مصطفی قره باغی, احمدرضا
[ 1 ] - بررسی اثرات کمانش گیرها در جلوگیری از انتشار دینامیکی کمانش در خطوط لوله دریائی
It is undeniable that instability plays a significant role in the design of pipelines. Local buckles induced by excessive force on specific part of pipeline can locally reduce the collapse pressure of a pipeline and cause local failure. Periodic placement of buckle arrestors along the pipeline can ensure that collapse only effect the length of pipe between two arrestors on either side of the in...
[ 2 ] - بررسی سرعت انتشار کمانش دینامیکی در خطوط لوله دریائی
A pipeline is considered as shell structure so its design is based on stability concepts due to the exerted high pressure, local instability is probable to occur and so prevention of its occurrence and propagation are important subjects in its design. In this paper, dynamic buckle propagation has been modeled by 3D finite element method, results are verified with experimental tests and velocity...
[ 3 ] - Application of Artificial Neural Network and Fuzzy Inference System in Prediction of Breaking Wave Characteristics
Wave height as well as water depth at the breaking point are two basic parameters which are necessary for studying coastal processes. In this study, the application of soft computing-based methods such as artificial neural network (ANN), fuzzy inference system (FIS), adaptive neuro fuzzy inference system (ANFIS) and semi-empirical models for prediction of these parameters are investigated. Th...
[ 4 ] - Experimental Investigation of the Effect of Splitter Plate Angle on the Under-Scouring of Submarine Pipeline Due to Steady Current and Clear Water Condition
Submarine pipelines are appropriate method for transmission of oil and gas from sea bed. Free spans may occur due to the natural uneven seabed or by under-scouring. Vortex Induced Vibration (VIV) can happen in such free spans at high Reynolds number. Resonance occurs if the frequency of vortex shedding is close to the pipeline’s natural frequency leading to its fatigue that can break the pipeli...
[ 5 ] - Improvement of the heave motion of a semi-submersible platform with damping sheets subjected to sea waves
In this study, the damping sheets were attached to a semi-submersible platform to mitigate the heave motions. We first examined a typical GVA4000 semi-sub under a monochromatic linear wave train in deep water. an analytical method based on diffraction theory was used to determine the heave motion response. The results revealed that the analytical results show good agreement with available exper...