A propeller-ice contact model

Dissertation

Harri Soininen

Research output: ThesisDissertationMonograph

Abstract

The propeller-ice loads consist of both actual contact loads due to propeller penetration into an ice block and non-contact loads that are hydrodynamic disturbance loads generated by the presence of an ice block in the vicinity of a propeller. In this work the contact loads are studied experimentally during a milling type open propeller ice contact. A model of the ice failure process is developed based on the experiments. An effective load model is also developed in order to be able to calculate load levels. In the laboratory experiments a tool having a propeller-like profile was attached to a pendulum and impacted with an ice sheet. The global loads on the tool and the pressure distribution along the tool profile at mid-depth of the ice sheet were measured. The failure process was observed. A process model was formed. The blade leading edge opens cracks towards the groove formed by the previous blade and accordingly the face side hardly experiences any contact at all. On the back side a spall is formed and the ice is crushed within the spall. In the case of large confinement local crushing may also occur instead of spalling. The crushed ice is extruded towards both the leading edge and the trailing edge of the profile. Two-dimensional behaviour is assumed. The failure loads of solid ice are studied with slip-line theory using the Mohr-Coulomb failure criterion. The pressure distributions due to extrusion of crushed ice are studied using both viscous and granular models. The effective load of a section is considered to be the average of instantaneous loads during the process. A simplified method to calculate the effective load is formed for various contact geometry and ice strength parameters. The total load of a blade is the integrated effective loads of each section. The calculated total load is validated against some measured full-scale values. A relatively good result is achieved.
Original languageEnglish
QualificationDoctor Degree
Awarding Institution
  • Aalto University
Supervisors/Advisors
  • Varsta, Petri, Supervisor, External person
Award date15 May 1998
Place of PublicationEspoo
Publisher
Print ISBNs951-38-5227-X
Electronic ISBNs951-38-5228-8
Publication statusPublished - 1998
MoE publication typeG4 Doctoral dissertation (monograph)

Fingerprint

Propellers
Ice
Pressure distribution
Spalling
Crushing
Pendulums
Extrusion
Hydrodynamics
Experiments
Cracks

Keywords

  • propellers
  • propeller blades
  • ice loads
  • loads (forces)
  • icebrakers

Cite this

Soininen, H. (1998). A propeller-ice contact model: Dissertation. Espoo: VTT Technical Research Centre of Finland.
Soininen, Harri. / A propeller-ice contact model : Dissertation. Espoo : VTT Technical Research Centre of Finland, 1998. 119 p.
@phdthesis{0db5a01e4415448888655842919a4f7c,
title = "A propeller-ice contact model: Dissertation",
abstract = "The propeller-ice loads consist of both actual contact loads due to propeller penetration into an ice block and non-contact loads that are hydrodynamic disturbance loads generated by the presence of an ice block in the vicinity of a propeller. In this work the contact loads are studied experimentally during a milling type open propeller ice contact. A model of the ice failure process is developed based on the experiments. An effective load model is also developed in order to be able to calculate load levels. In the laboratory experiments a tool having a propeller-like profile was attached to a pendulum and impacted with an ice sheet. The global loads on the tool and the pressure distribution along the tool profile at mid-depth of the ice sheet were measured. The failure process was observed. A process model was formed. The blade leading edge opens cracks towards the groove formed by the previous blade and accordingly the face side hardly experiences any contact at all. On the back side a spall is formed and the ice is crushed within the spall. In the case of large confinement local crushing may also occur instead of spalling. The crushed ice is extruded towards both the leading edge and the trailing edge of the profile. Two-dimensional behaviour is assumed. The failure loads of solid ice are studied with slip-line theory using the Mohr-Coulomb failure criterion. The pressure distributions due to extrusion of crushed ice are studied using both viscous and granular models. The effective load of a section is considered to be the average of instantaneous loads during the process. A simplified method to calculate the effective load is formed for various contact geometry and ice strength parameters. The total load of a blade is the integrated effective loads of each section. The calculated total load is validated against some measured full-scale values. A relatively good result is achieved.",
keywords = "propellers, propeller blades, ice loads, loads (forces), icebrakers",
author = "Harri Soininen",
note = "Project code: V8SU00273",
year = "1998",
language = "English",
isbn = "951-38-5227-X",
series = "VTT Publications",
publisher = "VTT Technical Research Centre of Finland",
number = "343",
address = "Finland",
school = "Aalto University",

}

Soininen, H 1998, 'A propeller-ice contact model: Dissertation', Doctor Degree, Aalto University, Espoo.

A propeller-ice contact model : Dissertation. / Soininen, Harri.

Espoo : VTT Technical Research Centre of Finland, 1998. 119 p.

Research output: ThesisDissertationMonograph

TY - THES

T1 - A propeller-ice contact model

T2 - Dissertation

AU - Soininen, Harri

N1 - Project code: V8SU00273

PY - 1998

Y1 - 1998

N2 - The propeller-ice loads consist of both actual contact loads due to propeller penetration into an ice block and non-contact loads that are hydrodynamic disturbance loads generated by the presence of an ice block in the vicinity of a propeller. In this work the contact loads are studied experimentally during a milling type open propeller ice contact. A model of the ice failure process is developed based on the experiments. An effective load model is also developed in order to be able to calculate load levels. In the laboratory experiments a tool having a propeller-like profile was attached to a pendulum and impacted with an ice sheet. The global loads on the tool and the pressure distribution along the tool profile at mid-depth of the ice sheet were measured. The failure process was observed. A process model was formed. The blade leading edge opens cracks towards the groove formed by the previous blade and accordingly the face side hardly experiences any contact at all. On the back side a spall is formed and the ice is crushed within the spall. In the case of large confinement local crushing may also occur instead of spalling. The crushed ice is extruded towards both the leading edge and the trailing edge of the profile. Two-dimensional behaviour is assumed. The failure loads of solid ice are studied with slip-line theory using the Mohr-Coulomb failure criterion. The pressure distributions due to extrusion of crushed ice are studied using both viscous and granular models. The effective load of a section is considered to be the average of instantaneous loads during the process. A simplified method to calculate the effective load is formed for various contact geometry and ice strength parameters. The total load of a blade is the integrated effective loads of each section. The calculated total load is validated against some measured full-scale values. A relatively good result is achieved.

AB - The propeller-ice loads consist of both actual contact loads due to propeller penetration into an ice block and non-contact loads that are hydrodynamic disturbance loads generated by the presence of an ice block in the vicinity of a propeller. In this work the contact loads are studied experimentally during a milling type open propeller ice contact. A model of the ice failure process is developed based on the experiments. An effective load model is also developed in order to be able to calculate load levels. In the laboratory experiments a tool having a propeller-like profile was attached to a pendulum and impacted with an ice sheet. The global loads on the tool and the pressure distribution along the tool profile at mid-depth of the ice sheet were measured. The failure process was observed. A process model was formed. The blade leading edge opens cracks towards the groove formed by the previous blade and accordingly the face side hardly experiences any contact at all. On the back side a spall is formed and the ice is crushed within the spall. In the case of large confinement local crushing may also occur instead of spalling. The crushed ice is extruded towards both the leading edge and the trailing edge of the profile. Two-dimensional behaviour is assumed. The failure loads of solid ice are studied with slip-line theory using the Mohr-Coulomb failure criterion. The pressure distributions due to extrusion of crushed ice are studied using both viscous and granular models. The effective load of a section is considered to be the average of instantaneous loads during the process. A simplified method to calculate the effective load is formed for various contact geometry and ice strength parameters. The total load of a blade is the integrated effective loads of each section. The calculated total load is validated against some measured full-scale values. A relatively good result is achieved.

KW - propellers

KW - propeller blades

KW - ice loads

KW - loads (forces)

KW - icebrakers

M3 - Dissertation

SN - 951-38-5227-X

T3 - VTT Publications

PB - VTT Technical Research Centre of Finland

CY - Espoo

ER -

Soininen H. A propeller-ice contact model: Dissertation. Espoo: VTT Technical Research Centre of Finland, 1998. 119 p.