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Analysis of the results of industrial active experiments on the 5-stand mill 2030 of PJSC NLMP has been presented. Technological factors influencing the occurrence of the chatter phenomenon have been outlined. Proposals have been formulated to identify the occurrence of the phenomenon of negative vibration effects based on statistical analysis of the loading modes of the working stands of the 2030 mill.

This study is focused on the effect of vibration induced by moving trains in tunnels on the surrounding ground and structures. A three-dimensional finite element model is established for a one-track railway tunnel and an adjacent twelve-storey building frame by using commercial software Midas GTS-NX (2019) and Midas Gen. This study considered the moving load effect of a complete train, which varies with space as well as with time. The effect of factors such as train speed, overburden pressure on the tunnel and variation in soil properties are studied in the time domain. As a result, the variations in horizontal and vertical acceleration for two different sites, i.e., the free ground surface (without structure) and the area containing the structure, are compared. Also, the displacement pattern of the raft foundation is plotted for different train velocities. At lower speeds, the heaving phenomenon is negligible, but as the speed increases, both the heaving and differential settlement increase in the foundation. This study demonstrates that the effect of moving train vibrations should be considered in the design of new nearby structures and proper ground improvement should be considered for existing structures.

In order to identify the external applied load on train bogie frame, the load response measured by sensor, e.g. strain gauges, is used in engineering practice. However, it is difficult to model the load-response correlation precisely since the bogie frame system characteristic is complicated, especially, it contains many modal vibration effects. The commonly used linear load-response correlation assumption thus deviates from the truth especially at resonant frequencies. A new approach to reduce the modal vibration effect from the load response based on single degree of freedom assumption is proposed in this article. The approach is applied on real measurement of Beijing Subway train bogie frame and the reduction performance is verified.

Ensuring the dynamic safety of buildings near open-pit mines during blasting is a critical concern for the normal conduct of mining operations. This study investigates the effects of blasting vibrations on brick–concrete structures by using deep-hole blasting tests conducted at the mine site, employing blasting vibration monitoring and numerical simulation techniques. The peak particle velocity and energy distribution characteristics of blasting waves in structural columns and brick walls were analyzed. Furthermore, a three-dimensional numerical model was developed to analyze the response characteristics of buildings to blasting vibrations. Considering the impact of a building’s natural frequency on blasting vibrations, harmonic response was utilized to identify the natural frequencies of different components. The relationship between these frequencies and a building’s natural frequency is discussed. Dangerous frequencies and components were identified. The findings of this study can serve as a theoretical foundation for understanding the damage mechanisms of buildings under blasting waves and for controlling the impact of blasting vibration effects.

Buildings close to the ground treated by the resonance- free vibratory hammer method are often vulnerable to excessive vibrations. An in situ test of an urban soft site was carried out to investigate the resonance-free vibratory hammer induced vibration effects during construction. Vibration pickups were set at the positions with distances of 15 m, 30 m, 50 m, and 100 m away from the vibration source. On the basis of the results obtained from this investigation, vibration effects of the resonance-free vibratory hammer and safe construction distances were systematically analyzed. The testing results indicate that the vibration in the vertical direction is stronger than that in the other two horizontal directions. The vertical vibration should be the main reference quantity for the foundation treatment by using the resonance-free vibratory hammer method. The predominant frequency of each measuring point in the same direction decreased with an increase of the distance from the vibration source (DFTVS). In terms of the measuring point with a DFTVS of 30 m, the peak values of velocity in all directions were within 5 mm/s, which meet the requirements of the allowable limit of building vibration. According to the in situ testing results, a model for calculating the acceleration exponent of the vibration caused by the resonance-free vibratory hammer technology was established by comprehensively considering the amplitude of acceleration, the attenuation coefficient of THE DFTVS, and the vibration correction factor. Finally, the reliability of the calculation model was verified through the comparison between the calculated results and field vibration experimental results, in which all the correlation coefficients of validation example were above 0.9.

The purpose of the present study was to investigate the effect of vibration on orthodontic tooth movement and safety assessment based on our previous basic research in animal experiments. A double-blind prospective randomized controlled trial using split-mouth design was conducted in patients with malocclusion. The left and right sides of maxillary arch were randomly assigned to vibration (TM + V) and non-vibration (TM) groups. After leveling, vibrations (5.2 ± 0.5 g-forces (gf), 102.2 ± 2.6 Hertz (Hz)) were supplementary applied to the canine retracted with 100 gf in TM + V group for 3 min at the monthly visit under double-blind fashion, and the canine on the other side without vibration was used as TM group. The amount of tooth movement was measured blindly using a constructed three-dimensional dentition model. The amount of canine movement per visit was 0.89 ± 0.55 mm in TM group (n = 23) and 1.21 ± 0.60 mm in TM + V group (n = 23), respectively. There was no significant difference of pain and discomfort, and root resorption between the two groups. This study indicates that static orthodontic force with supplementary vibration significantly accelerated tooth movement in canine retraction and reduced the number of visits without causing side effects.

Pedestrian-induced footbridge vibration comfort level is a complex problem that has been studied for a long time. However, no consensus has been reached on a quantitative calculation index for assessing vibration comfort level. Only simple comfort limits, rather than specific relationships between comfort level and the vibration endurance capacity of pedestrians, are currently available for assessing vibration comfort level of footbridges. This article aims to propose a sensitivity model for pedestrian-induced vibration comfort calculation based on the vibration endurance capacity of pedestrians and the vibration response of footbridges. The concepts of “human body resistance” and “vibration effect” were established according to the principle of probability and statistics. Mathematical definition of sensitivity was put forward. Calculation expressions for a pedestrian and pedestrians were deduced respectively. A theory of pedestrian-induced footbridge vibration comfort level was proposed. Field survey and experiment were conducted, the results of the field survey demonstrated that sensitivity values were in good agreement with the international vibration comfort standards. Furthermore, the field experiment results showed that the errors between the experimental results and the calculated results were within 6%. The proposed sensitivity theory can be used for pedestrian-induced footbridge vibration comfort quantitative calculation.

Summary This study is a prospective cluster-randomized controlled clinical trial involving 710 elderly subjects to investigate the long-term effects of low-magnitude high-frequency vibration (LMHFV) on fall and fracture rates, muscle performance, and bone quality. The results confirmed that LMHFV is effective in reducing fall incidence and enhancing muscle performance in the elderly. Introduction Falls are direct causes of fragility fracture in the elderly. LMHFV has been shown to improve muscle function and bone quality. This study is to investigate the efficacy of LMHFV in preventing fall and fractures among the elderly in the community. Methods A cluster-randomized controlled trial was conducted with 710 postmenopausal females over 60 years. A total of 364 participants received daily 20 min LMHFV (35 Hz, 0.3 g), 5 days/week for 18 months; 346 participants served as control. Fall or fracture rate was taken as the primary outcome. Also, quadriceps muscle strength, balancing abilities, bone mineral density (BMD), and quality of life (QoL) assessments were done at 0, 9, and 18 months. Results With an average of 66.0 % compliance in the vibration group, 18.6 % of 334 vibration group subjects reported fall or fracture incidences compared with 28.7 % of 327 in the control (adjusted HR = 0.56, p  = 0.001). The fracture rate of vibration and control groups were 1.1 and 2.3 % respectively ( p  = 0.171). Significant improvements were found in reaction time, movement velocity, and maximum excursion of balancing ability assessment, and also the quadriceps muscle strength ( p  < 0.001). No significant differences were found in the overall change of BMD. Minimal adverse effects were documented. Conclusion LMHFV is effective in fall prevention with improved muscle strength and balancing ability in the elderly. We recommend its use in the community as an effective fall prevention program and to decrease related injuries.

The present paper presents the rolling stock vibrodynamic impact model on railway pipelines, obtained on the basis of experimental studies conducted under field conditions at a railway station. The experimental research program provided for the determination of the effect of vibration-dynamic effects of rolling stock on the working condition of pipes and butt joints by conducting vibration-measuring work on the investigated section of the railway pipeline during the passage of various series of locomotives. The proposed modeling method makes it possible to obtain a correlation function of the oscillatory process of a railway pipeline, on the basis of which a spectral density is constructed to identify the amplitude-frequency range at which a stable resonance region occurs, leading to the destruction of the pipeline.

Purpose This paper aims to devote to the experimental analysis and modeling on the heat generation of angular contact ball bearings under vibration. Design/methodology/approach The experiments about vibration effect on bearing temperature are implemented. To explore the causes of bearing temperature rise, the shaft-bearing system is first simplified to a forced vibration model to analyze the bearing loads in vibration. Next, the vibratory-induced additional load is proposed and the spin power loss of balls is re-derived under vibration. The vibration-induced heat is integrated into a novel forecasting model of bearing power loss. For validation, the muti-node model for angular contact ball bearings is referred to create the thermal network of spindle front bearing, and then the contrast and discussion is done. Findings The simulation and test results both indicate that more energy is expended and more heat is generated with vibration. And the further quantitative comparisons between simulation results and experimental values of bearing temperature demonstrate the rationality and availability of constructed model on bearing heat generation. Originality/value The vibration-induced additional load is proposed and modeled, and the novel forecasting model for heat generation for high-speed angular contact ball bearings with vibration is constructed and validated.