Mechanical properties and fracture analysis of glass bubbles/epoxy particulate composite

The objective of this work was to manufacture and investigate the mechanical properties of particulate composites due to compression by empirical and numerical analyses. Glass bubbles as filler, instead of spherical solid particles, spreading randomly into epoxy resin to cure particulate composites as floating material possess the special features required. In experiments, the specimens were manufactured into two types: (1) coupons of the same particle size with varied particle volume fractions and (2) coupons of the same particle volume fraction with different particle sizes. From the compression tests, we obtained the fracture strength and observed the fracture surfaces to match our chosen crack growing model. As for numerical work, the two-dimensional (2-D) plane strain condition and three-dimensional (3-D) axis symmetry were used to simplify and simulate the problem. Following the finite element method (FEM), commercial software with eight-node quadratic isoparametric elements and quadrilateral rings was adopted and incorporated with element refinement and computation to yield the values and locations of the maximum tensile stresses of specimens. The numerical prediction compares well with experimental results. Finally, we find that for a fixed particle size, specimens with larger particle volume fraction will be reduced in strength, more obviously for smaller particles. However, for fixed volume fraction of particles, specimens will become stronger with larger particle size.