Dynamic strength criteria for basalt fibre-reinforced coral aggregate concrete

2021 ◽  
pp. 100983
Author(s):  
Qiang Fu ◽  
Wenrui Xu ◽  
Jiaqi He ◽  
Li Su ◽  
Hao Song ◽  
...  
Author(s):  
Evgeny Yu. Marchukov ◽  
Igor Egorov ◽  
Grigorii Popov ◽  
Anton Salnikov ◽  
Evgenii Goriachkin ◽  
...  

The results of multicriteria multidisciplinary optimization of three-stage low-pressure turbine are described in the paper. The aim of the optimization is to improve turbine operation process by three criteria: turbine outlet flow angle, value of residual swirl at the turbine outlet, and turbine efficiency. Moreover, the requirements of static and dynamic strength must be fulfilled for rotor blades. Full reprofiling of all blade rows is carried out while solving optimization problem. Reprofiling includes a change in both shape of flat blade sections (profiles) and threedimensional shape of the blades. The study is carried out with 3D numerical models of turbines both gas-dynamic and strength. The gas-dynamic improvement of turbine operation is performed as the first step. Then, strength improvement is carried out for the best variants in order to provide satisfactory margins of static and dynamic strength. Mutual strength and gas-dynamic optimization is done as the next step. The final variant of turbine that meets best the gas-dynamic and strength criteria is found as the result of this optimization.


2021 ◽  
Vol 97 (5) ◽  
pp. 51-61
Author(s):  
T.A. ILIUSHCHENKO ◽  
◽  
N.V. FEDOROVA ◽  
◽  

Dynamic strength criteria and crack resistance criteria are given for a typical plane-stressed reinforced concrete element with prestressed reinforcement in one direction. The criteria are constructed by generalizing the theory of plasticity of concrete and reinforced concrete G.A. Geniev on the area of existence of tensile stresses: "tension- tension" and "compression- tension". In general terms, the crack resistance condition and strength condition of a prestressed reinforced concrete plane-stressed element are presented in the form of an ellipse in the coordinates of the main stresses. In this case, in contrast to the criteria of crack resistance of a flat unstressed element, the principal axes of the ellipse don’t pass through the origin. The results of a comparative analysis of the calculated and experimental data on crack resistance and strength for prestressed reinforced concrete in the support zone of the beam of a monolithic reinforced concrete frame tested for a given design load and a special dynamic effect are given.


2019 ◽  
Vol 171 ◽  
pp. 310-319 ◽  
Author(s):  
G.C. Ganzenmüller ◽  
D. Plappert ◽  
A. Trippel ◽  
S. Hiermaier

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 991 ◽  
Author(s):  
Jacek Karliński ◽  
Mariusz Ptak ◽  
Leszek Chybowski

The article suggests and supports a simulation-based methodology for determining whether the dynamic strength of tire inflation restraining devices for tire inflation meet quality requirements and ensure operator safety during a potential tire explosion. Dynamic strength tests using an NM-600 safety shield and NK-0728 safety cage during a 29.5 R25X tire explosion at a pressure of 10 bar were presented as an example application of this methodology. The shield was subjected to destructive tests involving the use of a 2200 kg impactor, dropping it so that the minimum kinetic energy reached 20 kJ at the time of impact. Analyzed devices were constructed of S355 steel in accordance with EN 10025. The Cowper–Symonds model of material for strain rate phenomena was used in the calculations. Simulations of a 20 kJ ring impact against the cage were performed. The equivalent stress distribution was determined, and displacement contour lines for the maximum dynamic deformation value and plastic deformation were calculated. The plastic displacement obtained in numerical tests was equal to the permanent deformation recorded in the experimental test. Further, the simulations showed that the examined cage met the assumed strength criteria. The conducted tests confirmed the usefulness of the proposed methodology for assessing the dynamic strength of safety cages and shields for tire inflation. The full-scale, physical cage testing is difficult to implement because it requires placing a ring impacting the cage wall. This is a major boundary for closed cages, as considered in this publication. Thus, simulation-based methods are becoming a principal tool for safety assessment of tire inflation restraining devices.


2021 ◽  
Vol 256 ◽  
pp. 113078 ◽  
Author(s):  
Zhe Xiong ◽  
Wei Wei ◽  
Feng Liu ◽  
Chuying Cui ◽  
Lijuan Li ◽  
...  

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