The method is applied to railway tracks with step variation in foundation properties.
Many geotechnical projects today have demonstrated a need for improved soil foundation properties, namely physical and mechanical properties.
Wind turbines mounted on floating platforms are subjected to completely different and soft foundation properties, rather than onshore wind turbines.
The use of different types of sleepers is common on railway tracks, leading to variations in the foundation properties.
Viscous damping is emphasized in the studies, which illustrate the effect of the foundation properties on the stability behavior.
The developed analyses are performed on earthquake-induced synthetic response signals, which are computed from a benchmark linear frame structure under several earthquake excitations and at variable foundation properties.
A parametric study was performed to illustrate the sensitivity of the eigenfrequency and damping on the foundation properties, the latter being expressed using the notion of dimensionless parameters (slenderness ratio and flexibility factor).
Finally, effects of small scale parameter, width ratio, thickness of plate, elastic foundation properties, load value, boundary conditions and nonlinearity are studied for both nonlocal FSDT and classical plate theory (CPT) in detail.
It is found that a step variation in foundation properties leads to a reduction in the beam displacement and an increase in the resonance frequency for increasing step change, with the reverse occurring for decreasing step change.
The solution is obtained by decomposing the nonhomogeneous foundation properties and the beam displacement response into double Fourier summations which are solved in the frequency wavenumber domain, from which the space time domain response can be obtained.
A mixed theoretical and experimental impedance approach has been used to treat the bearing when fitted in a simple machine structure, thereby showing how resulting vibrations of the bearing pedestal can be calculated, with account taken of the effects of bearing, rotor and foundation properties.
