Application of instrumented micro-indentations to 'in situ' mechanical characterization of wooden structures: Part II - Analysis of different species

Flat punch instrumented micro-indentation tests were performed and analysed by using an original approach to assess strength characteristics of different wooden species. The quality of the perpendicular compression strength-indentation load correlation, using this particular type of indenter, was investigated. It is found that some characteristic force values of the instrumented micro-indentation test are very well correlated to perpendicular compression ultimate strength. In this work, the characterization on pinewood was first led, by using highly selected 'clear' and 'straight grained' materials which, at the same time, were not affected by bad orientation of annual ring as well as by a moisture level higher than 12%. Then, in order to generalize the experimental procedure, a broadening of the method to generic 'clear' and 'straight grained' pinewood, fir wood and larch wood samples, characterized by a variable moisture level and annual ring orientation, was performed. The interpretation of the load over displacement trace, the development of an experimental set-up, the execution of tests on various materials and the estimation of reliability of correlations by a strict statistic approach are also discussed in detail. (c) 2005 Elsevier Ltd. All rights reserved.