Recent Developments in Predicting Impact and Shock Sensitivities of Energetic Materials （英）

Empirical, quantum mechanical and artificial neural network methods are three usual methods in recent years that were used to predict sensitivity of different classes of high explosives. Some recent developments in predicting sensitivity by various methods are reviewed and discussed for various classes of energetic materials.     

Effect of Porosity on free and forced vibration characteristics of the GPL reinforcement composite nanostructures

This article investigates the influence of porosity on free and forced vibration characteristics of a nanoshell reinforced by graphene platelets (GPL). The material properties of piece-wise graphene-reinforced composites (GPLRCs) are assumed to be graded in the thickness direction of a cylindrical nanoshell and estimated using a nanomechanical model. In addition, because of imperfection of the current structure, three kinds of porosity distributions are considered. The nanostructure is modeled using modified strain gradient theory (MSGT) which is a size-dependent theory with three length scale parameters. The novelty of the current study is to consider the effects of porosity, GPLRC and MSGT on dynamic and static behaviors of the nanostructure. Considering three length scale parameters ( $l_0=5h$, $l_1=3h$, $l_2=5h$ ) in MSGT leads to a better agreement with MD simulation in comparison by other theories. Finally, effects of different factors on static and dynamic behaviors of the porous nanostructure are examined in detail.     

Determination of the most sustainable bridge work programs through the improved structure level considerations

Bridges are vital parts of public road networks. They are maintained through the execution of maintenance interventions to ensure they continuously provide service to society. These interventions, however, should be executed in a way that results in the lowest overall negative impacts, i.e. the most sustainable work programs should be followed. A challenge in the determination of these work programs is that only some impacts are attributable to elements. Others, are only attributable to the bridge as a whole and require more modelling effort than what is currently done in many bridge management systems, and, therefore, require a different methodology to be used. In this paper, a methodology is proposed to determine the most sustainable work programs that systematically takes into account both element level and structure level impacts. The proposed methodology is demonstrated using it to determine the most sustainable work program for an example bridge. The advantages and disadvantages of the methodology, as well as possible future research directions, are discussed.     

A size-dependent exact theory for thermal buckling,free and forced vibration analysis of temperature dependent FG multilayer GPLRC composite nanostructures restring on elastic foundation

International Journal of Mechanics and Materials in Design - In this paper, thermal buckling and free/forced vibration characteristics of size-dependent composite cylindrical nanoshell reinforced...     

Theoretical Prediction of Physicochemical Properties,Performances and Sensitivities of some New Derivatives of Dinitro Triazolyl Triazine

In this paper, important properties of some new derivatives of dinitro triazolyl triazine as novel heterocyclic energetic compounds are evaluated and discussed by using some reliable models. The predicted properties are also compared with octahydro‐1,3,5,7‐tetranitro‐1,3,5,7‐tetrazocine (HMX) as a benchmark compound and 2,4,6‐trinitro‐1,3,5‐triazine (TNTA) as a theoretically new high performance energetic compound. It is shown that some of these compounds can be seen as interesting high‐nitrogen organic explosives with relatively low sensitivity which could be introduced for some important industrial applications. Since some of the new compounds have good oxygen balance, calculated specific impulses confirm that these compounds can be considered as suitable oxidizers in solid propellants.