Test-based equivalent-material method for collapse qualification of helically wound and layered cylindrical...

Area of Science:

• Materials Science
• Mechanical Engineering
• Structural Analysis

Background:

• Accurate collapse resistance qualification is vital for pressurized cylindrical shells in offshore, aerospace, and biomedical applications.
• Current methods like hyperbaric chambers are expensive, and simplified models often ignore critical factors such as residual stresses and imperfections.

Purpose of the Study:

• To develop a cost-effective and physically faithful method for qualifying the collapse resistance of layered cylindrical shells.
• To replace traditional, resource-intensive full-scale testing with a more accessible approach.

Main Methods:

• Introduction of the back-inferred equivalent-material method (EMM).
• EMM transforms flat-plate compression test data into a nonlinear constitutive law.
• This equivalent law is embedded into a homogeneous finite-element model to simulate hydrostatic collapse.

Main Results:

• The EMM successfully reproduces hydrostatic collapse behavior.
• Demonstrated accuracy on flexible-pipe carcass layers and steel-strip reinforced thermoplastic pipes.
• Results show close agreement with explicit-geometry simulations and hyperbaric measurements.

Conclusions:

• The proposed geometry-agnostic EMM offers a rapid, low-cost alternative to hyperbaric testing.
• This method provides physically faithful collapse resistance qualification for diverse layered shells.
• Enables broader application across energy, aerospace, and biomedical industries.