Work of fracture and of chips formation during linear cutting of particle-board

摘要

The aim of the study was to determine the work of fracture and the work of chips plastic deformation of laminated particle-board distinguishing, whole material and outer layers. Work of fracture obtained with the microtome cutting was compared to the specific fracture energy obtained with splitting tests. Experiments were performed on an instrumented microtome and splitting tests equipment. Materials subjected to study were particle-boards, which were produced to perform systematic studies of the material influence on the linear cutting process. Density profiles establishing each part of boards were determined with an X-ray densitometry. The results on the consumed energy show that the majority of the energy is consumed by the creation of chips and a smaller part of the energy is used for the work of fracture. Chips' forms, their order in the board and type of glue influence the energy of cutting more than boards' density profiles. The specific fracture energy calculated by non-linear elastic fracture mechanics physically characterise materials and enables materials comparison. Nevertheless, values obtained by this method cannot be applied directly to determine the work of fracture in a cutting process, as the crack path and process zone are different. Therefore, it is proposed to define the fracture toughness by means of linear elastic fracture mechanics without considering the consumed energy during crack propagation and to add values which have been obtained from separate measurements of friction and compression.