【作者】 刘芳；

【导师】 陈书明；

【作者基本信息】 吉林大学 ， 车辆工程， 2021， 硕士

【摘要】 随着现代社会的发展,汽车保有量持续增加,汽车噪声对人们的生活及环境产生了极大的干扰,且汽车车内噪声对驾乘人员的舒适性存在很大的影响。聚氨酯多孔材料作为汽车降噪材料之一,可用于降低车内噪声,提高车内环境质量。石油资源的枯竭以及环保意识的加强,使寻找聚氨酯主要原料之一-石油多元醇的替代品具有重大意义。另外,生物基聚氨酯多孔材料声学性能与传统石油基聚氨酯相比,并没有太大的优势。因此通过改变聚氨酯外观结构提高其声学性能,使生物基聚氨酯有更好的应用效果,这具有重要意义及工程实用性。本文响应国家绿色环保主题,采用菜籽油多元醇和椰子油多元醇作为石油多元醇的替代品,制备菜籽油和椰子油基聚氨酯多孔材料,并分析椰子油多元醇和菜籽油多元醇的含量对聚氨酯声学性能、力学性能、微观结构、老化性能的影响。研究表明菜籽油多元醇增强聚氨酯的声学性能,削弱其力学性能。本文进一步分析了聚氨酯各原料对聚氨酯声学性能和力学性能的影响,并以菜籽油多元醇、二苯基甲烷二异氰酸酯(MDI)、去离子水的含量为设计变量,平均吸声系数、杨氏模量为优化目标,采用响应面Box-Behnken设计方法设计试验。根据试验结果,建立了设计变量与优化目标之间的数学模型,最终确定了菜籽油和椰子油基聚氨酯的最佳配方,制备出综合性能(声学性能和力学性能)良好的聚氨酯多孔材料,并进行试验验证。并对比分析优化样品与优化前样品以及石油基聚氨酯的泡孔结构、声学性能以及力学性能。将声学黑洞引入聚氨酯多孔材料,分析声学黑洞结构对其声学性能的影响。通过改变一维和二维声学黑洞的函数系数和截断厚度,分析聚氨酯多孔材料的吸声曲线变化。研究表明,一维声学黑洞结构降低多孔材料的中低频声学性能,提高了多孔材料的高频声学性能;二维声学黑洞结构应用于多孔材料时,其高频声学系数显著提高,低频吸声系数略降低。其中,在一维声学黑洞结构中,函数系数和截断厚度对材料的全频段吸声性能有着较大的影响;在二维声学黑洞结构中,函数系数和截断厚度只影响了材料的中低频吸声性能。依据房间和汽车实际结构尺寸,构建房间和汽车简易模型,将一维和二维声学黑洞聚氨酯多孔材料应用于房间天花板和汽车顶棚,并对比石油基聚氨酯、菜籽油和椰子油基聚氨酯以及声学黑洞聚氨酯多孔材料时声压级的变化。结果表明,菜籽油和椰子油基聚氨酯与石油基聚氨酯对房间和汽车内部的噪声效果相差无几,声学黑洞多孔材料有效地改善了房间内部噪声和车内噪声。更多还原

【Abstract】 With the development of modern society,the automobile ownership in China is further advanced.Vehicle noise has greatly bad on people’s lives and the environment,and vehicle interior noise has a greater impact on the comfort of drivers and passengers.Polyurethane,as one of automobile noise reduction materials,has been used to reduce the vehicle interior noise and improve the vehicle environmental quality.Due to the depletion of petroleum resources and the strengthening of environmental awareness,it is great significance to find a substitute for petroleum polyol.In addition,the acoustic performance of bio-based polyurethane has no obvious advantages compared with traditional petroleum-based polyurethane.It is of important significance and engineering practicality to improve the application effect of bio-based polyurethane in automobiles by changing the appearance of polyurethane.In response to the national green environmental protection theme,rapeseed oil polyol and coconut oil polyol are used as substitutes for petroleum polyols to prepare rapeseed oil and coconut oil-based polyurethane.The influence of the coconut oil polyol and rapeseed oil polyol’ contain on the acoustic properties,mechanical properties,microstructure and aging properties of polyurethane were analyzed.The Study showed that rapeseed oil polyols enhance the acoustic properties of polyurethane and weaken its mechanical properties.The influence of the raw material of polyurethane on the acoustic and mechanical properties was also analyzed.The contents of rapeseed oil polyol,diphenylmethane diisocyanate,and deionized water were used as design variables.The average sound absorption coefficient and Young’s modulus were optimized targets.The response surface Box-Behnken design method was used to design the experiment.According to the experimental results,the mathematical model between the design variables and the optimization goal was established.Finally,the best formula of rapeseed oil and coconut oil-based polyurethane was determined,and the polyurethane with good comprehensive properties(acoustic and mechanical properties)was prepared and verified.The cell structure,acoustic properties and mechanical properties of the optimized sample and the pre-optimized sample as well as the petroleum-based polyurethane were compared.The acoustic black hole(ABH)was applied to the polyurethane,and the influence of the ABH structure on the acoustic performance of the polyurethane was analyzed.The effect of the function coefficient and cut-off thickness of one-dimensional and two-dimensional ABHs on the sound absorption coefficient of polyurethane were analyzed.The result showed that the one-dimensional and two-dimensional ABH structure reduced the mid-and low-frequency acoustic performance and improved the high-frequency acoustic performance of porous materials.The functional coefficient and cut-off thickness of the one-dimensional ABH structure have a great influence on the sound absorption performance of the material in the whole frequency range.The functional coefficient and cut-off thickness of the two-dimensional ABH structure only affect the mid-and low-frequency sound absorption performance of the material.One-dimensional and two-dimensional ABH polyurethane were applied to the room and vehicle.The changes in sound pressure level in the vehicle were compared when there was petroleum-based polyurethane,rapeseed oil and coconut-based polyurethane,and ABH polyurethane,respectively.The results showed that rapeseed oil and coconut oil-based polyurethane and petroleum-based polyurethane had almost the same effect on noise.The ABH polyurethane greatly reduced the noise.更多还原