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To investigate the response characteristics of the rotor system in a high-temperature molten salt pump, a specific model of a cold salt pump was selected as the research object. The natural frequencies and mode shapes, critical speeds, and harmonic response analysis based on modal analysis of the rotor system with and without prestress were computed. The results indicate that with prestress, the natural frequencies of the rotor are higher compared to the rotor without prestress, and there is no clear pattern among the various vibration modes. The calculated critical speed for the second mode is much higher than the rotor’s operating speed. This suggests that the rotor system will not experience resonance at its operating speed, meeting design requirements and ensuring stable operation. When the rotor of the cold salt pump is subjected to unbalanced forces, vibrations occur in the x, y, and z directions. The region with the largest vibration amplitude is located at the fifth-stage impeller. At a frequency of 52 Hz, the corresponding harmonic response displacement reaches its maximum value, and this frequency remains unchanged with variations in the magnitude and position of the unbalanced force. Therefore, it is advisable to avoid operating the rotor system at the critical speeds corresponding to the first and second modes. Furthermore, the operating speed of the rotor system is much lower than the critical speeds corresponding to the first and second modes, so axial unbalanced forces generally do not affect the normal operation of the rotor system.

The Horn Transducer (HT) is one of the key components in ultrasonic applications, consisting of a front mass, piezoelectric, and back mass parts. Previously, most of the research focused on vibration study of the front mass part based on modal analysis, but the other parts were ignored; therefore, the research results have limitations to actual usage. This research presents the vibration analysis of HT included all parts, based on harmonic response analysis (HRA). First, a conventional HT of 28 kHz, 50 W, 220 V, front mass-radius ( R ) of 29 mm, and height ( H ) of 5 mm was investigated for the vibration analysis. Next, proposed designs were also investigated by varying the R as 27 mm - 32 mm, and H as 4 mm - 8 mm. All results were analyzed to find a suitable shape and investigated the designs that affected the vibration. The simulation results revealed that the longitudinal amplitude depends on R and H . In addition, the simulation results were consistent with an experiment and previous work. Finally, the suitable design with R of 29 mm and H of 7 mm provided the optimum vibration at 27,250 Hz. The outcomes of this research were applied to develop a high-performance ultrasonic cleaner.

This study examines the means of reducing the damage to the branches of Camellia oleifera in the process of vibration picking and solving the problems of low equipment-development efficiency and slow product renewal caused by using traditional test methods to determine vibration picking parameters. In this study, the optimal vibration parameters were determined by using the self-response (branch acceleration and strain) law of the Camellia oleifera tree, and finite element analysis and experiments are used to solve this problem. The 3D model of Camellia oleifera was built by Solidworks. The natural frequencies of Camellia oleifera were analyzed by modal analysis, the vibration frequency and amplitude were determined by harmonic response analysis, and transient analysis was used to compare with the test results. The results show that the optimal vibration frequency range of Camellia oleifera is 4~10 Hz, and the average correlation coefficient between the maximum synthetic acceleration and the simulated value is 0.85, which shows that the model can reliably predict the vibration response. At the same time, the best vibration parameters were determined to be 9 Hz, 60 mm and 10 s. Under these parameters, the abscission rate of the Camellia oleifera fruit was 90%, and the damage rate of the flower bud was 13%. The mechanized picking effect of Camellia oleifera fruit was good. This study can quickly determine the vibration picking parameters of Camellia oleifera fruit and effectively improve the development speed of vibration picking of Camellia oleifera fruit.

The hydraulic system is very important in the aircraft structural system, but the hydraulic pipeline is prone to cracks or even breaks due to vibration problems during system operation, causing major hidden dangers to flight safety. Using ANSYS Workbench to carry out modal analysis and harmonic response analysis of pipelines, the influence of different inlet pressures on pipeline vibration under pulsation excitation is compared and analyzed, which provides theoretical guidance for pipeline vibration research.

Additive Layer Manufacturing (ALM) is one of the fabricating methods because it permits outrageous customization, quick prototyping of wanted designs and low volume creation of items. FDM printer goes under the material expulsion class. The filament is constrained into the hot extruder. The filament is warmed first and afterward stored, through the spout, onto a form stage layer-by-layer to frame the total 3D structure. A printer equipped for printing a 1.5-meter cubic-sized object was designed in SOLIDWORKS CAD software and manufactured into a functioning model. The Frame, Linear guide rail, and Z-axis rails were subjected to static structural, modal and harmonic response analysis with ANSYS Workbench. The designed parts were investigated by modal analysis to get the natural frequency. The effect on the guide rails and frame due to external forces, stepper motor, and extruder were examined with harmonic response analysis. The frequency at which the amplitude rises drastically from a phase angle of 0 degrees to 180 degrees was obtained using harmonic response analysis as well. The model was further subjected to motion analysis using ADAMS dynamic software.

Vibratory harvesting is the primary method used to harvest red jujubes. This study aimed to improve the efficiency of vibratory harvesting for red jujubes and identify the optimal parameters for harvesting at different jujube tree diameters. A model for the forced vibration dynamics of jujube trees was established, and a three-dimensional model was constructed for different diameter variations. A kinematic simulation analysis was then conducted to determine the inherent frequency and modal vibration patterns of jujube trees. Harmonic response analysis was performed to study the displacement and acceleration responses of jujube trees with different diameters to different vibration factors. Subsequently, vibration tests were carried out on the jujube trees. The results showed that the vibration characteristics of trees with different diameters were distinct at each vibration order, and the maximum number of vibrating branches differed at different orders of vibration. The vibration frequency ranges for vibration harvesting of jujube trees with 30 mm, 50 mm, and 70 mm diameters were determined as 4–30 Hz, 6–25 Hz, and 17–29 Hz, respectively. Furthermore, the study obtained the optimal vibration parameters for jujube trees by establishing the regression equations of harvest rate and each vibration factor. For jujube trees with a diameter of 30 mm, the optimal parameters included a vibration frequency of 30 Hz and a vibration amplitude of 15 mm. For jujube trees with a diameter of 50 mm, the optimal parameters included a vibration frequency of 18.55 Hz and a vibration amplitude of 12.52 mm. Lastly, for jujube trees with a diameter of 70 mm, the optimal parameters included a vibration frequency of 6 Hz and a vibration amplitude of 15 mm. This study provides a theoretical foundation and technical support for improving the efficiency of vibratory harvesting and identifying the optimal vibration harvesting parameters for jujube trees with different diameters.

Forced vibration of vertical guideway of vertical lathe can decreases machining accuracy of vertical lathe. Hydrostatic bearing can improve stability of bearing system, and has been applied to vertical guideway of vertical lathe in recent years. However, variation law of modal parameters of hydrostatic vertical guideway under different working conditions and influence mechanism of hydrostatic bearing on its modal parameters are unclear. To this end, we conduct the modal and harmonic response analysis of vertical guideway with hydrostatic bearing and without hydrostatic bearing based on finite element method (FEM). The results show that hydrostatic bearing can improve the low-order natural frequencies and low-order resonance frequencies of vertical guideway under certain working conditions, and can reduce amplitude of vertical guideway. Additionally, the accuracy of finite element simulation is validated by experimental modal analysis (EMA). This investigation provides theoretical basis for identifying weak links, determining optimal working condition, and improving stability of hydrostatic vertical guideway.

Symmetry and asymmetry jointly govern the dynamics and surface integrity of thin-wall AA7075 end milling. In this work, a symmetry-aware simulation and experimental framework is developed to connect process parameters with milling forces, dynamic response, surface quality, and through-thickness residual stress. A mechanistic milling-force model is first established for multi-tooth end milling, where the periodically repeated tooth-order excitation provides a nominally symmetric load pattern along the tool path. The predicted forces are then used as input for finite-element modal and harmonic-response analysis of a thin-walled component, revealing how symmetric and anti-symmetric mode shapes interact with the tooth-order excitation to generate locally amplified, asymmetric vibration of the compliant wall. Orthogonal and single-factor milling experiments on AA7075 thin-wall specimens are performed to calibrate and validate the force model, and to quantify the influence of feed per tooth, axial depth of cut, spindle speed, and radial width of cut on deformation, surface roughness, and geometric accuracy. Finally, a thermo-mechanically coupled finite-element model is employed to evaluate the residual-stress field, showing a characteristic pattern in which an initially symmetric thermal–mechanical loading produces depth-wise symmetry breaking between tensile surface layers and compressive subsurface zones. The proposed symmetry-aware framework, which combines milling-force theory, finite-element simulation, and systematic experiments, provides practical guidance for selecting parameter windows that suppress vibration, control residual stress, and improve the machining quality of thin-wall AA7075 components.

The amplifier rod, also known as a concentrator, is an important component in ultrasonic transducer devices. Its main functions are amplitude amplification and impedance matching, playing a crucial role in ultrasonic machining systems. This article conducts modal analysis and harmonic response analysis of the horn and the tool-added horn, using simulation software, gradually studying the dynamic performance of the catenary linear horn in ultrasonic machining. The optimized frequency of the amplitude rod is obtained, and the effect of the resulting vibration frequency in actual processing is verified through atomization effect tests. The results show that the resonance frequency obtained by finite element analysis has a small error with the actual test, only 0.789%, and magnification error of about 0.165%, which meet the design requirements. It provides reliable design basis and data foundation for the engineering application of the variable rod in ultrasonic machining.

This study presents design, construction, and demonstration of a patented die system (UltraDRAW) used for deep drawing applications with utilization of ultrasonic vibrations. The developed system enables application of high-frequency vibrations onto the blank holder of die system in axial direction. Such design is considered to be effective in improving drawability of blank material, resulting in drawing of blanks with greater limiting drawing ratio (LDR) and lower forming load. For this purpose, an innovative ultrasonic horn with specific geometry, used directly as blank holder, was designed with steady-state harmonic response analyses using finite element method. To evaluate the performance of developed system, a series of cup drawing experiments using conventional and ultrasonically assisted die system were performed on cold-rolled low carbon steel sheets of DC01 and DC04 under dry and lubricated surface conditions. Compared to conventional drawing, UltraDRAW improved LDR and cup depth by 9.4% and 26.5% (for DC01) and 15.1% and 43.6% (for DC04) with reduction in forming load by 22.2% (for DC01) and 18.2% (for DC04).