Abstract Due to the increasing awareness around the environmental crisis and the depletion of petroleum resources, together with the inherent issues connected with the use of composite systems such as their disposal and recycling and the health problems associated with the use of some raw materials, new legislative rules on global scale have been promulgated to fight environmental issues and will be hoping adopted by several countries. Based on these considerations, the new generation of composite systems will have to minimize the environmental impact with a more efficient use of energy resources and materials and where possible, replace synthetic or petroleum materials with more sustainable components, like natural ones. Therefore, the aim of this paper is to investigate the sound transmission loss of a new sandwich structure in bio-composite material based on hemp fibers and bio-epoxy resin in order to further extend the application fields of natural fibers composite (NFC) materials. Measurements in the impedance tube were first used to assess the sound transmission loss at normal incidence. By using measured mechanical properties, a Finite Element Method was used to predict sound transmission loss in the same boundary condition. Finally, the so determined mechanical model has been used to predict the sound transmission loss in a diffuse field.

中文翻译：

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一种新型轻质麻/生物环氧树脂夹层结构的传声损失研究

摘要 由于对环境危机和石油资源枯竭的认识不断提高，以及与复合系统使用相关的固有问题（例如其处置和回收利用）以及与某些原材料的使用相关的健康问题，新的立法已经颁布了全球范围的规则来应对环境问题，并希望得到一些国家的采纳。基于这些考虑，新一代复合系统必须通过更有效地利用能源和材料来最大限度地减少对环境的影响，并在可能的情况下，用更可持续的成分（如天然成分）替代合成或石油材料。所以，本文的目的是研究基于大麻纤维和生物环氧树脂的生物复合材料中新型夹层结构的传声损失，以进一步扩展天然纤维复合（NFC）材料的应用领域。阻抗管中的测量首先用于评估垂直入射时的声音传输损失。通过使用测量的机械性能，有限元方法用于预测相同边界条件下的声音传输损失。最后，如此确定的机械模型已用于预测扩散场中的声音传输损失。阻抗管中的测量首先用于评估垂直入射时的声音传输损失。通过使用测量的机械性能，有限元方法用于预测相同边界条件下的声音传输损失。最后，如此确定的机械模型已用于预测扩散场中的声音传输损失。阻抗管中的测量首先用于评估垂直入射时的声音传输损失。通过使用测量的机械性能，有限元方法用于预测相同边界条件下的声音传输损失。最后，如此确定的机械模型已用于预测扩散场中的声音传输损失。