Spring-in angle as molding distortion for thermoplastic matrix composite

Salomi, A.; Garstka, T.; Potter, KD; Greco, Antonio; Maffezzoli, Alfonso

doi:10.1016/j.compscitech.2008.06.024

Cited by 34 publications

(17 citation statements)

References 20 publications

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“…6 The Radford model assumes that spring-in is due to the anisotropic thermal properties and the resin cure shrinkage. In the case of thermoplastic matrix composites, since there is no cure, crystallization shrinkage would take the place of cure shrinkage.…”

Section: Spring-in Problem: Backgroundmentioning

confidence: 99%

Predicting dimensional distortions in roll forming of comingled polypropylene/glass fiber thermoplastic composites: On the effect of matrix viscoelasticity

Lynam

Milani

Trudel-Boucher

et al. 2013

Journal of Composite Materials

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Thermal deformations that occur during formation of long-fiber-reinforced composites have been a continued challenge for manufacturers as the final shape of a given part can be different from the original mold shape. The ensuing dimensional distortions can be difficult to predict due to complex thermo-mechanical behaviour of composite laminates during different forming cycles. This study intends to model the fundamental mechanisms that lead to thermal deformations during forming of a thermoplastic matrix composite comprised of comingled polypropylene and E-glass fibers. While the discussion is framed around a custom-design multi-stage roll-forming process, it is also relevant to a wider range of thermoplastic composites manufacturing processes. A methodology is developed to characterize the thermal mechanical behavior of the material, optimize the manufacturing process, and predict the magnitude of resulting spring-in angle due to thermal deformations. It is found that the process control parameters can be optimized first such that the crystallization of the matrix occurs at an ideal position along the forming line. Once the process is optimized, the developed numerical model, with a thermoelastic material behaviour, can give an adequate prediction of spring-in at the end of the process. Finally, through a comparative study, it is discussed how for other manufacturing processes, such as compression molding, including a thermoviscoelastic liquid/solid material behaviour may be required to yield accurate spring-in predictions.

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Section: Spring-in Problem: Backgroundmentioning

confidence: 99%

Predicting dimensional distortions in roll forming of comingled polypropylene/glass fiber thermoplastic composites: On the effect of matrix viscoelasticity

Lynam

Milani

Trudel-Boucher

et al. 2013

Journal of Composite Materials

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“…The deformed blank model is transferred from the thermostamping process to the springback procedure. It is assumed that process‐induced distortions mainly come from the thermal shrinkage of composites in the cooling stage . Incremental formulations for thermal strains are defined and added to the mechanical strains.…”

Section: Finite Element Simulationsmentioning

confidence: 99%

Simulation and Analysis of Process‐Induced Distortions in Hemispherical Thermostamping for Unidirectional Thermoplastic Composites

Liu

Zhang

et al. 2018

Polymer Composites

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This work aims at analyzing process‐induced distortions (PIDs) for unidirectional thermoplastic composites in the thermoforming process and evaluating the effects of fiber reorientations and stamping‐induced stresses. Hemispheres with symmetric and asymmetric lay‐ups are manufactured by the thermostamping process. A simulation method of PIDs is developed and a constitutive model is presented to reflect fiber reorientations in thermostamping. Additionally, stamping‐induced stresses are embedded in the simulation. Good correlation is obtained between the prediction and experimental results. Regarding hemispheres with the symmetric lay‐up [0/90/0/90]S, stamping‐induced stresses play a dominant role in PIDs and determine the deformation trend; fiber reorientations contribute approximately 76% to thermal distortions. Stamping‐induced stresses could be neglected in the PID prediction for the investigated three different asymmetrical lay‐ups, and contributions made by fiber reorientations range from 18% to 28%. Both fiber reorientations and stamping‐induced stresses are significant factors for PIDs for unidirectional thermoplastic composites in the thermoforming process. POLYM. COMPOS., 40:1786–1800, 2019. © 2018 Society of Plastics Engineers

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“…They reported that spring‐in increases with increasing tool forming temperature, and that the void content in the part increases with decreasing tool forming temperature. Salomi et al have investigated the spring‐in angle of thermoformed commingled glass and polypropylene L‐shape laminates. They formed L‐shapes with different internal radii and noted that for parts with a very small inside corner radius, the spring‐in angle is greater due to defects that occur in the corner.…”

Section: Introductionmentioning

confidence: 99%

Effect of tool temperature on dimensional fidelity and strength of thermoformed polyetheretherketone composites

Fortin

Fernlund

2019

Polymer Composites

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This article presents an experimental study of the effect of tool/consolidation temperature on dimensional fidelity and curved beam strength of thermoformed carbon/PEEK composites made of continuous fibers and random oriented strands (ROS). When processing continuous fiber carbon/PEEK composites, higher tool/consolidation temperatures give higher curved beam and inter-ply strength and more repeatable process induced deformations. Spring-in increases with tool temperature but the spring-in is repeatable and flange warpage is reduced because of lower resin viscosity and increased material flow during consolidation. For the ROS material form, no increase in curved beam strength was observed with higher consolidation temperatures and failure was not governed by the inter-ply strength of the laminate because of the shorter fibers. Lower tool/consolidation temperatures gave less spring-in and flange warpage was not dependent on consolidation temperature. Spring-in for both material forms was found to be thermo-elastic with no effects from crystallization shrinkage. K E Y W O R D Sspring-in, strength, thermoforming, thermoplastic composites, warpage

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Spring-in angle as molding distortion for thermoplastic matrix composite

Cited by 34 publications

References 20 publications

Predicting dimensional distortions in roll forming of comingled polypropylene/glass fiber thermoplastic composites: On the effect of matrix viscoelasticity

Predicting dimensional distortions in roll forming of comingled polypropylene/glass fiber thermoplastic composites: On the effect of matrix viscoelasticity

Simulation and Analysis of Process‐Induced Distortions in Hemispherical Thermostamping for Unidirectional Thermoplastic Composites

Effect of tool temperature on dimensional fidelity and strength of thermoformed polyetheretherketone composites

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