Effect of moisture on creep fracture of full scale wooden structural materials

Research Project

Project/Area Number	25450254
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Research Field	Wood science
Research Institution	Utsunomiya University (2015-2016) Building Research Institute (2013-2014)
Principal Investigator	Nakajima Shiro 宇都宮大学, 地域デザイン科学部, 教授 (00344010)
Co-Investigator(Kenkyū-buntansha)	中川貴文国土技術政策総合研究所, 建築研究部, 主任研究官 (60414968)
Project Period (FY)	2013-04-01 – 2017-03-31
Project Status	Completed (Fiscal Year 2016)
Budget Amount *help	¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000) Fiscal Year 2015: ¥390,000 (Direct Cost: ¥300,000、Indirect Cost: ¥90,000) Fiscal Year 2014: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000) Fiscal Year 2013: ¥3,640,000 (Direct Cost: ¥2,800,000、Indirect Cost: ¥840,000)
Keywords	クリープ破壊 / クリープ変形 / 製材 / 構造用単板積層材 / 実大材 / 標準状態 / 湿度変動環境下 / 粘弾性モデル / 湿度変動下 / 個別要素法 / 木質複合材料 / 曲げ強度 / 水分分布
Outline of Final Research Achievements	The effect of the moisture on the creep fracture of full scale lumbers and full scale laminated veneer lumbers were clarified through the test results of the long term loading tests. The long term loading test was conducted in two different climates, the climate of the standard condition and the dry and humid cyclic climate. The creep fracture and the duration of time to failure was estimated by modeling the test specimens as small elements of viscoelastic materials. Common to the both materials the duration of time to failure was shorter and the deformation was larger for the test specimens tested in the dry and humid cyclic climate. The test results were well estimated by the proposed model. Though the absolute deformation was not well estimated and this is an agenda for future research works.