Dynamic Response of a Cylindrical Shell Panel to Explosive Loading

1991 ◽  
Vol 113 (3) ◽  
pp. 273-278 ◽  
Author(s):  
D. Redekop ◽  
P. Azar
Keyword(s):  
Cylindrical Shell ◽  
Dynamic Response ◽  
Numerical Solutions ◽  
Free Field ◽  
Nonlinear Behavior ◽  
Explosive Loading ◽  
Shell Panel ◽  
Linear And Nonlinear ◽  
Nonlinear Geometric ◽  
Steel Cylindrical Shell

The dynamic response of steel cylindrical shell panels subjected to external free-field air-blast loading is investigated. The cases of rectangular and square panels having hinged and immovable boundary conditions are considered. Approximate theoretical solutions are presented for linear and nonlinear geometric behavior. Numerical solutions are given for linear, nonlinear geometric and general nonlinear behavior. Results from the theoretical and numerical solutions are compared for several panel rise cases, and conclusions are drawn.

Research on Dynamic Response of Q235 Steel Cylindrical Shell Subjected to Lateral Explosion Loading

2013 ◽  
Vol 631-632 ◽  
pp. 864-869
Author(s):  
Fu Yin Gao ◽  
Yuan Long ◽  
Chong Ji ◽  
Chang Xiao Zhang
Keyword(s):  
Cylindrical Shell ◽  
Dynamic Response ◽  
Nonlinear Dynamic ◽  
Computer Code ◽  
Nonlinear Dynamic Response ◽  
Q235 Steel ◽  
Explosion Loading ◽  
Experimental Researches ◽  
Oil Gas ◽  
Steel Cylindrical Shell

Experimental researches were presented on dynamic characteristics of Q235 steel cylindrical shell impacted-explosive laterally by 75g cylindrical TNT dynamite at the center．The dynamic response was obtained under different distances with different setting ways of explosive sources．By means of an explicit nonlinear dynamic finite element computer code LS-DYNA，the nonlinear dynamic response process of cylindrical shell subjected to laterally explosion loading were numerically simulated with ALE coupling method. The numerical simulation results were in good agreement with experimental data. The results provided important reference for the blast-resistant properties analysis and safety assessment of oil-gas pipes safety.

Chaotic Oscillations of a Shallow Cylindrical Shell-Panel With a Concentrated Elastic-Support

2000 ◽  
Author(s):  
Takao Yamaguchi ◽  
Ken-ichi Nagai
Keyword(s):  
Cylindrical Shell ◽  
Numerical Solutions ◽  
Harmonic Balance Method ◽  
Type Equation ◽  
Inertia Force ◽  
Chaotic Oscillations ◽  
Shallow Cylindrical Shell ◽  
Chaotic Response ◽  
Modes Of Vibration ◽  
Shell Panel

Abstract This paper presents numerical solutions on chaotic oscillations of a shallow cylindrical shell-panel excited by a periodic acceleration. The shell with rectangular boundary is simply supported along all edges, and the center of the shell is supported by an elastic spring. The Donnell-Mushtari-Vlasov type equation is used with the modification of an inertia force. The governing equation is reduced to a nonlinear differential equation of a multi-degree-of-freedom system by the Bubnov-Galerkin procedure. To estimate regions of the chaotic response, periodic solutions of steady state response are first calculated by the harmonic balance method. Next, time evolutions of the chaotic motion are obtained numerically by the Runge-Kutta-Gill method. The chaotic response accompanied with a dynamic snap-through is identified both by means of Lyapunov exponents and Poincaré projections. For the shell with a spring, the Lyapunov dimension is smaller than for the case without the spring. Multiple modes of vibration contributes to the generation of chaos, in paticular, the higher modes of vibration are significant.

scholarly journals A Pseudospectral Algorithm for Solving Multipantograph Delay Systems on a Semi-Infinite Interval Using Legendre Rational Functions

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
E. H. Doha ◽  
D. Baleanu ◽  
A. H. Bhrawy ◽  
R. M. Hafez
Keyword(s):  
Numerical Solutions ◽  
Rational Functions ◽  
Absolute Error ◽  
Delay Systems ◽  
Infinite Interval ◽  
Algebraic Equations ◽  
Collocation Points ◽  
Nonlinear Algebraic Equations ◽  
Linear And Nonlinear ◽  
Pseudospectral Scheme

A new Legendre rational pseudospectral scheme is proposed and developed for solving numerically systems of linear and nonlinear multipantograph equations on a semi-infinite interval. A Legendre rational collocation method based on Legendre rational-Gauss quadrature points is utilized to reduce the solution of such systems to systems of linear and nonlinear algebraic equations. In addition, accurate approximations are achieved by selecting few Legendre rational-Gauss collocation points. The numerical results obtained by this method have been compared with various exact solutions in order to demonstrate the accuracy and efficiency of the proposed method. Indeed, for relatively limited nodes used, the absolute error in our numerical solutions is sufficiently small.

Nonlinear behavior of Helmholtz resonator with a compliant wall for low frequency, broadband noise control

2021 ◽  
pp. 1-29
Author(s):  
Maya Pishvar ◽  
Ryan L Harne
Keyword(s):  
Dynamic Response ◽  
Low Frequency ◽  
Nonlinear Behavior ◽  
Helmholtz Resonator ◽  
Broadband Noise ◽  
Sound Attenuation ◽  
Wall Material ◽  
Modeling Framework ◽  
Compliant Wall ◽  
Broadband Sound

Abstract Low frequency sound attenuation is often pursued using Helmholtz resonators (HRs). The introduction of a compliant wall around the acoustic cavity results in a two-degree-of-freedom (2DOF) system capable of more broadband sound absorption. In this study, we report the amplitude-dependent dynamic response of a compliant walled HR and investigate the effectiveness of wall compliance to improve the absorption of sound in linear and nonlinear regimes. The acoustic-structure interactions between the conventional Helmholtz resonator and the compliant wall result in non-intuitive responses when acted on by nonlinear amplitudes of excitation pressure. This paper formulates and studies a reduced order model to characterize the nonlinear dynamic response of the 2DOF HR with a compliant wall compared to that of a conventional rigid HR. Validated by experimental evidence, the modeling framework facilitates an investigation of strategies to achieve broadband sound attenuation, including by selection of wall material, wall thickness, geometry of the HR, and other parameters readily tuned by system design. The results open up new avenues for the development of efficient acoustic resonators exploiting the deflection of a compliant wall for suppression of extreme noise amplitudes.

Sensitivity analysis of geotechnical site conditions effect on the seismic response of a saturated inhomogeneous poroviscoelastic soil profile

2018 ◽  
Vol 15 (6) ◽  
pp. 661-677 ◽  
Author(s):  
Toufiq Ouzandja ◽  
Mohamed Hadid
Keyword(s):  
Soil Properties ◽  
Seismic Response ◽  
Pore Water ◽  
Soil Profile ◽  
Water Saturation ◽  
Free Field ◽  
Response Spectra ◽  
Response Analysis ◽  
Content Type ◽  
Linear And Nonlinear

Purpose This paper aims to present the investigation of the linear and nonlinear seismic site response of a saturated inhomogeneous poroviscoelastic soil profile for different soil properties, such as pore-water saturation, non-cohesive fines content FC, permeability k, porosity n and coefficient of uniformity Cu. Design/methodology/approach The inhomogeneous soil profile is idealized as a multi-layered saturated poroviscoelastic medium and is characterized by the Biot’s theory, with a shear modulus varying continuously with depth according to the Wichtmann’s model. Seismic response analysis has been evaluated through a computational model, which is based on the exact stiffness matrix method formulated in the frequency domain assuming that the incoming seismic waves consist of inclined P-SV waves. Findings Unlike the horizontal seismic response, the results indicate that the vertical one is strongly affected by the pore water saturation. Moreover, in the case of fully saturated soil profile, the same vertical response spectra are found for the two cases of soil behavior, linear and nonlinear. Originality/value This research is a detailed study of the geotechnical soil properties effect on the bi-directional seismic response of saturated inhomogeneous poroviscoelastic soil profile, which has not been treated before; the results are presented in terms of the peak acceleration ratio, as well as the free-field response spectra and the spectral ratio (V/H).

scholarly journals Nonlinear force-free modeling of magnetic fields in flare-productive active regions

2015 ◽  
Vol 11 (S320) ◽  
pp. 167-174
Author(s):  
M. S. Wheatland ◽  
S. A. Gilchrist
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Boundary Data ◽  
Numerical Solutions ◽  
Free Field ◽  
Active Regions ◽  
Coronal Magnetic Field ◽  
Nonlinear Force ◽  
The Magnetic Field ◽  
Force Free Field

AbstractWe review nonlinear force-free field (NLFFF) modeling of magnetic fields in active regions. The NLFFF model (in which the electric current density is parallel to the magnetic field) is often adopted to describe the coronal magnetic field, and numerical solutions to the model are constructed based on photospheric vector magnetogram boundary data. Comparative tests of NLFFF codes on sets of boundary data have revealed significant problems, in particular associated with the inconsistency of the model and the data. Nevertheless NLFFF modeling is often applied, in particular to flare-productive active regions. We examine the results, and discuss their reliability.

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