Prediction and optimization of yarn path in braiding of mandrels with flat faces

Abstract

Braided preforms are used in many applications to make modern textile composites. Mechanical properties of braided composites are strongly dependent on braided preform’s characteristics such as braid angle and yarn spacing. In this paper, theoretical relationships are presented to predict these parameters in braiding of a mandrel with flat faces. These relationships are very simple in deriving and coding and also they are suitable for sharp edges. It was observed that considering the distance between the yarn’s fell point on the mandrel and guide ring plane is an important issue to calculate an accurate braid angle. Braid angle and yarn spacing was also measured experimentally. Theoretical relations predictions are in close agreement with experimental measurements. The effects of the mandrel aspect ratio and the mandrel eccentricity to produce a part with variable braid angle are investigated. It is observed that while mandrel dimension aspect ratio has no significant effect, the braid angle can be considerably varied from one face to another face by locating the mandrel out of the center of the machine. An optimization process is proposed to find the best mandrel eccentricity to manufacture a preform with desired braid angles on individual faces.

Robot trajectory optimization control of braiding for three-dimensional complex preforms

“…In the braiding process, the convergence length has a great influence on the braiding angle, 20 thus affecting the quality of the preform. Therefore, it is necessary to adjust the robot posture and take-up speed to compensate the braiding angle error.…”

Study on the simulation of annular axis braiding process and braiding angles’ prediction method

“…The braiding angle indicates the angle between the yarn and the axial direction of the mandrel. 9 Braiding angle is the main technical parameter [10][11][12] to represent the braided preform and it shows the yarn direction and determines the structure of the braided preform, 13,14 thus influencing the mechanical property of the braiding composite reinforcement. 15,16 In terms of the standard linear cylindrical mandrel, the yarn's braiding angles at different locations on the surface of the mandrel are theoretically the same and correspond to the radius of the mandrel, the carrier speed, and the mandrel's take-up speed as shown in equation (1).…”

Modeling method of irregular cross section annular axis braided preform based on finite element simulation

“…The mandrel is usually linear and moves in a straight line under the traction of the driving device, and the yarns are interlaced and attached to the surface of the mandrel to form the braided preform, which can be used to process braided composites. 2 Braiding angle and yarn spacing are main parameters of braided preform. 3 Many scholars studied the structure of braided preform usually by means of geometric modeling.…”