速生杨木改性材蠕变性能的初步研究

A Primary Study of the Creep Properties of Modified Fast-growing Poplars

为了研究改性增强后的杨木蠕变性能,对杨木素材进行不同处理,分别用浓度为15%、25%、40%的酚醛树脂胶和浓度为30%的脲醛树脂胶对试件进行处理,并测量其最大破坏力.分别用其最大载荷的30%和50%的力进行加载试验.对不同处理方法所得到材料的性能进行分析.结果如下:(1)在不同的应力水平下,同类型的试件蠕变变形不遵循相同的规律;在相同应力水平下,不同材料瞬时弹性变形相差不大.(2)素材无论是在极限强度的30%的力还是50%的力作用下其稳定性都是最差的.(3)用不同浓度的酚醛树脂胶处理过的试件在极限强度的30%或50%的力的作用下,稳定性能比素材强得多,并且不同浓度处理的试件的稳定性差别不大.(4)经脲醛树脂胶处理后的试件稳定性最好.(5)相对湿度是影响蠕变的重要因素,特别是对素材影响最大.

In order to study the creep properties of a modified fast-growing poplar, the paper treated its raw materials in different ways according to practical situations by using phenol-formaldehyde resin adhesive of 15%, 25% and 40% concentrations and urea- formaldehyde of 30% concentration. Its maximum fracture force was measured and its load test was conducted by using 30% and 50% force of the maximum load. An analysis of the data from different treating ways shows： （1） at different stress levels, the creep of same-type samples does not follow a same rule and at a same stress level, there is little difference of instantaneous elastic deformation between different materials; （2） whether the raw materials are under the force of 30% or 50%ultimate strength, their stability is the worst; （3） the stability of the samples treated with different concentrations of phenol-formaldehyde is, under the force of 30% or 50% ultimate strength, much stronger than that of the raw materials arid there is little difference of stability among the samples treated by different concentrations; （4） the samples treated with urea-formaldehyde resin have the best stability; and （5） relative humidity is an important factQr to affect its creep, especially the creep of its raw materials.