Efficient and accurate methods for computational simulation of netting structures with mesh ...

144 Pages·2014·12.15 MB·English

by  Amelia Prada Arquer

Efficient and accurate methods for
computational simulation of netting
structures with mesh resistance
to opening

Amelia de la Prada Arquer

DOCTORAL THESIS

Advisor: Manuel González Castro
Programa Oficial de Doctorado en Ingeniería Industrial

Ferrol, July 2014

A mi familia:
Florian, Amelia y Manuel

To my family:
Florian, Amelia y Manuel

Aknowledgements
This Ph.D. thesis has been conducted at the Mechanical Engineering
Laboratory of University of A Coruña, headed by Prof. Javier Cuadrado. This
research was motivated by the project PSE-REDES, Subproject 3, Simulation,
experimentation and design of fishing gears, supported by the Spanish Ministry of
Science and Innovation.
First, I wish to express my special gratitude to Prof. Manuel González, my
advisor, for his excellent advice, dedication, patience, and the passion for research
and well-finished work he has transmitted to me. Also, I would like to thank to Prof.
Javier Cuadrado, for giving me such a great opportunity.
I would like to thank my colleagues at the Mechanical Engineering
Laboratory: Alberto, Daniel, David, Emilio, Florian, Fran, Miguel, Roland and
Urbano. For the fabulous work environment they have provided, their useful advice
and the enjoyable hours we have spent together.
During my doctorate, I have made a stay at the IFREMER at Brest, under the
supervision of Daniel Priour. I am grateful for his kindness and the very interesting
and productive conversations that helped me to better understand the fishing nets’
behaviour. Also, many thanks to his research team for welcoming me so warmly.
Finally, I owe my heartfelt thanks to my close people: to my parents, for
supporting me despite the distance that separates us; and last but no least to my
husband, Florian, for his love and support, which always encourage me to give the
best of myself.

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Agradecimientos
Esta tesis doctoral ha sido realizada en el Laboratorio de Ingeniería Mecánica
de la Universidad de A Coruña, dirigido por el profesor Javier Cuadrado. Esta
investigación fue motivada por el proyecto PSE-REDES, Subproyecto 3, Simulación,
experimentación and rediseño de artes y dispositivos de pesca, financiado por el
Ministerio de Ciencia e Innovación de España.
En primer lugar, me gustaría dar las gracias al profesor Manuel González, mi
director de tesis, por sus excelentes consejos, dedicación, paciencia y la pasión por la
investigación y el trabajo bien hecho que ha sabido trasmitirme. También agradecer
al profesor Javier Cuadrado, por haberme brindado esta gran oportunidad.
Quiero dar las gracias a mis compañeros del Laboratorio de Ingeniería
Mecánica: Alberto, Daniel, David, Emilio, Florian, Fran, Miguel, Roland and
Urbano, por el fabuloso ambiente de trabajo, sus utilísimos consejos y las agradables
horas que hemos pasado juntos.
Durante mi doctorado he realizado una estancia en el IFREMER en Brest,
bajo la supervisión de Daniel Priour. Le estoy muy agradecida por su amabilidad y
las interesantes conversaciones que me ayudaron a entender mejor el
comportamiento de las redes de pesca. Me gustaría agradecer también a su equipo de
investigación, por haberme proporcionado una acogida tan cálida.
Finalmente, me gustaría dar las gracias a aquellas personas que siempre han
estado a mi lado, a mis padres, por su cariño y apoyo a pesar de la distancia que nos
separa y, por último, a mi esposo Florian, por su amor y apoyo que siempre me
impulsan a dar lo mejor de mí.
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Abstract
Current research in computational simulation of fishing gears focuses on
efficient numerical models that accurately predict the behaviour of the netting
structure. This thesis is collection of four papers related to the development of a new
model that includes the mesh resistance to opening.
Firstly, several nonlinear stiffness models of a net twine are developed. The
net twine is modelled as a double-clamped beam and its force-displacement response
is calculated by finite element analysis and approximated with three different
models. The proposed models overcome the drawbacks of previous models. The
twine model is based on the bending stiffness and other geometrical properties of the
netting material, so, a procedure to quantify them is presented. Although the
methodology is similar to the previous studies, several original contributions are
introduced, like a simpler experimental set-up. This procedure is also used to validate
the presented twine models with experimental data.
Regarding the simulation, the performance of a fishing gear is mainly
determined by its equilibrium shape. In this thesis, the robustness and efficiency of
gradient-based energy minimization methods and Newton iteration are compared by
applying them to a set of benchmark problems.
Finally, a lumped mass formulation for netting structures is developed. The
lumped mass formulation is widely used to model netting structures, but in this thesis
the linear springs that traditionally connect the nodes are replaced by the developed
twine model. Besides, the knots are modeled as spheres instead of point masses.
Although the expressions of the presented model are more complex than those of the
spring model, it has been demonstrated that both models have a similar
computational overhead. To validate the model, a netting panel is simulated and
compared with experimental results.

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