Numerical Investigation into GFRP Composite Pipes under Hydrostatic Internal Pressure

Glass-fiber-reinforced plastic (GFRP) composite pipes are used extensively in high-performance applications, due to their high stiffness and strength, corrosion resistance, and thermal and chemical stability. In piping, composites showed high performance due to their long service life. In this study, glass-fiber-reinforced plastic composite pipes with [+/- 40](3), [+/- 45](3), [+/- 50](3), [+/- 55](3), [+/- 60](3), [+/- 65](3), and [+/- 70](3) fiber angles and varied pipe wall thicknesses (3.78-5.1 mm) and lengths (110-660 mm) were subjected to constant hydrostatic internal pressure to obtain the pressure resistance capacity of the glass-fiber-reinforced plastic composite pipe, hoop and axial stress, longitudinal and transverse stress, total deformation, and failure modes. For model validation, the simulation of internal pressure on a composite pipe installed on the seabed was investigated and compared with previously published data. Damage analysis based on progressive damage in the finite element model was built based on Hashin damage for the composite. Shell elements were used for internal hydrostatic pressure, due to their convenience for pressure type and property predictions. The finite element results observed that the winding angles from [+/- 40](3) to [+/- 55](3) and pipe thickness play a vital role in improving the pressure capacity of the composite pipe. The average total deformation of all designed composite pipes was 0.37 mm. The highest pressure capacity was observed at [+/- 55 degrees](3) due to the diameter-to-thickness ratio effect.

Automated summary

In this study, glass-fiber-reinforced plastic composite pipes with various fiber angles, wall thicknesses, and lengths were subjected to hydrostatic pressure to analyze their pressure capacity, stress, and deformation. The results showed that composite pipes with a fiber angle of ±55 degrees and larger wall thickness had higher pressure capacity.