Long-term fracture toughness of wood

Mikael Fonselius

Research output: Book/ReportReport

2 Citations (Scopus)

Abstract

Long-term fracture toughness of spruce, pine and Kerto LVL material has experimentally been determined. In mode II loading (forward shearing mode) an end-cracked beam specimen was used, while the compact tension specimen was used in mode I loading (opening mode). The specimens were exposed to a constant load, while the relative humidity was cyclically changed between 40 and 90 %. The length of a whole cycle was two weeks. In mode II loading the cyclical humidity conditions reduced the time to failure drastically in contrast to constant humidity conditions. For an end-cracked spruce beam loaded to 75 % of its short-term capacity the life time was reduced from 66 to 4 days. The duration of load effect is similar for pine material under cyclic humidity conditions. For Kerto LVL material the effect is more severe. In mode I loading no general conclusions could be drawn, as so few specimens were broken during the loading time of seven months.
Original languageEnglish
Place of PublicationEspoo
PublisherVTT Technical Research Centre of Finland
Number of pages62
ISBN (Print)951-38-3918-4
Publication statusPublished - 1991
MoE publication typeD4 Published development or research report or study

Publication series

SeriesValtion teknillinen tutkimuskeskus. Tutkimuksia - Research Reports
Number718
ISSN0358-5077

Fingerprint

Fracture toughness
Wood
Atmospheric humidity
Shearing

Keywords

  • timber
  • constructional timber
  • spruce
  • pine
  • Kerto LVL
  • fracture toughness
  • moisture content

Cite this

Fonselius, M. (1991). Long-term fracture toughness of wood. Espoo: VTT Technical Research Centre of Finland. Valtion teknillinen tutkimuskeskus. Tutkimuksia - Research Reports, No. 718
Fonselius, Mikael. / Long-term fracture toughness of wood. Espoo : VTT Technical Research Centre of Finland, 1991. 62 p. (Valtion teknillinen tutkimuskeskus. Tutkimuksia - Research Reports; No. 718).
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Fonselius, M 1991, Long-term fracture toughness of wood. Valtion teknillinen tutkimuskeskus. Tutkimuksia - Research Reports, no. 718, VTT Technical Research Centre of Finland, Espoo.

Long-term fracture toughness of wood. / Fonselius, Mikael.

Espoo : VTT Technical Research Centre of Finland, 1991. 62 p. (Valtion teknillinen tutkimuskeskus. Tutkimuksia - Research Reports; No. 718).

Research output: Book/ReportReport

TY - BOOK

T1 - Long-term fracture toughness of wood

AU - Fonselius, Mikael

PY - 1991

Y1 - 1991

N2 - Long-term fracture toughness of spruce, pine and Kerto LVL material has experimentally been determined. In mode II loading (forward shearing mode) an end-cracked beam specimen was used, while the compact tension specimen was used in mode I loading (opening mode). The specimens were exposed to a constant load, while the relative humidity was cyclically changed between 40 and 90 %. The length of a whole cycle was two weeks. In mode II loading the cyclical humidity conditions reduced the time to failure drastically in contrast to constant humidity conditions. For an end-cracked spruce beam loaded to 75 % of its short-term capacity the life time was reduced from 66 to 4 days. The duration of load effect is similar for pine material under cyclic humidity conditions. For Kerto LVL material the effect is more severe. In mode I loading no general conclusions could be drawn, as so few specimens were broken during the loading time of seven months.

AB - Long-term fracture toughness of spruce, pine and Kerto LVL material has experimentally been determined. In mode II loading (forward shearing mode) an end-cracked beam specimen was used, while the compact tension specimen was used in mode I loading (opening mode). The specimens were exposed to a constant load, while the relative humidity was cyclically changed between 40 and 90 %. The length of a whole cycle was two weeks. In mode II loading the cyclical humidity conditions reduced the time to failure drastically in contrast to constant humidity conditions. For an end-cracked spruce beam loaded to 75 % of its short-term capacity the life time was reduced from 66 to 4 days. The duration of load effect is similar for pine material under cyclic humidity conditions. For Kerto LVL material the effect is more severe. In mode I loading no general conclusions could be drawn, as so few specimens were broken during the loading time of seven months.

KW - timber

KW - constructional timber

KW - spruce

KW - pine

KW - Kerto LVL

KW - fracture toughness

KW - moisture content

M3 - Report

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T3 - Valtion teknillinen tutkimuskeskus. Tutkimuksia - Research Reports

BT - Long-term fracture toughness of wood

PB - VTT Technical Research Centre of Finland

CY - Espoo

ER -

Fonselius M. Long-term fracture toughness of wood. Espoo: VTT Technical Research Centre of Finland, 1991. 62 p. (Valtion teknillinen tutkimuskeskus. Tutkimuksia - Research Reports; No. 718).