Santos Jonnathan D, Fernández Alex, Ripoll Lluís, Blanco Norbert
Grupo de Investigación en Nuevos Materiales y Procesos de Transformación (GIMAT), Universidad Politécnica Salesiana, Calle Vieja 12-30 y Elia Liut, Cuenca 010105, Ecuador.
Analysis and Advanced Materials for Structural Design (AMADE), Department of Mechanical Engineering and Industrial Construction, Universitat de Girona, Avda. M. Aurèlia Capmany 61, 17003 Girona, Spain.
Polymers (Basel). 2022 Jan 27;14(3):506. doi: 10.3390/polym14030506.
The use of continuous fiber as reinforcement in polymer additive manufacturing technologies enhances the mechanical performance of the manufactured parts. This is the case of the Carbon-Fiber reinforced PolyAmide (CF/PA) used by the MarkForged MarkTwo 3D printer. However, the information available on the mechanical properties of this material is limited and with large variability. In this work, the in-plane mechanical properties and the interlaminar fracture toughness in modes I and II of Markforged's CF/PA are experimentally investigated. Two different standard specimens and end-tabs are considered for the in-plane properties. Monolithic CF/PA specimens without any additional reinforcement are used for the interlaminar fracture toughness characterization. Two different mode I specimen configurations are compared, and two different test types are considered for mode II. The results show that prismatic specimens with paper end-tabs are more appropriate for the characterization of the in-plane material properties. The use of thick specimens for mode I fracture toughness tests complicates the characterization and can lead to erroneous results. Contrary to what has been reported in the literature for the same material, fracture toughness in mode I is lower than for mode II, which agrees with the normal tendency of traditional composite materials.
在聚合物增材制造技术中使用连续纤维作为增强材料可提高所制造零件的机械性能。MarkForged MarkTwo 3D打印机使用的碳纤维增强聚酰胺（CF/PA）就是这种情况。然而，关于这种材料机械性能的可用信息有限且变化很大。在这项工作中，对Markforged的CF/PA的面内机械性能以及I型和II型层间断裂韧性进行了实验研究。考虑了两种不同的标准试样和端接片用于面内性能测试。没有任何额外增强材料的整体CF/PA试样用于层间断裂韧性表征。比较了两种不同的I型试样配置，并考虑了II型的两种不同测试类型。结果表明，带有纸质端接片的棱柱形试样更适合用于表征面内材料性能。使用厚试样进行I型断裂韧性测试会使表征变得复杂，并可能导致错误的结果。与文献中关于相同材料的报道相反，I型断裂韧性低于II型，这与传统复合材料的正常趋势一致。
