Article’s

Rotodynamic analysis plays a critical role in evaluating the structural integrity and operational stability of high-speed turbomachinery. Traditional finite element (FE) modelling often employs computationally intensive three-dimensional solid elements, which significantly increase degree-of-freedom count and processing overhead. This study presents a streamlined yet highly accurate finite element modelling framework for a single disc, ball-bearing-supported rotor system using one-dimensional line body elements in ANSYS Workbench. The shaft continuum is discretized using Timoshenko beam elements (BEAM188) incorporating shear deformation, rotary inertia, gyroscopic coupling, and distributed material damping. Concentrated disc inertia is represented using zero-dimensional point mass elements (MASS21), while flexible bearing supports with direct radial and cross-coupled angular stiffness and damping are modelled via specialized spring damper elements (COMBI214) and custom APDL command scripts. Modal analysis is conducted under stationary and spinning conditions to identify natural frequencies, mode shapes, and critical whirl speeds via Campbell diagrams. Furthermore, forced vibration responses are evaluated in both frequency (harmonic analysis) and time domains (transient dynamic analysis) under rotating unbalance excitation (dynamic analysis) under rotating unbalance excitation (m=e 0.00157 kg⋅m m=e 0.00157 kg⋅m). Numerical). Numerical results demonstrate exceptional agreement with experimental benchmarks from literature, with natural frequency prediction errors remaining below 2.89% across all investigated modes and an identified first critical speed of 1416.2 RPM. Transient response profiles accurately capture the steady-state vibration amplitudes and orbital trajectories across varied rotational speeds (700 RPM, 910 RPM, and 1200 RPM). The proposed line-element methodology drastically reduces computational complexity while maintaining high fidelity, offering an efficient framework for industrial rotodynamic design, model updating, and diagnostic assessment. results demonstrate exceptional agreement with experimental benchmarks from literature, with natural frequency prediction errors remaining below 2.89% across all investigated modes and an identified first critical speed of 1416.2 RPM. Transient response profiles accurately capture the steady-state vibration amplitudes and orbital trajectories across varied rotational speeds (700 RPM, 910 RPM, and 1200 RPM). The proposed line-element methodology drastically reduces computational complexity while maintaining high fidelity, offering an efficient framework for industrial rotodynamic design, model updating, and diagnostic assessment.