Research On The Damage Mechanism Of Deep-sea Solid Buoyant Materials

In recent years,with the implementation of China's "Ocean Power Strategy",China's exploration and development of the deep-sea has accelerated noticeably.In the process of deep-sea exploration and development,the higher requirements for the deep-sea materials are put forward.In this paper,solid buoyancy materials applied to deep sea exploration and resource development are deeply studied.In this paper,ANSYS Workbench software was used to simulate the unidirectional compression of solid buoyancy materials with different bead volume fractions.Then the stress distribution of the materials were analyzed and the compressive strength of the solid buoyancy materials were obtained.The solid buoyancy material samples of different hollow glass beads volume fraction were prepared with glass bubble filled E-51 epoxy,and methyl six hydrogen phthalic anhydride as curing agent,N,N-dimethyl benzyl amine as the accelerator.The compression and bending properties of the material were tested,and the failure mechanism of materials was also analyzed.Finally,the prediction model for compressive strength of solid buoyancy material was established by comparing the experimental data with the simulation results.The stress distribution analysis on two kinds of composites unit cell model showed that there were significant stress concentrations within the solid buoyancy materials and the maximum stress on the bead was much larger than that on the resin matrix.So the compression performance of hollow glass bead shell had an important influence on that of the solid buoyant materials.By the comparison and analysis of the maximum stress on the resin and bead shells with their respective compressive strengths,the simulated strength of the solid buoyancy material was obtained.Through experiments,it was found that with the increase of the volume fraction of hollow glass beads,the density of solid buoyancy material decreased,and the porosity increased.At the same time,the microsphere content improvement was responsible for the decrease of the strength and modulus of solid buoyant materials.During the process of compression test,the destruction of the materials mainly resulted from the shear failure of the resin matrix if the volume fraction of the microbeads is low(?45%).On the contrary,matrix's shear yielding and microbeads,crushing were both liable for the material damage if the volume fraction of the microbeads is high(?50%).Moreover,during the process of bending test,the material destruction was mainly caused by the shear of the microbeads if the volume fraction of hollow glass beads was low(<45%).The materials destruction mainly resulted from the debonding between the beads and the resin if the volume fraction of hollow glass beads was high(?50%).Comparing the simulated compressive strength with the experimental one,it is found that the calculated value well agreed with the experimental results.The maximum error was 14.5%,which was acceptable in consideration of the inevitable error factor.By comparing the calculation results of the two models,it was found that the body-centered cubic model was more suitable for the simulation of the compressive strength of solid buoyancy materials.