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Finite Element Modellierung des Druckverhaltens von Polymer‐Schäumen hoher und geringer Dichte
Author(s) -
Alvarez P.,
Mendizabal A.,
Petite M.M.,
RodríguezPérez M.A.,
Echeverria A.
Publication year - 2009
Publication title -
materialwissenschaft und werkstofftechnik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.285
H-Index - 38
eISSN - 1521-4052
pISSN - 0933-5137
DOI - 10.1002/mawe.200900417
Subject(s) - finite element method , voronoi diagram , materials science , modulus , representative elementary volume , compressive strength , composite material , structural engineering , mathematics , geometry , engineering
In this work, different methodologies were studied by means of finite element modelling (FEM) with the aim of predicting the mechanical behaviour of high and low relative density (ρ r ) polymeric foams. Virtual structures which resemble the real ones were created by various computer‐based tools. These tools were employed to make up both “unit cells” and random structural units so‐called “Representative Volume Elements” (RVE). Low ρ r foams are usually modelled as regular (tetrakaidecahedron) and irregular (Voronoi tessellations) 3D structures made of structural elements (beams and shells). These types of finite elements are only applicable if the ratio between longitudinal and axial dimensions exceeds a certain value and therefore, there is a practical relative density limit above which these elements are not suitable. Alternatively, virtual low ρ r foams were created by means of cellular automata which allow a close control of bubble growth and final cell character and do not show the previous limitation. Additionally, virtual high ρ r structures (ρ r > 0.5) consisting of isolated bubbles or cells were created by random incorporation of cell sets whose size distributions adjust to experimentally measured ones. A random sequential adsorption algorithm (RSA) which accurately controls final thickness of ligaments between cells was programmed for this purpose. FEM results of this kind of virtual foams are compared with experimentally tested mechanical properties. Moreover, impact of structural parameters (mean cell size) on elastic modulus and compressive collapse stress is critically assessed.