Since the non-linear dynamic response under various high-speed conditions can directly affect the life of gear transmission systems. In addition, the transmission error and dynamic mesh force play a key role in noise and harshness analysis of gear bearing coupled systems. So, in this piece of work, a 12 degree of freedom dynamic model is developed to probe the vibration response by using finite element method and taking into account the bearing and flexible shafts in the first part. Subsequently, some meshing gear characteristics such as dynamic and vibration acceleration response under different rotational speeds (1000-9000 rev/minute) were analyzed whereas critical speed appeared at 6500 rev/minute. Then, the stability analysis is performed to investigate the dynamics behind the critical speed by using MASTA. It was observed that natural frequency of 0.45 kHz for a fourth harmonic order is analogous to critical speed which further causes sudden elevation in both dynamic mesh force and transmission error.

Cavitating flows around a rotating circular cylinder at the low Reynolds number flow (Re = 400) are numerically investigated. The computation is performed by incorporating a compressible homogeneous liquid-vapor two-phase flow and a homogeneous equilibrium mass transfer model. The simulation is well-validated for the cavitating and non-cavitating flows over various objects in literature. The computation is then carried out for the rotating cylinder to analyze the combined effects of cavitation and self-rotation on the resultant load. The results state a high influence of the rotation speed ratios γ (a ratio of the cylinder's rotation velocity to the flow velocity) on the flow regime. For non-cavitation, the Karman vortex street is observed for γ < 2.0 while a nearly steady state results in a higher value. Under the Magnus effect, a larger lift is produced but also obviously increases the friction drag on the cylinder. Regarding the cavitation condition, the computation demonstrates an obvious reduction in the friction drag, leading to a decrease of the total drag of a rotating cylinder by about 52% compared to that without cavitation, while retaining reasonable lift. Almost constant load on the cylinder is found at low γ > 1.5 and cavitation number σ̍p0−pv12ρU02≤ 1.0, which is significant for designing and extending the working durability of an underwater moving object.

Basing on the theory shock longitudinal of solid body into elastic bar, authors define speed of the piles weighting canter in shocking time, they also define kinetic energy of weighting canter and define vibration energy of the pile driven in two layers foundation base, pile bearing side friction q1#q2 pile bottom encounters constant resistance.

This paper consider the collision of hammer to pile driven into two layers foundation base, piles bearing side friction q1 ≠ q2, applies the theoretical basis of longitudinal collision of elastic bars and method of wave propaganda DAlember, determine the velocity of pile heads in the time interval, compress work of elastic buffering on pile head, from the calculation of coefficient of energy transfer from hammer to pile, choosing pile head buffering and hammer heads according to the coefficient of energy transfer calculated.

Removed at authors request