Expansion of indicial function approximations for 2-D subsonic compressible aerodynamic loads

, Article ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE) ; Volume 1 , 2012 , Pages 519-528 ; 9780791845172 (ISBN) Farsadi, T ; Javanshir, J ; Sharif University of Technology

2012

Abstract

This article deals with the new generation of proper Mach dependent exponential approximations of the indicial aerodynamic functions toward the aeroelastic formulation of 2-D lifting surface in the subsonic compressible flow. The indicial lift response is a useful starting point in the development of a general time-domain unsteady aerodynamic theory. By definition, an indicial function is the response to a disturbance that is applied instantaneously at time zero and held constant thereafter; that is a disturbance given by a step function. If the indicial response is known, then the unsteady loads to arbitrary changes in angle of attack can be obtained through the superposition of indicial...

Aeroelastic Analysis of Aircraft Composite Wings in a Compressible Flow

, M.Sc. Thesis Sharif University of Technology Farsadi, Touraj (Author) ; haddadpour, Hassan (Supervisor)

Abstract

In this research, an anistropic thin-walled beam composite is used to consider the effects of fiber orientation and lay-up configuration on the aeroelastic stability and response of an aircraft wing. The circum ferentially asymmetric stiffness (CAS) model consists of a group of non-classical effects; such as transverse shear, material anisotropic, warping inhibition, etc. The aerodynamic load has been modeled based on the strip theory and compressible unsteady flow in the finite- state form. In addition, to form the mass, stiffness and damping matrices of non-conservative aeroelastic systems the extended Galerkin’s method (EGM) and the method of separation of variables has been used. After...

Buckling behavior of composite triangular plates

, Article International Journal of GEOMATE ; Volume 2, Issue 2 , 2012 , Pages 253-260 ; 21862982 (ISSN) Farsadi, T ; Heydarnia, E ; Amani, P ; Sharif University of Technology

GEOMATE International Society 2012

Abstract

This paper is to do a brief research on the buckling behavior of composite triangular plates with various edge boundary conditions and in-plane loads. It may be regarded as a right and simple numerical method for the analysis of composite triangular thin plate using the natural Area coordinates. Previous studies on the solution of triangular plates with different boundary conditions were mostly based on the Rayleigh-Ritz principle which is performed in the Cartesian coordinate. In this method, the energy functional of a general triangular plate is derived and the Rayleigh-Ritz method is utilized to derive the governing eigenvalue equation for the buckling problem. The geometry is presented...

Use of rubber modification technique to improve fracture-resistance of hoop wound composites

, Article Materials and Design ; Volume 30, Issue 6 , 2009 , Pages 1976-1984 ; 02641275 (ISSN) Abadyan, M ; Khademi, V ; Bagheri, R ; Haddadpour, H ; Kouchakzadeh, M. A ; Farsadi, M ; Sharif University of Technology

2009

Abstract

Toughness improvement of an epoxy resin and respective hoop wound composite were investigated systematically using amine-terminated butadiene acrylonitrile (ATBN) liquid rubber. Rubber modification improves fracture toughness of epoxy resin with slight reduction in the glass transition temperature (Tg), flexural and compressive properties of resin. Impact resistance of composite is improved by rubber modification similar to modified resin. Interlaminar shear strength (ILSS), compressive modulus and strength, and flexural strength of composite decreased slightly with rubber modification. To interpret the data, the void content of composite samples was determined and the damaged surfaces of...