Dynamic properties of additively-manufactured materials are generally under-characterized compared to static properties. Material extrusion (MEX) is the most readily available and economical method of 3D printing available. In order to reduce weight and material costs, most commercial MEX slicing software utilizes a concept called infill, often in the form of lattices, which fills the 3D space with a computer-generated design. In this study, finite element modeling of representative volume elements is utilized to predict the speed of sound for a polylactic acid–based structure with varying infill percentages. Experimental validation of the sound speeds for a subset of infill percentages are measured using an underwater acoustic through-transmission technique at frequency ranges which correspond to the assumptions used in the modeling approach. Significant anisotropy in elasto-dynamic response was observed numerically and experimentally. Insertion loss of the printed panels was also measured as part of general discussion of the effectiveness of the underwater acoustic method for air-filled samples. This work provides a framework for both characterization and design of MEX-printed parts for acoustic applications.

中文翻译：

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使用均质化方法对材料挤出填充物进行弹性动力学表征

与静态特性相比，增材制造材料的动态特性通常未被充分表征。材料挤出 (MEX) 是最容易获得且经济的 3D 打印方法。为了减轻重量和材料成本，大多数商业 MEX 切片软件都采用称为填充的概念，通常采用晶格的形式，通过计算机生成的设计填充 3D 空间。在这项研究中，利用代表性体积元素的有限元建模来预测具有不同填充百分比的聚乳酸基结构的声速。使用水声穿透技术在与建模方法中使用的假设相对应的频率范围内测量填充百分比子集的声速的实验验证。通过数值和实验观察到弹性动力响应的显着各向异性。还测量了印刷面板的插入损耗，作为水声法对充气样品有效性的一般讨论的一部分。这项工作为声学应用的 MEX 打印部件的表征和设计提供了一个框架。