碳纤维-热塑性复合材料三维打印及其自监测

为改善热塑性材料三维打印结构件的力学性能，并对其所受应力应变状态进行实时自监测，提出一种连续碳纤维-热塑性复合材料（CFTC）并联臂三维打印技术，并基于碳纤维压阻效应开展打印结构自感知特性相关研究.以东丽T300B-3000-40B连续碳纤维丝和直径为1.75 mm的聚乳酸（PLA）丝为例，通过实验确定最优打印工艺参数范围；制备CFTC试样并对其进行强度测试；针对结构件常见承载形式，研究CFTC试样在轴向拉伸和三点弯曲2种状态下的自感知特性.三维打印CFTC试样比纯PLA试样具有更高的强度，最大拉伸强度提高了540%以上；所打印的CFTC试样具有良好的自感知特性，拉应变灵敏度均值为3.148，弯曲应变灵敏度均值为1.31，线性相关系数大于0.94；研究结果为高强度自感知智能结构件的制造提供了一种新的技术方法.
Abstract: A kind of three-dimensional (3D) printing technology based on parallel structure for continuous carbon fiber-thermoplastic composite (CFTC) was put forward, in order to improve the mechanical properties of 3D-printed thermoplastic structure, as well as to monitor its strain/stress state in real-time. Self-sensing characteristics of 3D-printed structures based on carbon fiber piezoresistive behaviors were investigated. Optimum printing process parameters were determined taking example for TORAY Torayca company T300B-3000-40B carbon fibers and polylactic acid (PLA) filament with diameters of 1.75 mm. The strength of 3D-printed CFTC specimens was investigated under uniaxial tension tests. And self-sensing characteristics of CFTC specimens were analyzed under both uniaxial tension and three-point bending tests, considering structural parts' common load bearing forms. Continuous carbon fibers significantly improve the strength of the 3D-printed structure by over 540% in tensile strength, compared with pure PLA specimen. 3D-printed CFTC specimen has an excellent self-sensing behavior.The average tensile gauge factor of CFTC specimen is 3.148 and the average flexural gauge factor is 1.31 with all the linear coefficients larger than 0.94. Results can help to produce 3D printing high-strength and self-sensing smart structures.