Absorption of water by molded plastics / Maik Brehm in KUNSTSTOFFE INTERNATIONAL, Vol. 110, N° 7 (2020)  

[article]  inKUNSTSTOFFE INTERNATIONAL > Vol. 110, N° 7 (2020) . - p. 43-46 Titre : Absorption of water by molded plastics : Numerical simulations help to describe and understand diffusion processes Type de document : texte imprimé Auteurs : Maik Brehm, Auteur ; Achim Frick, Auteur Année de publication : 2020 Article en page(s) : p. 43-46 Langues : Anglais (eng) Catégories : Déformations (mécanique) Diffusion (physique) Humidité -- Absorption:Eau -- Absorption Polyamide 66 Résistance des matériaux Simulation par ordinateur Index. décimale : 668.4 Plastiques, vinyles Résumé : What does the simulation of a diffusion process have to do with the simulation of a temperature field ? Simply put, they share the same differential equation. This property can be exploited in such a way that diffusion processes can be simulated with the aid of finite element programs. Such numerical simulation vividly reveals how such processes take place and how water absorption can influence the design of molded plastics. Note de contenu : - Change in mechanical properties - Standards and guidelines - Analogy between diffusion and heat transfer - Validation illustrated with the example of a plate - Demonstrator part - An open housing - Figure : Test setup and simulation: How does a component behave after three years of water absorption? A simulation quickly provides information, e. g. about water saturation, deformation and (in the figure on the right) the von Mises equivalent stress - Fig. 1 : Water absorption of polyamide 66 over time when aged in 40 °C warm water according to : The change in water absorption over time varies with the thickness of the specimen, but the saturation value remains the same. A simulation conducted on a specimen thickness of 2 mm shows good agreement with the experimental curve - Fig. 2 : FE model of the demonstrator: The meshing was carried out with ten hexahedral elements across the wall thickness. The more elements provided across the thickness, the better the transient diffusion process can be modeled. The simulations were carried out on a quarter model with symmetry boundary conditions - Fig. 3 : True stress-strain curves for PA66 at 20 °C : As the water content increases, the rigidity and strength of the material decrease - Fig. 4 : Water saturation, deformation and stress over time (shown as a quarter model) : Maximum deformation occurs after 116 days, while maximum stress in the steady state occurs only after 1157 days - Table 1 : Comparison of the equations for diffusion and heat transport - Table 2 : Material properties for PA66 immersed in water at 40 °C: these are required for a diffusion simulation En ligne : https://drive.google.com/file/d/1A8iWNphqOMEm2sMIflO542q5fVYKOH36/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=34817 [article]

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How tightly sealed are connectors really ? / Achim Frick in KUNSTSTOFFE INTERNATIONAL, Vol. 111, N° 6 (2021)  

[article]  inKUNSTSTOFFE INTERNATIONAL > Vol. 111, N° 6 (2021) . - p. 37-40 Titre : How tightly sealed are connectors really ? : Measurement method for the exact leakage determination of polymer-metal hybrid parts Type de document : texte imprimé Auteurs : Achim Frick, Auteur ; Marcel Spadaro, Auteur ; Markus Rettenberger, Auteur ; Michael Gehde, Auteur Année de publication : 2021 Article en page(s) : p. 37-40 Langues : Anglais (eng) Catégories : Adhésion métal/polymère Assemblages multimatériaux Connecteurs électriques Cuivre Etanchéité Matières plastiques -- Moulage par injection Perméation Polypropylène Index. décimale : 668.4 Plastiques, vinyles Résumé : The interfacial tightness of hybrid polymer-metal parts such as injection-molded connectors represents a decisive quality characteristic. Until now, however, there has been a lack of suitable measurement technology with which to quantify the media tightness of such molded parts. A new method delivers significantly more accurate results than previous test methods. Note de contenu : - Limits of the differential pressure leakage method - The new DTP method - Setup for the comparison of the measurement methods - Only one method shows clear differencees - Figure : The DDP method enables more accurate determination of the tightness of polymer-metal hybrids - Fig. 1 : Tthree-dimensional view of a test specimen with metal insert and test specimen located between pressure and measuring chamber, arrows show possible permeation paths and interfacial leakage paths - Fig. 2 : Leakage measurement results using different measuring methods on the same samples at 23 °C (averages from five measurements each): in contrast to the differential pressure method, clear differences in the leakage rate can be seen with the helium vacuum test - Fig. 3 : Differentiation between permeation and interfacial leakage determined by using DTPM on thermally post-treated, adhesion-modified polymer-metal hybrids at 23 °C: thermal post-treatment of the hybrid parts clearly influences the leakage rate as well as its development over time - Table : Injection molding conditions for the production of the investigated test specimens En ligne : https://drive.google.com/file/d/1DtKqECMAMcGQYjiiim4f_NE-Q2CV4kUQ/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36177 [article]

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Material-based process control recommended / Achim Frick in KUNSTSTOFFE PLAST EUROPE, Vol. 94, N° 8/2004 (08/2004)

[article]  inKUNSTSTOFFE PLAST EUROPE > Vol. 94, N° 8/2004 (08/2004) . - p. 132-135 Titre : Material-based process control recommended Type de document : texte imprimé Auteurs : Achim Frick, Auteur ; Arif Rochmann, Auteur ; Claudia Stern, Auteur Année de publication : 2004 Article en page(s) : p. 132-135 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.4 Plastiques, vinyles Résumé : Influence of process conditions on the end-use properties of injection mouldings - A company can enhance its prospects of success by integrating materials testing in the injection moulding process through an appropriate form of inline monitoring. While integrated process control will permit efficient quality management, it does not take the morphology of the part into account and will therefore not permit a definitive statement to be made on the quality of the moulded part. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=7812 [article]

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