RT journal article T1 Exact general solutions for the mode shapes of longitudinally vibrating non-uniform rods via Lie symmetries A1 Nunes, Afonso A1 Da Silva, Samuel A1 Ruiz Serván, Adrián A2 Matemáticas K1 General solutions K1 Non-uniform rods K1 Mode shapes K1 Elementary rod theory K1 Lie symmetries AB A Lie symmetry method-based approach is proposed for systematically computing general solutions in closed-form for the mode shape equation of non-uniform and unconventional vibrating rods. The mode shape equation is modeled by the elementary rod theory, addressing polynomial, exponential, trigonometric, and hyperbolic cross-section variations. The method provides algorithmic order-reduction steps for solving the investigated mode shape equation, producing a first-order Riccati equation whose integration reveals the aimed solutions for the problem. Illustrative examples are presented, including original solutions in closed-form as well as solutions previously obtained in the literature by other approaches. Mode shapes from general solutions with appropriate rod boundary conditions are also considered for different examples. SN 1095-8568 YR 2022 FD 2022-11-10 LK http://hdl.handle.net/10498/34750 UL http://hdl.handle.net/10498/34750 LA eng DS Repositorio Institucional de la Universidad de Cádiz RD 10-may-2026