Banca de DEFESA: VINÍCIUS WENDEL DOS SANTOS MOURA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : VINÍCIUS WENDEL DOS SANTOS MOURA
DATE: 08/08/2022
TIME: 14:00
LOCAL: Pos Graduação Engenharia Civil
TITLE:

Reliability Analysis of Ovalized Pipelines and with Corrosion Defects Submitted to External Pressure Via Finite Element Method

KEY WORDS:

Pipelines; Corrosion; Ovalization; Structural Reliability; Collapse Pressure; Semiempirical Methods; Finite Element Method

PAGES: 87
BIG AREA: Engenharias
AREA: Engenharia Civil
SUMMARY:

The oil and natural gas industry generates billions of reais a year, this is about of Brazil. In fact, the quarterly reports of production and sales of oil and natural gas show an increase in production year after year. All these materials are carried through pipelines, one of the main structures of this economic activity. However, certain situations can occur with pipelines from their conception to their installation and operation, one of which is able of causing deformations in the shape of these pipelines, such as ovality, which must be considered in analysis of submarine pipelines. In operation, pipelines can suffer from corrosion, a natural process able of deteriorating their integrity and causing damage to their performance. These situations can manifest themselves in a way able of causing the collapse of the pipelines, so maintenance and investigation plans are important to prevent accidents, which in most cases have a great social, economic and environmental impact. This dissertation seeks to study the collapse pressure of ovalized pipelines with corrosion defects subjected to external pressure (subsea pipelines) associate with reliability analysis, a statistical study that seeks to estimate the probability of failure in order to meet a level of safety and guarantee of structural stability. For the reliability analysis, we tried to define the failure function and the random variables of the problem. In this work, the failure function will depend on the evaluation of the collapse pressure. Semi-empirical formulations coded in the Matlab program were used. The methods used were proposed by authors such as Netto, Bai and Bai, Klever and Tamano, and DNV. The results obtained by the semi-empirical formulations were compared with numerical simulations, one of the most accurate approaches, the Finite Element Method (FEM). Due to the complexity and non-linearity of the problem, the pipeline was simulated in a computational tool, authored by PADMEC, this algorithm uses FEM and other software in its iterations, pipelines data, corrosion defect and ovality are introduced into the program, then part of the pipeline is modeled and simulated (non-linear analysis) automatically by the computational tool, returning the value of the failure pressure. Two ovality models were considered in the algorithm, Motta's and Karadeniz's. The results obtained by the iterative process through the FEM were compared with the analytical results. The results showed that the semi-empirical formulations were consistent with the experimental results in the validation phase in Matlab, especially Netto's proposal. The formulation of the DNV standard and the formulation proposed by Bai and Bai proved to be conservative since they consider generalized corrosion by decreasing the thickness of the pipeline, where the greatest defect depth occurs.

BANKING MEMBERS:
Externo à Instituição - JEFFERSON WELLANO OLIVEIRA PINTO
Externa ao Programa - 1721844 - JULIANA VON SCHMALZ TORRES
Presidente - 2994651 - TIAGO ANCELMO DE CARVALHO PIRES DE OLIVEIRA