今日更新:Composites Part A: Applied Science and Manufacturing 1 篇,Composites Science and Technology 1 篇
From virtual to actual assisted tape placement − application of the Frenet frame to robotic steering trajectories
Gregório F.O. Ferreira, David Jones, Aswani Kumar Bandaru, Giovanni Zucco, Paul M. Weaver
doi:10.1016/j.compositesa.2024.108369
从虚拟到实际辅助胶带放置- Frenet框架到机器人转向轨迹的应用
A novel computational tool is presented that integrates the design and manufacturing of variable-angle tow composites for automated tape placement, facilitating the creation of tow-steered trajectories for cut-outs. Steering movements of the robot are planned and executed within a MATLAB virtual environment via short paths and linear commands. Leveraging piecewise-continuous clothoid splines and the Frenet frame, the tool furnishes crucial details on trajectory vectors, steering angles, and curvatures. Via four integrated modules, the user can define input parameters such as the robot’s actuators and structural geometry, allowing for the subsequent visualisation of the steered trajectories as well as the generation of the manufacturing code. Finally, to assess the potential and limitations of this methodology, the file containing all details is integrated into the Kuka KR L240-2 robot model to continuously steer a carbon fibre/PEEK tape around an elliptical cut-out in a composite panel using laser-assisted tape placement, representative of an access hole in an aircraft wing.
提出了一种新的计算工具,该工具集成了用于自动放置胶带的可变角度牵引复合材料的设计和制造,有助于创建用于切割的牵引轨迹。机器人的转向运动是通过短路径和线性命令在MATLAB虚拟环境中规划和执行的。利用分段连续的样条和Frenet框架,该工具提供了关于轨迹矢量、转向角度和曲率的关键细节。通过四个集成模块,用户可以定义输入参数,如机器人的执行器和结构几何形状,从而实现转向轨迹的可视化以及制造代码的生成。最后,为了评估该方法的潜力和局限性,将包含所有细节的文件集成到库卡KR L240-2机器人模型中,使用激光辅助胶带放置,连续地引导碳纤维/PEEK胶带围绕复合材料面板上的椭圆切口,代表飞机机翼的访问孔。
Experimental and numerical study of the thermomechanical properties of flexible self-reinforced polyimide composite membrane
Cheng Lu, Xin Yang, Huiqi Shao, Siyi Bi, Nanliang Chen, Guangwei Shao, Jinhua Jiang
doi:10.1016/j.compscitech.2024.110775
柔性自增强聚酰亚胺复合膜热力学性能的实验与数值研究
Polyimide membranes are favored in the aerospace field for their excellent comprehensive properties, but new application requirements demand higher strength, modulus and thermal expansion properties. Here, self-reinforced polyimide composite membranes (SRPICM) with varying fiber tow arrangement densities were fabricated by unidirectional reinforcement of polyimide fiber tows to enhance the thermomechanical properties of the membranes while maintaining the characteristics of low thickness and flexibility. A micro-scale representative volume element model with interface, and a macro-scale model containing cracks were developed based on the membranes' morphology to investigate the tensile and thermal expansion behavior of SRPICM. Experimental and numerical analyses demonstrated that fiber tows significantly improved the longitudinal tensile properties of SRPICM, with maximum increases in modulus and strength to 34.02 GPa and 1.26 GPa, respectively, over 13 times those of pure PI membranes. Further, the test results, combined with the two-scale finite element model revealed the evolution of longitudinal and transverse tensile deformation and thermal expansion behavior of SRPICM. The validity of the two-scale model was confirmed by experimental results, attributed to the practical consideration of interfacial bonding, prefabricated cracks and thermal residual stress effects during initial modeling. Notably, SRPICM with 10 fiber tows/20 mm arrangement density exhibited excellent longitudinal tensile properties (modulus and strength of 14.01 GPa and 470.89 MPa, respectively) and a longitudinal thermal expansion close to zero (0.03 μm/m°C), making it an ideal material for aerospace applications.
聚酰亚胺膜以其优异的综合性能在航空航天领域受到青睐,但新的应用要求对其强度、模量和热膨胀性能提出了更高的要求。本文通过单向增强聚酰亚胺纤维束,制备了具有不同纤维束排列密度的自增强聚酰亚胺复合膜(SRPICM),以提高膜的热机械性能,同时保持膜的低厚度和柔韧性。基于膜的形貌,建立了含界面的微尺度代表性体积元模型和含裂纹的宏观尺度模型,研究了SRPICM的拉伸和热膨胀行为。实验和数值分析表明,纤维束显著改善了SRPICM的纵向拉伸性能,模量和强度的最大增幅分别达到34.02 GPa和1.26 GPa,是纯PI膜的13倍以上。结合双尺度有限元模型,揭示了SRPICM纵向和横向拉伸变形及热膨胀行为的演变规律。由于在初始建模时实际考虑了界面结合、预制裂纹和热残余应力效应,实验结果证实了双尺度模型的有效性。值得注意的是,具有10根纤维束/20 mm排列密度的SRPICM具有优异的纵向拉伸性能(模量和强度分别为14.01 GPa和470.89 MPa),纵向热膨胀接近于零(0.03 μm/m°C),使其成为航空航天应用的理想材料。