Stress in Flat Plates

Keyword(s):  
2014 ◽  
Vol 47 (02) ◽  
pp. 221-237 ◽  
Author(s):  
Hamdy Aboutaleb

ABSTRACT Background: Today, tubularized incised plate (TIP) urethroplasty is the most commonly performed operation for distal and mid-penile hypospadias. Reports from different centers worldwide confirm its nearly universal applicability and low complications rate. Aim: Evaluation of the urethral plate characters and its effect on the outcome of TIP urethroplasty. Materials and Methods: Between 2010 and 2013, 100 children with primary distal penile hypospadias underwent TIP urethroplasty. Urethral plates were categorized as flat, cleft, and deeply grooved. Postoperatively, patients were followed-up for evaluation of meatal stenosis, fistula formation, and glandular dehiscence at 1 st , 3 rd and 6 th months. Patients were followed-up for urethral calibration by urethral sound 8 Fr at 3 rd and 6 months follow-up. Data were statistically analysed using Epi info program to correlate between the width, plate shape, and complications. Results: Mean age at surgery was 4.3 years. Patients were followed-up for an average period of 6.4 months. Pre-operative location of the meatus was reported as coronal in 46, subcoronal in 50 and anterior penile in 4 cases. Urethral plate characters were flat in 26 cases, cleft in 52, and deeply grooved in 22. Urethral plate width was >8 mm in 74 cases and <8 mm in 26. Patients with urethral plate <8 mm had a statistically significant higher fistula rate (P = 0.004) and failed 8 Fr calibrations in 26.9% (P = 0.01) compared with the patients with urethral plate >8 mm. In addition, we also founds higher fistula rate and failed 8 Fr calibrations in flat urethral plate. Conclusions: An adequate urethral plate width (>8 mm) is essential for successful TIP repair. Lower success rates with flat plates may need buccal mucosal augmentation to improve the results.


2021 ◽  
Vol 11 (6) ◽  
pp. 2736
Author(s):  
Min Sook Kim ◽  
Young Hak Lee

In this study, the structural behavior of reinforced concrete flat plates shear reinforced with vertical grids made of a glass fiber reinforced polymer (GFRP) was experimentally evaluated. To examine the shear strength, experiments were performed on nine concrete slabs with different amounts and spacings of shear reinforcement. The test results indicated that the shear strength increased as the amount of shear reinforcement increased and as the spacing of the shear reinforcement decreased. The GFRP shear reinforcement changed the cracks and failure mode of the specimens from a brittle punching to flexure one. In addition, the experimental results are compared with a shear strength equation provided by different concrete design codes. This comparison demonstrates that all of the equations underestimate the shear strength of reinforced concrete flat plates shear reinforced with GFRP vertical grids. The shear strength of the equation by BS 8110 is able to calculate the punching shear strength reasonably for a concrete flat plate shear reinforced with GFRP vertical grids.


Acoustics ◽  
2019 ◽  
Vol 1 (1) ◽  
pp. 92-116 ◽  
Author(s):  
Stéphane Moreau

In future Ultra-High By-Pass Ratio turboengines, the turbomachinery noise (fan and turbine stages mainly) is expected to increase significantly. A review of analytical models and numerical methods to yield both tonal and broadband contributions of such noise sources is presented. The former rely on hybrid methods coupling gust response over very thin flat plates of finite chord length, either isolated or in cascade, and acoustic analogies in free-field and in a duct. The latter yields tonal noise with unsteady Reynolds-Averaged Navier–Stokes (u-RANS) simulations, and broadband noise with Large Eddy Simulations (LES). The analytical models are shown to provide good and fast first sound estimates at pre-design stages, and to easily separate the different noise sources. The u-RANS simulations are now able to give accurate estimates of tonal noise of the most complex asymmetric, heterogeneous fan-Outlet Guiding Vane (OGV) configurations. Wall-modeled LES on rescaled stage configurations have now been achieved on all components: a low-pressure compressor stage, a transonic high-pressure turbine stage and a fan-OGV configuration with good overall sound power level predictions for the latter. In this case, hybrid Lattice–Boltzmann/very large-eddy simulations also appear to be an excellent alternative to yield both contributions accurately at once.


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