Natural frequency calculation of open laminated conical and cylindrical shells by a meshless method Songhun Kwak, Kwanghun Kim, Yonguk Ri, Gwangil Jong and Hyonil Ri Eur. Phys. J. Plus, 135 5 (2020) 434 Published online: 25 May 2020 DOI: 10.1140/epjp/s13360-020-00438-0