Saturated Impulse Research Articles

Locally Exponential Stability of Discrete-time Complex Networks with Impulsive Input Saturation

In this paper, the problem of exponential stabilization for a class of discrete-time complex network with saturated impulse input is investigated. Based on the inductive method, convex analysis, and auxiliary matrix, several Lyapunov-type stability criteria are derived for exponential stability of discrete-time complex network with impulsive input saturation. Two examples are also presented to illustrate the effectiveness and the feasibility of the obtained results.

Saturated impulse for fully clamped square plates under blast loading

Saturated impulse refers to the critical value, beyond which the deflection of a beam or plate under pulse loading will no longer increase with further applied load. The present paper investigates the saturated impulse of fully clamped square plates subjected to a blast loading that is assumed to be a uniformly distributed Linearly Rising Exponentially Decaying (LRED) pressure pulse. Considering both bending moment and membrane force, the transient dynamic plastic response is predicted by a rigid, perfectly plastic (R-PP) model characterized by travelling plastic hinge lines and time-dependent velocity field. The saturated duration, saturated impulse, saturated deflection, as well as the evolution of deformation mechanism are explored. By comparing three characteristic durations, i.e. the travelling duration of the plastic hinge lines, saturated duration and loading duration, the dynamic responses of a square plate are classified into three types such that a regime map on the loading parameters’ plane is constructed accordingly. The correlation is made between the results obtained from the elastic-plastic numerical simulation and the R-PP theoretical approximation. To facilitate engineering designs, a method of replacing the LRED pressure pulse by an equivalent rectangular pressure pulse is proposed to predict the maximum deflection of fully clamped square plates.

Saturated impulse for pulse-loaded rectangular plates with various boundary conditions

Saturated impulse refers to the critical value after which the deflection of the beam or plate under pulse loading will not increase with further applied load. This paper investigates this phenomenon for rectangular plates under rectangular pulse-loading with various symmetric boundary conditions, e.g. two opposite edges of the plate are fully clamped while the other two edges are simply supported or free. For rectangular plates with symmetric boundaries under rectangular pressure pulse, the saturated duration and saturated impulse are merely dictated by the deformation mechanism, not by the boundary conditions. Then the effects of the aspect ratio and the boundary condition on the saturation impulse for elastic-plastic plates are revealed through numerical simulation. Bilinear elastic-plastic rectangular plates, with fully clamped boundaries and simply supported boundaries, subjected to rectangular pulse-loading are taken as typical examples. Subsequently, the saturation phenomenon is summarized from square plates to rectangular plates. The correlation is made between the results obtained from elastic-plastic analysis and those predicted by the rigid-plastic approximation. Finally, based on numerical simulation, theoretically and practically meaningful empirical expressions on the saturation phenomenon are proposed to facilitate engineering designs.

The saturated impulse of fully clamped square plates subjected to linearly decaying pressure pulse

Saturated impulse refers to the critical value, beyond which the deflection of a beam or plate under pulse loading will no longer increase with further applied load. Previous studies have explored the saturated impulse for structures under rectangular pressure pulse loading. The present paper investigates the saturated impulse for fully clamped square plates subjected to linearly decaying pressure pulse, which is closer to the pulse produced by explosive loading. Both rigid-plastic model and elastic-plastic model are employed to study the saturated duration, saturated impulse, saturated deflection, etc. The results indicate that the saturated impulse exists if the decaying duration is greater than a certain value (i.e. the minimum decaying duration), and a saturation regime map is constructed accordingly. To facilitate engineering designs, an empirical expression for saturated duration is provided based on the elastic-plastic numerical results. In addition, a method is proposed to predict the deflection of fully clamped square plates, which replaces the linearly decaying pressure pulse with an equivalent rectangular pressure pulse. Inspired by Youngdahl's pioneering work, the proposed method has explicit physical meaning and wide range of application.

The Saturated Impulse for Fully Clamped Square Plates Subjected to Linear-Decay Pressure Pulse

Saturated impulse refers to the critical value beyond which the deflection of the beam or plate under pulse loading will no longer increase with further applied load. Previous effort has been made to study the saturate impulse for structures under rectangular pressure pulse loading. Through theoretical analysis, the present paper investigates the saturated impulse for fully clamped square plates subjected to linear-decay pressure pulse, which is closer to explosive loading pulse. The results indicate that the saturated impulse does exist if the decay duration is greater than a certain value (i.e. the minimum decay duration). The saturated impulse, saturated deflection and saturated duration all have nonlinearly relations with the dimensionless applied pressure, and grow with the increase of the decay duration.

A new approach for high density saturated impulse noise removal using decision-based coupled window median filter

A new decision-based algorithm has been proposed for the restoration of digital images which are highly contaminated by the saturated impulse noise (i.e., salt-and-pepper noise). The proposed denoising algorithm performs filtering operation only to the corrupted pixels in the image, keeping uncorrupted pixels intact. The present study has used a coupled window scheme for the removal of high density noise. It has used sliding window of increasing dimension, centered at any pixel and replaced the noisy pixels consecutively by the median value of the window. However, if the entire pixels in the window are noisy, then the dimension of sliding window is increased in order to obtain the noise-free pixels for median calculation. Consequently, this algorithm has been found to be able to remove the high density salt-and-pepper noise and also preserved the fine details of the four images, Lena, Elaine, Rhythm, and Sunny, used as test images in this study (The latter two real-life images have been acquired using Sony: Steady Shot DSC- S3000). Experimentally, it has been found that the proposed algorithm yields better peak signal-to-noise ratio, image enhancement factor, structural similarity index measure and image quality index, compared with the other state-of-art median-based filters viz. standard median filter, adaptive median filter, progressive switched median filter, modified decision-based algorithm and modified decision-based unsymmetric trimmed median filter.

Saturated impulse for pulse-loaded elastic-plastic square plates

This paper investigates the phenomenon of saturated impulse in elastic-plastic plates whilst a fully clamped square plate is taken as a typical example, and the correlation is made between the saturated impulse obtained from the elastic-plastic analysis and that predicted by the rigid-plastic approximation. The present analysis suggests that two saturated impulses can be defined for an elastic, perfectly plastic structure: one is for the maximum deformation and the other is for the permanent (final) deformation of the structure. In general, the former is smaller than the latter. For the clamped square plates calculated, these two saturated impulses in the high load range lie between the upper and the lower bounds of the saturated impulse obtained from a rigid, perfectly plastic analysis; and finally, a “saturated duration” for loading pulse (critical pulse length) is proposed.

Saturation impulses for dynamically loaded structures with finite-deflections

The concept of ''Saturation Impulse'' for rigid, perfectly plastic structures with finite-deflections subjected to dynamic loading was put forward by Zhao, Yu and Fang (1994a). This paper extends the concept of Saturation Impulse to the analysis of structures such as simply supported circular plates, simply supported and fully clamped square plates, and cylindrical shells subjected to rectangular pressure pulses in the medium load range. Both upper and lower bounds of nondimensional saturation impulses are presented.

Large dynamic plastic deflection of a simply supported beam subjected to rectangular pressure pulse

This paper concerns the dynamic behaviour of rigid, perfectly plastic simply supported beams with finite deflections by considering both bending moments and axial forces. In the case of rectangular pressure pulse loading, approximate rigid-plastic theoretical solutions are obtained for both medium load and high load; to this end a parabolic law between bending moment and axial force as yield condition is approximated by a circumscribing or an inscribing rectangle. The concept of Saturation Impulse is put forward for the dynamic response of rigid, perfectly plastic structures with finite deflections subjected to rectangular pressure pulse. The value of dimensionless saturation impulse for both simply supported and fully clamped beams are given.