جستجوی مقالات مرتبط با کلیدواژه "triangular plate" در نشریات گروه "مکانیک"

An elaborate numerical study with a validated LS-DYNA® immersed boundary method fluid-solid interaction code is used to characterize the influence of pre-detonation pressure and time duration on plastic deformation of thin steel triangular plates subjected to gaseous detonation. Other objectives of this numerical simulation such as estimation of deflection and stress contour of material at high strain rate are derived based on a strain-rate dependent Johnson-Cook material model. Simulation relies on the modeling of detonation by chemical reaction kinetic and its propagation by Conservative Element Solution Element (CESE) solver. Immersed boundary method is used to simulate the interface motion between the detonating gas and the deforming plate to facilitate the assessment of fluid pressure distribution on the plate surface. The numerical tool relates the pressure distribution and gaseous detonation parameters to the plate macroscopic deformation by employing multi-species reactive Euler’s equations for the gas and Lagrangian equation for plate. Numerical method as an appropriate tool in the evaluation of the deflection profile of the triangular plate shows that deflection decreases by the smaller size of the exposed area of the plate.

The understanding some characteristics of the influence of an interior gaseous detonation within a confined space on plate deformation is valuable for production purposes. In this study, the center of mass displacement of thin steel triangular plates subjected to acetylene and oxygen mixture detonation loading is investigated theoretically. Empirical modeling is presented to find the relationships between effective parameters in the gas detonation forming process such as mechanical properties of plate, impulse of applied load, plate geometry and strain-rate sensitivity effect and center of mass displacement of the triangular plate. Some important parameters, including plate thickness and yield strength, different triangular clamp sizes were studied to show the exposed area effect on the center of mass displacement. The results from non-dimensional analysis demonstrated a good agreement compared with experimental data and showed that the center of mass displacement decreases greatly with involving thicker plate. Non-dimensional analysis as a profitable tool in the evaluation of the center of mass displacement demonstrates that midpoint deflection was decreased by the smaller size of the exposed area of the plate.

The response of thin steel plates subjected to gaseous mixture detonation loading is investigated analytically to determine the possible permanent deformation of center of steel plates clamped in triangular clamping frames. Deformation profiles of plates with different thicknesses under various pre-detonation pressures are investigated which shows large plastic deformations with the maximum deformation happening at the center of mass of the triangular plate. By adopting an energy method approach developed earlier for circular plates, and incorporating a newly developed condition, upper bounds are obtained for the center of mass deformation of the triangular plate. Besides, some important parameters, including plate thickness and yield strength were studied to show the exposed area effect on the deformation profile. The results from analytical studies demonstrate a good agreement compared with experiments and show that the center of mass displacement decreases greatly with involving thicker plate and strain rate influence. Energy method as a useful tool reveals that that midpoint deflection was decreased by the smaller size of the exposed area of the plate.

The aim of this study is investigating the center of mass deflection to thickness ratio of triangular plates using the GMDH-type neural networks and comparing it with results of laboratory tests performed on a narrow triangular plate using water-hammer apparatus. Also, the study focuses on the overall deformation, strain and impact transmission. Dimensionless input variables are used to investigate the center of mass deflection of triangular plate with changing variables. A simpler polynomial expression is derived using GMDH-type neural network and dimensionless number. The vector of coefficients of quadratic sub-expressions involved in GMDH-type networks is obtained by Singular Value Decomposition (SVD) method. SVD can improve the proficiency of GMDH-type networks to model the intricate process of deformation of triangular plates. Obtaining results by applying a GMDH model and comparing them with actual data indicates good agreement between model output and experimental data. The advantages of this approach are in the simplification of computation and convenient application to parametric study for impact behavior.

In this paper, an experimental and numerical study on the inelastic deformation of fully clamped circular, rectangular and triangular plates under the low-velocity hydrodynamic loads has been conducted using the drop-hammer machine. In the experimental section, steel and aluminum plates with three different geometries of circular, rectangular and triangular in different thicknesses of 1 to 3 mm were examined. Experiments were carried out under different levels of energy by changing the height and mass of the hammer and the maximum permanent transverse deflection was recorded as the test output. For better understanding the effect of effective parameters in these experiments, the Design-Expert software was used. In this software, the simultaneous effect of these parameters was investigated using the response surface method. The plate thickness, the standoff distance of the hammer and the mass of hammer were considered as independent quantitative parameters, and the geometry of the plates along with the material of plates was considered as independent qualitative parameters. The obtained regression model has a confidence level of 95% for output prediction. Accordingly, the p-value for the model is less than 0.05, which means that the regression model is significant. The values of R2 and R2adj was 0.9803 and 0.97131, respectively. The results of the regression model have a good agreement with experimental results. In all experiments, the standoff distance of the hammer was the most effective parameter while the mass of the hammer had the least effect on the response. The optimum conditions for each plate were also determined.