Papers by Keyword: ERA

Abstract: There are some extreme conditions in the process of metallic jet penetrating the explosive reaction armor (ERA), such as high instantaneity, large deformation, et al. Based on the smoothed particle hydrodynamics (SPH) method, the generalized density approximate formula is proposed and the Held criterion is introduced. Then the numerical SPH model of metallic jet penetrating the explosive reaction armor is built to study its protection mechanics. The calculation result meets well with the theoretical value. The influences of some parameters, such as thickness of plate and attacking angle, on the protecting effect of explosive reaction armor are analyzed, aiming at providing references for the related engineering application.

Abstract: A ship is a large and multifunctional marine structure operating on the sea. In practice, the environmental noise on a ship has many complicated components and they influence the vibration of the ship structure. Besides the stochastic excitations such as waves and winds, there are also propeller- and host-induced harmonic excitations. In this paper, NExT/ERA algorithm program and a ship model have been made to realize the modal parameters identification of ship structure in the presence of both white noise and harmonic excitations. Moreover, whether the signal filtering technology has a great effect on the results of modal analysis is discussed. In order to study and analyze the influence of the harmonic excitations, experiments under different signal-to-noise ratio (SNR) conditions have been carried out. This has a guiding significance to the engineering practice.

Abstract: Structural health monitoring (SHM) is an emerging field in civil engineering, offering the potential for continuous and periodic assessment of the safety and integrity of civil infrastructure. In this paper, a distributed computing strategy for modal identification of structure is proposed, which is suitable for the problem of solving large volume of data set in structural health monitoring. Numerical example of distribute computing the modal properties of truss illustrates the distributed out-put only modal identification algorithm based on NExT / ERA techniques and EFDD. This strategy can also be applied to other complicated structure to determine modal parameters.