Fracture and fatigue in wood
Publication Name: John Wiley and Sons Ltd.
Damage in wood is principally the result of fatigue. Fatigue is the process of progressive localised irreversible change in a material, and may culminate in cracks or complete fracture if conditions that initiated or propagated the process persist. Comprehensive understanding of fatigue and fracture in engineered wood components must be founded on a proper understanding of the damage processes.
Although wood is the world’s most widely used structural material, whether measured by volume consumed or value of finished construction, its behaviour is not well understood even by people who have spent their careers studying it.
* What is known about failure processes comes almost entirely from empirical evidence collected for engineering purposes.
* Hypotheses about behaviour of wood are based on macroscopic observation of specimens during and following tests.
* With only limited resources and the need to obtain practical results quickly, the timber engineering research community has steered away from the scientific approach.
* Forestry practices are changing and are known to influence characteristics of wood cells therefore there is a need to periodically reassess the mechanical properties of visually graded lumber the blackbox approach.