Vibration Acceleration Amplitude Research Articles

Researching the Influence of Preload on Vibration Characteristics in the Ballistic Recorder Vibration Damping System

In this study, the vibration characteristics of a bullet-loaded recorder’s vibration damping system under various preload conditions are investigated through theoretical analysis, numerical simulations, and experimental verification. The findings indicate that the inclusion of a polyurethane elastomer vibration damping buffer layer between the cartridge and the recorder, along with the application of a specific preload, significantly reduces the amplitude of vibration acceleration transmitted to the recorder’s interior. This, in turn, enhances the overload resistance of the cartridge’s internal circuit. Numerical simulation results and theoretical analysis suggest that increasing the preload on the buffer material between the elastomer and the recorder reduces both the frequency ratio and damping ratio of the damping system. This reduction further decreases the amplitude of vibration transmitted to the recorder. However, excessively high preload generates substantial compressive stress within the recorder under static conditions, intensifying during the projectile’s accelerated movement. As a consequence, deformation and damage occur to the internal circuitry. Therefore, ensuring that the recorder possesses the structural strength necessary to withstand increased preload is crucial. This balancing act improves the recorder’s resistance to shock, vibration, and overload, while also preventing excessive stress-induced damage.

Predicting ground vibrations from railway tunnels using an improved 2.5D FEM-PML model with soil spatial variability

PurposeThis study establishes a method for predicting ground vibrations caused by railway tunnels in unsaturated soils with spatial variability.Design/methodology/approachFirst, an improved 2.5D finite-element-method-perfect-matching-layer (FEM-PML) model is proposed. The Galerkin method is used to derive the finite element expression in the ub-pl-pg format for unsaturated soil. Unlike the ub-v-w format, which has nine degrees of freedom per node, the ub-pl-pg format has only five degrees of freedom per node; this significantly enhances the calculation efficiency. The stretching function of the PML is adopted to handle the unlimited boundary domain. Additionally, the 2.5D FEM-PML model couples the tunnel, vehicle and track structures. Next, the spatial variability of the soil parameters is simulated by random fields using the Monte Carlo method. By incorporating random fields of soil parameters into the 2.5D FEM-PML model, the effect of soil spatial variability on ground vibrations is demonstrated using a case study.FindingsThe spatial variability of the soil parameters primarily affected the vibration acceleration amplitude but had a minor effect on its spatial distribution and attenuation over time. In addition, ground vibration acceleration was more affected by the spatial variability of the soil bulk modulus of compressibility than by that of saturation.Originality/valueUsing the 2.5D FEM-PML model in the ub-pl-pg format of unsaturated soil enhances the computational efficiency. On this basis, with the random fields established by Monte Carlo simulation, the model can calculate the reliability of soil dynamics, which was rarely considered by previous models.

Vibration effect on Rayleigh–Taylor instability of sedimenting suspension

In this paper, the effect of vertical vibration on the Rayleigh–Taylor instability at the lower interface of a sedimenting suspension layer sandwiched between viscous fluids is studied numerically and theoretically. It is shown numerically that the vibration suppresses the amplitudes of interface perturbations and enlarges the widths of granular fingers, postponing the nonlinear growth stage. By modeling the suspension as a fluid with its effective density and viscosity, stability analyses are carried out, and the dominant growth rate and the dominant wave number predicted by the dispersion relation agree with the numerical results, especially for cases with strong vibrations. Because of the small-scale flow induced by the particles, high vibration acceleration amplitude and low vibration frequency, which correspond to a large vibration power input, increase the kinetic energy spectra at the high wave number regime, a phenomenon contrary to the vibration effect for pure fluid cases.

ВИБРОДИАГНОСТИКА ЗДАНИЙ НА ПРИМЕРЕ УЧЕБНО-ЛЕКЦИОННОГО КОМПЛЕКСА МГРИ

The article provides the results of vibration diagnostics of the MGRI building in order to establish the level of vibrations on the soil foundation and study the nature of the distribution of vibration levels across floors. A significant decrease in vibration acceleration amplitudes was noted with increasing distance from the source to the vibration receiver. The opposite picture is observed when studying the floor-by-floor distribution of vibration background across floors of a building. As the floor increases, the vibration components increase, and the vertical component grows faster than the horizontal one.

Calculating permissible deviations of vibration accelerations of printed circuit assemblies by simulation modeling

Objectives. A variety of technical condition control methods are used in the production and operation of printed circuit assemblies (PCA) for radio-electronic means (REM). The main methods are optical, electrical, and thermal. However, not all possible defects can be detected using these methods. For example, a weakened PCA fastener in a block or the incorrect installation of an electric radioelement (ERE) on a printed circuit board (PCB) can be detected only by analyzing the mechanical characteristics of the REM. These factors, in particular, are the values of the vibration acceleration amplitudes on ERE or at selected PCB control points (hereinafter referred to as the PCA vibration acceleration amplitude). In order to draw a conclusion about the presence of a defect, the measured values of the vibration acceleration amplitudes obtained as a result of testing PCA for the effects of harmonic vibration are compared with the permissible values calculated during the simulation of mechanical processes in PCA. This takes into account the variations in the physical and mechanical parameters of materials and geometric parameters of the PCA design. The aim of this paper is to determine the permissible values of PCA vibration acceleration amplitudes to be compared with the measured values.Methods. The Monte Carlo simulation method is used to calculate the permissible deviations of vibration accelerations. This consists in repeatedly calculating the values of the vibration acceleration amplitudes at random values of the physical and mechanical parameters of materials and geometric parameters of the PCA design within their tolerances.Results. Experimental verification of this method was carried out using the SolidWorks software for modeling mechanical processes. This enabled the tolerance values for PCA vibration acceleration at the control point at the first resonant frequency to be established and experimental data to be obtained when introducing various defects. The results of comparing the measured values with the calculated tolerance enabled conclusions to be made with regard to the possibility of detecting PCA defects.Conclusions. Using this method of calculating tolerances for the PCA vibration acceleration amplitude allows the presence of defects in REM that do not affect the electrical or thermal characteristics of REM to be determined, thus increasing the efficiency of technical condition control.

Numerical modelling of traffic-induced dynamic loading on a two-story residential building

BackgroundThis paper presents a numerical modelling procedure of dynamic loading due to traffic on a two-story residential building. In developing countries cities and towns, poor quality narrow road sections with high traffic density are common. In such cases, ground vibration due to traffic could be higher and lightweight buildings located closer are exposed to traffic-induced dynamic loading. Design codes require a proper assessment of such vibrations. However, a clear and definite procedure of assessment is not usually provided. This research presents an assessment procedure of dynamic loading due to traffic on a soil foundation system of light weight buildings based on numerical modeling. Traffic induced ground vibration acceleration amplitudes, frequencies and durations were measured, and the dynamic loads were calculated from measured vibration accelerations and vibrating mass of the vehicle. A two-story residential building with flexible square shallow footings was modelled together with the foundation soil using PLAXIS-2D. The dynamic load was modelled as harmonic loading considering the highest amplitude of vibration measured.ResultsOn the calculation stage, static loading analysis, dynamic loading analysis and free vibration dynamic analysis were carried out. A maximum increase in extreme total displacement of the soil to 22.03 mm was observed after the dynamic loading from 18.96 mm extreme total displacement due to static loading. Extreme effective mean stress in the soil increased to 112.81 kPa from 110.5 kPa, due to the dynamic loading. In addition, a differential settlement of 3.14 mm between two adjacent footings was observed after the traffic induced ground vibration. Furthermore, the Mohr–Coulomb plastic points were observed to be concentrated to the side of the soil-foundation system which the dynamic load was acting on.ConclusionThe regular exposure to traffic-induced vibrations may cause frequent change in stress and deformation response of the foundation-soil system. In areas where lightweight buildings are exposed to regular traffic induced vibrations, proper assessment of the effect should be carried out and measures should be taken to mitigate the problem. Improving road surfaces and limiting vehicle speed are possible remedial measures to reduce ground vibrations due to traffic.

Transformational deformation models of continuous thin‐walled structural elements with support elements of finite sizes: Theoretical foundations, computational, and physical experiments

AbstractA method of experimental study of forced bending vibrations of unfixed spans of continuous thin‐walled structural element fixed on rigid support elements of finite dimensions has been developed using instrumental means for registration of vibration acceleration amplitudes. The technique is realized on beams with different types of their fixing under the loading of one of the beam section with an external force that varies in time according to a harmonic law. Experimental dependences of amplitude values of vibration accelerations in specific points of certain spans of the beam on the frequency of external load have been obtained. These results indicate the passage of vibrations through the fixed sections due to the transformation of bending vibration modes of the loaded section into longitudinal transverse‐shift vibrations of the fixed sections during the transition across the boundary from the unfixed section to the fixed one (from the fixed to the unfixed section). For the theoretical study of the described phenomenon a transformational model of the flat beam deformation is constructed on the basis of the refined Timoshenko model with additional account of the deformability of the section with fixation to a rigid support element of finite length on one of its face surfaces. The corresponding equations of motion of the unfixed and fixed sections are derived. The corresponding kinematic and force conditions of their conjugation are formulated. On their basis, analytical solutions of two specific problems are found in the linear approximation. One‐dimensional finite elements for modeling the dynamic response of continuous beam of the considered class are also constructed. Numerical experiments have been carried out for a flat beam made of aluminum alloys D16AT, AMg‐6 and unidirectional fiber reinforced plastic. The presence of a significant transformation of the stress‐strain state parameters of the considered beams at the transition across the boundary from unfixed to fixed sections and a significant increase in the level of transverse tangential stresses on the fixed section of the beam in the vicinity of the interface of the unfixed section with the fixed one have been revealed.

Investigation on the Damping Effect of FST System under Moving Load Using the Track–Tunnel-Layered Saturated Ground Model

In this paper, a single-tier beam-spring-damping system and a two-tier beam-spring-damping system are adopted to simulate the FT (fixed track) and FST (floating slab track) system, respectively. The tunnel is modeled as an infinitely long Euler—Bernoulli beam embedded in the layered saturated soil. By solving the governing equations of the saturated soil and employing the TRM (transmission and reflection matrices) method, the frequency response function of the tunnel-layered saturated soil model is obtained. Making use of the interaction between the tunnel and track systems, the track system is coupled with the tunnel-layered saturated ground model. The solutions for the dynamic response of the track system–tunnel-layered saturated ground model under moving loads in the time–space domain are obtained using the inverse Fourier integral transform. To evaluate the damping effect of the FST system on the vibration of tunnel and soil, four damping coefficients are defined and the vibration results of the FT system–tunnel-layered saturated soil model are compared with those of the FST system–tunnel-layered saturated soil under different moving loads and soil conditions. The numerical results show that both the vibration displacement and acceleration amplitude are attenuated after using the FST system, and the damping coefficient of acceleration is about 30% greater than that of the displacement. In addition, the damping effect of the FST system on the ground surface vibration is associated with the embedded depth of the tunnel and the soil stiffness.

Effect of Multiple Reclosing Time Intervals on Axial Vibration of Winding

When a transformer suffers a permanent fault, it will suffer a short-circuit impulse again after reclosing. If the previous vibration of the winding is not attenuated completely and the winding is subjected to a secondary impulse within a short time, the secondary vibration response will have a superposition. The aim of this study was to analyze the effect of the anti-short-circuit ability of operational transformers subjected to a secondary short-circuit current impulse. In this paper, a model is established for calculating axial vibration in transformer windings and effects on the vibration response of windings under different closing phase angles and short-circuit intervals are analyzed. The results show that the vibration acceleration of windings is a V-shaped variation at phase angles from 0° to 180°, reaching the maximum values at 0° and 180° and reaching the minimum value at 90°. When the transformer recloses on a permanent short circuit, due to the superposition effect, the vibration acceleration amplitude of the secondary impulse will be greater than that of the primary impulse, but as the reclosing interval increases, the superposition effect decreases continuously. When the interval is 600 ms, the superposition effect for the vibration acceleration of the secondary impulse attenuates to 83.3%. The superposition effect is not significant after 600 ms. The research provides a theoretical reference for transformer closing-control strategies.

Analysis of the acceleration of the multi-level vibration of the tank as firing

Aiming at the system level vibration problem caused by the strong impact load during the tank firing, the tank is divided into several levels according to the vibration transmission path, such as barrel, cradle, turret, seat ring, car body and wheel. The multi-level vibration response characteristics of the tank during firing are obtained by arranging acceleration sensors at the typical positions of each level. Based on the time domain analysis method, the vibration acceleration at the positions of cradle, turret, seat ring, car body and wheel is analyzed, and the pulse amplitude and pulse time of vibration acceleration at each level are obtained. The analysis shows that under the action of firing load, the acceleration amplitude of muzzle, cradle, turret, seat ring, vehicle body and wheel decreases in turn. And the peak acceleration at the muzzle position is the largest, about 1400g, and the peak acceleration at the wheel position is the smallest, about 0.6g. The results will provide support for obtaining the multi-level vibration characteristics of the tank under the fire load and revealing the vibration transmission law of the tank under the fire load.

Dynamic analysis of power-law non-Newtonian fluids under low-frequency vertical harmonic vibration by dynamic mode decomposition

Resonance acoustic mixing (RAM) technology applies an external low-frequency vertical harmonic vibration to convey and mix the non-Newtonian fluid across space. However, although this method is used for various applications, its mechanism is yet not well understood. This paper investigates the flow characteristics of the power-law non-Newtonian fluids in RAM by the phase-field numerical simulation method and proposes a mixing index to study the effect of vibration acceleration amplitude, vibration frequency, and filling rate on mixing. Dynamic mode decomposition is used to decompose the vorticity field data into spatial–temporal coherent structures to explore the dynamic mechanism of mixing under the above parameters. The results show that the increase in vibration acceleration amplitude can promote mixing uniformity and rate. The decrease in vibration frequency will increase the mixing of non-Newtonian fluids, but the effect of improvement is no longer obvious when the frequency exceeds a threshold. On the one hand, increasing the vibration acceleration amplitude and decreasing the vibration frequency and filling rate appropriately can induce the 0 Hz and half of the vibration frequency component accounting for the most energy. On the other hand, it can also increase the number of modes traversed by large-scale vortices developing into small-scale vortices. Both of them can improve the mixing rate and uniformity of non-Newtonian fluids.

Performance Analysis of Short-Span Simply Supported Bridges for Heavy-Haul Railways with A Novel Prefabricated Strengthening Structure

A novel prefabricated strengthening structure (NPSS) is proposed to improve the vertical stiffness and load-bearing capacity of existing short-span bridges for heavier axle-load trains passing through. The strengthening principle of the NPSS is revealed through theoretical derivation. A refined calculation model is prepared to investigate the effects of two important parameters on the structural behavior of the bridge, including the support stiffness and the installation location of the NPSS. The calculation model is also verified with four-point bending test of a bridge removed from a heavy-haul railway. With the calculation model and the response surface methodology (RSM), the functional relationships among the crucial mechanical indexes of the bridge and the two parameters of the NPSS are methodically established. Thus, the optimal values of the parameters are determined via a multi-objective optimization model and the analysis hierarchy process-fuzzy comprehensive evaluation method. Furthermore, the feasibility of the optimal parameters is appropriately verified based on simulations of the vehicle–track–bridge dynamics. The existence of the NPSS with optimal parameters could enhance the vertical stiffness of the bridge by 21.0% and bearing capacity by 19.5%. In addition, it could reduce the midspan dynamic deflection amplitude by 23.4% and vertical vibration acceleration amplitude of the bridge by 25.2%. The results of the study are expected to contribute to the capacity development and rehabilitation of existing heavy-haul railways with low cost and convenient construction without railway outage.

Sediment vibration characteristics based on accelerometer measurements

The study of the vibration phenomenon of pebbles under turbulence is still a gap despite recent technological advancements in measurement capabilities. In this study, the vibration process of a fully exposed, isolated smart pebble on a rough bed was measured using a miniature inertial accelerometer and combined with simultaneous local measurements of the near-bed velocities. The paper conducts a series of experimental studies with different flow conditions. The test data match well with the manually observed phenomena, indicating the authenticity of the sediment vibration data collected by the measurement system. The test results show that the pebble motion (before entrainment) subjected to turbulence is a nonlinear vibration process, and its vibration types include in-situ vibration and ex-situ strong vibration. The probability distribution for the amplitude of vibration acceleration is well parameterized by the normal distribution. The vibration intensity tends to increase before approaching the threshold, but it weakens when approaching the point. The sediment vibration frequency is within 20–25 Hz, similar to the flow pulsation frequency and belongs to low-frequency vibration. The data indicate that the near-bed flow velocity is most directly related to the particle vibration events.

Influence of unsupported sleepers on the dynamic stability of ballasted bed based on wheelset impact tests

The unsupported sleeper can change the load characteristics of ballast particles and thus affect the dynamic stability of a ballasted bed. In this work, a laboratory test was constructed on a ballasted track containing unsupported sleepers. The ballasted track was excited by a wheelset, and the influence of unsupported sleepers on the dynamic stability of a ballasted bed was studied. The results show that the main frequency of the sleeper vibration appeared at 670 Hz, and the first-order rigid vibration mode at the frequency of 101 Hz had a significant effect on the condition without the unsupported sleeper. When the sleepers were continuously unsupported, the vibration damping effect of ballasted bed within the frequency range of 0–450 Hz was better than that at higher frequencies. Within the frequency range of 70–250 Hz, the vibration damping effect of the ballasted bed with unsupported sleepers was better than that without the unsupported sleeper. Owing to the excitation from the wheelset impact, the lateral resistance of the ballasted bed with unsupported sleepers whose hanging heights were 30, 60, and 90 mm increased by 37.43%, 12.25%, and 18.23%, respectively, while the lateral resistance of the ballasted bed without the unsupported sleeper remained basically unchanged. The unsupported sleeper could increase the difference in the quality of the ballasted bed between two adjacent sleepers. In addition, test results show that the hanging height of the unsupported sleeper had little effect on the lateral resistance of a ballasted bed without external excitation, but had an obvious effect on the rate of change of the lateral resistance of a ballasted bed and the acceleration amplitude of the sleeper vibration under the wheelset impact.

Investigation of Geotechnical Seismic Isolation Bed in Horizontal Vibration Mitigation

Recently, a ground-borne vibration mitigation solution using rigid wave impeding blocks embedded in the foundation bed of buildings/embankments has emerged as a passive vibration isolation mechanism, wherein energy dissipation due to material damping was often ignored. The present study aims to examine the performance of a flexible foundation bed composed of a sand-rubber mixture (SRM) for ground-borne vibration isolation, referred to as geotechnical seismic isolation (GSI) bed, an emerging trend in low-cost earthquake mitigation studies. Field investigation consisting of vibration measurement on a model footing resting on a GSI bed with SRM and SRM-geogrid composite subjected to horizontal sinusoidal vibration of frequency 10 to 30 Hz with acceleration amplitude of 0.18 g to 0.33 g were undertaken. Further, a three-dimensional finite-element analysis of a model footing resting on a GSI bed made of geogrid reinforced SRM composite is presented. The strain-dependent nonlinear response of soil and SRM were accounted for using suitable hypoelastic and hyperelastic constitutive formulations, respectively. For the GSI bed, SRM with 10% to 50% rubber content and biaxial geogrids were studied. The numerical simulation and field study results were found to be comparable with a nominal difference that verifies the adequacy of the developed numerical modeling procedure. It was observed that GSI (30% rubber content) effectively reduced the vibration acceleration amplitude of the model footing above 40% and 55% for without and with geogrid reinforcement, respectively. Overall, the field experimental and numerical results demonstrate the proposed geogrid reinforced GSI bed as an effective ground vibration mitigation solution for typical industrial environments.

Dynamic Response Characteristics of Roadway Surrounding Rock and the Support System and Rock Burst Prevention Technology for Coal Mines

Anchor cables (bolts) act as the main support system and play an important role in improving the rock burst resistance and stability of the roadway surrounding the rock. In this study, the dynamic response characteristics of the roadway surrounding the rock and the support system under different shock intensities were investigated. The following findings were obtained. The stress wave propagation process under dynamic shock was divided into a stress vibration initiation stage, a stress fluctuation stage, and a stress adjustment stage. In the stress vibration initiation stage, the surface mass of the roadway surrounding the rock started to vibrate, and the pretension of the anchor cables (bolts) was reduced; in the stress fluctuation stage, the failure of the roadway surrounding the rock intensified, and the anchor cables (bolts) were damaged to some extent; and in the stress adjustment stage, the roadway deformation of the surrounding rock and the axial forces of the anchor cables (bolts) tended to stabilize. As the dynamic shock intensity increased, the vibration velocity, displacement increment, and acceleration amplitude of the mass of the roadway surrounding the rock increased exponentially. The critical shock energy of the roadway surrounding the rock was 105 J, above which the damage to the rock was aggravated. The larger the pretension of the anchor cables (bolts) was and the higher the dynamic shock intensity was, the more severe the damage to the anchor cables (bolts) was. Given the dynamic response characteristics of the roadway surrounding the rock and support elements under shock, a full anchor cable yielding support technology is proposed to effectively control the stability of the roadway surrounding the rock under dynamic shock, providing a reference for the construction of the support systems for preventing rock bursts in similar roadways.

Experimental research on efficiency and vibration of polycrystalline diamond compact bit in heterogeneous rock

To explore the rock-breaking efficiency and vibration characteristics of polycrystalline diamond compact bit in heterogeneous rock, this paper analyzes the typical vibration characteristics and failure modes of polycrystalline diamond compact bit. Then, the transverse combination of rocks was innovatively used to simulate a situation of soft-hard interbedded formation, forming three kinds of transversely combined heterogeneous rock samples with different degrees of heterogeneity. We conducted a series of laboratory rock-breaking experiments and the experimental results indicate that rock heterogeneity greatly impacted vibration acceleration, lateral bending moment, rate of penetration, and drilling trend. With the increase in weight on bit and rotation speed, the rate of penetration gradually increases. However, the tangential, axial, and radial vibration acceleration amplitude of the bit all increase simultaneously, which implies that the vibration impact generated by rock-bit interaction increased. The difference in the cutting depth of the drill bit in the heterogeneous formation causes low efficiency. The stronger the heterogeneity, the lower the rate of penetration. Rock heterogeneity, especially the rock properties of the combined rock samples, significantly impact acceleration and lateral bending moment. As rock heterogeneity increased, the bit acceleration increased significantly, intensifying the bit vibration; the lateral bending moment increased slightly, but its fluctuation intensified. The strength difference of heterogeneous rock causes eccentricity, the harder rock exerts greater force on the bit, causing the bit to deviate from the original trajectory. The greater the difference, the greater the eccentricity, consequently, the more the bit shifts to the softer side. Adjusting rotation speed and depth of cut control may be feasible solutions to solve the problem of low drilling speed and high vibration in heterogeneous formation. It is hoped that the findings in this paper will be helpful to explore a reasonable way to reduce vibration while maintaining high efficiency.

Online anomaly detection and remaining useful life prediction of rotating machinery based on cumulative summation features

The bearing is the core component of the gearbox transmission system. Once it is damaged during operation, it will cause the shutdown of the mechanical equipment for maintenance. It has important application significance to carry out fault detection and remaining useful life (RUL) prediction. Whereas, some bottlenecks, such as the noise interference of state characteristics, the excessive dependence of supervised learning on prior samples, and the practical RUL online calculation, restrict the industrial application of RUL prediction for rotating machinery equipment. To overcome the above problems, this paper introduces the discrete wavelet transform (DWT) to decrease the noise of the vibration acceleration signal obtained, and then uses the sliding average method to weaken the transient excitation. To make the state characteristics of the monitored bearing trendy, linear, and monotonic, this paper proposes a new set of state interpret indicators: energy and cumulative summation feature (CSF) to reflect the bearing health status. Based on the available bearing health information, the fault boundary threshold is established through the 3[Formula: see text] criteria, which serves as the basis for first predicting time (FPT) detection. Once the FPT point is determined, this paper applies CSF to replace the original vibration acceleration amplitude as the degradation indicator, which has better linearity and monotonicity than amplitude-based indicators, and which is conducive to the implementation of simple structure curve fitting to carry out the overall RUL prediction. Comparing with existing methods, such as relevance vector machine (RVM), deep belief network (DBN), and particle filtering (PF)-based methods, the experimental results demonstrate that the proposed method has the best RUL prediction efficiency and the fastest convergence.

A new design of boring bar using TiNi3 alloy to reduce vibration in turning operations

In turning operations, vibration is a significant problem that leads to an imperfect surface, cutting tool damage, and unstable production. Vibration affects not only the workpiece’s surface quality, but also the cutting tool life, and ultimately the overall process cost. Since Shape Memory Alloys (SMA) has a very high vibration damping capacity, the effect of using TiNi3 alloy as the turning tool holder material is investigated in this paper. The tool holder vibrations are investigated analytically and numerically in both external and internal turning operations. The analytical study utilizes the Laplace Transformation Method to find the natural frequency and the beam’s displacement as a function of time and the longitudinal axis. The numerical study is performed using transient and Modal Analysis using ANSYS software. A comparison of the analytical and numerical results shows that they were very close to each other. The numerical study shows that TiNi3 alloy decreases vibration amplitude and acceleration for external and internal turning operations. It is shown that the use of TiNi3 alloy in the turning cutting tools decrease the vibration acceleration amplitudes by 43.1% and 40.2% for internal and external turning operations, respectively. Additional improvement in the performance of the internal turning cutting tool is achieved by presenting a new model of the boring bar that depends on the integrating of TiNi3 alloy and carbide material. Optimization of five steps is made to obtain the optimal design of the presented model. The new model shows that the optimized boring bar decreases the vibration acceleration by 60.2% compared to the commercial boring bar. Therefore we strongly recommend it for manufacturing turning tool holders.

VIBRATION CHARACTERISTICS TEST AND ANALYSIS OF HANGING CUP TRANSPLANTER

The vibration of the hanging cup transplanter affected the hole size and tray seedling quality. This paper takes the 2ZP-2 hanging cup transplanter as the research object, studies the vibration characteristics of the transplanter when it works, deduces the mathematical model of the transplanter-soil vibration characteristics, and solves the steady-state vibration response. The Danish B&K vibration test system carried out the vibration test. Studies have shown that the vertical vibration of the transplanter is greater than that of the lateral vibration and the forward vibration. The main factors affecting the vertical vibration of the transplanter are the forward speed of the transplanter, the soil compaction, and the planting depth. When the forward momentum of the transplanter is in the range of 0.8~2.4 km/h, the vertical vibration acceleration increases with increasing forward speed of the transplanter. According to the power, spectral density curve, and spectral curve, the spectrum range of the vertical vibration energy peak is 0~10 Hz, the vibration frequency is between 4.5~5.5 Hz, and the corresponding vibration acceleration amplitude is 0.03~0.33 m/s2. The research results can provide a reference for improving the operating speed, comfort, and structural optimization.