Quasi-static compressive testing up to densification of some selected auxetic structures in two different directions was performed to determine complete deformation behaviour of these structures. Furthermore, the high strain rate experimental testing of selected auxetic cellular structures was performed to determine also the deformation behaviour at higher strain rates. Subsequently, representative discrete computational models built with the beam finite elements were developed and validated by experimental data. The values of the critical strain rate determined by analytical expressions and visual observation of deformation procedure in experiments were also compared. Validated discrete computational models were used for further optimisation of auxetic structure geometry to obtain user defined response during dynamic compression loading by applying functionally graded porosity.
B.03 Paper at an international scientific conference
COBISS.SI-ID: 20847126The presentation will give a short overview of cellular materials in general. Initially, their properties, fabrication procedures and application possibilities will be discussed. Then their geometrical characterization, experimental testing and computational modelling within the finite element method of various cellular metal types will be described. The geometrical characterisation is based on the analysis of micro computed tomography scans and proper recognition of their internal cellular structure, taking into account the statistical distribution of morphological and topological properties. The results of conducted geometrical analysis provided means to develop methodology for proper 2D and 3D geometrical modelling of irregular cellular materials and consequent formation of computational models. The numerical models were validated by quasi-static and dynamic mechanical experimental tests supported by infrared thermography.
B.04 Guest lecture
COBISS.SI-ID: 20960278In the lecture, auxetic cellular structures, which exhibit negative Poisson’s ratio, will be discussed. Negative Poisson’s ratio is a consequence of internal structure deformation. This effect is useful for many different applications to enhance mechanical properties. Several 2D and 3D auxetic structures will be introduced. Experimental results of some selected auxetic structures, tested under quasi-static and dynamic loading conditions, will be presented. Furthermore, representative discrete computational models built with the beam finite elements and homogenised computational models that were validated by experimental data will be shown as well. They were developed to explore the auxetic response at different loading conditions and material distribution (including porosity variation).
B.04 Guest lecture
COBISS.SI-ID: 21029142