Fractal Approach to Sound Absorption Behavior in Cashmere Fiber Assembly

Sound absorption property in fiber assembly requires specifying relationship with structural characteristic. Fractal approach seems to be a potentially useful tool to describe hierarchical systems and is suitable to link the structure and acoustic properties of fiber assembly. In this paper, we show a new method to detect the inner microstructure of cashmere fiber assembly, which is micro-CT scanner. Furthermore, the pore area fractal dimension of fiber assembly is calculated, using 2D images of the inner cross-section. And the sound absorbing behavior of assembly is measured.. Correlation between the fractal dimension of fiber assembly and its structural characteristics and the acoustic absorption property is also studied. The results indicate that the pore area fractal dimension is negative correlated with porosity of assembly, and the maximum acoustic absorption coefficient grows linearly with increasing pore area fractal dimension, while the critical frequency moves towards lower frequency.