摘要
本文以网络共聚物(蓖麻油/TDI+HEMA)为阻尼材料,对自由阻尼板作了噪声频谱分析,观察到在约千周以上频区,声压级较裸钢板有明显降低,对覆盖阻尼材料的钢条样品的内耗变频测量表明,内耗随频率而增加,说明自由阻尼板声压级的降低是由自身内耗随频率增大所引起。比较了线型聚合物聚碳酸脂后,提出将这一随频率增大内耗分为两部分:一部分为分子链弛豫过程的贡献,另一部分的内耗机制与分子链交联有关,可以用两端钉扎弦的阻尼共振型内耗定性解释。
In″Panel Experiment″,two diagrams of sound pressure level vs.frequency areobtained for a free damping panel(bare panel adds Castor oil/TDI+HEMA)and a bare panel.It is found that the sound pressure level of the tree damping panel is much lower than that of thebare panel above 1 kc.The vibration reed experimental data show that the internal friction(I-F)of a free damping strip raises as frequency increased,which verifies that the increasing of theI-F is responsible to the decreasing of sound pressure level of the free damping panel.Com-paring with the linear polymer PC,the I-F of network copolymer increased with frequencymay be divided into two parts.One part is contributed to relaxation process and the other maybe related with the crosslink of chains and explained by the damping resonance of a string pin-ned at ends.
关键词
声压级
共聚物
振动
噪声
材料
sound pressure level
internal friction
network copolymer
relaxation
