| 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 |
in KUNSTSTOFFE INTERNATIONAL > Vol. 110, N° 7 (2020) . - p. 43-46
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