In this research, residual strength and stress concentration factor of laminated composites with a circular open hole are studied analytically, numerically and experimentally. The numerical study was carried out using the finite element method. Moreover an analytical study was carried out with developing of point stress criterion. Mechanical testing was performed to determine the un-notched ten...

Accretion disk reflection spectra, including broad iron emission lines, bear the imprints of the strong Doppler shifts and gravitational red-shifts close to black holes. The extremity of these shifts depends on the proximity of the innermost stable circular orbit to the black hole, and that orbit is determined by the black hole spin parameter. Modeling relativistic spectral features, then, give...

The critical field of a thin superconducting film with a blind circular hole is found theoretically. It is shown that the value of the critical field is sensitive to the bottom thickness, but the orbital momentum, i.e., the number of vortices which nucleate inside the hole, is not sensitive. A simple boundary condition for a steplike thin film is derived and used for comparative numerical analy...

With the increasing complexity of engineering geological conditions, problem tensile-shear failure bolts is becoming more serious. Accurate modelling performance bolted rough joints subjected to load essential for support design. In this paper, based on theoretical criteria bolt failure, mechanical model Pile element in FLAC3D program modified, and accuracy modified verified by numerical experi...

Based on the FLAC3D numerical software, a roadway excavation and support model was established. The stability of surrounding rock FRP bolt force characteristics in Yuhuasi mining area Jinshandian Iron Mine were analyzed. distribution law plastic zone simulated, deformation simulated. data for 6 months tested site, weak links determined, optimized. Parameters, optimized effect is better, which p...

In this paper, numerical simulations of circular boreholes under internal hydraulic pressure are carried out to investigate the energy transferred to the surrounding rock and the breakdown pressure. The simulations are conducted by using a micromechanical continuum damage model proposed by Golshani et al. (2006). The simulation results suggest that the borehole breakdown pressure and the energy...

We study the effects of an external magnetic field, which is assumed to be uniform at infinity, on the marginally stable circular motion of charged particles in the equatorial plane of a rotating black hole. We show that the magnetic field has its greatest effect in enlarging the region of stability towards the event horizon of the black hole. Using the Hamilton-Jacobi formalism we obtain the b...

The cracks and holes in underground engineering are the critical factors that cause instability of surrounding rock. It is helpful to control stability rock study samples with combined defects holes. In this study, PFC 2D used analyze numerical models. Seven models single circular hole double different angles established, fracture angle varies from 0° 90° an interval 15°. First, uniaxial compre...