Analysis of Advanced Pore Morphology (APM) Foam Elements Using Compressive Testing and Time-Lapse Computed Microtomography.

Matej Borovinsek,Michal Vopalensky,Ivana Kumpova,Jan Sleichrt,Matej Vesenjak,Petr Koudelka,Daniel Kytyr

doi:10.3390/ma14195897

Abstract

Advanced pore morphology (APM) foam elements are almost spherical foam elements with a solid outer shell and a porous internal structure mainly used in applications with compressive loading. To determine how the deformation of the internal structure and its changes during compression are related to its mechanical response, in-situ time-resolved X-ray computed microtomography experiments were performed, where the APM foam elements were 3D scanned during a loading procedure. Simultaneously applying mechanical loading and radiographical imaging enabled new insights into the deformation behaviour of the APM foam samples when the mechanical response was correlated with the internal deformation of the samples. It was found that the highest stiffness of the APM elements is reached before the appearance of the first shear band. After this point, the stiffness of the APM element reduces up to the point of the first self-contact between the internal pore walls, increasing the sample stiffness towards the densification region.

Highlights

To determine how the deformation of the internal structure and its changes during compression are related to its mechanical response, in-situ time-resolved X-ray computed microtomography experiments were performed, where the Advanced pore morphology (APM) foam elements were 3D scanned during a loading procedure
Advanced pore morphology (APM) foam elements (Figure 1) are almost spherical elements made from closed-cell foam and enveloped with a solid outer shell [1,2,3], which were developed by the Fraunhofer Institute IFAM in Bremen [4,5]
Observation of the compressive behaviour of APM foam samples using two different methods, micro-computed tomography coupled with in-situ compressive testing, enabled new insights into the deformation behaviour of the APM foam samples to be determined

Summary

Introduction

When all the voids between the spherical APM elements are filled with a polymer filler, an APM-based polymer matrix foam is obtained with improved mechanical properties [9,10]. Due to their specific properties [11,12] and their versatile combinations with other filler materials, APM foam elements have a wide range of applications in layers of composite materials [13,14], in components for functional thermal conductivity [15], in components for absorbing impact energy [16] and vibrations [7] and inside hollow construction parts for their reinforcement against local wall buckling [5,17,18]. Using them as a filler material inside hollow components is especially advantageous, since they can fill even complex internal cavities of hollow components [19]

Methods

Results

Discussion

Conclusion