ABSTRACT

The PMMA frustums applied as observation windows in the deep-sea manned cabins are vital substructures.The accurate measurement and calculation of the real displacement of PMMA frustums are important for designing the space between the window and the metal pressure hull. The total displacement during service of the submersible is time-dependent due to the viscoelastic properties of PMMA material. In this paper, the total displacement analysis of PMMA frustums with time-deformation behavior based on the viscoelastic model is conducted and parts of the results are verified by experiments. The displacement of the window during the load holding phases and the recovery behavior under different unloading modes are studied, in which the deformation recovery time for solving the residual deformation problem is recommended. Finally, an explicit formula to calculate the axial displacement of PMMA frustums with different thickness-diameter ratios at variable holding-time and pressures is formed for preliminary deep-sea window design.

摘要

深海载人舱作为观察窗使用的PMMA平截头体是重要的下部结构。PMMA平截头体实际位移的准确测量和计算对于窗口与金属耐压船体之间的空间设计具有重要意义。由于 PMMA 材料的粘弹性，潜水器在使用期间的总位移与时间有关。本文基于粘弹性模型对具有时变行为的PMMA截头锥体进行了总位移分析，并通过实验验证了部分结果。研究了窗口在载荷保持阶段的位移和不同卸载模式下的恢复行为，其中建议了解决残余变形问题的变形恢复时间。最后，