Abstract
Reviewing the modern knowledge of Tribology and the past experimental data on friction, the coefficient of friction between wood and steel is not well known especially under a high contact pressure. Thus, a new testing method named compression-pullout test is introduced to measure the sliding coefficients of static and kinetic frictions between wood and steel plates under heavy loading. The most important finding is that the friction is categorized into complete and incomplete frictions. The former is the case that the relative displacement between wood and steel is identical to the sliding as a rigid body, while the latter is that plastic deformation due to shear yielding of wood is associated with the sliding. Heavy contact especially with rough steel is apt to bring incomplete friction, in that the coefficient of friction is smaller than that of the complete friction under light contact. This means that the Amontons-Coulomb's law is not valid in the entire range from light to heavy contact.
