| Popis: |
This research aims to provide theoretical proof for the further study on the factors of stress relaxation under different conditions. In this study, use Pinus sylvestris and dynamic stress-strain test system, though change temperature and moisture to research the stress relaxation of wood. The results showed that the temperature and moisture content on the stress relaxation have a significant impact. With temperature enhancing or moisture content rising, stress dramatically relaxation and residual stress rapidly decreased. In other words, the initial stress decreased gradually and the relaxation rate was rise. It was also found that, under same conditions, compared with the tangential section of the Pinus sylvestris, the radial section has larger initial stress and smaller stress relaxation rate. Besides, the initial stress of late wood is larger than early wood but the stress relaxation rate is smaller. Key words: Pinus sylvestris, tensile stress relaxation |
