Multi-Scale Low-Entropy Method for Optimizing the Processing Parameters during Automated Fiber Placement.

Zhenyu Han,Hongya Fu,Yunzhong Fu,Shouzheng Sun

doi:10.3390/ma10091024

Abstract

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.

Highlights

A popular type of prepregs are laminated and cured to be fiber-reinforced composites [1,2,3,4], which have a number of advantages in comparison to metal-based structures, including the fact that they offer lightweight and stiff surfaces, which resist corrosion well and are believed to have a relatively long fatigue life [5]
The results show that the low-entropy optimization method can reduce void content effectively, and further improve the mechanical properties of laminates
The recent introduction of airplanes with parts made by the Automated Fiber

Summary

Introduction

A popular type of prepregs are laminated and cured to be fiber-reinforced composites [1,2,3,4], which have a number of advantages in comparison to metal-based structures, including the fact that they offer lightweight and stiff surfaces, which resist corrosion well and are believed to have a relatively long fatigue life [5]. Composite materials are increasingly used as large and complex primary structures in aeronautics industry. Their well-known manufacturing weaknesses, such as pores and micro-crack, drive many companies to develop new methods to obtain better part quality. The recent introduction of airplanes with parts made by the Automated Fiber. An AFP machine consists of a computer controlled robotic arm with a placement head end effector that lays bands of prepreg strips onto a mold to construct the lay-up. The bands are made with 8–32 prepreg strips, called tows, which are aligned side-by-side by the placement head. The machine accurately places the bands on the mold respecting the proper ply angles and covering technique.

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Conclusion