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Modeling of moisture‐induced stress in PMMA: A simple approach to consider sorption behavior in FEM
Author(s) -
Geertz Guru,
Wieser Jürgen,
Alig Ingo,
Heinrich Gert
Publication year - 2017
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.24378
Subject(s) - materials science , sorption , composite material , finite element method , moisture , isothermal process , relative humidity , humidity , stress (linguistics) , cracking , bending , diffusion , swelling , environmental stress cracking , deformation (meteorology) , structural engineering , thermodynamics , stress corrosion cracking , chemistry , philosophy , linguistics , physics , organic chemistry , adsorption , alloy , engineering
Moisture‐induced stresses in amorphous thermoplastics are studied in detail using the finite element method (FEM). The approach is based on the coefficient of moisture expansion which is derived from the sorption behavior (i.e., changes of mass, density and elastic properties). The required model parameters were obtained by isothermal diffusion and swelling experiments at different levels of relative humidity at room temperature. In the analysis, the evolutions of moisture‐induced stresses in a model system have been analyzed, i.e., drying sheets of poly(methyl methacrylate). The calculated stresses during drying are discussed with regards to the sorption models. Results indicate that these computational models are essential in capturing the accurate moisture‐induced stress. Finally, the simulation results were verified by three‐point bending. The implemented method shows the potential to predict environmental stress cracking due to humidity by FEM. This is important for the improved design of plastics parts. POLYM. ENG. SCI., 57:3–12, 2017. © 2016 Society of Plastics Engineers