Evaluation of computed tomography data from fibre reinforced polymers to determine fibre length distribution / D. Salaberger in INTERNATIONAL POLYMER PROCESSING, Vol. XXVI, N° 3 (07/2011)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXVI, N° 3 (07/2011) . - p. 283-291 Titre : Evaluation of computed tomography data from fibre reinforced polymers to determine fibre length distribution Type de document : texte imprimé Auteurs : D. Salaberger, Auteur ; K. A. Kannappan, Auteur ; J. Kastner, Auteur ; J. Reussner, Auteur ; Thomas Auinger, Auteur Année de publication : 2011 Article en page(s) : p. 283-291 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Composites à fibres de verre -- Moulage par injection Distribution et orientation des fibres Polypropylène Tomographie Index. décimale : 668.4 Plastiques, vinyles Résumé : Sub-µm computed tomography (sub-µm-CT) was used to determine the fibre orientation and fibre length distribution in long glass fibre filled polypropylene. For data evaluation two different concepts based on the application of a sequence of different filters were applied. The first concept is based on segmentation by binarisation using a global threshold, followed by a detailed analysis of regions where fibres are touching. The second concept is based on analysis of the original gray value image. For each voxel the local fibre orientation is determined by calculating the Hessian Matrix and analysing its Eigen values. The effectivity of the two data analysis concepts in determining orientation and length was investigated. For this purpose the algorithms were applied to specimens with four different levels of fibre content: 1, 5, 10 and 30% by weight. To quantify the level of error in fibre determination, a minimum and average probability for correct fibre determination were estimated. The results show a strong dependence of the level of error on the fibre content. Whilst the determination of fibre orientation is not significantly affected, determination of fibre length distribution is significantly influenced by fibre content. For samples with fibre content above 5%, concept 1 does not produce correct representations of all fibres. In particular, problems arise if the fibres are touching. Concept 2 delivers much better results and represents most of the fibres correctly even at higher fibre content levels and for touching fibres. This was proven by using artificial CT-data sets generated by CT-simulation and by systematic comparisons. A practical application of the CT-evaluation pipeline is presented for glass fibre reinforced rings produced by injection-moulding and extrusion. For both samples the orientation tensors are calculated and the orientations of the fibres are visualized in three dimensions by colour coding. DOI : 10.3139/217.2441 En ligne : https://drive.google.com/file/d/15DktodBbq3PtqHSxKBi1KJakcP88_5BR/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=12407 [article]

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Measurement and numerical simulation of void and warpage in glass fiber reinforced molded chunky parts / Stefan Kleindel in INTERNATIONAL POLYMER PROCESSING, Vol. XXX, N° 1 (03/2015)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXX, N° 1 (03/2015) . - p. 100-112 Titre : Measurement and numerical simulation of void and warpage in glass fiber reinforced molded chunky parts Type de document : texte imprimé Auteurs : Stefan Kleindel, Auteur ; D. Salaberger, Auteur ; R. Eder, Auteur ; H. Schretter, Auteur ; C. Hochenauer, Auteur Année de publication : 2015 Article en page(s) : p. 100-112 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Composites à fibres de verre -- Moulage par injection Déformations (mécanique) Gauchissement (matériaux) Moulage par injection -- Défauts Polyamide 6 Simulation par ordinateur Index. décimale : 668.9 Polymères Résumé : The aim of this paper is to determine the reason for the large warpage of an injection molded chunky part made of glass fiber reinforced polyamide 6. State of the art commercial 3D injection molding simulation software was used to predict the warpage of the part. While the simulation predicted a product virtually free of warpage the molded parts showed a large deformation. Several molding experiments and X-ray computed tomography (?CT) scans of the moldings have been performed to figure out the reason for this. The ?CT scans revealed voids in the thick walls of the part. It was found that these defects were the main cause of the unreliable simulation results. Therefore it is concluded that voids can have a major influence on the reliability of numerical warpage predictions. This paper shows a simplified method to determine the zones were voids will appear and shows the comparison with ?CT-data. Note de contenu : - PROBLEM DESCRIPTION - MEASUREMENTS - EXPERIMENTS : Initial case - Variant - NUMERICAL ANALYSIS : Computational mesh - Material data - Fiber orientation - Warpage prediction - Process settings - Solver settings - RESULTS AND DISCUSSION : Experimental results - µCT results - Simulation results - Prediction of porous zones DOI : 10.3139/217.2984 En ligne : https://drive.google.com/file/d/1d_Zb9TKitwRi7zAjPmz5RFAXco_AJv4m/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=23427 [article]

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Prediction and validation of short fiber orientation in a complex injection molded part with Chunky geometry / Stefan Kleindel in INTERNATIONAL POLYMER PROCESSING, Vol. XXX, N° 3 (07/2015)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXX, N° 3 (07/2015) . - p. 366-380 Titre : Prediction and validation of short fiber orientation in a complex injection molded part with Chunky geometry Type de document : texte imprimé Auteurs : Stefan Kleindel, Auteur ; D. Salaberger, Auteur ; R. Eder, Auteur ; H. Schretter, Auteur ; C. Hochenauer, Auteur Année de publication : 2015 Article en page(s) : p. 366-380 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Composites à fibres -- Moulage par injection Composites à fibres courtes Distribution et orientation des fibres Prévision, Théorie de la Rhéologie Index. décimale : 668.4 Plastiques, vinyles Résumé : The paper shows the capability of state-of-the-art models and software to predict the fiber orientation distribution (FOD) on injection molded parts with a complex and thick-walled geometry. Predictions by the standard Folgar-Tucker model and the Reduced Strain Closure model were compared to measurements of the fiber orientation distribution obtained by X-ray Computed Tomography. Measurements and simulations were performed under different processing conditions to investigate the influence of injection velocity and packing pressure on the FOD. It was found that the predicted fiber orientation is in good qualitative agreement with the measurements. The measured orientation shows a distinct shell-core structure with high alignment of the fibers in flow direction in the shell layer and a orientation perpendicular to the flow direction in the core layer. While the orientation in the shell layer is predicted fairly well, a significant deviation is found in the prediction of the orientation in the core layer. Note de contenu : - MEASUREMENTS - EXPERIMENTAL - NUMERICAL : Computational mesh - Material data - Fiber orientation - Solver settings - RESULTS : Influence of the processing conditions on the fiber orientation - Results of the fiber orientation prediction - DISCUSSION : The mesh - Solver settings - Boundary condition for the fiber orientation - Rheological model - Suggestions for further investigations DOI : 10.3139/217.3047 En ligne : https://drive.google.com/file/d/1N1uretG0XwJdlIfK-nUmpBC-VUCobfhP/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=24332 [article]

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