About the destruction of spheroplastics by compression and torsion | Mekhanika | kompozitsionnykh | materialov i konstruktsii
> Volume 24 > №1 / 2018 / Pages: 29-45

About the destruction of spheroplastics by compression and torsion


Syntactic foams combining low density with high strength and a number of other useful properties are widely used in aerospace and shipbuilding industries. The mechanism of their destruction depends on the type of thermal-force loading due to the complex microstructure. In this paper we present an experimental study of the deformation and fracture of spheroplastics under various conditions of complex loading. The spheroplastic was an epoxy-diane syntactic foam with glass microballoons as a filler. The thickness of the glass microballoon walls was 1 μm, the average diameter was about 20 μm, the volume content in the composite was 60%. Loading was a different combination of joint and consistent compression and torsion. We also investigated the material destruction at a fixed position of the loading system clamps as a result of the aftereffect. The tests were carried out at various temperatures. Temperature affects the type of destruction of the matrix, the degree of filler particles mobility during the deformation of the composite and the state of the interphase boundaries. Analysis of loading trajectories, relaxation curves and fracture surfaces under various loading regimes and temperatures is carried out. On the basis of the analysis it was concluded that the spheroplastic under complex loading demonstrates the behavior peculiar to granular materials in which the movement of particles is impeded by adhesion with a binder. Characteristic features of granular materials are manifested with increasing compliance of the matrix and the accumulation of microstructural defects that weaken the bond between the filler particles.