Abstract: In view of the domestic solid buoyancy materials of hollow glass beads for “Fendouzhe” human-occupied vehides (HOV), using a controlled temperature isostatic pressure test device, 1 018 cyclic load tests at 110 MPa hydrostatic pressure were carried out. For the materials before and after hydrostatic pressure cyclic load test, quasi-static tensile, compression, impact, stress relaxation and dynamic mechanical thermal analysis tests were carried out respectively. The mechanical properties of materials before and after cyclic loading were analyzed. Finally, X-ray micro-CT was used to analyze the microstructure of the material. The results show that: After 1 018 cycles of 110 MPa hydrostatic pressure loading, the tensile strength, elongation at break, compressive strength, tensile elastic modulus and compressive elastic modulus of the material are greatly reduced,and the macroscopic mechanical properties of the material are decreased. X-ray micro-CT showed that: After cyclic loading, the internal hollow glass microspheres had a good shape and no significant change in microsphere breakage rate. The internal hollow glass microspheres of solid buoyancy had a good compressive performance. The change of the properties of solid buoyancy materials is mainly due to the change of the properties of resin substrate, which leads to material aging and property attenuation.

Key words: solid buoyancy materials, cyclic loading, mechanical properties, X-ray micro-CT, composites