Engineer Atefe Abdoli, Engineer Amin Zamiri, Doctor Jamal Zamani, Doctor Ali Mozafari,
Volume 8, Issue 2 (12-2013)
Abstract
Due to the importance of determining the pelastic manner of thin wall shells against the explosive loading, up to the maximum process of deformation, examining the manner of this kind of structures is on the agenda.concidering repeated reaction of explosive shock wave from two ends and the walls of the structure, pressure distribution derived from explosion of explosive in closed shells, is too complicated. in this article with concidering the simpled pressure distribution profile, a mathematical model is presented for determining the maximum deformation of closed shells.in order to verifying this model, some experimental tests are designed and implemented on three scales of aluminium shells with cone-cylinder in two different materials. Also these deformations are compared with Johnes theoretical model related to long cylinders. Finally due to the difference of the geometric shape of the shells, in both theoretical and experimental modes, according to no dimensional number, presented by Zhao, one semi-experimental model is given for predicting the maximum deformation of this kind of shells under explosive loading.
Mahmood Mobin, Jamal Zamani, Ali Mozafari,
Volume 9, Issue 1 (7-2014)
Abstract
The plastic behavior of materials depends on their strain rate sensitivity. The main objective of this paper is the analysis of the effect of strain rate sensitivity on plastic behavior of cylindrical shells under internal pressure loading and hence a large number empirical tests have been conducted on aluminum cylindrical shells. We have also manufactured and used a hydrostatic test machine to perform the internal static, semi-static and dynamic pressure loading of the specimens in the strain rate range between 1 to 0.00001 ( / Sec). On the other hand we used the explosive loading in order to simulate the super dynamic loading of cylindrical shells. Using the data of this complete set of experimental tests and the analytical formulation helped us perform our desirable analysis on the effect of the strain rate and loading rate on the behavior of aluminum made cylindrical structures. We also extracted some semi-experimental terms which show the relation between the strain and strain rate. The analysis of the results shows that as the loading rate increases, the failure load and failure strain of the structures which are made of strain rate sensitive materials, increase.
Mehdi Rahimi Nasrabadi, Ahmad Mozafari,
Volume 13, Issue 1 (7-2017)
Abstract
Identifying minor amounts of explosives with sensitivity, selectivity, accuracy and speed can be a great advantage for applications related to national security and environmental monitoring.Unfortunately, identification with high reliability of explosives is still a challenge and is largely unfulfilled. Today, fluorescence-based methods are widely used to detect explosives and products derived from their destruction in complex matrices. Due to the special electrical properties and fluorescence emission of Quantume dots due to the interaction with various compounds, including explosives, the use of this nanopaticle for the development of various sensors has become a key factor in recent years. Nitro-aromatic explosives caused various quantum dots to be quenched by different mechanisms.For this reason, detection and identification of these species is carried out. In this review, the application of quantum dots as sensors of nitroaromatic compounds and their mechanism is investigated.
