Dynamic Plastic Analysis of Impulsively Loaded Viscoplastic Rectangular Plates With Finite Deflections

1986 ◽  
Vol 53 (3) ◽  
pp. 667-674 ◽  
Author(s):  
David Hui ◽  
J. G. de Oliveira
Keyword(s):  
Pressure Pulse ◽  
Dynamic Pressure ◽  
Rectangular Plates ◽  
Finite Deflections ◽  
Equilibrium Equations ◽  
Dynamic Nature ◽  
Sensitive Material ◽  
Energy Balance Method ◽  
Runge Kutta Method ◽  
Plastic Analysis

An energy balance method for the dynamic plastic analysis of thin rectangular plates made of a strain-rate sensitive material, taking into account the influence of finite-deflections, is proposed. The particular case of a fully clamped plate under uniformly distributed dynamic pressure pulse or blast loading is studied in some detail. In addition to the nonaxisymmetric and dynamic nature of the problem, the analysis considers important nonlinearities in the strains, equilibrium equations, and constitutive equations. Nonlinear ordinary differential equations in various regimes of plate deflections and loading histories are derived and solved using a Runge–Kutta method. Comparisons are made with existing experimental data.

Large Deflections of Rectangular Plates

1971 ◽  
Vol 15 (02) ◽  
pp. 164-171
Author(s):  
Norman Jones ◽  
R. M. Walters
Keyword(s):  
Approximate Method ◽  
Rectangular Plate ◽  
Large Deflections ◽  
Rectangular Plates ◽  
Finite Deflections ◽  
Perfectly Plastic ◽  
Aspect Ratios ◽  
Plastic Analysis ◽  
Theoretical Procedure

An approximate rigid, perfectly plastic analysis which retains the influence of finite deflections is presented herein for a uniformly loaded, fully clamped rectangular plate. This theoretical procedure provides reasonable engineering estimates of the permanent deflections of rectangular plates according to the recent experiments of Hooke and Rawlings on plates with aspect ratios in the range 1/3 ≤ β ≤ 1. The approximate method also predicts values which agree fairly well with the tests of Young on long rectangular plates β = 1/3), and for large permanent deflections gives similar values to the analysis by Greenspon when β = 1.

Using phase field and third-order shear deformation theory to study the effect of cracks on free vibration of rectangular plates with varying thickness

2020 ◽  
Vol 71 (7) ◽  
pp. 853-867
Author(s):  
Phuc Pham Minh
Keyword(s):  
Free Vibration ◽  
Shear Deformation ◽  
Phase Field ◽  
Deformation Theory ◽  
Plate Thickness ◽  
Shear Deformation Theory ◽  
Rectangular Plates ◽  
Equilibrium Equations ◽  
Third Order ◽  
Free Vibration Frequency

The paper researches the free vibration of a rectangular plate with one or more cracks. The plate thickness varies along the x-axis with linear rules. Using Shi's third-order shear deformation theory and phase field theory to set up the equilibrium equations, which are solved by finite element methods. The frequency of free vibration plates is calculated and compared with the published articles, the agreement between the results is good. Then, the paper will examine the free vibration frequency of plate depending on the change of the plate thickness ratio, the length of cracks, the number of cracks, the location of cracks and different boundary conditions

scholarly journals Multi-satellite simultaneous observations of magnetopause and atmospheric losses of radiation belt electrons during an intense solar wind dynamic pressure pulse

2016 ◽  
Vol 34 (5) ◽  
pp. 493-509 ◽  
Author(s):  
Zheng Xiang ◽  
Binbin Ni ◽  
Chen Zhou ◽  
Zhengyang Zou ◽  
Xudong Gu ◽  
...  
Keyword(s):  
Solar Wind ◽  
Radiation Belt ◽  
Pressure Pulse ◽  
Electron Flux ◽  
Dynamic Pressure ◽  
Energetic Electron ◽  
Solar Wind Dynamic Pressure ◽  
Angle Scattering ◽  
Radiation Belt Electrons ◽  
Atmospheric Loss

<p><strong>Abstract.</strong> Radiation belt electron flux dropouts are a kind of drastic variation in the Earth's magnetosphere, understanding of which is of both scientific and societal importance. Using electron flux data from a group of 14 satellites, we report multi-satellite simultaneous observations of magnetopause and atmospheric losses of radiation belt electrons during an event of intense solar wind dynamic pressure pulse. When the pulse occurred, magnetopause and atmospheric loss could take effect concurrently contributing to the electron flux dropout. Losses through the magnetopause were observed to be efficient and significant at <i>L</i> ≳ 5, owing to the magnetopause intrusion into <i>L</i> ∼ 6 and outward radial diffusion associated with sharp negative gradient in electron phase space density. Losses to the atmosphere were directly identified from the precipitating electron flux observations, for which pitch angle scattering by plasma waves could be mainly responsible. While the convection and substorm injections strongly enhanced the energetic electron fluxes up to hundreds of keV, they could delay other than avoid the occurrence of electron flux dropout at these energies. It is demonstrated that the pulse-time radiation belt electron flux dropout depends strongly on the specific interplanetary and magnetospheric conditions and that losses through the magnetopause and to the atmosphere and enhancements of substorm injection play an essential role in combination, which should be incorporated as a whole into future simulations for comprehending the nature of radiation belt electron flux dropouts.</p>

Dusk side clockwise vortex generation and aurora intensity decrease after Solar Wind Dynamic Pressure Decrease

2021 ◽  
Author(s):  
Jinyan Zhao ◽  
Quanqi Shi ◽  
Anmin Tian ◽  
Ruilong Guo ◽  
Xiao-Chen Shen
Keyword(s):  
Solar Wind ◽  
Pressure Pulse ◽  
Dynamic Pressure ◽  
Simulation Method ◽  
Solar Wind Dynamic Pressure ◽  
Ionospheric Currents ◽  
The Earth ◽  
Sudden Decrease ◽  
Pulse Arrival ◽  
Observation Results

&lt;p&gt;A solar wind dynamic pressure increase/decrease leads to the compression/expansion of the Earth&amp;#8217;s magnetosphere. In response, field-aligned currents, which are carried by precipitating or escaping plasma particles, are generated in the magnetosphere and in lead to variations in the auroral intensity. In this study, we investigate magnetospheric and ionospheric responses (including magnetospheric plasma vortex, ionospheric currents and aurorae) to a sudden decrease in solar wind dynamic pressure (SW P&lt;sub&gt;dyn&lt;/sub&gt;), which is critical for further understanding of the solar wind-magnetosphere-ionosphere coupling. We focused on a SW P&lt;sub&gt;dyn&lt;/sub&gt; decrease event that monitored by OMNI. A counter-clockwise plasma vortex was generated in the dusk side magnetosphere uncovered by using MHD simulation method and a clockwise equivalent ionospheric currents (EIC) vortex was generated in the dusk side ionosphere within about ten minutes after the pressure pulse arrival. Simultaneously, the observation results of Spherical Elementary Currents (SECs) showed that the EIC vortex region is dominated by downward field-aligned currents and the ground-based All-Sky Imager (ASI) observations in the vicinity of this EIC vortex showed that the aurorae diminished. These observations are consistent with the scenario proposed by Shi et al. (2014) that flow vortices in the magnetosphere generated by SW P&lt;sub&gt;dyn&lt;/sub&gt; sudden decrease carry downward field-aligned currents into the dusk side ionosphere, generating ionospheric current vortex and thereby modulating auroral activity on the dusk side.&lt;/p&gt;

Large-amplitude vibration of imperfect angle-ply laminated rectangular plates for various materials

2015 ◽  
Vol 12 (4) ◽  
pp. 313-318
Author(s):  
He Huang ◽  
David Hui
Keyword(s):  
Large Amplitude ◽  
Fiber Strength ◽  
Composite Plates ◽  
Rectangular Plates ◽  
Modulus Ratio ◽  
Backbone Curve ◽  
Fiber Volume ◽  
Runge Kutta Method ◽  
Amplitude Vibration ◽  
Large Amplitude Vibration

This paper deals with the solution of modified-Duffing ordinary differential equation for large-amplitude vibration of imperfect angle-ply rectangular composite plates. The boundary condition is simply supported and in-plane movable. The initial condition for the vibration is an initial vibration amplitude. This vibration problem is solved numerically by Runge-Kutta method. The effect of plate imperfection is studied and proved that a typical backbone curve will show up in case of a relatively large imperfection. Three different composite materials are then chosen to reveal the influence of young’s modulus ratio. Four fiber volumes are assumed to study its effect on the vibration mode. It turns out that either increasing the fiber strength or increasing the fiber volume in a composite will lead to an increase of its overall strength. And this will further trigger the plate vibration to behave more nonlinearly.

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