古建筑落叶松木构件自然老化材性变化OA北大核心CSTPCD

In order to explore the change of wood properties of ancient building members under natural aging,a part of larch(Larix principis-rupprechtii Mayr)timber member of ancient building,which is about 350 years old,and a new timber with the same species and similar annual wheel width were used in this study.Small clear specimens were processed to measure the material properties(color,dry density and material mechanics property parameters)and non-destructive testing(NDT)parameters(micro-drill resistance value and velocity of ultrasonic wave).The nondestructive testing,physical and mechanical properties parameters of specimens were compared to analyze the variation and distribution,and then the multiple regression model for the physical and mechanical properties of ancient building timber were established based on the parameters measured in this study.The study results showed that the measured material property parameters and NDT parameters of the natural ageing wood specimens were significantly attenuated.And there is a highly significant difference in the color of natural aging specimens and new timber specimens.It was also found that the coefficients of variation of the parameters of natural aging specimens were all higher than those of new timber specimens,but both of them conformed to a normal distribution.Moreover,the developed model for the evaluation of physical and mechanical property parameters of larch timber members has a good evaluation performance.