Discussion of an evaluation method for mode I fracture toughness and bending strength perpendicular to grain with structural glulam
2010
Kambe, W., Tokyo Univ. of Science, (Japan). Faculty of Engineering | Iijima, Y.
In the latest articles, the strength of bolted connections loaded perpendicular to the grain have been studied with fracture mechanics. To estimate the strength of such connections, we need some material properties, e.g., fracture toughness and bending strength perpendicular to the grain (the properties used in the previous papers). However, the test method for bending strength was not described, and the number of test samples was insufficient. Therefore, evaluation of the data for construction design and establishment of a database is important. In this study, we conducted CT tests, three-point bending tests for the strength perpendicular to the grain and block shear tests. Additionally we analyzed the data by statistical methods. As a result, the 5% lowest value based on two-parameter Weibull distribution with 15% of the lower data is the lowet of all statistical methods. The 5% lowest value based on the normal distribution and the two-parameter Weibull distribution with 15% of the lower data, and the 5th percentile value based on ISO13910 are lower by all methods. Next the average value and standard deviation of model fracture toughness and bending strength perpendicular to the grain, by strength grading of three wood species, are presented in this paper.
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