the cracked brazilian disc (cbd) specimen is widely used in order to determine mode-i/ii and mixed-mode fracture toughness of a rock medium. in this study, the stress intensity factor (sif) on the crack-tip in this specimen is calculated for various geometrical crack conditions using the extended-finite element method (x-fem). this method is based upon the finite element method (fem). in this m...

The investigation of the effects of cracks or similar weaknesses on the load carrying capacity of structural elements such as columns, beams and shells is an important problem in civil, mechanical, earthquake and aerospace engineering. In this paper, adaptive neuro-fuzzy inference system (ANFIS) and artificial neural network (ANN)model have been successfully used for the buckling analysis of sl...

OBJECTIVE This article assesses the position-dependent injury tolerance of the hip in the frontal direction based on testing of eight postmortem human subjects. METHODS For each subject, the left and right hemipelvis complex was axially loaded using a previously developed test configuration. Six positions were defined from a seated femur neutral condition, combining flexed, neutral, and exten...

This study evaluates the feasibility of using antenna array to detect crack defects in metal pipes. Antenna arrays are set at port a pipe radial direction, and microwave signal can be effectively coupled into pipe. It produce orbital angular momentum (OAM) waves. The cracks will change transmission characteristics, they inspected by time domain reflectometry (TDR) vector network analyzer (VNA)....

In this study, the piston's failure mechanism in pneumatic down hole(DTH) impactor has been investigated. Failed piston microstructure and hardness have analysed using SEM, nanoindentation Vickers tester. The stress state of during impact process was studied ABAQUS finite element software. results show that carburized layer transits from acicular martensite phase to plate surface towards inside...

the prevalent method of irrigation in paddy fields in iran is continuous ponding, which changes to intermittent method at the time of water shortage. soil cracks are the main problem in intermittent irrigation. in this study, effects of adding rice straw on some soil physical characteristics and cracks were studied in paddy soils of the guilan province of iran. the experiment was performed as s...

Abstract The fracture process of the metal cylindrical shell under action implosion is numerically simulated by AUTODYN finite element software for expansion cracks on surface cases loading. Numerical computations were used to determine effect law engineering factors such as energy density explosives, thickness, and material crack-related parameters. results show that radius along axial directi...