Strain Measurements within Fibre Boards. Part II: Strain Concentrations at the Crack Tip of MDF Specimens Tested by the Wedge Splitting Method

Materials

Gerhard Sinn¹  Ulrich Müller³  Johannes Konnerth² 

[1] Department of Material Sciences and Process Engineering, Institute of Physics and Material Sciences, BOKU–University of Natural Resources and Life Sciences, Peter Jordan Straße 82, Vienna AT-1190, Austria;Department of Material Sciences and Process Engineering, Institute of Wood Technology and Renewable Resources, BOKU–University of Natural Resources and Life Sciences, Konrad Lorenzstraße 24, Tulln an der Donau 3430, Austria; E-Mail:;Wood K plus–Competence Centre for Wood Composites and Wood Chemistry, Altenberger Straße 69, Linz 4040, Austria; E-Mails:

关键词: electronic laser speckle interferometry;    wedge splitting;    medium density fiber board;    fracture mechanics;    process zone;   

DOI  :  10.3390/ma5081495

来源: mdpi

【 摘 要 】

This is the second part of an article series where the mechanical and fracture mechanical properties of medium density fiberboard (MDF) were studied. While the first part of the series focused on internal bond strength and density profiles, this article discusses the fracture mechanical properties of the core layer. Fracture properties were studied with a wedge splitting setup. The critical stress intensity factors as well as the specific fracture energies were determined. Critical stress intensity factors were calculated from maximum splitting force and two-dimensional isotropic finite elements simulations of the specimen geometry. Size and shape of micro crack zone were measured with electronic laser speckle interferometry. The process zone length was approx. 5 mm. The specific fracture energy was determined to be 45.2 ± 14.4 J/m² and the critical stress intensity factor was 0.11 ± 0.02 MPa.

【 授权许可】

CC BY   
© 2012 by the authors; licensee MDPI, Basel, Switzerland.