【摘要】 利用Flax等提出的声共振散射模型,以铁中多孔石墨为例数值上研究了平面声纵波入射时固体中多孔媒质球体背向散射纵波和散射横波的频谱以及不同阶分波的共振散射谱,并由此研究了铁中多孔球形石墨不同模式的共振频率随石墨孔隙率的变化。结果表明,球形石墨的背向散射谱及各阶分波中的共振频率均随孔隙率的增加向低频移动,其形态也发生变化。因此,如果用实验测定球墨铸铁样品的超声背向散射谱或各阶分波中共振频率,有可能确定多孔石墨的孔隙率。更多还原

【Abstract】 The acoustic resonant scattering spectra of a porous sphere embedded in an elastic matrix is studied based on the resonant scattering theory proposed by Flax et al. Taking nodular cast iron as an example, some numerical computations are made for acoustic backscattering and resonant scattering spectra of certain partial waves. The change of acoustic resonance frequencies of different modes as a function of the porosity of porous spherical scatterers is also simulated. The numerical results show that the backscattering spectra change remarkably and the resonance peaks in the scattered partial waves of each order move to lower values with increasing porosity. Therefore experimental measurements of the backscattering spectra or resonance frequencies of the scattered partial waves may be used in evaluation of the porosity of spherical graphite in solid matrix.更多还原