Study on the four-point bending beam method to improve the testing accuracy for the elastic constants of wood

Abstract

Using the static analysis of ANSYS 19 longitudinal, radial, and transverse beam specimens of spruce, pine, and beech were subjected to stress and strain analysis under symmetrical four-point bending and asymmetrical four-point bending, respectively. The effects of wood grain on the surface of the specimen and its stress properties on the transverse and longitudinal strain at the center of the specimen surface were studied experimentally. The results show that the four-point bending beam method is suitable for testing the elastic modulus, Poisson's ratio and shear modulus of wood. The elastic modulus, Poisson's ratio and shear modulus of Larch chord and radial and Western Canadian spruce transverse specimens were tested by four point bending beam method. Their effectiveness was verified by axial tension method, square plate torsional strain method and free rod torsional vibration method. The four-point bending method of two groups of half bridge test has successfully improved the test accuracy of wood Poisson's ratio, and its effectiveness has been verified by axial tension method.The asymmetric four point bending method adopts the ±45°strain gauge full bridge measurement method, which is simple and effective to improve the measurement accuracy of wood shear modulus.

Simulation of Spent Fuel Assembly Transport Vertical Drop Based on LS-DYNA

“…The elastic-plastic model is adopted for the constitutive relationship. Considering that the transport cask should meet the economic and safety requirements, the shell material is 304 stainless steel, and the shock absorber is filled with birch wood [8] . The material property parameters are shown in Table 1.…”