Evaluation of structural integrity after ballast-flying impact damage of a GFRP lightweight bogie frame for railway vehicles

To evaluate the structural integrity of a GFRP composite bogie frame induced by ballast-flying phenomena under driving environments of urban trains, an experimental and numerical approach was used in this study. In the experimental approach, a low-velocity impact test and residual compression test after impact were conducted to investigate impact responses and the degradation of mechanical properties of glass fiber/epoxy 4-harness satin woven laminate composites applied to a bogie frame. The numerical approach was comprised of two linked phases. The impact analysis was first conducted to determine the mechanical degradation of a composite bogie frame due to ballast-flying impact, and then the static analysis was done to evaluate the structural integrity of the damaged composite bogie frame with the residual stress and strain results obtained from impact analysis. To verify the reliability of finite element models used for numerical analysis of a composite bogie frame, the proposed finite element models were evaluated by comparing the results of the impact test for specimens. The evaluation results of structural integrity after impact for bogie frame indicated that there was an insignificant effect on structural integrity by impact damage induced by the ballast flying of composite bogie frame. This reason is because the location of post-impact residual compression occurring on the bogie frame does not exert a significant influence on the load required for the structural integrity evaluation.