Fracture toughness of wood and transparent wood biocomposites in the toughest LT-direction

• Fracture toughness and mechanisms of crack growth are characterized for transparent wood polymer biocomposites and compared to native wood, with the crack normal to the fiber direction (LT fracture plane). Side-grooved specimen geometries generated pure mode I crack growth, whereas previous investigations commonly report 90° crack path deflection. Crack growth micromechanisms were analyzed by experimental fracture tests and in-situ microscopy observations. Large damage zones around the crack tip with fiber bundle bridging and pull-out were observed in the crack wake, justifying more advanced cohesive zone modeling suitable for composite materials design. The polymer matrix resulted in much higher fracture energy of the biocomposites compared to native wood due to increased local cohesive strength. This strength increased from the polymer contribution and more homogeneous stress distribution in the wood fibers. 

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Kompositmaterial och -teknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Composite Science and Engineering (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik -- Teknisk mekanik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering -- Applied Mechanics (hsv//eng)

Nyckelord

Composite materials

Crack propagation

Ductile fracture

Fracture testing

Fracture toughness

Biocomposite

Cohesive zones

Fiber direction

Fracture plane

In situ fracture test

Mode I crack

Multi-functional materials

Orthotropic

Specimen geometry

Wood polymers

Crack tips

Construction Engineering

Byggteknik

Publikations- och innehållstyp

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