Abstract:

Based on the models of tracheid and ray cell, and by means of computer sampling simulation, the longitudinal elastic moduli were evaluated with corresponding equations and calculating methods for juvenile and mature wood from plantation Chinese Fir(Cunninghamia lanceolata) and Masson Pine (Pinus massoniana).There was a great agreement between estimated values and measured values for the elastic moduli of two species. This research report presented a practical way to study on the longitudinal elastic modulus of wood from above two species and ones with similar structure, and it was useful to develop the theory on the mechanical behaviors of softwoods.Variations of the longitudinal elastic modulus were estimated for specimens from Chinese Fir and Masson Pine when latewood percentage and structural parameters of tracheid were changed in the specimens. Results showed that the longitudinal elastic moduli increased with increasing of latewood percentage, tracheid length,and thickness of cell wall, and it decreased with increasing of radial and tangential diameter of tracheid. Finding and conclusion in this paper can be used in the practice to improve the wood properties of softwood through using the modern biological technology.

Key words: Softwood, Tracheid, Ray, Elastic modulus