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In response to the issues of vibrations affecting the construction safety, speed, and accuracy of suspended structures due to dynamic disturbances during lifting, environmental disturbances, and improper operator actions, this paper investigates the application of the Active Rotary Inertia Driver (ARID) system for double-rope suspended structures, namely analyzes, and applies control to the vibration response of double-rope suspended structures under external excitations. Taking the double-rope suspended structure as an example, a dynamic analytical model of the double-rope suspended structure is established based on D’Alembert’s principle. Through shake table tests, the dynamic response characteristics and vibration control effects of the double-rope suspended structure under various external excitations are studied, and the influence of the twisting radius of the suspended structure on the control effect is analyzed. The experimental results show that the ARID control system achieves significant control effects on the swing and torsional vibrations of the suspended structure, which validates the accuracy of the theoretical model for the ARID control system and demonstrates its feasibility for practical applications.

Based on the virtual soil pile model, this study investigates the torsional vibration of rock-socketed piles while considering the influence of bottom sediment. First, the bottom sediment is perceived as a virtual soil pile, however, its parameters are still determined according to the characteristics of the sediment. The pile, along with the virtual soil pile, is partitioned vertically into numerous segments in accordance to the stratified characteristics of the rock and soil around the pile. To account for the radial inhomogeneity arising from construction disturbance, the surrounding soil is divided into multiple annular zones characterized by progressively varied soil properties in the radial direction. The governing equations which delineate the soil-pile system under torsional dynamic loading are subsequently formulated and solved to yield an analytical solution for pile complex impedance. After ensuring reliability, the established analytical solution is employed to examine the coupling effect of bottom sediment parameters, pile parameters, and construction disturbance on the torsional vibration characteristics of rock-socketed piles.

In this paper, we describe a coupled nonlinear electromechanical torsional vibration model of a high-speed permanent magnet synchronous motor driven system based on the Lagrange–Maxwell theory. The chaotic state is induced by external excitation forces. A multitime delay feedback control scheme is derived to suppress chaos in such vibrations. An analytical criterion condition for chaos is deduced by Melnikov’s method. Detailed numerical studies, including bifurcation diagram, phase portrait, and a Poincaré map, confirm the analytical prediction. It is revealed that the chaotic motion can be effectively suppressed by reducing or increasing the feedback parameters of the multitime delay feedback control scheme.

Bending and torsional vibrations caused by moving vehicle loads are likely to affect the traffic safety and comfort for girder bridges with limited torsional rigidity. This paper studies the use of cables made of shape memory alloy (SMA) as the devices of reinforcement and vibration reduction for girder bridges. The SMA cables are featured by their small volume, expedient installation. To investigate their effect on the vibration of girder bridges, theoretical analysis, numerical simulation and experimental study were conducted in this paper. For bending vibration, the governing equations of the girder with and without SMA cables subjected to moving vehicle loads were derived, while for torsional vibration, the finite element (FE) simulations were used instead. The results of bending and torsional vibrations obtained by the analytical approach and FE simulations, respectively, were compared with the experimental ones from model testing. It was confirmed that the SMA cables can restrain the vibration of the girder bridge effectively.

This paper is concerned with the lateral and torsional coupled vibration of monosymmetric I-beams under moving loads. To this end, a train is modeled as two subsystems of eccentric wheel loads of constant intervals to account for the front and rear wheels. By assuming the lateral and torsional displacements to be restrained at the two ends of the beam, both the lateral and torsional displacements are approximated by a series of sine functions. The method of variation of constants is adopted to derive the closed-form solution. For the most severe condition when the last wheel load is acting on the beam, both the conditions of resonance and cancellation are identified. Once the condition of cancellation is enforced, the resonance response can always be suppressed, which represents the optimal design for the beam. Since the condition for suppressing the torsional resonance is exactly the same as that for the vertical resonance, this offers a great advantage in the design of monosymmetric I-beams, as no distinction needs to be made between the suppression of vertical or torsional resonance.

The torsional dynamic response of a pile embedded in transversely isotropic saturated soil is investigated while allowing for the construction of disturbance effect. The dynamic governing equations of soil are established based on Biot’s poroelastic theory. By virtue of the continuous conditions of stress and displacement of adjacent disturbance circle and the boundary conditions of pile-soil coupling system, the circumferential displacement of soil and the shear stress on pile-soil contact surface are derived. Subsequently, a closed-form solution for the torsional dynamic response of a pile is derived in the frequency domain. By using inverse Fourier transform and the convolution theorem, a quasi-analytical solution for the velocity response of the pile head subjected to a semi-sine excitation torque is derived in the time domain. The proposed analytical solution is verified by comparing with the two existing solutions available in literature. Following the present solution, a parameter study is undertaken to portray the influence on the complex impedance, twist angle and torque of pile.

Presented in this paper is a numerical solution for torsional vibration analysis of a functionally porous nanotube under a magnetic field. The size effect in microscale can be captured using the nonlocal couple stress theory that predicts softening and hardening in micro-size. The torsional vibration of functionally porous nanotube with magnetic field based on nonlocal couple stress theory is examined. The governing equation is derived using Hamilton’s principle and the generalized differential quadrature method (GDQM) was employed to solve it. A comparison between the results of this work with the other paper reveals the accuracy of this study. The effects of some parameters such as porosity, magnetic field, and small-scale parameters were investigated. The results show that different materials have different behavior in micro-size that can be covered softening and hardening.

The crankshaft is the most important moving part of a reciprocating compressor. As such, it plays a key role in the petrochemical industry. Frequently, the crankshaft cracks and the crank bearing scuffs because of torsional vibration. Therefore, further study on crankshaft vibration is needed to promote development of the high-speed reciprocating compressor. The Modal and Harmonic analysis of the crankshaft was done with the Finite Element Method. The first 6 modals of the crankshaft were calculated using the Lanzos method, and the 3rd and 6th modal shapes of the shaft are torsional. The results showed that bending, torsion and combinations of both are modal shapes of the shaft. Torsional resonance is the main form of shafting dynamic characteristics. Through the harmonic analysis, it found that the response frequency of maximum stress and distortion is 140Hz, and that maximum stress occurs at the transition of two cranks or crankpin junctions. These conclusions can provide some guidance for structure design and for solving the default problem for reciprocating compressor.

Moment of inertia of crankshaft system is variable with crank angle, which may induce complex torsional vibration of reciprocating machines. In this paper, a two-degree-of-freedom dynamic model of a crankshaft-absorber system considering the variable moment of inertia of crankshaft is established by the application of Lagrange's equations. Using the method of multiple scales, average equations under primary and 1:2 internal resonances are obtained to determine the steady-state amplitudes. Theoretical analyses are employed to investigate the effect of variable moment of inertia on system modes. It is found that a critical variable moment of inertia exists in this system. When the actual variable moment of inertia is close to it, stable amplitudes of the system are extremely small, or a rebound phenomenon will appear. Besides, the effects of physical parameters on this threshold are studied and an approximate formula is derived. Finally, the correctness of theoretical analyses are verified by contrast with numerical integration.