Cure-dependent thermomechanical modelling of the stress relaxation behaviour of composite materials during manufacturing

Brauner, Christian; Frerich, Tim; Herrmann, Axel S.

doi:10.1177/0021998316656924

Cited by 23 publications

(8 citation statements)

References 25 publications

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“…These geometrical distortions often result in costly rejection of the part (Brauner et al, 2017;Mesogitis et al, 2014). Part distortion is inevitably induced by preform asymmetry, prevented in practice by the consistent use of symmetrical preform architectures.…”

Section: Distortions: Warpage and Spring-inmentioning

confidence: 99%

“…Part distortion is inevitably induced by preform asymmetry, prevented in practice by the consistent use of symmetrical preform architectures. In symmetrical parts, distortions are observed to originate mainly from mold/part differential thermal expansion (Brauner et al, 2017;Dong et al, 2004;Golestanian and El-Gizawy, 2001). Other reported sources of distortion include recurrent resin rich zones and differential in-plane and the through-thickness cure shrinkage as well as differential thermal expansions of the composite constituents (Hsiao and Gangireddy, 2008;Khoun et al, 2011;Ruiz and Trochu, 2005).…”

Section: Distortions: Warpage and Spring-inmentioning

confidence: 99%

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Process Induced Defects in Liquid Molding Processes of Composites

Hamidi

Altan

2017

International Polymer Processing

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Liquid Composite Molding (LCM) processes are cost efficient manufacturing alternatives to traditional autoclave technology for producing near-net shape structural composite parts. However, process induced defects often limit wider usage of LCM in structural applications. Thorough knowledge of these defects, as well as their formation mechanisms and prevention techniques, is essential in developing improved LCM processes. In this article, process induced defects in liquid molding processes of composites, categorized into preform, flow induced and cure induced defects, are reviewed. Preform defects are further presented as fiber misalignment and fiber undulation (waviness and wrinkling). The respective causes, detrimental effects, and possible prevention methods of these defects are presented. Thereafter, flow induced defects are classified as voids and dry spots. Dry spot formation mechanisms in LCM processes and available prevention techniques are summarized. In addition, void formation mechanisms, adverse effects on composite properties, and removal techniques are presented. Cure induced defects include microcracks, void growth and geometrical distortions (warpage and spring-in). Each of these defects are discussed along with their underlying causes as well as their control and reduction schemes.

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Section: Distortions: Warpage and Spring-inmentioning

confidence: 99%

Section: Distortions: Warpage and Spring-inmentioning

confidence: 99%

Process Induced Defects in Liquid Molding Processes of Composites

Hamidi

Altan

2017

International Polymer Processing

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“…It is due to the complexity of the mathematical description of the processes that occur in the moulded PCM, as well as the necessity to consider their mutual influence (Figure 1). Therefore, the moulding of a composite product is usually considered with the use of several models describing the processes in the moulded material, such as chemo-viscous [20][21][22][23][24][25], thermal [26][27][28][29][30] and force [31][32][33][34][35][36] models. Mathematically, these processes are described independently of each other, and their mutual influence is considered as follows.…”

Section: Introductionmentioning

confidence: 99%

Determination of the Composite Panel Moulding Pressure Value

et al. 2022

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Currently, prefabricated panel structures are typical products made of polymeric composite materials. The integrity of the composite panels, their structure and accuracy of making a contour are largely associated with the manifestation of residual technological stresses. The above phenomena and associated stress-strain behaviour inevitably occur in the process of moulding of the composite products. However, their value, nature, time of occurrence and dynamics of growth can be fully controlled and regulated. The paper deals with the study of the effect of moulding pressure on the quality of a composite product. A dependence is presented that allows us to determine the time for the degassing of the polymeric composite material package at the given temperature and pressure to obtain a monolithic and nonporous structure. It is shown that the peak of the maximum volatile-matter yield for the considered binder types lies in the temperature range where the degree of curing does not exceed 10%; that is, the viscosity values do not prevent the removal of volatile fractions. The effect of moulding pressure on the values of the volume content of the reinforcing material has been studied, and the dependence of the required thickness of the absorbent layer on the parameters of the package of polymer composite material and pressure has been obtained. The dependence of the required thickness of absorbent layer on the parameters of the package of polymeric composite material and pressure has been obtained. The mathematical model developed by us provides an opportunity to predict the stress-strain behaviour of a composite structure at any time during the moulding process. The model is closely related to chemo-viscous and thermal models. It allowed us to synthetize a method for choosing the rational parameters of the moulding process (temperature, pressure, and time), materials of additional layers and equipment. The experiments proved the presence of several defects, such as de-lamination of edges, waviness, swelling and poor adhesion of upper layers in the specimen of the composite panel cooled stepwise in the absence of the vacuum pressure. The surface quality of the specimen of the panel cooled stepwise under vacuum pressure was significantly better, and no visible defects were observed. The obtained theoretical values of deflections, considering the change in physic-mechanical characteristics that depend on the temperature and rheonomic properties of the material, showed an error that did not exceed 7%, compared to the experimental data. Our results can be applied at the enterprises engaged in designing and manufacturing panel structures of polymeric composite materials.

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“…The studies conducted on composite materials so far have focused mainly on manufacturing technologies and strength tests [49,50,51,52,53]. According to the information available in the scientific and industrial literature, composite materials have not yet been subjected to detailed vibroacoustic tests.…”

Section: Introductionmentioning

confidence: 99%

Impact of Application of Selected Composite Materials on the Weight and Vibroactivity of the Upper Gearbox Housing

2019

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In this paper, exploratory studies on the application of fibre-reinforced polymer composites in the construction of gearbox housing elements that are used for transport means, as an alternative to traditionally used materials, were undertaken. Composite materials with three types of reinforcement were used: a glass-chopped strand mat, glass fabric, and carbon fabric. The manufactured elements were subjected to weight assessment and vibroactivity tests, including the recording of vibration and noise. The obtained results were compared to the values recorded for housings made of steel. It has been found that composite housings, while maintaining geometric similarity, are characterised by at least 60% lower weight compared to steel housings. It has been shown that in the frequency range below 1 kHz, composite housings are characterised by the presence of resonant frequencies with higher amplitudes than steel housings. At higher frequency ranges—above 1 kHz—composite housings had a lower vibroactivity level than steel housing. They allowed a significant reduction in the level of vibration and noise in this frequency range. The results obtained indicate that composite gearbox housings can be a good alternative to steel-based solutions.

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Cure-dependent thermomechanical modelling of the stress relaxation behaviour of composite materials during manufacturing

Cited by 23 publications

References 25 publications

Process Induced Defects in Liquid Molding Processes of Composites

Process Induced Defects in Liquid Molding Processes of Composites

Determination of the Composite Panel Moulding Pressure Value

Impact of Application of Selected Composite Materials on the Weight and Vibroactivity of the Upper Gearbox Housing

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