Nguyen Hieu Tri, Crittenden Kelly, Weiss Leland, Bardaweel Hamzeh
Institute for Micromanufacturing, College of Engineering and Science, Louisiana Tech University, Ruston, LA 71272, USA.
Department of Mechanical Engineering, College of Engineering and Science, Louisiana Tech University, Ruston, LA 71272, USA.
Polymers (Basel). 2022 May 19;14(10):2071. doi: 10.3390/polym14102071.
Modern 3D printed components are finding applications in dynamic structures. These structures are often subject to dynamic loadings. To date, research has mostly focused on investigating the mechanical properties of these 3D printed structures with minimum attention paid to their modal analysis. This work is focused on performing experimental modal analysis of 3D printed structures. The results show that the adhesion type has the most significant impact on the vibration response and parameters obtained from the modal analysis. The average dynamic modulus, natural frequency, and damping coefficient increased by approximately 12.5%, 5.5%, and 36%, respectively, for the specimens printed using skirt adhesion compared to those printed using raft adhesion. SEM analysis suggests that the 3D printed specimens with skirt adhesion yielded flattened layers, while raft adhesion resulted in rounded layers. The flattened layers of the specimens with skirt adhesion are likely an indication of an enhanced heat transfer between the 3D printer bed and the specimen. The printed specimens with skirt adhesion are in direct contact with the printer bed during the printing process. This enhances the heat transfer between the specimen and the printer bed, causing the layers to flatten out. The enhanced heat transfer yields a better inter-layer diffusion, resulting in improved physical bonding at the layers' interface. The improved bonding yields higher stiffnesses and natural frequencies. For the specimens with skirt adhesion, the improved heat transfer process is also likely responsible for the enhanced damping properties. The strengthened inter-layer bonding at the layer-layer interface provides better energy dissipation along the contact lines between the layers.
现代3D打印部件正在动态结构中得到应用。这些结构经常受到动态载荷的作用。迄今为止，研究主要集中在研究这些3D打印结构的力学性能，而对其模态分析关注较少。这项工作的重点是对3D打印结构进行实验模态分析。结果表明，附着类型对振动响应和从模态分析中获得的参数影响最为显著。与采用筏式附着打印的试样相比，采用裙边附着打印的试样的平均动态模量、固有频率和阻尼系数分别提高了约12.5%、5.5%和36%。扫描电子显微镜分析表明，采用裙边附着的3D打印试样产生了扁平层，而筏式附着则产生了圆形层。采用裙边附着的试样的扁平层可能表明3D打印平台与试样之间的热传递增强。在打印过程中，采用裙边附着的打印试样与打印平台直接接触。这增强了试样与打印平台之间的热传递，导致层变平。增强的热传递产生了更好的层间扩散，从而改善了层界面处的物理结合。改善的结合产生了更高的刚度和固有频率。对于采用裙边附着的试样，热传递过程的改善也可能是阻尼性能增强的原因。层-层界面处增强的层间结合沿着层之间的接触线提供了更好的能量耗散。
