Window Seat Weight Reduction Exploration With Nontraditional Seat Geometry

Abstract

This article provides an overview of the design and exploratory testing of a nontraditional submersible window seat design. Typically, window seat geometry is guided by the American Society of Mechanical Engineers-Pressure Vessels for Human Occupancy-1 (ASME-PVHO-1) engineering standard as well as other references by ASME, Stachiw, etc. As viewing area increases, window seat geometry is partly driven by the size of the acrylic window and not solely by the requirements for a hull penetration of equivalent size. The discrepancy in strength and stiffness between the submersible hull materials and acrylic window can result in a window seat that is overbuilt relative to the required hull integrity. This research focuses on nontraditional window seat geometries that decrease weight while performing comparably to designs that conform to the ASME-PVHO-1 standard. A novel window seat is proposed with reductions in window seat weight between 22% and 33%. Design methodology, assumptions, Fine Element Analysis (FEA) results, deviations from the standard, and empirical design studies are summarized in detail. Two scale model windows were tested to their design depth for 102 cycles and showed acceptable signs of wear. FEA constraints were validated using strain gauge and displacement measurements on the conical and low pressure faces of the windows. Short Term Critical Pressure (STCP) testing was conducted in a hydrostatic pressure chamber where the two model windows reached 79% and 86% of their design pressure.

Prediction of the service life of deep-sea conical acrylic portholes at designing

“…2), which include the cone angle α and the ratio of thickness to diameter from the low-pressure side h/D. In [4], considerable attention was paid to the design of the porthole body and ways to ensure sealing, however, optimal engineering solutions were not proposed. The authors of [5] found that for a taper angle α = 90° and a relative thickness h/D = 0.41, there are no tensile strains in the porthole, however, the influence of design parameters on the creep of the porthole under operating conditions was not evaluated.…”

Durability of Acrylic Products during Heat Aging

“…However, there are still no methods to determine the reserve coefficient for acrylic products [24,25]. This is due to versatility of design types and conditions of operation of acrylic products [26], and also due to the fact that PMMA, like the other polymeric materials, significantly changes its mechanical properties over time [27,28]. Thus, a comprehensive prediction is made when analyzing the performance of acrylic products, and this prediction takes into account both the deformability of the structure in operation and loss of mechanical performance of the PMMA.…”

Influence of Geometric Parameters of Conical Acrylic Portholes on Their Stress–Strain Behaviour

“…Paper [14] summarises the information about structural types of acrylic portholes but does not give any algorithms for selection of their optimal shape depending on operating conditions. Considerable attention in [15] is paid to the design of the porthole body and ways to ensure its tightness; however, no optimal engineering solutions are proposed. The authors of [16] found that at the tapering angle of α = 90 • and relative thickness of h/D = 0.41 no tensile strains were observed in the porthole, but they did not assess the effect of design parameters on the porthole stress state.…”