RESEARCH OF MAXILLARY IMPACTED CANINE IN ORTHODONTIC TREATMENT BASED ON NANOINDENTATION EXPERIMENTS

2017 ◽  
Vol 17 (07) ◽  
pp. 1740029
Author(s):  
BIN WU ◽  
YUNYUN ZHU ◽  
RUXIN LU ◽  
BIN YAN ◽  
YIPENG FU ◽  
...  
Keyword(s):  
Orthodontic Treatment ◽  
Strain Curve ◽  
Root Apex ◽  
Stress Strain Curve ◽  
Third Order ◽  
Stress Variation ◽  
The Third ◽  
Ogden Model ◽  
Impacted Canine ◽  
Good Agreement

This study selected the maxillary labial impacted canine as the research object to build the model of periodontal ligament (PDL) and simulate the process of orthodontic treatment. This paper obtained stress–strain curve by calculating and analyzing the data of nanoindentation experiments. The parameters were identified through curve fittings by ABAQUS. The fitting results show that the third-order Ogden model is in good agreement with the experimental data which demonstrate that the third-order Ogden model is able to reflect the material properties of the PDL. In this paper, orthodontic process of the maxillary labial impacted canine was simulated. The results show that inside and outside surfaces of PDL all have stress variation, the stress on the root apex and dental cervix of PDL is relatively large, the maximum appears at dental cervix and the minimum appears close to tooth impedance center.

A Two-Dimensional Potential Flow Model of the Wave Field Generated by a Semisubmerged Body in Heaving Motion

1988 ◽  
Vol 32 (02) ◽  
pp. 83-91
Author(s):  
X. M. Wang ◽  
M. L. Spaulding
Keyword(s):  
Free Surface ◽  
Boundary Conditions ◽  
Potential Flow ◽  
Flow Model ◽  
Second Order ◽  
Two Dimensional ◽  
Third Order ◽  
The Third ◽  
Potential Flow Model ◽  
Good Agreement

A two-dimensional potential flow model is formulated to predict the wave field and forces generated by a sere!submerged body in forced heaving motion. The potential flow problem is solved on a boundary fitted coordinate system that deforms in response to the motion of the free surface and the heaving body. The full nonlinear kinematic and dynamic boundary conditions are used at the free surface. The governing equations and associated boundary conditions are solved by a second-order finite-difference technique based on the modified Euler method for the time domain and a successive overrelaxation (SOR) procedure for the spatial domain. A series of sensitivity studies of grid size and resolution, time step, free surface and body grid redistribution schemes, convergence criteria, and free surface body boundary condition specification was performed to investigate the computational characteristics of the model. The model was applied to predict the forces generated by the forced oscillation of a U-shaped cylinder. Numerical model predictions are generally in good agreement with the available second-order theories for the first-order pressure and force coefficients, but clearly show that the third-order terms are larger than the second-order terms when nonlinearity becomes important in the dimensionless frequency range 1≤ Fr≤ 2. The model results are in good agreement with the available experimental data and confirm the importance of the third order terms.

scholarly journals A space structural mechanics model of silicene

2020 ◽  
Vol 234 (1-2) ◽  
pp. 3-10
Author(s):  
Mohsen Motamedi
Keyword(s):  
Natural Frequencies ◽  
Strain Curve ◽  
Structural Mechanics ◽  
Dynamics Simulation ◽  
Mode Shapes ◽  
Two Dimensional ◽  
Stress Strain Curve ◽  
Beam Elements ◽  
Mechanics Model ◽  
Good Agreement

The two-dimensional nanostructures such as graphene, silicene, germanene, and stanene have attracted a lot of attention in recent years. Many studies have been done on graphene, but other two-dimensional structures have not yet been studied extensively. In this work, a molecular dynamics simulation of silicene was done and stress–strain curve of silicene was obtained. Then, the mechanical properties of silicene were investigated using the proposed structural molecular mechanics method. First, using the relations governing the force field and the Lifson–Wershel potential function and structural mechanics relations, the coefficients for the BEAM elements was determined, and a structural mechanics model for silicene was proposed. Then, a silicene sheet with 65 Å × 65 Å was modeled, and Young’s modulus of silicene was obtained. In addition, the natural frequencies and mode shapes of silicene were calculated using finite element method. The results are in good agreement with reports by other papers.

scholarly journals Effects of layer shift and yarn path variability on mechanical properties of a twill weave composite

2016 ◽  
Vol 51 (7) ◽  
pp. 913-925 ◽  
Author(s):  
MY Matveev ◽  
AC Long ◽  
LP Brown ◽  
IA Jones
Keyword(s):  
Numerical Analysis ◽  
Strain Curve ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Element Analysis ◽  
Damage Propagation ◽  
Macro Scale ◽  
Twill Weave ◽  
Modulus Reduction ◽  
Good Agreement

Experimental and numerical analyses of a woven composite were performed in order to assess the effect of yarn path and layer shift variability on properties of the composite. Analysis of the geometry of a 12 K carbon fibre 2 × 2 twill weave at the meso- and macro-scales showed the prevalence of the yarn path variations at the macro-scale over the meso-scale variations. Numerical analysis of yarn path variability showed that it is responsible for a Young’s modulus reduction of 0.5% and CoV of 1% which makes this type of variability in the selected reinforcement almost insignificant for an elastic analysis. Finite element analysis of damage propagation in laminates with layer shift showed good agreement with the experiments. Both numerical analysis and experiments showed that layer shift has a strong effect on the shape of the stress–strain curve. In particular, laminates with no layer shift tend to exhibit a kink in the stress–strain curve which was attributed solely to the layer configuration.

scholarly journals Ratcheting response of biological tissues over asymmetric loading cycles

2021 ◽  
Author(s):  
Mahboubeh Sadat Hashemi
Keyword(s):  
Experimental Data ◽  
Strain Curve ◽  
Biological Tissues ◽  
Parametric Model ◽  
Stress Strain Curve ◽  
Stress Variation ◽  
Ratcheting Strain ◽  
Asymmetric Loading ◽  
Model Predictions ◽  
Failure Region

The purpose of this study is to examine the ratcheting phenomenon in a variety of biological tissues including the trabecular bone, meniscus, articular cartilage and skin, and propose a parametric model to predict the ratcheting strain of these tissues. Furthermore, utilizing experimental data, and the influence of different mechanical and biological parameters on the ratcheting strain are discussed. The dependency of ratcheting on frequency, stress rate, stress variation, physiological environment, and tissue sites is demonstrated. Besides, stiffness of the toe and linear regions in each cycle, and the modulus of the failure region of the stress-strain curve are computed. The energy dissipation in different cycles at two frequencies of 1 Hz and 10 Hz is discussed. A parametric model was employed to predict ratcheting behavior of the said biological tissues. The model predictions of the strain accumulation in tissues are found in agreement with the experimental data.

On the Collapse of Long, Thick-Walled Tubes Under External Pressure and Axial Tension

1993 ◽  
Vol 115 (1) ◽  
pp. 15-26 ◽  
Author(s):  
R. Madhavan ◽  
C. D. Babcock ◽  
J. Singer
Keyword(s):  
Strain Curve ◽  
External Pressure ◽  
Combined Loading ◽  
Flow Rule ◽  
Two Dimensional ◽  
Stress Strain Curve ◽  
Axial Tension ◽  
Collapse Strength ◽  
Tension Loading ◽  
Good Agreement

The paper presents the results from a combined experimental and analytic study on the collapse of long, thick-walled tubes subjected to external pressure and axial tension. The experiments involved tubes of diameter-to-thickness ratio (Dm/t) 10 to 40. Collapse envelopes were obtained for two different pressure-tension loading paths. Collapse tests involving initially ovalized tubes were also carried out. The collapse strength predicted with a two-dimensional elasto-plastic model applying J2 flow rule was in good agreement with the experiments. The results show that the collapse strength under combined loading is strongly influenced by initial ovality and that the shape of the stress-strain curve has a significant influence on the tension-pressure collapse envelope.

scholarly journals Influence of Radiographic Position of Ectopic Canines on the Duration of Orthodontic Treatment

2009 ◽  
Vol 79 (3) ◽  
pp. 442-446 ◽  
Author(s):  
Padhraig S. Fleming ◽  
Paul Scott ◽  
Negan Heidari ◽  
Andrew T. DiBiase
Keyword(s):  
Treatment Duration ◽  
Orthodontic Treatment ◽  
Stepwise Regression ◽  
Root Apex ◽  
Horizontal Position ◽  
Duration Of Treatment ◽  
Length Of Treatment ◽  
Multiple Stepwise Regression Analysis ◽  
Impacted Canine ◽  
Vertical Height

Abstract Objective: To investigate the influence of radiographic position of palatally impacted canines on the length of treatment for orthodontic alignment. Materials and Methods: Treatment records of 45 consecutive successfully treated patients (36 unilateral, 9 bilateral) with ectopic palatal canines treated with surgical exposure and orthodontic traction were analyzed. The sample was based on orthodontic referrals over a 3-year period in Kent and Canterbury Hospital, UK. The duration of treatment was related to radiographic parameters including the height of the impacted canine, angulation of the long axis to the upper midline, mesiodistal position of the canine tip relative to the midline and adjacent incisors, and the anteroposterior position of the canine root apex. Results: Using multiple stepwise regression analysis, the horizontal position of the canine crown relative to adjacent teeth and maxillary dental midline showed a statistically significant correlation with the duration of treatment (P =.042), explaining 7.7% of the overall variance. However, treatment duration was found to be independent of the initial canine angulation (P = .915), vertical height (P =.065), and position of the canine apex (P = .937). Conclusions: Accurate prediction of treatment duration for orthodontic alignment of palatally impacted maxillary canines is difficult. However, the mesiodistal position of the canine may be a useful predictor of treatment duration. (Angle Orthod. 2009:79;442–446.)

Conventional and Auxetic SMA Cellular Structures

Aerospace ◽  
2005 ◽  
Author(s):  
Mohd R. Hassan ◽  
F. Scarpa ◽  
N. A. Mohammed ◽  
Y. Ancrenaz
Keyword(s):  
Room Temperature ◽  
Strain Curve ◽  
Tensile Tests ◽  
Core Material ◽  
Stress Strain Curve ◽  
Beam Elements ◽  
Commercial Code ◽  
Unit Cells ◽  
Novel Concept ◽  
Good Agreement

This work illustrates the manufacturing and tensile testing of a novel concept of honeycomb structures with hexagonal and auxetic (negative Poisson’s ratio) topology, made of shape memory alloy (SMA) core material. The honeycombs are manufactured using Nitinol ribbons having 6.40 mm of width and 0.2 mm of thickness. The ribbons were inserted in a special dye using cyanoacrilate to bond the longitudinal strips of the unit cells. The ribbons were subjected to tensile test at room temperature (martensite finish) and austenite finish temperature. Tensile tests at room temperature were performed on the honeycomb. The stress-strain curve obtained from the test on a single ribbon at room temperature was then used to develop nonlinear Finite Element beam elements using a commercial code. The beam elements were then used to model the honeycomb samples under tensile loading. Good agreement is observed between numerical nonlinear simulations and the experimental results.

Constitutive Relation of Open-Celled Metal Foams Based on the Mesoscopic Behavior of Random Cells

2007 ◽  
Vol 340-341 ◽  
pp. 403-408 ◽  
Author(s):  
Ling Ling Hu ◽  
Xiao Qing Huang ◽  
Li Qun Tang
Keyword(s):  
Experimental Data ◽  
Mechanical Behavior ◽  
Constitutive Relation ◽  
Metal Foam ◽  
Strain Curve ◽  
Metal Foams ◽  
Stress Strain Curve ◽  
Yield Strain ◽  
Compression Process ◽  
Good Agreement

The constitutive relation for open-celled metal foams with random characteristics of cells was constructed based on the mechanical behavior and the distribution of the cells, which implied the effect of the mesoscopic characteristics of the cells on the macroscopic behavior of the foam. The constitutive relation was able to represent the whole three phases of the stress-strain curve of the open-celled metal foam with merely one expression. Besides, the explicit expressions for the foam’s yield strain and yield stress were supplied. Experimental data was employed to check the constitutive relation. It was found that the constitutive relation was able to represent accurately the whole compression process of the foams, and the calculated yield points had a good agreement with the experimental results.

Tensile stress/strain characterization of non-linear materials

1981 ◽  
Vol 16 (2) ◽  
pp. 107-110 ◽  
Author(s):  
J Margetson
Keyword(s):  
Strain Curve ◽  
Uniaxial Stress ◽  
Aerodynamic Heating ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Strain Characterization ◽  
Least Squares Fit ◽  
Experimental Values ◽  
Good Agreement

A uniaxial stress/strain curve is represented empirically by a modified Ramberg-Osgood equation ∊=(σ/E) + (σ/σo)m. Firstly E is extracted then σo and m are determined from two points on the experimental curve. These values are improved iteratively by a least squares fit using all the experimental points on the curve. The procedure is used to generate stress/strain relationships for a variety of materials and there is good agreement with the experimental values. The method is also applied to a simulated aerodynamic heating experiment.

An Upper Bound Approach on Deformation of Two-Phase Materials in Uniaxial Tension

1983 ◽  
Vol 105 (1) ◽  
pp. 39-44 ◽  
Author(s):  
Y. Tada ◽  
M. Oyane ◽  
S. Shima ◽  
T. Sato ◽  
M. Omura
Keyword(s):  
Upper Bound ◽  
Volume Fraction ◽  
Strain Curve ◽  
Second Phase ◽  
Strength Ratio ◽  
Stress Strain Curve ◽  
Two Phase ◽  
Second Phase Particles ◽  
Strength And Deformation ◽  
Good Agreement

Strength and deformation of two-phase materials are investigated by the upper bound approach in relation to the volume fraction of the second-phase particles, yield strength ratio and bond strength between the constituents, shape of the particles, and environmental hydrostatic pressure. The stress-strain curve of a two-phase material is estimated as an application of this method. The calculated results are in good agreement with experimental ones.

Sign in / Sign up

Export Citation Format

Share Document