Research On Influence Of Cracks On Acoustics Capability Of Wood

Our country is faced with forestry problem,this serious problem mainly is the demand of wood is more and more huge and the forest resource of our county is more and more less. We should deforest reasonable and increase the value of wood. Wood cracks will reduce the quality of the wood and ruin the using value of the wood, so, the research which is focus on the Wood cracks become significative.In our reaseach, the purpose of the experiment is to mensurate the crack information effective and veracious without making cracks artificially. In this way, we can use the wood resource rensonbleIn this paper, four kinds of wood are chosen as research object, such as poplar, birch, larch, Pinus sylvestris. On the surface and internal of the specimen, we prefabricat different sizes of cracks, the direction of which are paralleled the texture ,plumded the texture and along the two directions. The standing wave method is introduced in the experiment, the frequency range of the incident acoustic wave is 125Hz-2000Hz, the normal sound absorption coefficient of four kinds of wood, which are whole or have small cracks and serious cracks , are examined. Analyzing and comparing the influence of different species, different sizes of crack of the sample to the sound absorption coefficient.To predict properties of wood the variance of the thermal conductivity neural network versus the physical a model based on artificial was proposed. The forecast results show that the model with higher accuracy.The results show that the wood cracks have obvious influence to the sound absorption coefficient, and the value of sound absorption coefficient will be increased by the augment of the crack size of the sample.The purpose of this study is to provide a theoretical basis in the non-destructive testing of wood.