Application of instrumented micro-indentations to ‘in situ’ mechanical characterization of wooden structures: Part I—Analysis of highly selected and decayed pinewood samples

The need for an experimental protocol, which allows determining overall mechanical properties of wooden structures by using a local, non-destructive and ‘in situ’ implemented testing procedure, has pushed towards the definition of several methodologies.In this work, an application of an instrumented micro-indentation, based upon a flat punch, is investigated, aimed at defining a technique less affected by typical discontinuities, defects and alterations of wooden materials, which, severely, jeopardize the reliability of all the other available testing procedures.First, a calibration of the experimental procedure is carried out, taking care of the influence on the collected data of the actual samples dimensions, their weight, number of growth rings, growth rings width, distance between indentation location and latewood layer and depth along indentation axis. Then, an application of testing procedure on pinewood is performed and strict criterion in executing experiments and choosing wooden specimens is defined to improve the reliability of results. At last, the capability of instrumented micro-indentations in detecting overall mechanical properties of new and decayed samples is checked out, stating the high sensitivity and effectiveness of the procedure.