Ali Reza Zarei, Hadi Motamed Shariyati, Behnam Ghzanchayi,
Volume 8, Issue 2 (12-2013)
Abstract
Recently almost all of the analytical methods have been used for analyzing and detecting of explosives, because of their importance in demining and unexploded ordnances operations. Fluorescence technique is one of the analytical methods. The unique features of this method caused to lots of researches in the mentioned applications. In present study, the fluorophores such as pyrene, phenol red, malachite green, methylene blue and fluorescein as the fluorescent compounds and TNT, 2,4-DNT, 4-NT, TNB and NB as the nitro aromatic compounds were used to measure the fluorescence quenching (Stern–Volmer constant) using the Stern-Volmer relation. For example, quenching constants for the fluorophores pyrene, phenol red, malachite green, methylene blue and fluorescein versus TNT were calculated 33368 M-1, 14086 M-1, 4413 M-1, 2214 M-1, and 1757 M-1 respectively. According to the results the maximum amount of quenching constants were achieved for pyrene and phenol red as the sensitive fluorophore.
Seyedhossein Hosseini, Mohammad Shariyat, Rahmatollah Ghajar,
Volume 10, Issue 2 (11-2015)
Abstract
In the present paper, nonlinear dynamic analysis of low-velocity impact of rectangular composite plates reinforced by SMA strips is investigated. In this regard, effects of the instant phase changes and the local and istatantaneous non-uniform distribution of transformation of the austenite to martensite phases and vice versa is considered, for the first time, implementing a written user defined material subroutine code in the ABAQUS/EXPLICIT finite element analysis code. In contrast to the available models which have used the approximate plate theories, a 3D finite element simulation is utilized for extracting the impact responses based on the elasticity theory. Finally, effects of different parameters such as the in-plane preloads, eccentricity, and indenter energy on the impact responses of the hybrid composite plate are investigated. The simulation results indicate that the SMA can absorb a remarkable portion of the stored impact-induced strain energy due to the superelastic and hysteretic natures of the SMA material, which results in increasing impact strength of the composite plate and decreasing the damage caused due to the impact. Moreover, results show that in the cases of the eccentric impact and presence of the tensile preloads, the contact force increases due to the less movability of the impacted point of the plate a fact that may lead to higher damages.
