激励磁场和铁粉含量对磁性聚氨酯泡沫吸声性能的影响

Effect of excitation magnetic field and iron powder content on sound absorption properties of magnetic polyurethane foam

添加了磁性颗粒的新型聚氨酯泡沫因其既具有泡沫材料优良的吸声性能又具备智能材料的可调可控的特点,成为多功能声学材料领域新的研究热点。磁性聚氨酯泡沫的吸声特性与其制备原料和制备条件有密切的关系,然而关于铁粉含量和激励磁场对材料吸声性能的影响目前尚无一致且完整的结论。制备了50、100、150和200 mT等4种不同激励磁场条件下,分别添加15%、40%和80%(质量分数)等3种不同羟基铁粉质量百分数的10种磁性聚氨酯泡沫试样。旨在研究激励磁场强度和铁粉含量等制备条件对磁性聚氨酯泡沫吸声性能的影响。利用阻抗管通过传递函数法实验测试得到了各试样在64~1600 Hz频率范围内的吸声系数曲线。结果表明增加铁粉含量在总体上提高了测试频段内的吸声系数,而激励磁场的增加会导致吸声系数曲线右移,并且提高吸声系数的峰值。铁粉含量和激励磁场强度综合影响磁性泡沫的吸声性能,磁性聚氨酯泡沫的吸声系数频率特性可根据应用需求进行设计。

The new polyurethane foam with magnetic particles has become a new research focus in the field of multifunctional acoustic materials because of its excellent sound absorption properties and controllable properties as a smart material.The sound absorption properties of magnetic polyurethane foam are closely related to the preparation of raw materials and preparation conditions.However,there are no consistent and complete conclusions about the influence of iron powder content and excitation magnetic field on the sound absorption properties of magnetic polyurethane foam.In this paper,10 kinds of magnetic polyurethane foam samples with 3 different magnetic particle percentages of 15wt%,40wt%and 80wt%,are prepared under different excitation conditions of 50 mT,100 mT,150 mT and 200 mT,respectively.The purpose of this study is to study the influence of magnetic field strength and iron powder content on the sound absorption properties of magnetic polyurethane foam.The sound absorption coefficient curves of each sample in the frequency range of 64~1600 Hz were obtained by using impedance tube and transfer function method.The results show that increasing the content of iron powder can improve the sound absorption coefficient band as a whole within the test frequency,while the increase of magnetic field leads to the right shift of sound absorption coefficient curve and increase the peak value of sound absorption coefficient.The iron powder content of the raw material and the excitation magnetic field intensity affect the sound absorption properties of magnetic polyurethane foam comprehensively,and the sound absorption coefficient frequency characteristics of magnetic polyurethane foam can be designed according to application requirements.