Abstract:The magneto-rheological effects in iron-elastomer composites (IEC) were investigated by simulation, surface topography, and 3D representation. The simulated behavior of magneto-rheological elastomeric composites in the presence of an external magnetic field was determined and the influence of magnetic intensity on the isotropic distribution of iron filler particles in IECs was investigated. The magnetic intensity distribution was analyzed from the edge of the surface towards the center of the IEC. The samples were characterized for microstructural images after experimental tests using both micro-computed tomography (µCT) and scanning electron microscopy (SEM). The adhesion of filler particles within the matrix of the magneto-rheological elastomer (MRE) composite and their distributions were also investigated. µCT showed the overall 3D representation of IEC and the inner distribution of filler particles revealed the presence of some porosity which may be due to bubbles and voids in the matrix of the composite. Finally, a mechanism was established governing particle-particle interactions on the basis of dipole-dipole interactions.

The internal structure of fiber reinforced geopolymer composite was investigated by microfocus X-ray computed tomography (µCT) under mechanical impact. µCT is a non-destructive, multi approach technique for assessing the internal structures of the impacted composites without compromising their integrity. The three dimensional (3D) representation was used to assess the impact damage of geopolymer composites reinforced with carbon, E-glass, and basalt fibers. The 3D representations of the damaged area with the visualization of the fiber rupture slices are presented in this article. The fiber pulls out, and rupture and matrix damage, which could clearly be observed, was studied on the impacted composites by examining slices of the damaged area from the center of the damage towards the edge of the composite. Quantitative analysis of the damaged area revealed that carbon fabric reinforced composites were much less affected by the impact than the E-glass and basalt reinforced composites. The penetration was clearly observed for the basalt based composites, confirming µCT as a useful technique for examining the different failure mechanisms for geopolymer composites. The durability of the carbon fiber reinforced composite showed better residual strength in comparison with the E-glass fiber one.

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Iron particles ranging from 50 to 150 µm are incorporated in an elastomer matrix to obtain magnetorheological elastomer (MRE) composites, aiming to investigate their effects on the surface morphology. The isotropic and anisotropic distribution of fillers are estimated in MRE composites. A simulation analysis is carried out to predict the particle distribution in MRE composites, and a correlation between the experimental observation and simulation analysis is established. The volume fraction of 30 vol% is chosen as the optimal quantity for the filler amount in elastomer composite.

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