FRACTURE TOUGHNESS OF GLULAM ELEMENTS UNDER SUSTAINED LOADING
Abstract
The paper deals with methodology and some results of crack growth diagnostics while testing large and small samples of laminated wood for long-term cracking resistance of the first and second forms of destruction by approaches of fracture mechanics. Methods of fracture mechanics for calculation of wooden structures is rather prospective because the design of solid and laminated wood contains large amounts of various natural and technological heterogeneities such as : knots, fibres slope, cracks of various origins, adhesive bonding to plastic and notched butt joints, trimming, cuts, holes, glued rods. In the samples of plywood there were pre-specified crack shift (second form) and normal margin (the first form). The nature of germination cracks is described. Tests were carried out on levels of stress intensity factor 0,6, 0,7, 0,8-destructive values. Loading time is up to 540 days under long static loading and up to 2 million cycles under cyclic loading. Tests were conducted under laboratory and field conditions. The article reproduces the results of tests on long crack growth resistance large size (140х170х2800 mm) and small (60х60х400 mm) samples under static and cyclic loadings and describes the features of crack germination in specimens under sustained loading. The fracture mechanics parameters are more sensitive to the environmental influences than standardized strength ones. It is possible to use approaches of fracture mechanics to the assessment of bearing capacity of wooden structures along with the traditional approach based on calculating the stresses in the structure.
About the Authors
V. A. Kabanov
Southwest State University
Russian Federation
Russian Federation
A. V. Masalov
Southwest State University
Russian Federation
Russian Federation
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Review
For citations:
Kabanov V.A., Masalov A.V. FRACTURE TOUGHNESS OF GLULAM ELEMENTS UNDER SUSTAINED LOADING. Proceedings of the Southwest State University. 2016;(4):96-102. (In Russ.)
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