Geometrical modelling of foam structures using implicit functions

► We suggest a new method to create computer models of open-cell ceramic foams. ► Our models avoid sharp edges and include cavities, coatings and closed cell windows. ► The possible morphology can be very versatile and location depending. ► The model could be fitted well to the CT data of a carbon-based alumina foam. Mechanical, thermo-mechanical, and fluid dynamic simulations of open-cell foams require an accurate geometry model. Usually, models are derived from computer- tomography (CT) data which do not allow analysing systematically variation and optimisation of the geometry. On the other hand, entirely computer generated models are mostly assembled of primitive objects like cylinders. This disregards strut thickness variations and node rounding which are observed in real open-cell foams. This paper presents an approach to generate models of ceramic open-cell foams using simple objects with variable thickness generated by implicit functions. This approach can also account for cavities within struts and nodes, which are observed in many real foam structures. The specific rounding at the foam nodes can be modelled by applying the transformation of Blinn. The quality of the generated foam models is verified using CT data of real foams.