Implementation of a viscoelastic material model to predict the compaction response of dry carbon fiber preforms

Bublitz, Dennis; Colin, David; Drechsler, Klaus

doi:10.1016/j.compositesa.2021.106718

Cited by 10 publications

(4 citation statements)

References 39 publications

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“…The extension-extension coupling entries 𝑆𝑆 12 , 𝑆𝑆 13 and 𝑆𝑆 23 are set to zero. The entry 𝑆𝑆 33 which describes the behavior in thickness direction is defined by a viscoelastic material model as described in [15]. The remaining entries of the compliance matrix are set to constant values.…”

Section: Methodsmentioning

confidence: 99%

Chaining of Compaction with Flow Simulations to Predict the Filling Behavior in Resin Transfer Molding Processes

Bublitz

Thalhamer

Schwöller

et al. 2022

MSF

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Closed mold injection processes such as resin transfer molding have an increasing importance for manufacturing high quality carbon fiber reinforced parts at high production rates. One major challenge during this process is to avoid resin rich corners, which are a result of a non-uniform compaction of the preform in the tool. The objective of this work is to predict compaction defects in the preform and their effects on the filling behavior. We use numerical compaction simulations to calculate the preform geometry after tool closing, which is subsequently transferred into the infiltration simulation to model the filling behavior. Additionally, the fiber volume content and the material orientations are transferred from the mechanical simulation. Areas in the tool, which are not filled by the reinforcement, are modelled as flow channels with high permeability. The achieved results prove the significant influence of the compaction state on the filling behavior. The novel method supports the design of RTM tools and helps to optimize the manufacturing process.

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Section: Methodsmentioning

confidence: 99%

Chaining of Compaction with Flow Simulations to Predict the Filling Behavior in Resin Transfer Molding Processes

Bublitz

Thalhamer

Schwöller

et al. 2022

MSF

Self Cite

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“…If the rig’s deformation is significant in this region, the reference points will no longer move identically to the actual cavity, thereby affecting the accuracy of the measurements. An alternative approach is to use a video-extensometer 7 to directly monitor the gap between the plates. Indirect thickness measurement methods determine the cavity gap from the UTM´s crosshead position with a subtraction for the machine compliance from the displacement containing the sample´s displacement.…”

Section: Introductionmentioning

confidence: 99%

Achieving highly accurate cavity thickness measurements in fabric compaction

Sousa,

Liu,

Lomov

et al. 2024

Journal of Composite Materials

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The compaction of a fabric reinforcement in a Universal Testing Machine (UTM) allows to determine the achievable fiber volume fraction across a wide range of pressures, a valuable information for composite manufacturing. As seen in the first international compressibility benchmark, inaccuracies in the fabric stack thickness measurement, the approach to compliance correction and the non-parallelism between compaction plates resulted in highly inaccurate compression curves. In this paper, the different variability sources affecting indirect thickness methods, based on the machine displacement, and direct methods with laser sensors are presented and its impact on the accuracy is estimated. In conclusion, both thickness measurement methods produced similar results; however, the thickness measured by direct methods experienced more variability due to minor changes in the rig’s displacement or the orientations between plates, combined with other sources of variability such as external interferences or vibrations from the compaction plate which led to variations in measurement precision throughout the tests.

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“…In recent decades, composite materials have risen to prominence owing to their superior strength, stiffness, and durability compared to traditional materials, resulting in their widespread adoption across various applications 1–4 . The Liquid Composite Molding (LCM) process, widely embraced for molding composite materials, is extensively utilized in aerospace, automotive, marine, and civilian sectors for the high‐volume production of high‐quality carbon fiber‐reinforced components 5–7 . As illustrated in Figure 1A, the preforming stage of dry fiber preforms plays a pivotal role in the Liquid Composite Molding process.…”

Section: Introductionmentioning

confidence: 99%

“…extensively utilized in aerospace, automotive, marine, and civilian sectors for the high-volume production of high-quality carbon fiber-reinforced components. [5][6][7] As illustrated in Figure 1A, the preforming stage of dry fiber preforms plays a pivotal role in the Liquid Composite Molding process. As shown in Figure 1B, compaction serves as the primary deformation mode for the fabric in the thickness direction during preforming.…”

mentioning

confidence: 99%

A creep/recovery model of dry fiber fabric during compaction considering temperature and in‐plane tension

Si,

An,

Xie

et al. 2024

Polymer Composites

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In the manufacturing of fiber‐reinforced composite materials, the preforming stage of dry fiber fabric entails compaction operations carried out under constant pressure, a specific preforming temperature, and in‐plane tension. Throughout this process, permanent deformation and creep/recovery behavior are observed in the fabric, correlating with factors such as time, sustained pressure, temperature, and in‐plane tension. Effective control of fiber volume fraction and material composition necessitates a thorough comprehension of these phenomena as well as the capacity to predict them with accuracy. To solve this, a viscoelastic‐plastic model was put forth, which provides an account of the viscous effects on the fabric during its stages of compression and recovery. The proposed model incorporates changed Burgers units to manage time‐dependent deformations and plastic units to address permanent deformations. Through the application of a single set of parameters, the model precisely and comprehensively characterizes through‐thickness creep/recovery behavior of preformed dry fiber fabrics under varying conditions, including creep stress, temperature, and in‐plane tension. To enhance the practical utility of the model, an application has been developed and validated against experimental data conducted under diverse test conditions. The results demonstrate consistency between experimental curves and model‐predicted curves across various compression scenarios.Highlights A viscoelastic‐plastic model was proposed with a single parameter set. Stress, temperature, and in‐plane tension all exacerbated creep/recovery. Model captures temp. and time‐related creep/recovery with in‐plane tension. The model has been transformed into a practical application tool.

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Implementation of a viscoelastic material model to predict the compaction response of dry carbon fiber preforms

Cited by 10 publications

References 39 publications

Chaining of Compaction with Flow Simulations to Predict the Filling Behavior in Resin Transfer Molding Processes

Chaining of Compaction with Flow Simulations to Predict the Filling Behavior in Resin Transfer Molding Processes

Achieving highly accurate cavity thickness measurements in fabric compaction

A creep/recovery model of dry fiber fabric during compaction considering temperature and in‐plane tension

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