3D printing defects are often used to explain the mismatch between numerical predictions and experimental results of additively manufactured acoustic materials. Although they are often perceived as desirable, as in most cases, they improve the absorptive behaviour of the system, occurring gains are unplanned and uncontrollable. Among different 3D printing inaccuracies, surface roughness provides additional acoustic losses, mostly due to the enlargement of the boundary layer thickness. On the other hand, roughness is responsible for the shift of the operating frequency compared to the numerical predictions. The goal of this research is to provide efficient modelling methods to capture the effects of surface roughness arising from the additive manufacturing process. First, a direct modelling method will be discussed, which can be computationally expensive as it relies on an accurate geometrical representation of surface roughness. Second, an alternative indirect modelling approach will be presented, which mimics the presence of roughness by adjusting specific air parameters in the locations of interest of the smooth geometry to reduce the computational cost. The two strategies will be compared with each other and to the results of an experiment where additional roughness is added to target locations within the design.

中文翻译：

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对增材制造材料中的表面粗糙度影响进行高效建模

3D 打印缺陷通常用于解释增材制造声学材料的数值预测与实验结果之间的不匹配。尽管它们通常被认为是理想的，但在大多数情况下，它们改善了系统的吸收行为，但发生的收益是计划外且无法控制的。在不同的 3D 打印误差中，表面粗糙度会带来额外的声学损失，这主要是由于边界层厚度的增大造成的。另一方面，与数值预测相比，粗糙度是导致工作频率发生变化的原因。这项研究的目标是提供有效的建模方法来捕获增材制造过程中产生的表面粗糙度的影响。首先，将讨论直接建模方法，该方法的计算成本可能很高，因为它依赖于表面粗糙度的精确几何表示。其次，将提出另一种间接建模方法，该方法通过调整平滑几何形状感兴趣位置中的特定空气参数来模拟粗糙度的存在，以降低计算成本。这两种策略将相互比较，并与实验结果进行比较，其中在设计中的目标位置添加了额外的粗糙度。