Effect Of Plate Length Research Articles

Effect of Plate Length on Construct Stiffness and Strain in a Synthetic Short-Fragment Fracture Gap Model Stabilized with a 3.5-mm Locking Compression Plate.

To evaluate the effect of 3.5-mm locking compression plate (LCP) length on construct stiffness and plate and bone model strain in a synthetic, short-fragment, fracture-gap model. Six replicates of 6-hole, 8-hole, 10-hole, and 12-hole LCP constructs on a short-fragment, tubular Delrin fracture gap model underwent four-point compression and tension bending. Construct stiffness and surface strain, calculated using three-dimensional digital image correlation, were compared across plate length and region of interest (ROI) on the construct. The 12-hole plates (80% plate-bone ratio) had significantly higher construct stiffness than 6-hole, 8-hole, and 10-hole plates and significantly lower plate strain than 6-hole plates at all ROIs. Strain on the bone model was significantly lower in constructs with 10-hole and 12-hole plates than 6-hole plates under both compression and tension bending. Incremental increases in construct stiffness and incremental decreases in plate strain were only identified when comparing 6-hole, 8-hole, and 10-hole plates to 12-hole plates, and 6-hole to 12-hole plates, respectively. Strain on the bone model showed an incremental decrease when comparing 6-hole to 10-hole and 12-hole plates. A long plate offered biomechanical advantages of increased construct stiffness and reduced plate and bone model strain, over a short plate in this in vitro model.

Effect of plate length on drag reduction of square faced bluff body

This study investigates the impact of splitter plates on drag reduction in square-faced bodies using a water flow channel with three different splitter plate lengths: 2.5 cm, 1.8 cm, and 1.25 cm. The height and thickness were kept constant at 2.5 cm and 3 mm. Reynolds numbers ranging from 8977.5 to 3847.5 were tested. Results showed that increasing the Reynolds number increased the pressure hill height for both splitter plates forward as well backward. In the first case the forward splitter plate, shorter lengths resulted in reduced pressure hill heights. For the backward splitter plate, longer lengths led to larger pressure hill heights. The best drag reduction effect is got when the splitter plate length and the model length are of equal length. Overall, the effective drag reduction effect is shown by the backward splitter plate compared to the forward, the difference in value is almost 30%. These results are eminent for getting a perception of relation that exist between splitter plate length and drag reduction in square-faced bodies.

In vitro analysis and in vivo assessment of fracture complications associated with use of locking plate constructs for stabilization of caprine tibial segmental defects

PurposeLocking plate fixation of caprine tibial segmental defects is widely utilized for translational modeling of human osteopathology, and it is a useful research model in tissue engineering and orthopedic biomaterials research due to its inherent stability while maintaining unobstructed visualization of the gap defect and associated healing. However, research regarding surgical technique and long-term complications associated with this fixation method are lacking. The goal of this study was to assess the effects of surgeon-selected factors including locking plate length, plate positioning, and relative extent of tibial coverage on fixation failure, in the form of postoperative fracture.MethodsIn vitro, the effect of plate length was evaluated using single cycle compressive load to failure mechanical testing of locking plate fixations of caprine tibial gap defects. In vivo, effects of plate length, positioning, and relative tibial coverage were evaluated using data from a population of goats enrolled in ongoing orthopedic research which utilized locking plate fixation of 2 cm tibial diaphyseal segmental defects to evaluate bone healing over 3, 6, 9, and 12 months.ResultsIn vitro, no significant differences in maximum compressive load or total strain were noted between fixations using 14 cm locking plates and 18 cm locking plates. In vivo, both plate length and tibial coverage ratio were significantly associated with postoperative fixation failure. The incidence of any cortical fracture in goats stabilized with a 14 cm plate was 57%, as compared with 3% in goats stabilized with an 18 cm plate. Craniocaudal and mediolateral angular positioning variables were not significantly associated with fixation failure. Decreasing distance between the gap defect and the proximal screw of the distal bone segment was associated with increased incidence of fracture, suggesting an effect on proximodistal positioning on overall fixation stability.ConclusionsThis study emphasizes the differences between in vitro modeling and in vivo application of surgical fixation methods, and, based on the in vivo results, maximization of plate-to-tibia coverage is recommended when using locking plate fixation of the goat tibial segmental defect as a model in orthopedic research.

Effect of Plate Length on Subduction Kinematics and Slab Geometry: Insights From Buoyancy‐Driven Analog Subduction Models

AbstractSubduction style is controlled by a variety of physical parameters. Here we investigate the effect of subducting plate length on subduction style using laboratory experiments of time‐evolving buoyancy‐driven subduction in 3‐D space. The investigation includes two experimental sets, one with a lower (~740) and one with a higher (~1,680) subducting plate‐to‐mantle viscosity ratio (ηSP/ηM). Each set involves five models with a free‐trailing‐edge subducting plate and variable plate length (20–60 cm, scaling to 1,600–4,800 km), and one model with a fixed‐trailing‐edge subducting plate representing an infinitely long plate. Through determining the contact area between subducting plate and underlying mantle, plate length affects the resistance to trenchward motion of the subducting plate and thus controls the partitioning of the subduction velocity (vS) into the subducting plate velocity (vSP) and trench velocity (vT). This subduction partitioning thereby determines the subduction style by controlling the dip angle of the slab tip once it first touches the 660 km discontinuity. The low ηSP/ηM models display two subduction styles. Short plates (≤40 cm) induce a higher subduction partitioning ratio (vSP/vS), promoting trench advance and slab rollover geometries, whereas longer plates (≥50 cm) lead to a lower vSP/vS, producing continuous trench retreat and backward slab draping geometries. In contrast, the high ηSP/ηM models exclusively show trench retreat with draping geometries, as the high ηSP/ηM enables less slab bending before its tip touches the 660 km discontinuity. Our study indicates that future modeling work should consider the effects of plate length on the style and evolution of subduction.

Minimally invasive osteosynthesis of adult tibia fractures by means of rigid fixation with anatomic locked plates

Main principle of biological fixation by minimally invasive locked plate osteosynthesis (MILPO) in lower extremity long bone fractures is relative stability which is provided by using long plate with limited number of screws. Some biomechanical studies have been reported about this issue. However, clinical studies are still missing. The aims of this retrospective extended case series were to evaluate the clinical and radiological results of adult tibia fractures treated by MILPO and the effect of plate length and screw density on complication rates. Twenty tibia fractures in 19 patients (mean age 42.3 years) operated by MILPO were reviewed. According to the AO classification, diaphyseal and metaphyseal fractures without intraarticular extensions were simple and wedge-type fractures, whereas all intraarticular fractures were comminuted. Number of screws, cortices and empty screw holes proximal and distal to the fracture, plate-span ratio (plate length divided by overall fracture length), plate-screw density (number of inserted screws divided by number of plate holes), fixation failures, delayed or nonunion, malalignment and leg length discrepancy were documented. Mean follow-up was 16 (range 12–26) months. On average, 4 screws with 6 cortices were used both proximally and distally in all fractures. Only in diaphyseal fractures, one screw hole close to the fracture was omitted. Average plate-screw density and plate-span ratio were 0.68 and 4, respectively. Mean union time was 3 months. There were no cases of delayed or nonunion on the final follow-up. Plate bending was observed in one patient who had fair result. The remaining 18 (94.8 %) patients showed good and excellent results. Satisfactory results can be achieved despite low plate-span ratio and high plate-screw density in simple and wedge-type diaphyseal fractures of the tibia. Additionally, plate-screw density can be higher at metaphysis in intraarticular fractures, in which essential point is a perfectly stable fixation that provides early motion.

椀形レーザフォーミングの収縮量に及ぼす板長と初期曲率半径の影響

椀形レーザフォーミングの収縮量に及ぼす板長と初期曲率半径の影響

Transverse Bending of Rectangular Plates with Single- or Double-Edge Cracks

The stress intensity factors of rectangular plates with single - or double - edge cracks under transverse bending are evaluated by the body-force doublet method. The stress field due to a pair of point moments (doublets) in a semi-infinite plate is used to solve these problems. According to the results, the effect of plate length on KI is less under transverse bending than under uniform tension in rectangular plates of the same form.

Transverse bending of rectangular plates with a single-edge crack or double-edge cracks.

The stress intensity factors of rectangular plates with a single-edge crack or double-edge cracks under transverse bending are evaluated by the body-force doublet method. The stress field due to a pair of point moments (doublet) in a semi-infinite plate is used to solve these problems. According to the results, the effect of plate length on K1 is less under transverse bending than under uniform tension, in rectangular plates of the same form.

平板の突合せ溶接進行中の拘束材・仮付け溶接に作用する引裂力について

This paper deals with the effect of welding conditions on separating forces produced in restraints like strong backs or tack welds during butt welding.The calculations have been carried out on variations of separating forces during welding under various conditions of heat input, plate length and restraint or tack weld pitch, using the finite element method explained previously. It is assumed that the rigidity of restraints and tack welds is infinite.The main conclusions obtained in the study are summarized as follows:The larger the effective molten pool length on the mechanical point of view (lM) is, the larger is the difference of separating forces between restraints and tack welds. The result depends on the type of restraint: in case of restraint like strong back, the restraint acts as a restraint after heat source passed through it, but in case of tack weld, the tack weld melts and cannot act as a restraint after heat source passed through it.The maximum separating force produced in an end restraint or an end tack weld ((Fy/h)emax) can be characterized as follows.(Fy/h)emax in the end tack weld is smaller than in the end restraint under the following conditions:lp=1200mm 416≤lM≤1663 (mm) 6000≤q/υh≤24000 (cal/cm2)where lp is a restraint or tack weld pitch, lM is an effective molten pool length on the mechanical point of view and q/υh is heat input per unit thickness and unit weld length.(Fy/h)emax increases as the heat input (q/υh) increases under consta-nt lM and decreases as the effective molten pool length (lM) increases under constant q/υh.Effect of plate length (L) on (Fy/h)emax depends on the welding conditions (q/υh, lM) and plate length (L).A restraint pitch has larger effects on (Fy/h)emax than a tack weld pitch.These results can be applied to tow electrodes submerged arc welding under the conditions that distance between leading electrode and trailing electrode (lLT) is small compared to lM.