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Vibration-assisted cutting is a promising technique widely utilized to enhance machining efficiency and achieve superior material finishes compared to traditional cutting methods. However, the underlying mechanism of how vibration impacts material properties and deformation requires an in-depth understanding. In this study, molecular dynamics (MD) simulations were employed to investigate the atomic-scale effects of vibration on copper. The result reveals significant changes in the mechanical behaviours of copper under different cutting conditions. The high-frequency vibration of the cutting tool introduces a notable temperature rise to the workpiece, which is considered beneficial for improving the material removal efficiency. Additionally, the cyclic loading of the tool assists in reducing cutting forces and polishing the machined surface to enhance the surface integrity. Furthermore, the analysis of dislocations and defects suggests that vibration effectively prevents large-scale lattice deformations and visible cracks, thereby enhancing surface finish. This research provides insights into the role of vibration in improving cutting processes and surface quality. [ABSTRACT FROM AUTHOR]

For fragile products, packaging requires cushioning protection to prevent irreversible damage from accidental falls, transportation impacts, and other causes. The new polyurethane foam (PUF) material demonstrates superior cushioning and vibration isolation performance in practical applications, effectively minimizing damage from vibrations. Drop and vibration experiments were conducted on packages comprising novel PUF, expandable polyethylene, ethylene–vinyl acetate copolymer foam, and bracelets. Results verify that the new PUF material outperforms in cushioning and vibration isolation, as observed from the acceleration response. Furthermore, a random vibration analysis of a packaging unit involving different thicknesses of PUF materials and bracelets reveals the enhanced vibration isolation effect within a specific thickness range. The vibration results of the bracelet's outer packaging align closely with finite element simulation results, validating the effectiveness of designing and optimizing the outer packaging. Through finite element simulation, deeper understanding and prediction of the bracelet's vibration response under various conditions is achieved, facilitating optimized packaging design for better protection and vibration damping. [ABSTRACT FROM AUTHOR]

A liquid launch vehicle is an important carrier in aviation, and its regular operation is essential to maintain space security. In the safety assessment of fluid launch vehicle body structure, it is necessary to ensure that the assessmentmodel can learn self-response rules from various uncertain data and not differently to provide a traceable and interpretable assessment process. Therefore, a belief rule base with interpretability (BRB-i) assessment method of liquid launch vehicle structure safety status combines data and knowledge.Moreover, an innovative whale optimization algorithm with interpretable constraints is proposed. The experiments are carried out based on the liquid launch vehicle safety experiment platform, and the information on the safety status of the liquid launch vehicle is obtained by monitoring the detection indicators under the simulation platform. The MSEs of the proposed model are 3.8000e-03, 1.3000e-03, 2.1000e-03, and 1.8936e-04 for 25%, 45%, 65%, and 84% of the training samples, respectively. It can be seen that the proposed model also shows a better ability to handle small sample data. Meanwhile, the belief distribution of the BRB-i model output has a high fitting trend with the belief distribution of the expert knowledge settings, which indicates the interpretability of the BRB-i model. Experimental results show that, compared with other methods, the BRB-i model guarantees the model's interpretability and the high precision of experimental results. [ABSTRACT FROM AUTHOR]

• A systematic experimental study to investigate the influence of vibration amplitude, frequency, and subsequent vibration-induced acceleration on oil recovery. • Image analysis-based methodology to quantify dislodgment effectiveness, representing a form of oil recovery, is developed. • Experimental observations demonstrate seismic vibrations' effect in dislodging an entrapped fluid. • The observed data serve as a reference tool for computational studies while implementing them in the reservoir simulations. The impact of seismic vibrational amplitude and frequency in dislodging an entrapped diesel globule in a pore model is experimentally studied. The effective change occurring inside a 3D printed pore model estimated from a systematic image analysis methodology is developed to represent the oil recovery. The pore model is subjected to sinusoidal vibrations with amplitudes ranging from 0.1 mm to 2 mm and frequencies ranging from 5 to 100 Hz. Dislodgment of entrapped diesel is observed for frequency values between 40 and 80 Hz with vibration amplitude above 0.5 mm. Even though increasing the vibration frequency increases the vibration-induced acceleration, the dislodgment of the entrapped fluid is not observed at higher frequencies. Smaller vibration amplitudes imparted by the shaker and a possible slip flow at the oscillating walls occurring at higher frequencies are reasoned for this observation. [ABSTRACT FROM AUTHOR]

In this study, factors affecting average shot velocity in the Surface Mechanical Attrition Treatment (SMAT) process were investigated numerically. The numerical model was developed by using the finite element method. The effects of frequency, amplitude, and projection distance parameters on shot velocity were simulated. Response Surface Methodology (RSM) was used to evaluate the simulation results. ANOVA tables were used for statistical evaluation. Moreover, the regression equations derived from simulation results were compared with the theoretical equations. Besides, the effect of the amount of shot in the SMAT chamber on the velocity of the shot is simulated. The results showed that apart from frequency and amplitude, projection distance also had a significant impact on shot velocity. [ABSTRACT FROM AUTHOR]

Industrial vibration monitoring is crucial for anticipating equipment failures and ensuring smooth machinery operations. To address this need, we propose a Siloxene-Ecoflex elastomeric macro-pillared self-powered triboelectric vibration sensor (SP-TVS) that offers exceptional detection capabilities, with an ultra-wide frequency range (0.01–15 kHz) and acceleration range (0.1–7.0 g). The SP-TVS combines a facile fabricated elastomeric macro-pillar of nanocomposite paired with a flexible thin film of styrene-ethylene-butylene-styrene (SEBS) to realize the TVS. The SP-TVS exhibits high-frequency response (up to 15 kHz) due to the random high elastic vibration behavior of the macro-pillars and demonstrates excellent acceleration sensitivity of 2.033 V/g (0.1–0.5 g), 1.455 V/g (0.5–2.0 g), and 1.116 V/g (2.0–7.0 g) at r2 = 0.99 in low, medium, and high acceleration ranges and enables subtle vibration amplitude detections. Finally, the SP-TVS has been successfully deployed on various machineries, employing a sophisticated Artificial Intelligence algorithm to process sensor data, performs self-powered machinery identification, vibration inspection, and fault monitoring, showcasing its significant potential for a wide range of industrial monitoring applications. [Display omitted] • Triboelectric vibration sensor is designed and fabricated using all elastomeric Siloxene-Ecoflex pillars and SEBS film. • Inherent elasticity and random vibration of pillars allows a broad range of vibration frequency detection (0.1–15 k Hz). • Frequency tunability can be obtained in ultra-wide range vibration (0.1–7 g) by varying the pillar dimensions. • The vibration features of various machineries can be acquired and processed for long-term condition monitoring. • A highly sophisticated AI model allows machinery identification, vibration inspection and fault monitoring in real time. [ABSTRACT FROM AUTHOR]

Abstract We performed theoretical investigation on mechanisms of LiD/LiH/LiT+H 2 O reactions with second order perturbation theory (MP2). Calculations of enthalpy change and reaction rate constant are in agreement with experimental data and other theoretical values. Results show that two reaction channels exist for LiD + H 2 O reaction, and channel 1 is the main reaction channel. Kinetic Isotope Effect (KIE) is not so large although fracture of isotope bond takes place in the reaction, which is noticeably different from theoretical maximums of primary isotope effect. Individual contributions of KIE effect are listed as follows η vib > η rot > η tun > η pot > η trans , indicating that main contribution of isotope effect results from vibration factor. [ABSTRACT FROM AUTHOR]

Purpose The purpose of this study was to compare the effects of an 8-week whole-body vibration training program in various frequency and amplitude settings under the same acceleration on the strength and power of the knee extensors. Methods Sixty-four young participants were randomly assigned to 1 of 4 groups with the same acceleration (4  g ): high frequency and low amplitude ( n  = 16, 32 Hz, 1 mm) group, medium frequency and medium amplitude ( n  = 16, 18 Hz, 3 mm) group, low frequency and high amplitude ( n  = 16, 3 Hz, 114 mm) group, and control ( n  = 16, no vibration) group. All participants underwent 8 weeks of training with body mass dynamic squats, 3 sessions a week. Results The results showed that the high frequency and low amplitude group increased significantly in isometric contraction strength and 120°/s isokinetic concentric contraction strength; the medium frequency and medium amplitude group increased significantly in 60°/s and 120°/s isokinetic strength of both concentric and eccentric contraction; and the low frequency and high amplitude group increased significantly in 60°/s and 120°/s isokinetic eccentric contraction strength. Conclusion All frequency and amplitude settings in the 8-week whole-body vibration training increased muscle strength, but different settings resulted in various neuromuscular adaptations despite the same intensity. [ABSTRACT FROM AUTHOR]

The electromagnetic field can cause an essential change of the dynamic behavior of the railgun. The evaluation of the dynamics performance of railgun is a mandatory task. Here, a nonlinear electromagnetic force equation of the railgun is given in which the clearance, the thickness and the width of the rail are considered. Based on it, the nonlinear electromechanical coupled dynamics equations of Euler beam rails for the railgun are proposed. Using the equations, the nonlinear free vibration frequency of the railgun is investigated and the effects of the system parameters on the frequency are analyzed. The nonlinear forced responses of the rail to the electromagnetic excitation are investigated as well. The results show that as the nonlinearity of the railgun system is considered, the vibration frequencies of the railgun system increase; as the current in the rail increases, the difference between the natural frequencies and the nonlinear vibration frequencies increases significantly; the nonlinearity of the railgun system is more obvious for smaller distance between the two rails, smaller rail thickness, and smaller stiffness of the elastic foundation; the unstable dynamics state of the rail system occurs when the armature runs to the exit of the railgun. The results are useful for design and application of the railgun system. [ABSTRACT FROM AUTHOR]

The paper presents the results of experimental research conducted on the newly constructed post-tensioned pre-stressed concrete road bridge situated over water plant of water reservoir under dynamic field load tests in Topola village (Poland). The dynamic loads consist of four heavy trucks passing at different speeds, through threshold and braking at the midspan. The obtained results from field load tests and the calculation of dynamic coefficients, values of amplitudes of vibration velocities and frequencies of two bridge spans have allowed to assessment of effectiveness of structural solutions applied at this bridge and establish some guidelines for using of this type of construction process in design structural solutions located over water plants in the future engineering practice. Wide range of conducted dynamic tests have allowed for comprehensive evaluation of the concrete elements effort of bridge structure. Final conclusions confirmed the observations taken from the research under static load. [ABSTRACT FROM AUTHOR]

Study of the vibration frequencies at different cutting conditions is an alternative to the use of impact hammer test for identification of natural frequencies of the machining structure and calculation of stability lobe diagrams. Vibration frequencies not only depend on the natural frequencies of the structure, but also they are dependent on the spindle speed, damping ratio of the structure and the depth of cut. Ignoring these additional parameters would lead to errors in identification of the natural frequencies of the system and considerable deviation of the calculated stability lobe diagrams from actual cutting tests. In this study modified Nyquist method is used to investigate the effects of spindle speed, depth of cut and damping ratio of the structure on vibration frequencies. The quality of frequency prediction is compared to linear and nonlinear time domain simulations and machining experiments. [ABSTRACT FROM AUTHOR]

Abstract: Sonic drill rig can obtain good drilling and sampling effects in sand gravel layer with high-frequency vibration and low speed rotation of the power head. The drilling speed of sonic drill is five times than traditional rotary drilling method. Meanwhile, it does not need slurry to protect wall of borehole during drilling, so it has the following advantages: good fidelity of rock and soil samples and less environmental pollution. As a consequence, it has a good application prospect in the exploration of hydropower station, environmental protection drilling and other fields. In the paper, combining drilling experiment of domestic sonic drill rig YGL-S100 in Xiangjiaba hydropower station, the influence of sonic drill's vibration frequency on rock fragmentation effect and the reasonable choice of drilling technology had been researched and analyzed. Further, improving the sonic drill properties and optimizing drilling technology parameter were carried out. [Copyright &y& Elsevier]

Abstract: Using modified Nyquist contours, the dominant poles of the closed loop delay-differential equation for machining systems such as milling are identified. Contours with constant damping ratio of the dominant poles are constructed using this method. These contours are similar in shape to the stability lobes, but move upwards and to the right as the instability parameter increases. Additionally, it is possible to study the movement of the dominant poles to the right-hand side of the complex plane as the system becomes unstable by increasing the depth of cut at a constant spindle speed. The movement of the dominant pole is shown to be towards the right (unstable) and upward (higher vibration frequency) of the complex plane. In some cases, there would be a jump of vibration frequency due to the change of the lobe number. It is also shown that the damping ratio of the structure strongly affects both the vibration frequency and the damping ratio of the dominant poles in the closed loop system. Finally, in two milling experiments with two different spindle speeds and continuously increasing depth of cuts, vibration frequencies are measured and compared to the theoretical predictions. The measurements agree with the theoretical predictions, particularly in the unstable cutting conditions. [Copyright &y& Elsevier]

Highlights: [•] DFT calculations show that [aEMMIM][BF4] capture CO2 with a 1:1mol stoichiometry. [•] The energy barriers of [aEMMIM]+CO2 and [aEMMIM][BF4]+CO2 were calculated. [•] [BF4] confers on [aEMMIM][BF4] a favorable CO2 absorption. [•] Calculated and experimental frequencies of [aEMMIM][BF4]+CO2 are consistent. [ABSTRACT FROM AUTHOR]

Abstract: The purposes of this study are to develop a simulator generating a ski board vibration in actual skiing and to perform the basic construction for clarifying the ski sliding mechanism, which still has not been clarified completely. In the simulator developed in this study, the surface on the bottom of the ski was assumed as to be a snowy slope and a mass of snow (snow pack) assuming a skier had slid on this ski bottom surface. A ball vibrator connected to a large- sized compressor was installed onto the ski panel in order to vibrate a ski board. The compressed air from the compressor rotated a steel ball in the vibrator at high speed, causing vibration on the ski. A dynamic friction force (F) was detected by the digital force gauge when the snow pack was sliding from the top of the ski to the tail on the surface formed by the bottom of the ski. A coefficient of kinetic friction (μk) was calculated using this dynamic friction force. Furthermore, the velocity and acceleration of the snow pack were measured by two high speeded cameras. The experiment for confirming the validity of this simulator was carried out in the temperature conditions of -5°C. The velocity and acceleration of the snow pack with vibration were higher than without vibration. On the other hand, the coefficient of kinetic friction (μk) with vibration was lower than without vibration. From these results, the simulator is suitable for studying the role of vibration in ski sliding and for clarifying the ski sliding mechanism. [Copyright &y& Elsevier]