effect of drying on wood fracture surfaces from specimens loaded in wet condition

• Published in: Wood science and technology Vol. 32; no. 2; pp. 83 - 94
• Main Authors: Kifetew, G, Thuvander, F, Berglund, L, Lindberg, H
• Format: Journal Article
• Language: English
• Published: Berlin Springer 1998; Springer Nature B.V
• Subjects: Applied sciences; Cell walls; damage; Drying; Drying ovens; Exact sciences and technology; Failure mechanisms; Forestry and Wood Technology; fracture; Fracture surfaces; greenwood; latewood; Mechanical woodworking and drying; microscopy; Pinus sylvestris; Polymer industry, paints, wood; Polymera konstruktionsmaterial; Polymeric Composite Materials; Scanning electron microscopy; Skog och träteknik; Wood; Wood. Paper. Non wovens; Scanning electron microscopy; Gymnospermae; Coniferales; Spermatophyta; Softwood; Fracture surface; Experimental study; Pinus sylvestris; Late wood; Early wood; Drying
• ISSN: 0043-7719; 1432-5225; 1432-5225
• DOI: 10.1007/BF00702589

The study describes the effect of drying on fracture surfaces of Scots pine Pinus silvestris L. Microtomed specimens of isolated and combined early- and latewood, in green and oven-dried/resoaked state were loaded to failure in uniaxial tension parallel to the grain. The fracture surfaces were studied using scanning electron microscopy (SEM). Both green early- and latewood samples showed rough fracture surfaces, which in latewood was dominated by intrawall failure. In the resoaked state, transwall failure dominated and fracture surfaces were more flat, indicating a more brittle fracture process. Although variation in the data was large, the strength of the resoaked samples were generally lower than those of paired green samples. The observations support irreversible cell wall damage formed during drying which severely affects the failure mechanism.