نتایج جستجو برای: open transverse crack

تعداد نتایج: 460930  

Journal: :Nature materials 2008
K J Koester J W Ager R O Ritchie

Bone is more difficult to break than to split. Although this is well known, and many studies exist on the behaviour of long cracks in bone, there is a need for data on the orientation-dependent crack-growth resistance behaviour of human cortical bone that accurately assesses its toughness at appropriate size scales. Here, we use in situ mechanical testing to examine how physiologically pertinen...

B Brahim F Ahmed, H Abdelhamid S Ahmed

In this paper, we use the hybrid h-p version of the finite element method to study the effect of an open transverse crack on the vibratory behavior of rotors, the one-dimensional finite element Euler-Bernoulli beam is used for modeling the rotor, the shape functions used are the Hermite cubic functions coupled to the special Legendre polynomials of Rodrigues. The global matrices of the equation...

In the vibration of a cracked structure with small amplitude oscillations, the crack necessarily is not fully open or fully closed. Therefore, in order to provide a realistic model for the crack, one should relate the stiffness and damping at the crack location to the amount of the opening of the crack. In this study, a continuous model for vibration of a beam with a fatigue crack under low amp...

Journal: :journal of mechanical research and application 2012
s. moradi p. alimouri

in this study, the vibration of cracked plates is investigated using the differential quadrature method and experimental modal analysis. the crack, which is assumed to be open, is modeled by the extended rotational spring. with its finite length, the crack divides the plate into six segments. then, the differential quadrature is applied to the governing differential equations of motion and the ...

2001
Kathleen R. McDonald John R. Dryden Frank W. Zok

Effects of matrix cracks and the attendant interface debonding and sliding on both the longitudinal and the transverse thermal diffusivities of a unidirectional Nicalon/MAS composite are investigated. The diffusivity measurements are made in situ during tensile testing using a phase-sensitive photothermal technique. The contribution to the longitudinal thermal resistance from each of the cracks...

1999
Ting Zhu Wei Yang

The intrinsic coupling between the mechanical and the electric _elds assigns a unique feature for the fracture in a piezoelectric solid[ We model the kink of a crack by continuous distribution of edge dislocations and electric dipoles[ The problem admits an approach based on the Stroh formalism[ A set of coupled singular integral equations are derived for the dislocation and electric dipole den...

2006
J. L. Rose C. M. Lee T. R. Hay Y. Cho I. K. Park

The critical subject of transverse crack detection in a rail head is treated in this paper. Conventional bulk wave ultrasonic techniques often fail because of shelling and other surface imperfections that shield the defects that lie below the shelling. A guided wave inspection technique is introduced here that can send ultrasonic energy along the rail under the shelling with a capability of fin...

2004
H. Jiang Y. Huang C. Liu

There exist two fracture mechanisms in facesheets of sandwich composites consisting of the 08 and 908 plies, namely crack growth and crack blocking. The former is undesired since it may lead to failure of facesheets and even the core in sandwich composites. A shear-lag model is developed in this article and it gives a simple criterion governing these two mechanisms. It is established that, for ...

2012
Masa Suresh Kumar Kesarabandi Raghavendra

This paper describes fractographic features observed in aerospace composites failed under tensile loads. Unidirectional Carbon Fibre Reinforced Plastic (UD CFRP) and Unidirectional Glass Fibre Reinforced Plastic (UD GFRP) composite specimens were fabricated and tested in tension. The morphology of fractured surfaces was studied at various locations to identify failure mechanism and characterist...

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