جستجوی مقالات مرتبط با کلیدواژه « green-naghdi theory » در نشریات گروه « مکانیک »

In this paper, the behavior of a stationary crack in a generalized diffusion-thermoelasticity medium under temperature and concentration shock has been investigated. Cracks have been modeled using the extended finite element method and stress intensity factors have been obtained using the interaction integral method. To study the phenomenon of heat dissipation and concentration, generalized Green-Naghdi and non-Fickian theories have been used. The extended finite element method has been developed to discrete equations in space and the Newmark implicit method has been used to calculate time integrals. For different loads (heat shock and concentration), stress intensity factors and temperature and concentration distribution at the crack tip have been studied. The effect of stress wave velocity, concentration wave and temperature wave on stress intensity factors for straight and oblique cracks has also been investigated. It is observed that for the case where the speed of the stress wave, and the temperature wave are the same and greater than the speed of the concentration wave, the increase of the stress intensity factors is faster and higher in other states.

In this paper, the stress intensity factor for circumferential crack in an isotopic cylinder has been determined. The thickwalled cylinder is subjected to a one-dimensional axisymmetric thermal shock on the outer surface according to the classic thermoelasticity (CTE), Green-Lindsay (G-L) and Green-Naghdi (G-N) theories. The considered unified form of governing equations involves CTE, G-L and G-N theories. The effects of temperature-strain coupling and the inertia term in governing equations are considered. The circumferential crack stress intensity factor determinates using weight function method. Considering relaxation times in generalized theories governing equations result in predicting higher temperature and stress values in comparison with CTE. Also, generalized theories stress intensity factor is higher than CTE significantly. Moreover, the maximum stress intensity factor in generalized theories occurs for a crack that the peak of stress wave reaches to its tip. Because of neglecting energy dissipation in G-N type II governing equations, its maximum of stress and stress intensity factor is higher than G-L theory.