木材径向反复受压应力-应变模型研究

通过木材小清材试样的单调加载和反复加卸载试验,研究了木材径向全表面受压试样在单调加载和反复加卸载作用下的应力-应变关系.试验结果表明:单调加载应力-应变曲线和反复加卸载骨架曲线在应变小于0.16时基本重合,在应变大于0.16时,两者数值差异逐渐增大,但仍可由同一数学模型进行描述;木材反复卸载、再加载过程中,再加载路径与卸载路径分别由线性和双折线模型表达.综合考虑木材单向横纹受压以及反复加卸载过程中的典型特征,建立了反复荷载作用下木材径向全表面受压应力-应变模型.基于所建模型编写了MATLAB程序,对比分析了模型计算结果与试验结果,两者吻合较好.

Research on Radial Stress-strain Model of Wood under Repeated Compressive Loading

The radial stress-strain relationship of wood under monotonic and repeated compressive load was studied, according to the tests on the clear wood specimens under monotonic and repeated compressive load. The results show that the monotonic compressive stress-strain curve and the skeleton curve of repeated compressive stress-strain curve are well coincident when the strain is less than 0.16. When the strain is over 0.16, the difference between these two is gradually increased, but they can still be described by the same mathematical model. In the cyclical process, the reloading path and unloading path are expressed by linear and double fold line models, respectively. Based on the comprehensive consideration of the typical characteristics of unidirectional compression and repeated loading and unloading, the stress-strain model of wood under repeated compressive load was established. Based on the established model, a MATLAB program was then written into the MATLAB software. Good consistency was found between the predictions of the model and the test results.