Mechanical characteristics of aged Hinoki wood from Japanese historical buildings (short title: Mechanics of historical hinoki wood)

Abstract Wood is present in many cultural heritage object s in Japan thanks to its capacity to resist over long period of time. However, the evolution of its properties in regular use remains insufficiently known. The present study on the effect of wood aging takes advantage of the Japanese context where building traditions have been maintained for centuries. 3 -point bending test s were perf ormed in longitudinal (L) and radial (R) directions on small clear wood specimens cut from 8 historical samples and one modern reference considered of high quality by craftsmen. Although aged wood appeared more rigid and stronger than recent wood , after de nsity and humidity corrections were applied no significant variation of L and R rigidity or L strength was observed . The post -linear behaviour, however, was drastically influenced by wood age especially in R direction where the strength and rupture energy decreased markedly with the time elapsed since the wood was processed. Well -preserved a ged wood can be considered as safe as long as it is not loaded perpendicular to grain . Abstract Le bois est present dans de nombreux objets du patrimoine en bois du Ja pon du fait de sa capacite a resister sur de longues durees 7RXWHIRLVO¶pYROXWLRQGHVHVSURSULpWpVHQXVDJHdemeure insuffisamment connu e. /DSUpVHQWHpWXGHVXUO¶HIIHWGXYLHLOOLVVHPHQWGXERLVWLUHparti du contexte japonais ou les traditions construc tive s ont ete maintenues depuis des siecles. Les essais de flexion 3 points ont ete realises dans les directions longitudinal e (L) et radial e (R) VXUGHSHWLWVpFKDQWLOORQVGHERLVLVVXVGHSUpOqYHPHQWVKLVWRULTXHVHWG¶XQHUpIpUHQFHmoderne consideree d e la meilleure qualite par des restaurateurs . Bien que le bois âge semble plus rigide et plus resistant que le bois r ecent, apres correction sur la densite et O¶humidite G¶pTXLOLEUH aucune variation significative de rigidite L et R , ni de resistance L n¶HV t observee . Le comportement post -lineaire est par contre fortement influenc e SDUO¶kJHGXERLVVXUWRXWhal-00538802, version 1 - 18 Jan 2011