Pressure distribution for automated fiber placement and design optimization of compaction rollers

Jiang, Jun; He, Yuxiao; Ke, Yinglin

doi:10.1177/0731684419850896

Cited by 32 publications

(24 citation statements)

References 22 publications

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“…The compression force applied and controlled by the roller plays a vital role in the mechanical properties of tack and wrinkle formation. The compaction pressure distribution generated by roller on prepreg was investigated in [19,20], respectively. Besides, the compression force between the roller and tape and the guidance system leads to an initial defect in tape that affects the wrinkle formation.…”

Section: Methodsmentioning

confidence: 99%

Wrinkle Formation and Initial Defect Sensitivity of Steered Tow in Automated Fiber Placement

Kheradpisheh

Hojjati

2021

J. Compos. Sci.

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This paper aims to study the wrinkle formation of a prepreg with initial defect during steering in automated fiber placement (AFP). Wrinkle formation has a detrimental effect on the mechanical properties of the final product, limiting the AFP applications. A theoretical model for wrinkle formation has been developed in which a Pasternak foundation and a Koiter imperfection model are adapted to model viscoelastic characteristics of the prepreg tack and initial defect of the prepreg, respectively. The initial defect is defined as a slight deviation of the tow’s mid-plane from a horizontal shape. The initial defect is generated in the tow by moving the tow through the guidance system, pressure of the roller, and resin tackiness. Galerkin method, along with the finite difference method (FDM), are employed to solve the wrinkle problem equation. The proposed method is able to satisfy the different boundary conditions for the wrinkle problem completely. The numerical results show that increasing the initial defect leads to a decrease in critical load and an increase in critical steering radius. To validate the theoretical model, experimental results are presented and compared with model-predicted results. It is shown that the model is well able to capture the trends and values of wrinkle formation wavelengths obtained from the experiment.

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Section: Methodsmentioning

confidence: 99%

Wrinkle Formation and Initial Defect Sensitivity of Steered Tow in Automated Fiber Placement

Kheradpisheh

Hojjati

2021

J. Compos. Sci.

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“…The actual pressure distribution under the compaction roller is unknown in the LATP process, so during placement, the compaction roller applies the pressure while rotating. However, the effect of roller rotation on the normal pressure is negligible, and the dynamic case can be simplified into a static one [7]. To measure the contact area under the roller so that the pressure can be calculated, knowing the predetermined force, pressure-sensitive films are used, as demonstrated in Figure 2.…”

Section: Pressure Measurementmentioning

confidence: 99%

“…Secondly, inter-laminar void content in the final structure is a direct result of intimate contact development. Interlaminar voids reduce the mechanical performance of the final product [7]. The heat transfer might be reduced at the ply interfaces if they have incomplete intimate contact [4,8,9]; therefore, since the temperature affected the crystallinity, porosity, decomposition and residual stresses, we can conclude that intimate contact has a great influence on the characteristics of the final products produced with the LATP process [10][11][12][13][14][15][16][17][18][19][20][21][22][23].…”

Section: Introductionmentioning

confidence: 95%

The Factors That Affect the Expansion of the Tape for It to Avoid Side Effects in the Production of Composites in Online LATP Technology

Risteska¹,

Samak²,

Samak³

2021

J. Compos. Sci.

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During LATP (laser automated tape placement), the compaction roller contacts the prepreg and affects the pressure distribution directly. Moreover, the design parameters of the roller are optimized with the aim of improving pressure uniformity. This paper examines the impact of the contact line and surface that depends on the compaction force, the design of the roller, the angle of inclination and the angle of inclination of the strip. These factors significantly affect the expansion of the tape, and it is important to determine it to avoid side effects in the production of composites (formation of gaps or overlaps). Their presence increases the percentage of pores of the final material and thus reduces the mechanical properties. The results show that the pressure uniformity can be improved significantly by design optimization of the roller, which indicates that higher bond quality between layers is achieved. The lower the speed and higher the compact force in this technology give better intimate contact with a lower percentage of voids and good mechanical characteristics.

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“…The material of the rubber cover of the roller is silicone rubber, whose stress and strain behavior can be considered linear when the deformation is less than 25%. 22 In order to improve the calculation efficiency, the mandrel of the compaction roller and the mould was constrained as "rigid body," and the rubber cover was regarded as a linear elastomer. By adding the fixed constraint of the surface and applying concentrated force on the compaction roller axis to simulate the pressing process of the compaction roller, the relationship between the curvature of the mould surface and the laying force can be obtained.…”

Section: Calculation Of Normal Errormentioning

confidence: 99%

An improved path discretization method for automated fiber placement

2020

Journal of Reinforced Plastics and Composites

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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.

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Pressure distribution for automated fiber placement and design optimization of compaction rollers

Cited by 32 publications

References 22 publications

Wrinkle Formation and Initial Defect Sensitivity of Steered Tow in Automated Fiber Placement

Wrinkle Formation and Initial Defect Sensitivity of Steered Tow in Automated Fiber Placement

The Factors That Affect the Expansion of the Tape for It to Avoid Side Effects in the Production of Composites in Online LATP Technology

An improved path discretization method for automated fiber placement

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