GlassDeep R&D Project – Underwater Window Research Results

This publication presents the results of the GlassDeep R&D project, focused on the development of innovative multi-layered glass inserts for underwater windows in marine and submerged structures. The research was co-financed by the National Centre for Research and Development (NCBR).

The project progressed through four main stages:

1. Stage I – Computational Analysis and Preliminary Simulations:

   • Finite Element Method (FEM) simulations were conducted on multi-layered window models to verify structural assumptions based on patent PL 227109.

   • Material properties, geometry, and boundary conditions were analyzed.

   • The model included external glass, interlayer fluid, internal glass panes, spacer pads, and seals.

   • Both flat and round window configurations were optimized to ensure allowable stress σ_allow ≤ 40 MPa (well below the glass failure stress of 120 MPa).

   • Windows were verified for hydrostatic pressures up to 0.2 MPa under temperature variations (0–40°C), long-term load (10,000 hours), and cyclic pressure (0–0.55 MPa, 1 million cycles).

2. Stage II – Experimental Validation and Guidelines:

   • Collaboration with the Faculty of Ocean Engineering and Ship Technology at Gdańsk University of Technology enabled prototype testing at a 1:2 scale.

   • Tests confirmed reproducible material strength (140 ± 40 MPa) and agreement between computational predictions and experimental results.

   • Design guidelines were established for full-scale windows, including recommended thickness and number of glass panes to ensure a safety factor of 5 for hydrostatic pressure tests.

3. Stage III – Full-scale Prototype Development and Testing:

   • Full-scale round (1200 mm clear diameter) and rectangular (1200 x 1500 mm clear area) window prototypes were constructed.

   • Custom test rigs were built to simulate operational and extreme pressures: working pressure 0.15 MPa, test pressure 1.5 MPa, failure pressure up to 2.0 MPa.

   • Hydrostatic pressure tests confirmed that all prototypes withstand 0.6 MPa at 20°C, exceeding operational requirements.

   • Documentation and technical guidelines for construction, installation, and operational procedures were developed in accordance with DNV GL classification standards.

4. Stage IV – Final Evaluation and Commercial Feasibility:

   • Prototypes successfully passed pressure and leakage tests, confirming technical feasibility and reproducibility of material and structural properties.

   • The product can be adapted to specific client requirements, including different window sizes or operational conditions.

   • The project outcomes demonstrate that the GlassDeep underwater glass window is ready for commercialization, subject to final certification by a classification society.

Included Files:

• PDF reports of experimental assessments and evaluation of results

• Excel datasets containing measured parameters from experimental tests

This publication does not disclose proprietary production details; it focuses solely on experimental data and general design conclusions.