Effect of specimen gripping device, geometry and fixation method on microtensile bond strength, failure mode and stress distribution: Laboratory and finite element analyses

2012 ◽  
Vol 28 (5) ◽  
pp. e50-e62 ◽  
Author(s):  
Luís H.A. Raposo ◽  
Steven R. Armstrong ◽  
Rodrigo R. Maia ◽  
Fang Qian ◽  
Saulo Geraldeli ◽  
...  
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Bond Strength ◽  
Failure Mode ◽  
Fixation Method ◽  
Finite Element Analyses ◽  
Microtensile Bond Strength ◽  
Strength Failure ◽  
Device Geometry

scholarly journals A comparison between the capacity of 2D and 3D finite element models in analyzing the stress distribution in shear and microshear bond strength tests

2013 ◽  
Vol 1 (1) ◽  
pp. 41 ◽  
Author(s):  
Tathy Aparecida Xavier ◽  
Rafael Yagüe Ballester
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Bond Strength ◽  
Resin Composite ◽  
Adhesive Layer ◽  
3D Models ◽  
Test Set ◽  
Adhesive Interface ◽  
Set Up ◽  
Microshear Bond Strength

Numerical computational analyses by means of finite element method (FEM) have been allowing the understanding of how the test set-up configurations influence on stress distribution in the tested specimen. During such analysis, the models are simplified but, at the same time, they must allow obtaining enough data and, thus, enough knowledge for changing and standardizing the tests set-ups. This study aimed at comparing the capacity of 2D plane strain simplified finite element models, simulated in a previous study, in analyzing the shear and microshear bond strength tests set-ups, compared to 3D more refined models. Booth 2D and 3D models represented a resin-composite cylinder (with two different stiffness) adhered to a dentin flattened surface by means of an adhesive layer. The shear and microshear specimens had dimensions in a 5:1 ratio, except for the adhesive layer thickness, which remained constant in booth-sized models. It was simulated a load applied by an orthodontic wire-loop in all the cases, varying the distance from the load to the adhesive interface. The 2D models showed to be enough for analyzing the stress distribution patterns along the dentin-adhesive interface. They also allowed verifying the influence of variables such as the relative thickness of the adhesive layer and the distance between the loading and the adhesive interface on the stress distribution. However, the 2D plane strain models showed an opposite effect of the elastic modulus of the resin-composite cylinder on the stress concentration. Furthermore, they lead to a different prediction with respect to the real test set-up configurations. As the 3D models were built with more realistic geometrical refinements compared to the simplified 2D models, they should be considered as more reliable than the 2D models for analyzing the shear and microshear bond strength test set-ups.

scholarly journals Chitosan in different concentrations added to a two-step etch-and-rinse adhesive system: influence on bond strength to dentin

2017 ◽  
Vol 20 (4) ◽  
pp. 55
Author(s):  
Rafael Avellar de Carvalho Nunes ◽  
Flávia Lucisano Botelho do Amaral ◽  
Fabiana Mantovani Gomes França ◽  
Cecilia Pedroso Turssi ◽  
Roberta Tarkany Basting
Keyword(s):  
Bond Strength ◽  
Failure Mode ◽  
Failure Modes ◽  
Resin Composite ◽  
Adhesive System ◽  
Fracture Pattern ◽  
Test Machine ◽  
Microtensile Bond Strength ◽  
Etch And Rinse ◽  
Strength Tests

<p class="Corpo"><strong>Objective</strong>: the aim of the present study was to evaluate the influence of adding different concentrations of chitosan to an experimental two-step etch-and-rinse adhesive system on the bond strength and failure mode to dentin. <strong>Material</strong> <strong>and</strong> <strong>Methods</strong>: thirty-two flat dentin surfaces were obtained from extracted human third molars and divided into four groups  (n=8) for application of the adhesive systems: AD - conventional two-step adhesive system (Adper Single Bond 2); EXP – experimental two-step etch-and-rinse adhesive system; Chi0.2% - EXP with addition of 0.2% Chitosan; Chi0.5% - EXP with addition of 0.5% Chitosan. Resin composite build-ups were made and the composite/dentin specimens were sectioned to obtain rectangular beams with a bond area of approximately 1mm<sup>2</sup>. After 24 hours, the sticks were submitted to microtensile bond strength tests in a universal test machine. The fracture pattern was evaluated under a stereoscopic loupe at 40X magnification. <strong>Results</strong>: one-way analysis of variance showed that the type of adhesive system had no significant effect on the bond strength values (p = 0.142), showing the mean bond strength values (standard deviation), in MPa, for the groups as follows: AD=20.1 (5.4); EXP=16.6 (2.3); Chi0.2%=16.1 (2.8); Chi0.5%=16.9 (2.3). In all the groups there was predominance of cohesive fractures in dentin, representing 68 to 82% of the failure modes. <strong>Conclusion</strong>: the addition of 0.2 or 0.5% of chitosan had no influence on the bond strength and failure mode of an experimental two-step etch-and-rinse adhesive system to dentin.</p><p class="Corpo"><strong>Keywords</strong></p><p class="Corpo">Chitosan; Dental Adhesives; Failure Mode; Microtensile Bond Strength.</p>

A method for the measurement of residual stresses using a fracture mechanics approach

1989 ◽  
Vol 24 (1) ◽  
pp. 23-30 ◽  
Author(s):  
K J Kang ◽  
J H Song ◽  
Y Y Earmme
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress Distribution ◽  
Fracture Mechanics ◽  
Residual Stresses ◽  
Residual Stress Distribution ◽  
The State ◽  
Two Dimensional ◽  
Finite Element Analyses ◽  
Simple Method

A simple method for measuring residual stresses in a plate is described. In this method residual stresses are evaluated using a fracture mechanics approach, that is, the strains or displacements measured at a point on the edge of a plate as a crack is introduced and extended from the edge are used to deduce the state of stresses that existed in the uncracked plate. Through finite element analyses and experiments this method is shown to be valid and effective for measuring the two-dimensional residual stress distribution of a welded plate.

Finite Element Analysis of Bolted Flanged Joints Subjected to External Loads

2015 ◽  
Vol 750 ◽  
pp. 324-329
Author(s):  
He Hui Wang ◽  
Ya Juan Feng ◽  
Wen Min Zhu ◽  
Zhi Ming Zhang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Ansys Software ◽  
Element Analysis ◽  
Strength Failure ◽  
Sealing Performance ◽  
External Loads

Since external loads affect the sealing performance of bolted flanged joints, this paper calculated external loads of bolted flanged joints by using CAESAR II software and evaluated the effects of external loads on the sealing performance from the viewpoint of changes in contact gasket stress and flange rotation by using ANSYS software. The FE results showed that the contact gasket stress decreases a lot at the tension side and increases a little at the compression side. The paper also evaluated the stress distribution in bolted flanged joints subjected to external loads. The results suggested that the flange rotation and the overall stress increased compared with that of flange without external loads. External loads can induce unexpected leakage and strength failure of the bolted flanged joints during operation.

scholarly journals Laminated Glass Cantilevered Plates under Static and Impact Loading

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Luigi Biolzi ◽  
Antonio Bonati ◽  
Sara Cattaneo
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Impact Loading ◽  
Structural Performance ◽  
Laminated Glass ◽  
Finite Element Analyses ◽  
Tempered Glass ◽  
Low Velocity ◽  
Glass Plates ◽  
Experimental Findings

The structural performance of cantilevered laminated glass plates for different glass thicknesses and interlayers is considered in this paper. Heat-strengthened and tempered glass plies and two different interlayer films were utilized. The response of laminated glass specimens is then evaluated under low-velocity hard and semirigid impacts. Experimental findings were simulated and discussed by means of finite element analyses. In particular, this discussion includes the evaluation of the influence that the fixed edge clamping technique (number of clamps, their size, and their stiffness) has on the stress distribution in the specimens.

Finite Element Analyses Comparison Between Normal Teeth and Prosthetic Teeth

2015 ◽  
Vol 638 ◽  
pp. 155-160
Author(s):  
Horia Alexandru Petrescu ◽  
Daniel Vlasceanu ◽  
Andrei Stamate ◽  
Robert Bololoi ◽  
Stela Carmen Hanganu
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Life Span ◽  
Real Life ◽  
Finite Element Analyses ◽  
Natural Form ◽  
Second Molar ◽  
Normal Life ◽  
Natural Tooth ◽  
Life Behavior

Dental medicine represents a very important part of our life. As our appearance or looks is a major concern for us, a beautiful smile can improve our life. Moreover, our teeth health reflects on our overall health. This paper presents a method for highlighting the differences between a natural tooth and a prosthetic one. In order to determine the stress distribution in teeth during the use of prosthetics pivots, several virtual geometric models of the teeth were created (canine, first premolar, first molar and second molar), both in their natural form and when using pivots. The results obtained from these analyses were compared in order to reveal the behavior of a prosthetic tooth during normal life loads. Such results of real life behavior can be used by dental medics in order to predict the life span of restored teeth.

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.

Effect of final drawing with light reduction on the levelling of residual stress distribution in cold bar drawing

2000 ◽  
Vol 214 (11) ◽  
pp. 1389-1400 ◽  
Author(s):  
T Kuboki ◽  
M Akiyama ◽  
Y Neishi ◽  
K Kuroda
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress Distribution ◽  
Final Stage ◽  
Cold Drawing ◽  
Residual Stress Distribution ◽  
Finite Element Analyses ◽  
Light Reduction ◽  
The University ◽  
Levelling Effect

A method is proposed for producing a significant reduction in the magnitude of the residual stress generated after cold drawing of a bar. It consists basically of a skin pass at the final stage of drawing and has a good levelling effect on the residual stress distribution as long as the final reduction falls within a specific range. The method was first proposed as a result of elastic-plastic finite element analyses using the ELFEN code developed by Rockfield Software Limited at the University of Wales, Swansea. The validity of the proposed method was verified by measuring the residual stress using the Sachs method.

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