Han Zhenyu, Sun Shouzheng, Fu Hongya, Fu Yunzhong
School of Mechatronics Engineering, Harbin Institute of Technology, No.92, Xidazhi Street, Harbin 150001, China.
Materials (Basel). 2017 Sep 3;10(9):1024. doi: 10.3390/ma10091024.
Automated fiber placement (AFP) process includes a variety of energy forms and multi-scale effects. This contribution proposes a novel multi-scale low-entropy method aiming at optimizing processing parameters in an AFP process, where multi-scale effect, energy consumption, energy utilization efficiency and mechanical properties of micro-system could be taken into account synthetically. Taking a carbon fiber/epoxy prepreg as an example, mechanical properties of macro-meso-scale are obtained by Finite Element Method (FEM). A multi-scale energy transfer model is then established to input the macroscopic results into the microscopic system as its boundary condition, which can communicate with different scales. Furthermore, microscopic characteristics, mainly micro-scale adsorption energy, diffusion coefficient entropy-enthalpy values, are calculated under different processing parameters based on molecular dynamics method. Low-entropy region is then obtained in terms of the interrelation among entropy-enthalpy values, microscopic mechanical properties (interface adsorbability and matrix fluidity) and processing parameters to guarantee better fluidity, stronger adsorption, lower energy consumption and higher energy quality collaboratively. Finally, nine groups of experiments are carried out to verify the validity of the simulation results. The results show that the low-entropy optimization method can reduce void content effectively, and further improve the mechanical properties of laminates.
自动铺丝（AFP）工艺包含多种能量形式和多尺度效应。本文提出一种新颖的多尺度低熵方法，旨在优化AFP工艺中的加工参数，该方法能够综合考虑多尺度效应、能量消耗、能量利用效率以及微系统的力学性能。以碳纤维/环氧树脂预浸料为例，通过有限元法（FEM）获得宏观-细观尺度的力学性能。随后建立多尺度能量传递模型，将宏观结果作为边界条件输入微观系统，实现不同尺度之间的相互关联。此外，基于分子动力学方法计算不同加工参数下的微观特性，主要包括微观尺度吸附能、扩散系数熵焓值。然后根据熵焓值、微观力学性能（界面吸附性和基体流动性）与加工参数之间的相互关系，获得低熵区域，以协同保证更好的流动性、更强的吸附性、更低的能量消耗和更高的能量品质。最后，进行了九组实验以验证模拟结果的有效性。结果表明，低熵优化方法能够有效降低孔隙率，并进一步提高层压板的力学性能。
