Effect of Water Absorption on the Mechanical Property and Failure Mechanism of Hollow Glass Microspheres Composite Epoxy Resin Solid Buoyancy Materials

To study the water absorption of hollow glass microspheres(HGMs)composite epoxy resin solid buoyancy materials in the marine environment and its effect on the mechanical properties,the water absorption was measured by immersing the material in distilled water for 36 days at ambient temperature and fitted to Fick’s second law.The strength of materials before and after water absorption were tested by uniaxial experiments,and the effects of the filling ratio and water absorption on the mechanical properties of the materials were analyzed and explained.Finally,the failure modes and mechanism of the hollow glass microspheres composite material were explicated from the microscopic level by scanning electron microscope(SEM).This research will help solve the problems of solid buoyancy materials in ocean engineering applications.

The mechanical and water absorption properties of carbon fiber buoyancy materials under hydrostatic pressure

Buoyancy material technology is of paramount importance for the development of marine engineering.In this study,a novel carbon fiber buoyancy material(CFBM)is designed and prepared by utilizing composite circular tubes with light weight and high strength.To reveal the failure mechanism under hydrostatic pressure,a finite element model(FEM)based on the three-dimensional Hashin and Yeh failure criterion is developed and validated experimentally.Both the simulated and experimental results indicate that the hydrostatic strength of the CFBM is mainly determined by the buckling of carbon fiber tubes located at the edges of the CFBM.Parametric analysis is conducted to investigate the effect of the number of unit-cells,length,and wall thickness of carbon fiber tubes on the mechanical properties of the CFBM.In addition,a 60-day water absorption test of the CFBM at 12.5 MPa is conducted to characterize its durability.Experimental results indicate that the maximum water absorption rate of the CFBM is 0.59%and the hydrostatic strength is reduced by only 7.97%during the 60-day test period.Finally,the designed CFBM is used at the water depth of 1000 m as buoyancy material.Compared with traditional buoyancy materials,the proposed CFBM has significant advantages in both hydrostatic strength and density.This work has broad engineering application prospects and is of high significance for promoting the implementation of carbon fiber composites in the ocean engineering field.