Assessment of layer-wise stress redistribution in CFRP/GFRP hybrid lay-ups for type IV hydrogen pressure vessels

초록

Layer-wise load sharing and stress redistribution in carbon fiber reinforced polymer (CFRP) and glass fiber reinforced polymer (GFRP) hybrid lay-ups for Type IV hydrogen pressure vessels were investigated using finite element analysis (FEA). The all-CFRP baseline FEA model was validated by comparing its predicted failure initiation pressure and region with the measured burst pressure and observed rupture region. All hybrid lay-up conditions were compared using the same vessel geometry, contact conditions, and boundary conditions. The design variables were GFRP replacement location, number of replacement layers, stacking continuity, and helical winding angle, and a reduced model was used for parametric assessment. The results showed that continuous replacement of inner low angle helical layers reduced the maximum fiber direction stress and the in-plane shear stress in the cylinder region. Application to the actual winding pattern confirmed the same stress redistribution behavior. Excessive GFRP replacement further reduced the in-plane shear stress but increased the maximum fiber direction stress and shifted its location to a residual CFRP layer in the dome region. Based on these results, a layer-wise stress redistribution criterion is proposed for CFRP/GFRP hybrid lay-up design to control CFRP usage while maintaining structural safety in Type IV hydrogen pressure vessels.

키워드