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CONTENTS
Volume 5, Number 5, September 2018
 

Abstract
In this manuscript, buckling response of the functionally graded material (FGM) nanoplate is investigated. Two opposite edges of nanoplate is under linear and nonlinear varying normal stresses. The small-scale effect is considered by Eringen\'s nonlocal theory. Governing equation are derived by nonlocal theory and Hamilton\'s principle. Navier\'s method is used to solve governing equation in simply boundary conditions. The obtained results exactly match the available results in the literature. The results of this research show the important role of nonlocal effect in buckling and stability behavior of nanoplates. In order to study the FG-index effect and different loading condition effects on buckling of rectangular nanoplate, Navier\'s method is applied and results are presented in various figures and tables.

Key Words
buckling; functionally graded material; linear and nonlinear loading; nonlocal elasticity; Navier\'s method

Address
Department of Engineering, Imam Khomeini international university, Qazvin, Iran

Abstract
Detonation transmission between propane/oxygen (donor) and propane/air (acceptor) with an abrupt area change is experimentally studied. In the donor, there are two types of incident detonation waves: A self-sustained Chapman-Jouguet (CJ) detonation wave and an overdriven detonation wave that is a result of the difference in the initial donor pressure ratios. The piston work is used to characterize the strength of the incident detonation wave. For an incident CJ detonation wave, the re-initiation of a detonation wave in the acceptor depends on the initial pressure in the donor and the expansion ratio. The axisymmetric and non-axisymmetric soot patterns respectively correspond to direct detonation and detonation re-initiation. For an incident overdriven detonation wave, the re-initiation of a detonation wave in the acceptor strongly depends on the degree of overdrive.

Key Words
detonation; overdriven detonation; expansion ratio; piston work

Address
Yao-Chung Hsu, Yei-Chin Chao: Department of Aeronautics and Astronautics, National Cheng Kung University, 1 University Road, East district, Tainan 701, Taiwan
Kung-Ming Chung: Aerospace Science and Technology Research Center, National Cheng Kung University, 2500 Section 1, Chung-Cheng South Road, Guiren district, Tainan 711, Taiwan

Abstract
This work is concerned with the motion of propeller driven airplanes, flying at constant velocity on ascending or descending rectilinear trajectories. Its purpose is to provide important features of rectilinear flights that are required for airplane trajectory planning but that cannot be found already published. It presents a method for calculating the amount of fuel used, the restrictions on the trajectory parameters, as inclination and speed, which result from the load factor, the lift coefficient, the positivity and upper boundedness of the power available. It presents a complete discussion of both ascending and descending flights, including gliding. Some original remarks are made about the parameters of gliding. It shows how to construct tables of parameters allowing to identify rapidly flyable trajectories. Sample calculations are shown for the Cessna 182 and a Silver Fox like unmanned aerial vehicle.

Key Words
airplane rectilinear trajectory; inclined rectilinear motion, airplane equation of motion; automatic trajectory planning; gliding

Address
Department of Mathematics and Computer Science, Royal Military College of Canada, Kingston, Ontario, Canada


Abstract
This paper is the follow-on of a previous paper by the author where it was pointed out that the forthcoming, manned exploration missions to Mars, by means of complex geometry spacecraft, involve the study of phenomena like shock wave-boundary layer interaction and shock wave-shock wave interaction also along the entry path in Mars atmosphere. The present paper focuses the chemical effects both in the shock layer and on the surface of a test body along the Mars orbital entry and compares these effects with those along the Earth orbital re-entry. As well known, the Mars atmosphere is almost made up of Carbon dioxide whose dissociation energy is even lower than that of Oxygen. Therefore, although the Mars entry is less energized than the Earth re-entry, one can expect that the effects of chemistry on aerodynamic quantities, both in the shock layer and on a test body surface, are different from those along the Earth re-entry. The study has been carried out computationally by means of a direct simulation Monte Carlo code, simulating the nose of an aero-space-plane and using, as free stream parameters, those along the Mars entry and Earth re-entry trajectories in the altitude interval 60-90 km. At each altitude, three chemical conditions have been considered: 1) gas non reactive and non-catalytic surface, 2) gas reactive and non-catalytic surface, 3) gas reactive and fully-catalytic surface. The results showed that the number of reactions, both in the flow and on the nose surface, is higher for Earth and, correspondingly, also the effects on the aerodynamic quantities.

Key Words
hypersonic; rarefied aerodynamics; effects of chemical reactions in Mars entry; effects of chemical reactions in Earth re-entry; direct simulation Monte Carlo method

Address
Department of Industrial Engineering, University of Naples

Abstract
The objective of our study is to analyze the behavior of bonded, riveted and hybrid (bonded / riveted) steel / steel assemblies by tensile tests and to show the advantage of a hybrid assembly over other processes. the finite element method with the ABAQUS numerical code was used to model the fracture behavior of the different assemblies. Cohesive zone models (CZM) have been adopted to model crack propagation in bonded joints using a bilinear tensile separation law implemented in the ABAQUS finite element code. The riveted assemblies were modeled with the XFEM damage method identified in this ABAQUS numerical code. Both CZM and XFEM methods are combined to model hybrid assemblies. The results are consistent with the experimental results and make it possible to guarantee the validity of the applied numerical model. The use of a hybrid assembly shows a high resistance compared to other conventional methods, where the number of rivets has been highlighted. The use of the hybrid assembly improves mechanical strength and increases service life compared to a single lap joint and a riveted joint.

Key Words
single lap joint; riveted joint; hybrid joint; cohesive zone model (CZM); XFEM; steel E24

Address
M.C. Ezzine, A. Amiri, and K. Madani: Laboratoire Mécanique Physique des Matériaux (LMPM), Department of Mechanical Engineering, University of Sidi Bel Abbes, Sidi Bel Abbes 22000, Algeria
M. Tarfaoui: ENSTA Bretagne, MSN/LBMS/DFMS, 2 Rue François Verny, 29806, Brest, CEDEX 9, France


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