Von Mises equivalent stress distribution of the metal hub and the radial stress distribution of the composite rim at the speed of 20000rpm by the 3D finite element method. The materials and corresponding minimum value of interference fit of the flywheel rotor are determined based on the analysis results.

scholarly journals The Influence of Pelvic Tilt on Stress Distribution in the Acetabulum: Finite Element Analysis

2020 ◽  
Author(s):  
Kazuhiro Hasegawa ◽  
Tamon Kabata ◽  
Yoshitomo Kajino ◽  
Daisuke Inoue ◽  
Jiro Sakamoto ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Hip Joint ◽  
Tilt Angle ◽  
Pelvic Tilt ◽  
Biomechanical Analysis ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Von Mises

Abstract Background Finite element analysis (FEA) has been previously applied for the biomechanical analysis of acetabular dysplasia and osteotomy. However, until now, there have been little reports on the use of FEA to evaluate the effects of pelvic tilt on stress distribution in the acetabulum. Methods We used the Mechanical Finder Ver. 7.0 (RCCM, Inc., Japan) to construct finite element models based on 3D-CT data of patients, and designed dysplasia, borderline, and normal pelvic models. For analysis, body weight was placed on the sacrum and the load of the flexor muscles of the hip joint was placed on the ilium. The pelvic tilt was based on the anterior pelvic plane, and the pelvic tilt angles were -20°, 0°, and 20°. The load of the flexor muscle of the hip joint was calculated using the moment arm equation.Results All three models showed the highest values of von Mises stress in the -20° pelvic tilt angle, and the lowest in the 20° angle. Stress distribution concentrated in the load-bearing area. The maximum values of von Mises stress in the borderline at pelvic tilt angles of -20° was 3.5Mpa, and in the dysplasia at pelvic tilt angles of 0° was 3.1Mpa. Conclusions The pelvic tilt angle of -20° of the borderline model showed equal maximum values of von Mises stress than the dysplasia model of pelvic tilt angle of 0°, indicating that pelvic retroversion of -20° in borderline is a risk factor for osteoarthritis of the hip joints, similar to dysplasia.

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