Comparison of Biomechanical Effects of Different Configurations of Kirschner Wires on the Epiphyseal Plate and Stability in a Salter-Harris Type 2 Distal Femoral Fracture Model

2019 ◽  
Vol 109 (1) ◽  
pp. 13-21 ◽  
Author(s):  
Sermet Inal ◽  
Kadir Gok ◽  
Arif Gok ◽  
Ahmet Murat Pinar ◽  
Canan Inal

Background: We sought to investigate the different configurations of Kirschner wires used in distal femur Salter-Harris (SH) type 2 epiphyseal fracture for stabilization after reduction under axial, rotational, and bending forces and to define the biomechanical effects on the epiphyseal plate and the fracture line and decide which was more advantageous. Methods: The SH type 2 fracture was modeled using design software for four different configurations: cross, cross-parallel, parallel medial, and parallel lateral with two Kirschner wires, and computer-aided numerical analyses of the different configurations after reduction were performed using the finite element method. For each configuration, the mesh process, loading condition (axial, bending, and rotational), boundary conditions, and material models were applied in finite element software, and growth cartilage and von Mises stress values occurring around the Kirschner wire groove were calculated. Results: In growth cartilage, the stresses were highest in the parallel lateral configuration and lowest in the cross configuration. In Kirschner wires, the stresses were highest in the cross configuration and lowest in the cross-parallel and parallel lateral configurations. In the groove between the growth cartilage and the Kirschner wire interface, the stresses were highest in the parallel lateral configuration and lowest in the cross configuration. Conclusions: The results showed that the cross configuration is advantageous in fixation. In addition, in the SH type 2 epiphyseal fracture, we believe that the fixation shape should not be applied in the lateral configuration.

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Qin Xie ◽  
Duo Li

Abstract Background The application of intermaxillary traction is often accompanied by the unexpected movement of dentition, especially anchorage teeth. The aim of this study was to comprehensively compare the influence of cross-sectional shape of ribbon arch wires with edgewise and round wires on intermaxillary traction in Class II malocclusion treatment using FEA simulation. Methods The dentofacial structure was simulated in finite element software. A retraction force of 1.5 N was applied to different cross-sectional orthodontic arch wires: a ribbon wire (0.025 × 0.017-in. and 0.025 × 0.019-in.), a rectangular wire (0.017 × 0.025-in. and 0.019 × 0.025-in.) and a round wire (Φ 0.018-in. and Φ 0.020-in.). Results Among the three groups, ribbon wire (0.025 × 0.017-in. and 0.025 × 0.019-in.) exhibited the lowest displacement in the X-axis (12.61 μm and 12.77 μm, respectively) and Z-axis (8.99 μm and 9.06 μm, respectively). However, the 0.025 × 0.017-in. ribbon wire showed the highest Y-axis displacement. In the round wire group, Φ 0.020-in. wire displayed less rotation than Φ 0.018-in. wire, where the sagittal, frontal and occlusal rotation of Φ 0.020-in. wire was almost half of that of Φ 0.018-in. wire. The movement of the first molar region was intermediate between the ribbon arch group and the round wire group. Notably, the values of the 0.025 × 0.017-in. arch wire displacement, which were higher than those of any other group, peaked at 0.019 mm in the central incisor region with a spike-like shape. The deformation range of the Φ 0.018-in. wire group was the largest in this study. Conclusions The cross-section of the arch wire influenced force delivery in Class II intermaxillary traction. With the same shape, a larger cross-sectional area led to less mandibular dentition movement. For the rectangular arch wire and ribbon arch wire groups, since the height and width were inverted, the vertical displacement of anchorage teeth in the ribbon wire group was reduced, but the possibility of buccal tipping in mandibular anterior teeth also increased.


2021 ◽  
Author(s):  
Qin Xie ◽  
Duo Li

Abstract Background: The application of intermaxillary traction is often accompanied by the unexpected movement of dentition, especially anchorage teeth. The aim of this study was to comprehensively compare the influence of cross-sectional shape of ribbon arch wires with edgewise and round wires on intermaxillary traction in Class II malocclusion treatment using FEA simulation.Methods: The dentofacial structure was simulated in finite element software. A retraction force of 1.5 N was applied to different cross-sectional orthodontic arch wires: a ribbon wire (0.025×0.017-inch and 0.025×0.019-inch), a rectangular wire (0.017×0.025-inch and 0.019×0.025-inch) and a round wire (Φ 0.018-inch and Φ 0.020-inch).Results: Among the three groups, ribbon wire (0.025×0.017-inch and 0.025×0.019-inch) exhibited the lowest displacement in the X-axis (12.61 μm and 12.77 μm, respectively) and Z-axis (8.99 μm and 9.06 μm, respectively). However, the 0.025×0.017-inch ribbon wire showed the highest Y-axis displacement. In the round wire group, Φ 0.020-inch wire displayed less rotation than Φ 0.018-inch wire, where the sagittal, frontal and occlusal rotation of Φ 0.020-inch wire was almost half of that of Φ 0.018-inch wire. The movement of the first molar region was intermediate between the ribbon arch group and the round wire group. Notably, the values of the 0.025×0.017-inch arch wire displacement, which were much higher than those of any other group, peaked at 0.019 mm in the central incisor region with a spike-like shape. The deformation range of the Φ 0.018-inch wire group was the largest in this study.Conclusions: The cross-section of the arch wire influenced force delivery in Class II intermaxillary traction. With the same shape, a larger cross-sectional area would lead to less mandibular dentition movement. For the rectangular arch wire and ribbon arch wire groups, since the height and width were inverted, the vertical displacement of anchorage teeth in the ribbon wire group was significantly reduced, but the possibility of buccal tipping in mandibular anterior teeth also increased.


2007 ◽  
Vol 546-549 ◽  
pp. 1591-1596
Author(s):  
Wei Feng Dong ◽  
Yong Li ◽  
Jun Xiao

As for 2.5-D layer-to-layer angle interlock braided composites, the cross section of the warp tow was represented in double-convex lens form, and the center line of the warp tow was along the sinusoid. The arranging characteristic of weft tow fibers along the cross section outline of the longitude fibers was studied in detail. A novel finite element model for 2.5-D braided composites was established to predict elastic modulus. The finite element software ANSYS was adopted to study the mechanical properties of the model and presented its stress nephogram, and the influence of the braided structure parameters on the elastic modulus of this material was analyzed in detail. To validate this model, qualified experimental samples were made by VARTM technique, and then tensile tests were performed to determine the mechanical properties. The results show that the conclusions of finite element method (FEM) fit well with the experimental values, and this model can be used to predict effectively the macro modulus of 2.5-D braided composites.


1999 ◽  
Vol 12 (02) ◽  
pp. 88-91 ◽  
Author(s):  
D. D. Lewis ◽  
Susan M. Newell ◽  
O. I. Lanz

Successful treatment of humeral condylar fractures requires accurate reduction and rigid internal fixation which can be difficult to achieve in toy and/or miniature breed dogs. Stabilization of a Salter-Harris type IV physeal fracture of the numeral condyle was simplified by using Orthofix® partially-threaded Kirschner wire and provided excellent clinical results in a 1.5 kg miniature pinscher


Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4018
Author(s):  
Shuming Zhang ◽  
Yuanming Xu ◽  
Hao Fu ◽  
Yaowei Wen ◽  
Yibing Wang ◽  
...  

From the perspective of damage mechanics, the damage parameters were introduced as the characterizing quantity of the decrease in the mechanical properties of powder superalloy material FGH96 under fatigue loading. By deriving a damage evolution equation, a fatigue life prediction model of powder superalloy containing inclusions was constructed based on damage mechanics. The specimens containing elliptical subsurface inclusions and semielliptical surface inclusions were considered. The CONTA172 and TARGE169 elements of finite element software (ANSYS) were used to simulate the interfacial debonding between the inclusions and matrix, and the interface crack initiation life was calculated. Through finite element modeling, the stress field evolution during the interface debonding was traced by simulation. Finally, the effect of the position and shape size of inclusions on interface debonding was explored.


Author(s):  
Can Gonenli ◽  
Hasan Ozturk ◽  
Oguzhan Das

In this study, the effect of crack on free vibration of a large deflected cantilever plate, which forms the case of a pre-stressed curved plate, is investigated. A distributed load is applied at the free edge of a thin cantilever plate. Then, the loading edge of the deflected plate is fixed to obtain a pre-stressed curved plate. The large deflection equation provides the non - linear deflection curve of the large deflected flexible plate. The thin curved plate is modeled by using the finite element method with a four-node quadrilateral element. Three different aspect ratios are used to examine the effect of crack. The effect of crack and its location on the natural frequency parameter is given in tables and graphs. Also, the natural frequency parameters of the present model are compared with the finite element software results to verify the reliability and validity of the present model. This study shows that the different mode shapes are occurred due to the change of load parameter, and these different mode shapes cause a change in the effect of crack.


Author(s):  
Sheng Yu-ming ◽  
Li Chao ◽  
Xia Ming-yao ◽  
Zou Jin-feng

Abstract In this study, elastoplastic model for the surrounding rock of axisymmetric circular tunnel is investigated under three-dimensional (3D) principal stress states. Novel numerical solutions for strain-softening surrounding rock were first proposed based on the modified 3D Hoek–Brown criterion and the associated flow rule. Under a 3D axisymmetric coordinate system, the distributions for stresses and displacement can be effectively determined on the basis of the redeveloped stress increment approach. The modified 3D Hoek–Brown strength criterion is also embedded into finite element software to characterize the yielding state of surrounding rock based on the modified yield surface and stress renewal algorithm. The Euler implicit constitutive integral algorithm and the consistent tangent stiffness matrix are reconstructed in terms of the 3D Hoek–Brown strength criterion. Therefore, the numerical solutions and finite element method (FEM) models for the deep buried tunnel under 3D principal stress condition are presented, so that the stability analysis of surrounding rock can be conducted in a direct and convenient way. The reliability of the proposed solutions was verified by comparison of the principal stresses obtained by the developed numerical approach and FEM model. From a practical point of view, the proposed approach can also be applied for the determination of ground response curve of the tunnel, which shows a satisfying accuracy compared with the measuring data.


2012 ◽  
Vol 487 ◽  
pp. 855-859
Author(s):  
Shi Lun Feng ◽  
Yu Ming Zhou ◽  
Pu Lin Li ◽  
Jun Li ◽  
Zhi Yong Li ◽  
...  

Abaqus finite element software can implement three-dimensional excavation design calculation, so authors used Python of Abaqus core language made the 3D design of foundation pit supporting program come ture and also did intensive study of mesh optimization during the process. Authors also did intensive comparison and analysis about grid division of the complex geometry foundation pit, through a regularization partion about a variety of special-shaped pit, we made the automatic division about the structural grid of all kinds of shapes foundation pit successful. On this basis, we achieved better calculation effects of the model. The article will introduce problems about optimization of grid in procedure.


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