frame device
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2022 ◽  
Vol 12 (2) ◽  
pp. 722
Author(s):  
Nedim Pervan ◽  
Elmedin Mešić ◽  
Adis J. Muminović ◽  
Muamer Delić ◽  
Enis Muratović ◽  
...  

This paper describes comparative analysis of the biomechanical performances conducted on the external fixation devices whose frames are made out of two different material (stainless steel and composite material). Biomechanical properties were determined with experimental and FEM (finite element method) models which are used to study the movement of the fracture crack, establish stiffness of the design solutions and monitor generated stresses on the zones of interest. Geometric modeling of two fixation devices configurations B50 and C50 is used as a basis for structural analysis under the impact of axial load. Structural analysis results are confirmed with an experimental setup. Analyzed deflection values in the load and fracture zones are used to define the exact values of the stiffness for the construction design and fracture, respectively. The carbon frame device configuration has 28% lower construction stiffness than the one with the steel frame (for B50 configuration), i.e., 9% (for C50 configuration). In addition, fracture stiffness values for the composite frame application are approximately 23% lower (B50 configuration), i.e., 13% lower (C50 configuration), compared to steel frame. The carbon frame device has about 33% lower stresses at the critical zones compared to the steel frame at the control zone MM+ and, similarly, 35% lower stresses at the control zone MM-. With an exhausting analysis of the biomechanical properties of the fixation devices, it can be concluded that steel frame fixation device is superior, meaning it has better biomechanical characteristics compared to carbon frame fixation device, regarding obtained data for stresses and stiffnesses of the frame construction and fracture. Considering stresses at the critical zones of the fixation device construction, the carbon frame device has better biomechanical performances compared to steel frame devices.


2020 ◽  
Author(s):  
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2018 ◽  
Vol 56 (5) ◽  
pp. 670-673
Author(s):  
Syed Altaf Hussain ◽  
Charanya Vijayakumar

Background: Maxillary advancement with a rigid external distractor (RED) II is a commonly performed procedure for correcting midface hypoplasia. While there are various methods of anchoring the osteotomized maxillary segment to the halo device, the looped transpyriform wire is the simplest and most cost-effective. However, a common complication with this is the cutting through of the stainless steel traction wire across the pyriform buttress during distraction. The patient with cleft undergoing midface distraction is particularly vulnerable since the force needed for distraction is higher due to scarring from previous operations. Innovation and Design: A single-hole titanium plate is introduced as an interface between the bone of the pyriform buttress and the looped stainless steel traction wire attached to the external frame device. Evaluation: Twenty-four patients with cleft who underwent midface advancement using the external frame distractor before the introduction of the innovation were compared with 26 patients who underwent the same procedure after its introduction. The former group had 12.5% complication in the form of cut through of the traction wire, while the latter group had only 3.8% complication rate. Conclusion: Introduction of the titanium eyelet as an interface between the traction wire and the bone is a simple technical addition for a more reliable distraction using the RED II device in patients with cleft even in the presence of extensive scarring.


1977 ◽  
Vol 14 (2) ◽  
pp. 206-213 ◽  
Author(s):  
R. Perla

From a study of 205 slab avalanches it is concluded that failure initiates where the slope is 25° or steeper, that slab failure stress is in the range 102–104 N/m2, and that the slab failure plane is most commonly at a temperature of −5 °C or warmer.The in situ measurement of shear strength is still an unresolved problem. A statistical analysis of a shear-frame device shows that the device is sensitive to the rate of pull and to the frame area. The larger the frame area, the smaller the measured shear strength. Approximately 10 measurements are required to sample a mean shear strength of a slab failure plane to within 15% accuracy at 90% confidence.


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