An improved path discretization method for automated fiber placement

In the automated fiber placement process, the continuous placement paths need to be discretized into a finite number of path points because the laying head cannot continuously trace the predetermined curved path. However, the discretization of the placement path, which is a spatial curve, will inevitably introduce error. In this paper, an improved path discretization algorithm is proposed for the fiber placement of complex double-curved structures. Firstly, the discrete error was decomposed into normal direction and binormal direction, and they are correlated with the laying process and their influences on the laying quality are discussed, respectively. Secondly, the relationship between the binormal error and the overlap of the tow is analyzed with differential geometry, and the influence of the normal error on laying force is discussed by the pressure experiment and the finite element method. Finally, the improved path discretization algorithm has been verified on double-curved surface and compared with the traditional path discrete algorithms. The results showed that the number of discrete path points decreases by 45.8% on average compared with the chordal deviation discretization algorithm and by 63.1% compared with the equal-arc discretization algorithm.

Study Structure and Properties of Reinforcing Rolled Coils by V-Alloyed C – Mn – Si - Steel with Dual- and Multi-Phase Microstructures

Thermo-mechanical controlled rolling (TMCR) schedules have been studied on the wire line of 400/200 section rolling mill to manufacture 6.0 – mm - diameter reinforcing wire in coils by V-alloyed C – Mn – Si - steel that has dual-phase (DP - ferrite-martensite (bainite)) and multi-phase (MP - ferrite-martensite (bainite) - pearlite) microstructures.It has been established that high tensile strength and plasticity values were achieved in this 6.0 – mm wire in coils (YS0.2= 530-550 MPa; TS= 785 – 885 MPa; El5 = 15.0 – 29.0 %) which were in full compliance with national standard specifications such as ASТM A 615 (USA), JIS G 3112 (Japan) and KSD 3504 (the Republic of Korea)), when the TMCR schedules involving laying head temperatures ТLH from 1024 ºС to 1063 ºС were employed ensuring formation of MP microstructure.

Finite Element Analysis of Contact between Laying Head Pipe and High-Speed Wire Rod

Wire spinning, which is a deformation process of great complexity in laying head pipe, was simulated using MSC. Marc, a software for finite element analysis, with the aid of production data collected in a high-speed wire spinning production line. The stress condition and the temperature distribution of the laying head inner wall, under the condition of high speed dry sliding friction, were obtained. The effects of different feed speeds on the contact stress and the transient temperature of the easily-wear part were analyzed. The simulation result coincides with the actual wear condition in the laying head pipe, indicating the soundness of the finite element model and making a contribution to optimizing the special curve of the laying head pipe and the finished rolling speed.