Process induced residual stresses and distortions in pultrusion

Baran, İsmet; Tutum, Cem Celal; Nielsen, Michael Wenani; Hattel, Jesper Henri

doi:10.1016/j.compositesb.2013.03.031

Cited by 103 publications

(200 citation statements)

References 41 publications

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“…This approximation is well justified considering the remarkable difference, for pultruded products, between in plane (cross sectional) and out of plane (product length) dimensions, being the former of few square millimeters and the latter of several meters before the cutout. As a consequence, the problem can be reduced to a two dimensional plane strain analysis, as discussed in [25]. The corresponding transient distortions and the evolution of the process induced stresses and strains are calculated considering the temperature and the cure distributions, assuming the following contributions to the incremental total strain (Δ tot ):…”

Section: Fe Modelmentioning

confidence: 99%

“…The details of the relations between the stress and strain tensors used in the present FE approach can be found in [25]. The CHILE approach [25,27] has been implemented by means of user-routines in the commercial package ABAQUS to derive the instantaneous local resin elastic modulus ( ), assuming a linear relation of the stress and strain tensors. The corresponding expression for the resin elastic modulus, assuming secondary effects of temperature as negligible, is given as follows:…”

Section: Fe Modelmentioning

confidence: 99%

“…The evaluation of the DOC and the reaction rate has been obtained by means of an iterative inhouse developed routine implemented into the commercial software package ABAQUS [28], until the matching of temperature and DOC tolerances to reach the steady state. The DOC is obtained by using the following discretization [7,25]:…”

Section: Continuous Modelmentioning

confidence: 99%

“…In the second approach, the transient stresses, distortions, and frictional pull force are predicted using a sequentially coupled 3D thermochemical analysis together with a 2D plane strain mechanical analysis using the finite element method (FEM). In both cases the evolution of the mechanical properties of the processing material is computed using the cure hardening instantaneous linear elastic (CHILE) approach [25,27]. The paper is organized as follows: in Section 2 the theoretical modeling and the governing equations are described in detail, while in Section 3 the obtained results are exposed and discussed.…”

Section: Introductionmentioning

confidence: 99%

“…Besides, the temperature and the DOC gradients through the composite thickness also promote the development of residual stresses in the manufactured part [23]. A better understanding of these phenomena, which take place in the heating die as well as in the postdie region, is highly required to reduce process induced shape distortions and residual stresses and to obtain a realistic analysis of inservice loading scenarios and reliability assessments [24,25]. It should be noted that the general mechanical behavior of the composite material is orthotropic (transversely isotropic if only unidirectional fibers are used) and the coefficient of thermal expansion (CTE) of the polymer-matrix materials is usually much higher than that of the fibers.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Computational Approaches for Modeling the Multiphysics in Pultrusion Process

Carlone

Baran

Hattel

et al. 2013

Advances in Mechanical Engineering

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Pultrusion is a continuous manufacturing process used to produce high strength composite profiles with constant cross section. The mutual interactions between heat transfer, resin flow and cure reaction, variation in the material properties, and stress/distortion evolutions strongly affect the process dynamics together with the mechanical properties and the geometrical precision of the final product. In the present work, pultrusion process simulations are performed for a unidirectional (UD) graphite/epoxy composite rod including several processing physics, such as fluid flow, heat transfer, chemical reaction, and solid mechanics. The pressure increase and the resin flow at the tapered inlet of the die are calculated by means of a computational fluid dynamics (CFD) finite volume model. Several models, based on different homogenization levels and solution schemes, are proposed and compared for the evaluation of the temperature and the degree of cure distributions inside the heating die and at the postdie region. The transient stresses, distortions, and pull force are predicted using a sequentially coupled three-dimensional (3D) thermochemical analysis together with a 2D plane strain mechanical analysis using the finite element method and compared with results obtained from a semianalytical approach.

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Section: Fe Modelmentioning

confidence: 99%

Section: Fe Modelmentioning

confidence: 99%

Section: Continuous Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Computational Approaches for Modeling the Multiphysics in Pultrusion Process

Carlone

Baran

Hattel

et al. 2013

Advances in Mechanical Engineering

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An overview on current manufacturing technologies: Processing continuous rovings impregnated with thermoset resin

et al. 2021

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The demand for products made of fiber‐reinforced polymer composites (FRPC) is constantly growing. These lightweight products are characterized by high stiffness, high tensile strength, and high service life. FRPC processes that employ thermoset‐impregnated continuous rovings are easily automated and provide the products with the highest unidirectional tensile strength. A critical disadvantage of continuous fiber‐reinforced polymers is caused by relatively high production costs. Among others, three main factors contribute to these production costs: (1) material costs, especially when carbon fibers are used, (2) costs for manufacturing semi‐finished products, such as textiles or preimpregnated fabrics, and (3) costs for waste occurring along the entire chain of process steps. In this context, one group of processes shows outstanding characteristics: processes in which rovings are in situ impregnated with a thermoset resin and then directly processed. Wet filament winding and pultrusion are the most popular but not the only representatives of this group. For all these processes, in situ impregnation is the key element, and various technologies have been developed for this purpose, each with its own unique fluid‐mechanical effects on rovings. A fundamental understanding of these effects is crucial to achieve products of the utmost quality. The paper at hand provides an overview of manufacturing processes that employ in situ impregnation of continuous rovings, specifically focusing on impregnation technologies. On this basis, phenomenological models describing the effects on the rovings during processing (impregnation, tension, and spreading) are reviewed.

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An acrylic resin system for in‐situ pultrusion: Curing performances and rheology

Tian,

Zhang,

Xian

2023

Polymer Composites

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In recent years, the use of low viscosity and in‐situ polymerizable thermoplastic acrylic resins for advanced fiber reinforced composites has grown, specially to address the difficulty of fiber impregnation with high‐melt viscosity thermoplastic polymers. The present work investigated the curing kinetics, chemo‐rheology of an acrylic resin system for in‐situ pultrusion, and proposed the corresponding constitutive models. First, the curing kinetics was studied with the differential scanning calorimetry experiments. The viscosity development was obtained by a rheometer as functions of the degree of cure (DOC) and temperatures. The gelation point was acquired from the intersection point of storage and loss modulus curves through dynamic mechanical analysis test, which occurs at DOC of 0.65 determined by the cure kinetics model. Through the dynamic mechanical analysis, a four step cure hardening modulus model (modified CHILE approach) was proposed. The aforementioned models were applied in a case study to evaluate the influence of process parameters on the DOC, viscosity and physical behavior of the acrylic resin system in the pultrusion die.Highlights Material characterizations of an acrylic resin system are investigated. The cure kinetics and viscosity and elastic modulus models are proposed. A pultrusion case study is given.

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Process induced residual stresses and distortions in pultrusion

Cited by 103 publications

References 41 publications

Computational Approaches for Modeling the Multiphysics in Pultrusion Process

Computational Approaches for Modeling the Multiphysics in Pultrusion Process

An overview on current manufacturing technologies: Processing continuous rovings impregnated with thermoset resin

An acrylic resin system for in‐situ pultrusion: Curing performances and rheology

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