On determination of the critical external pressure for shells of rotation with dynamic loading

1996 ◽  
Vol 32 (4) ◽  
pp. 286-292
Author(s):  
I. Ya. Amiro ◽  
N. Ya. Prokopenko
2020 ◽  
Vol 835 ◽  
pp. 229-242
Author(s):  
Oboso P. Bernard ◽  
Nagih M. Shaalan ◽  
Mohab Hossam ◽  
Mohsen A. Hassan

Accurate determination of piezoelectric properties such as piezoelectric charge coefficients (d33) is an essential step in the design process of sensors and actuators using piezoelectric effect. In this study, a cost-effective and accurate method based on dynamic loading technique was proposed to determine the piezoelectric charge coefficient d33. Finite element analysis (FEA) model was developed in order to estimate d33 and validate the obtained values with experimental results. The experiment was conducted on a piezoelectric disc with a known d33 value. The effect of measuring boundary conditions, substrate material properties and specimen geometry on measured d33 value were conducted. The experimental results reveal that the determined d33 coefficient by this technique is accurate as it falls within the manufactures tolerance specifications of PZT-5A piezoelectric film d33. Further, obtained simulation results on fibre reinforced and particle reinforced piezoelectric composite were found to be similar to those that have been obtained using more advanced techniques. FE-results showed that the measured d33 coefficients depend on measuring boundary condition, piezoelectric film thickness, and substrate material properties. This method was proved to be suitable for determination of d33 coefficient effectively for piezoelectric samples of any arbitrary geometry without compromising on the accuracy of measured d33.


2019 ◽  
Vol 2 ◽  
pp. 61-70
Author(s):  
Oleksij Fomin ◽  
Alyona Lovska ◽  
Oleksandr Gorobchenko ◽  
Serhii Turpak ◽  
Iryna Kyrychenko ◽  
...  

An increase in the volume of bulk cargo transportation through international transport corridors necessitates the commissioning of tank containers. Intermodalization of a tank container predetermines its load in various operating conditions depending on the type of vehicle on which it is carried: aviation, sea, air or rail. The analysis of the operating conditions of tank containers, as well as the regulatory documents governing their workload, led to the conclusion that the most dynamic loads acting on the supporting structures during transportation by rail. Namely, during the maneuvering collision of a wagon-platform, on which there are tank containers. In this case, it is stipulated that for a loaded tank container, the dynamic load is assumed to be 4g, and for an empty (for the purpose of checking the reinforcement) – 5g. It is important to note that when the tank container is underfilled with bulk cargo and taking into account movements of fittings relative to fittings, the maximum value of dynamic load can reach significantly larger values. Therefore, in order to ensure the strength of tank containers, an improvement of their structures has been proposed by introducing elastic-viscous bonds into the fittings. To determine the dynamic loading of the tank container, taking into account the improvement measures, mathematical models have been compiled, taking into account the presence of elastic, viscous and elastic-viscous bonds between the fittings, stops and fittings. It is established that the elastic bond does not fully compensate for the dynamic loads acting on the tank container. The results of mathematical modeling of dynamic loading, taking into account the presence of viscous and elastic-viscous coupling in the fittings, made it possible to conclude that the maximum accelerations per tank container do not exceed the normalized values. The determination of the dynamic loading of the tank container is also carried out by computer simulation using the finite element method. The calculation takes place in the software package CosmosWorks. The maximum values of accelerations are obtained, as well as their distribution fields relative to the supporting structure of the tank container. The developed models are verified by the Fisher criterion. The research will contribute to the creation of tank containers with improved technical, operational, as well as environmental characteristics and an increase in the efficiency of the liquid cargo transportation process through international transport corridors.


2013 ◽  
Vol 842 ◽  
pp. 494-499 ◽  
Author(s):  
Evgenii V. Murashkin ◽  
Marina V. Polonik

We propose a mathematical model of large elastocreep deformations. As part of the constructed mathematical model the problem of deformation of the material in the vicinity of microdefect was solved. Integro-differential dependence of external pressure from irreversible deformations and displacements was obtained. The laws of loading material from vector displacements were calculated. We have shown that the monotonous laws of deformation can lead to non-monotonous stress changes.


2010 ◽  
Vol 49 (2) ◽  
pp. 192-200 ◽  
Author(s):  
G.H. Majzoobi ◽  
F. Freshteh-Saniee ◽  
S. Faraj Zadeh Khosroshahi ◽  
H. Beik Mohammadloo
Keyword(s):  

2018 ◽  
Vol 188 ◽  
pp. 04019 ◽  
Author(s):  
Antonios D. Tsolakis ◽  
Konstantinos I. Giannakopoulos ◽  
Andreas S. Gkertsos

Gears are the main machine element in vehicle power transmission trains. In commercial vehicles, power transmission trains design complexity consists of the determination of the loading parameters which depends upon the working environment of the performance vehicle. In the present work a gear failure under dynamic loading is investigated. The failed gear is part of a 2 speed gearbox of a Rotax DD2 2-stroke Open- Wheel performance vehicle (go-cart type). The gearbox was in racing conditions when failure occurred. The vehicle was speeding in 2nd Gear at wide open throttle when instantaneously the driver by fault downshifted to 1st gear. The result was for the first gears break a whole piece and eventually the system to go out of operation. Chemical composition of the examined metallic components was determined via EDAX chemical analysis.


1998 ◽  
Vol 41 (1) ◽  
pp. 156-162
Author(s):  
Koji SHIMIZU ◽  
Masahiro SUETSUGU ◽  
Takeshi SENOO ◽  
Susumu TAKAHASHI

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