Improvement and evaluation of polymer-matrix composite panels with hat stiffenersS. J. Li, L. H. Zhan, X. X. Ding, F. Chen, W. F. Peng, Y. A. Zhang, Y. W. Pu and X. Y. LiuMATEC Web of Conferences, 39 (2016) 01007DOI: https://doi.org/10.1051/matecconf/20163901007