Large pipes: ready for extreme forming!

Performance reliability of heavy-duty pipelines

Pipe and pipe fittings need reserve capacity to withstand forming and static loads.

More and more pipelines are being laid in areas where difficult geological conditions prevail. Such areas are increasingly susceptible to soil movements that exert longitudinal or bending forces and deform the pipeline. To reliably withstand these effects, pipe and pipe fittings need reserve forming and static load-bearing capacity. In extensive component testing on our “LiSA” (Limit State Analyzer) bending test stand, large pipes and fittings were analyzed under extreme loads. In the test, pipe specimens were subjected to 4-point bending while under high internal pressure. The components exhibited impressive formability: They could be bent well beyond buckling without causing the material to crack and without developing leaks.

Our experimental database includes large pipes manufactured with various productions processes (spirally welded and longitudinally welded UOE and HFI pipes). The results provide important initial data for the further development of safety criteria in pipeline design. “Strain-based design” measurement concepts are under discussion in pipeline industry’s professional circles the world over. We provide pipe manufacturers with the opportunity to optimize their products, because conclusions about advantageous material properties and forming processes can be drawn from the findings of component behavior. The experiments are supported by broad-based FEM analyses that document the conditions of critical deformations such as buckling or leakage.