Abstract: Aiming at improving compressed nature gas (CNG) cylinders wound layer resin anti-crack characteristic, a multi-scale modeling method is proposed to investigate the resin cracking mechanism. In the simulation model, the influences of gel content of winding layer and fiber diameter was discussed by micro-mechanics approach. Simulation results indicate that resin cracking degree is reduced as the gel content increases, and the resin cracking degree reaches the minimum point while the gel content was set to 34%. Then the influence of fiber diameter on the resin crack was discussed using a multi-scale model by setting gel content to 34%, and the simulation results indicate that fiber diameter almost has no effect on the cracking of the resin. Finally, the validaty of the multi-scale model is verified by experimental results. Since the gel content can be adjusted by precisely control the winding tensions, the study can be adopted to reduce the degree of resin cracking and provide the theoretical reference for improving the production of CNG-2 cylinders.

Key words: CNG, cylinder, gel content, winding layer, cracking