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The crack path and failure analysis of the blade in a gas turbine was investigated by fracture mechanical study using a numerical analysis. The Two fracture mechanics approach K-T is used to estimate the mechanical properties of the blade with semi elliptical defaults. In this analysis, the applied pressure is not constant, whereas is imported with a interaction between structure fluid. ANSYS Workbench 16.0 software were used with the computational fluid dynamics Software (CFD section), a steady state gas flow analysis was carried out, and the pressure distributions. In the structural analysis a node coordinate where we have the maximum principal stresses were explored. In this node, we have created a semi- elliptical crack and we have compared between them with the Stress Intensity Factors and T- stress values. The second parameter in the Williams' equation give a good information’s on the estimation and the direction of the crack path.

This work examines, some points of views on the burst pressure standards calculation on pipeline with external corrosion defect, a real test will be present. A validation of Clock Spring repair method will be focus on the second part. A FEM simulation should be a good tool to estimate the safety factor on the both parts. For the first, an inspection is given for a real pipe exhibiting a surface corrosion defect. The data collected by the intelligent pig are regrouped with the critical pressure establish by different codes ASME B31G, DNV RP F-101, Choi’s method, RSTRENG, Modified B31G code and SHELL 92. Effect of corrosion length and depth are studied. In the second part of this study is focused on the control of the made reinforcement calculation (thickness of the monchon to be installed) will be given in details according to the characteristics of the pipe, the composite material and the dimensions of the defect to be repaired. The principle of failure assessment (FAD) diagram is described and particularly the definition of the non dimensional applied crack tip loading kr, the non dimensional net applied stress (or load) Sr or Lr are given. The interest lays in the fact that many pipes defects are scratch or gouge types. It is noted the FAD with the presence of the different repairing methods doesn’t affect the interpolation curve but the working point position.

The need to transport petroleum and gas products through pipelines has resulted in the increased erosion of the pipeline materials used in the hydrocarbon industry. Erosion is a mechanical process that causes an eroded volume on the surface of a material. The erosion phenomenon of metallic structures, in petroleum industry, is a problem which affects many industrial sectors. The shocks between the sand particles and the structure surface cause a severe damage. It is manifested by spelling craters of different shapes and depths. The evaluation of static properties and lifetime of a pipeline under the impact of sand has been performed. In this study, was performed using sand blaster erosion machine to investigate the erosive behavior and mechanism relative to API X70 pipeline steel used in the hydrocarbons pipeline transportation on mechanical property, caused by sandblasting erosion in Saharan climate conditions.

This paper provides some critical review of the history and state of art of methods taking account the T-stress values. The methods proposed in the literature which measure T stress at constant distance near the crack/or notch tip are not conservative. Example from CT specimen loaded in mode I obtained by using 2D finite element method with the software ANSYS 15.0, are taking to support this argument. Numerical results confirm that the Ts-tress is not constant near or on back to the crack/nocth tip. A numerical method based on the Volumetric Method developed by Pluvinage is used to defined the T-stress value to take into account. This method is characterized by the determination of the effective stress Tef over an effective distance Xef ahead of the crack tip.