Design And Development Of Automated Pipeline Defect Detection System Based On Non-destructive Testing

Transmission of fluids along the pipelines and tunnels has become the major mode that is present in most of the worldwide fluid transportation applications.These pipelines transport water,sewage wastes,oil and gases.Pipelines are exposed to extreme weather conditions and due to several other reasons,leads to corrosion,erosion,deposition,cracks,pitting and etc.Therefore,pipeline inspections are scheduled regularly.Manual inspection is the most common form of assessing the physical and functional conditions of pipelines regularly in order to ensure the structure meets its expected service requirements and standards.However,several problems are present with this method due to insufficient inspection and condition assessment.Initial stage of the thesis presents the design,simulation,fabrication and testing of an External Pipeline Robot(EPR)with the capability of moving on pipelines with a variable diameter with 110 mm to 130 mm.Design stage of the robot presents three design phases with different moving mechanisms carried out using SolidWorks software which is also used for motion analysis of the designs.With reference to the motor torques obtained from the motion analysis motor selection is done.Finite Element Analysis(FEA)for the critical components is done using COMSOL Multi-physics software.The developed EPR is with the capability to integrate sensors or actuators as required for different applications.Then,the development of a Pipeline Defect Detection(PDD)system and designing main components of the system is done and presented.Vision system is developed by the integration of a camera module,a single board computer and a remote workstation.Vision based PDD system presented provides remote monitoring and analyzing features by utilizing the remote workstation for data storage.MATLAB based image acquisition algorithm is performed on LATTEPANDA single board computer,whereas the defect identification algorithm is performed on HP Envy 6-1012TX Ultra-Book laptop.GUI developed for the system visualizes the stages of image analysis and displays analysis result.External surface defects having significant appearance abnormalities are tested using the presented vision based PDD system.The final section of the research includes defect detection of cylindrical pipes based on forced vibration based method.A vibration analysis is done using COMSOL Multi-physics software for two models of pipes,one without a defect and the other with a hole.A free vibration analysis,harmonic forced vibration analysis and periodic vibration analysis is carried out on the two types of pipe models.A comparison is done for natural frequencies of both types of pipe models and respective maximum displacements.The discussed experimental setup consists of a ring type vibration generator based on Eccentric Rotating Mass(ERM)motor and a ring type vibration sensor based on Piezoelectric based vibration sensors.Two setups having different number of vibration locations and vibration measuring locations are tested.A pipe segment with(hole)and without a defect is tested and the results are presented.