Experimental investigation of mechanical and fracture properties of offshore wind monopile weldments: SLIC interlaboratory test results

A. Mehmanparast, J. Taylor, F. Brennan, I. Tavares

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

S355 structural steel is commonly used in fabrication of offshore structures including offshore wind turbine monopiles. Knowledge of mechanical and fracture properties in S355 weldments and the level of scatter in these properties is extremely important for ensuring the integrity of such structures through engineering critical assessment. An interlaboratory test programme was created to characterise the mechanical and fracture properties of S355 weldments, including the base metal, heat-affected zone, and the weld metal, extensively. Charpy impact tests, chemical composition analysis, hardness tests, tensile tests, and fracture toughness tests have been performed on specimens extracted from each of the 3 material microstructures. The experimental test results from this project are presented in this paper, and their importance in structural integrity assessment of offshore wind turbine monopiles has been discussed. The results have shown a decreasing trend in the Charpy impact energy and Jmax values with an increase in yield stress from base metal to heat-affected zone to weld metal. Moreover, the JIC fracture toughness value in the heat-affected zone and weld metal is on average around 60% above and 40% below the base metal value, respectively. In addition, the average Charpy impact energy value in the heat-affected zone and weld metal is around 5% and 30% below the base metal value, respectively. The effects of mechanical and fracture properties on the critical crack size estimates have been investigated, and the results are discussed concerning the impact of material properties on structural design and integrity assessment of monopiles.

LanguageEnglish
Number of pages17
JournalFatigue and Fracture of Engineering Materials and Structures
Early online date31 May 2018
DOIs
Publication statusE-pub ahead of print - 31 May 2018

Fingerprint

Metals
Heat affected zone
Welds
Offshore wind turbines
Structural integrity
Fracture toughness
Steel
Offshore structures
Structural design
Yield stress
Materials properties
Hardness
Cracks
Fabrication
Microstructure
Chemical analysis

Keywords

  • fracture toughness
  • monopile
  • offshore wind
  • weldments

Cite this

@article{272a10bdc2964831a4358a7af3a5b1eb,
title = "Experimental investigation of mechanical and fracture properties of offshore wind monopile weldments: SLIC interlaboratory test results",
abstract = "S355 structural steel is commonly used in fabrication of offshore structures including offshore wind turbine monopiles. Knowledge of mechanical and fracture properties in S355 weldments and the level of scatter in these properties is extremely important for ensuring the integrity of such structures through engineering critical assessment. An interlaboratory test programme was created to characterise the mechanical and fracture properties of S355 weldments, including the base metal, heat-affected zone, and the weld metal, extensively. Charpy impact tests, chemical composition analysis, hardness tests, tensile tests, and fracture toughness tests have been performed on specimens extracted from each of the 3 material microstructures. The experimental test results from this project are presented in this paper, and their importance in structural integrity assessment of offshore wind turbine monopiles has been discussed. The results have shown a decreasing trend in the Charpy impact energy and Jmax values with an increase in yield stress from base metal to heat-affected zone to weld metal. Moreover, the JIC fracture toughness value in the heat-affected zone and weld metal is on average around 60{\%} above and 40{\%} below the base metal value, respectively. In addition, the average Charpy impact energy value in the heat-affected zone and weld metal is around 5{\%} and 30{\%} below the base metal value, respectively. The effects of mechanical and fracture properties on the critical crack size estimates have been investigated, and the results are discussed concerning the impact of material properties on structural design and integrity assessment of monopiles.",
keywords = "fracture toughness, monopile, offshore wind, weldments",
author = "A. Mehmanparast and J. Taylor and F. Brennan and I. Tavares",
year = "2018",
month = "5",
day = "31",
doi = "10.1111/ffe.12850",
language = "English",
journal = "Fatigue and Fracture of Engineering Materials and Structures",
issn = "8756-758X",

}

TY - JOUR

T1 - Experimental investigation of mechanical and fracture properties of offshore wind monopile weldments

T2 - Fatigue and Fracture of Engineering Materials and Structures

AU - Mehmanparast, A.

AU - Taylor, J.

AU - Brennan, F.

AU - Tavares, I.

PY - 2018/5/31

Y1 - 2018/5/31

N2 - S355 structural steel is commonly used in fabrication of offshore structures including offshore wind turbine monopiles. Knowledge of mechanical and fracture properties in S355 weldments and the level of scatter in these properties is extremely important for ensuring the integrity of such structures through engineering critical assessment. An interlaboratory test programme was created to characterise the mechanical and fracture properties of S355 weldments, including the base metal, heat-affected zone, and the weld metal, extensively. Charpy impact tests, chemical composition analysis, hardness tests, tensile tests, and fracture toughness tests have been performed on specimens extracted from each of the 3 material microstructures. The experimental test results from this project are presented in this paper, and their importance in structural integrity assessment of offshore wind turbine monopiles has been discussed. The results have shown a decreasing trend in the Charpy impact energy and Jmax values with an increase in yield stress from base metal to heat-affected zone to weld metal. Moreover, the JIC fracture toughness value in the heat-affected zone and weld metal is on average around 60% above and 40% below the base metal value, respectively. In addition, the average Charpy impact energy value in the heat-affected zone and weld metal is around 5% and 30% below the base metal value, respectively. The effects of mechanical and fracture properties on the critical crack size estimates have been investigated, and the results are discussed concerning the impact of material properties on structural design and integrity assessment of monopiles.

AB - S355 structural steel is commonly used in fabrication of offshore structures including offshore wind turbine monopiles. Knowledge of mechanical and fracture properties in S355 weldments and the level of scatter in these properties is extremely important for ensuring the integrity of such structures through engineering critical assessment. An interlaboratory test programme was created to characterise the mechanical and fracture properties of S355 weldments, including the base metal, heat-affected zone, and the weld metal, extensively. Charpy impact tests, chemical composition analysis, hardness tests, tensile tests, and fracture toughness tests have been performed on specimens extracted from each of the 3 material microstructures. The experimental test results from this project are presented in this paper, and their importance in structural integrity assessment of offshore wind turbine monopiles has been discussed. The results have shown a decreasing trend in the Charpy impact energy and Jmax values with an increase in yield stress from base metal to heat-affected zone to weld metal. Moreover, the JIC fracture toughness value in the heat-affected zone and weld metal is on average around 60% above and 40% below the base metal value, respectively. In addition, the average Charpy impact energy value in the heat-affected zone and weld metal is around 5% and 30% below the base metal value, respectively. The effects of mechanical and fracture properties on the critical crack size estimates have been investigated, and the results are discussed concerning the impact of material properties on structural design and integrity assessment of monopiles.

KW - fracture toughness

KW - monopile

KW - offshore wind

KW - weldments

UR - http://www.scopus.com/inward/record.url?scp=85047788029&partnerID=8YFLogxK

UR - https://onlinelibrary.wiley.com/journal/14602695

U2 - 10.1111/ffe.12850

DO - 10.1111/ffe.12850

M3 - Article

JO - Fatigue and Fracture of Engineering Materials and Structures

JF - Fatigue and Fracture of Engineering Materials and Structures

SN - 8756-758X

ER -