Guillotine shear cutting model for decommissioning purposes

Guillotine shear cutting model for decommissioning purposes

De Groote, P.F.N.

Metrikine, A.V. (mentor)
Van der Meer, F.P. (mentor)
Belder, C. (mentor)
Hoving, J.S. (mentor)
Boot, A. (mentor)

Mechanical, Maritime and Materials Engineering

Offshore Engineering

Offshore and Dredging Engineering

2015-10-14

The purpose of this thesis is to estimate the required forces for a hydraulic decommissioning cutting tool. The reason for this thesis topic is because of clear regulations and demand according offshore decommissioning. Abandoned offshore structures require to be decommissioned after their lifespan. The low oil prices these days and the pressure on the decommissioning market gain opportunities for companies such as IHC IQIP to enter the market. As a result of a preliminary study, IHC IQIP might develop a new hydraulic shear cutter tool. In order to develop and design a shear cutting tool, preliminary investigations on the requirements have to be performed. The main interest were the required loads during the shear cutting action. An analysis by means of analytical and numerical model needs to determine the load cases during the cutting action. It is shown that a pipe subjected to opposite loads starts to deform plastically. Once the pipe is completely crushed between the loads, shear cutting takes place. This load will eventually be the design load. A numerical model is performed with advanced implicit non-linear models in NX Nastran. The analytical model is based on 2 phases. First a ring, composed of rigid shells and plastic hinges, is crushed by homogeneous blade shapes. Secondly the guillotine cutting load is determined by amusing the crushed pipe to be flat plate. Determine an equilibrium between the required force for penetration of the blades and the bearing capacity of the plate after penetration, results in the required cutting load. Finally both analytical and numerical, models are validated by an experimental setup. It is concluded that the numerical software used was not capable of shearing the deformed pipe. However the required load for crushing the pipe were satisfied according the experiments. The analytical model however underestimates the measured maximal load. Further studies are recommended for modelling non-homogenious blade shapes and improvements in the cutting model.

Guillotine
Shear Cutting
Decommissioning
Tubes
Pipe Crushing
Pipe Cutting
Offshore

http://resolver.tudelft.nl/uuid:79febaca-6560-482f-92f1-275f6a92d87e

2020-10-14

Student theses

master thesis

(c) 2015 De Groote, P.F.N.