Transverse compression failure of unidirectional composites

Abstract

The mechanical response of unidirectional composites subject to uniaxial transverse compressive loads was measured and analyzed by finite element simulation. Consistency in failure plane orientation was observed when comparing simulated matrix shear band angle to measured crack angle. A model based on hexagonal packing of fibers was proposed and the shear band angle was shown to depend on the fiber volume fraction. The effects of strong and weak fiber–matrix interfaces were considered using models with randomly distributed fibers for a valid statistical analysis. The results of these models showed that the composite compressive strength increased with the fiber loading for the strong interface case, while the strength was independent of the fiber loading for the weak interface case because of interface debonding. POLYM. COMPOS., 36:756–766, 2015. © 2014 Society of Plastics Engineers

Thermal oxidation aging of polydicyclopentadiene and composites

“…After 25 weeks of aging, samples aged in all three environments showed increases in T g , a result caused by secondary polymerization during long‐term thermal aging . Among the three environments, aging in the 100°C nitrogen environment produced the lowest T g (compared to 100°C air and 150°C air), a result attributed to the absence of an oxidized layer.…”