Modal Analysis Simulations Research Articles

Investigation of structural parameters influencing vibration characteristics of heavy-duty truck diesel tanks.

The working conditions of heavy-duty trucks are very complicated as the diesel shaking and resonance problems, which causes weld tears, separators to fall off, and other failures occur. Through experiments and finite element simulation, the natural frequency and vibration mode of a given 400 L diesel tank were calculated to study the influences of structural parameters such as the fill ratio (0.1-0.9), the number of baffle plates (0, 1, 2), the spacing of the plates (240 mm, 400 mm, 560 mm) and the aperture (38 mm, 78 mm, 118 mm) on the modal parameters with the wet mode method. The results of the hammering mode test and the simulation modal analysis agree well with the maximum error is 4.8%; the natural frequency of the diesel tank will increase with fill ratio decrease; the increase of the baffle plate number (0, 1, 2) can effectively increase the first-order natural frequency of the diesel tank, but the change of the natural frequency is not obvious on the higher order; the higher plates spacing has a smaller natural frequency; increasing the aperture will highly increase the natural frequency, 188 mm has better vibration safety.

Research on S-type fiber Bragg grating acceleration sensor for low-frequency vibration monitoring.

The acquisition of low-frequency vibration signals in earthquake exploration is a crucial aspect of seismic exploration technology. Addressing the difficulty current fiber optic sensors face in monitoring low-frequency vibrations, this paper proposes an acceleration sensor based on S-type Fiber Bragg Grating (FBG). First, an FBG acceleration sensor model is established and theoretically analyzed. Then, the impact of structural parameters on the sensor's sensitivity and natural frequency is examined, employing the ANSYS finite element analysis software for static stress and modal simulation analysis. Finally, a prototype is developed, and a low-frequency vibration testing system is assembled to test the sensor's performance. The results show that the sensor has a natural frequency of 34Hz, operates in a frequency band of 0.2-14Hz, has a dynamic range of 63.5 dB, a lateral interference of less than 3%, a sensitivity of ∼274.45 pm/g, good linearity, and is insensitive to temperature. The findings provide a reference for the development of similar sensors and further exploration of the lower frequency limit.

Determination of the Dynamic Modulus of Elasticity of Pine Based on the PZT Transducer

A new method for the determination of the dynamic modulus of elasticity (Ed) of pine wood, based on the transverse vibration excitation and electromechanical impedance (EMI) response of the lead zirconate titanate (PZT) transducer is proposed. The influence of the length to thickness ratio of the pine specimen on the measurement accuracy was studied through modal simulation analysis. Based on the results of the modal simulation, the size of the pine specimen was optimized, and the scanning frequency range of the EMI response was determined. On this basis, the EMI simulation and test of the pine specimen coupled with a PZT patch were carried out to verify the effectiveness of the novel method. The impedance simulation results of three kinds of pine specimens show that a unique and significant formant appears in the real part of each EMI response curve, and the maximum relative errors of the rectangular PZT patch and circular PZT patch are 1.34% and 1.81%, respectively. The impedance test results of three kinds of pine specimens indicate that the maximum relative errors of the rectangular PZT patch and circular PZT patch are 1.41% and 1.68%, respectively, compared with the corresponding results obtained by the traditional transverse vibration method. Simulation and experimental results verify the validity of the proposed method for the elastic modulus determination of pine wood.

Simulation study on the vibration durability test of an automotive plastic fuel tank based on fluid–structure coupling

In this study a new simulation technology based on fluid-structure coupling is to solve the problem of plastic fuel tank lifting lug fracture during vibration durability test, which has not been reported in the existing literature. The basic principle of fluid-structure coupling is summarised and the finite element model (FEM) of the fuel tank system established. Modal simulation analysis is carried out, and the FEM is updated and verified via the modal test method. A harmonic response analysis of the fuel tank system is performed. Simulation results show the maximum stress at the lifting lug is 29.69 MPa in the Z-direction vibration, exceeding the allowable fatigue strength. The resonance occurred, which is consistent with the result of the vibration durability test. To enable the fuel tank to pass the vibration durability test, this study proposes to optimise the fixture, thereby enhancing the natural frequency of the entire fuel tank system and avoiding an excitation frequency of 30 Hz. Through the harmonic response analysis and test verification, the fuel tank passes the vibration durability test. Therefore, the numerical simulation method based on fluid–structure coupling and the fixture optimisation scheme adopted is feasible and can considerably shorten the test cycle and improve efficiency.

Seeing the piano sound Exploration on utilizing finite element analysis to visualize piano sound

The study aims to provide a way for impaired people to learn music better through music visualization. We established a relationship between piano key frequencies and Chladni patterns. Firstly, we performed modal analysis simulations using ANSYS, covering the full range of excitable modes in the frequency range of the piano keys. However, since the natural frequencies of the simulation results were slightly different from experimental results, we used the hammering method to validate the simulation results and to demonstrate that the finite element modal analysis was able to simulate the dynamic properties of the circular plate well. Subsequent studies have found that different excitation frequencies in the lower frequency range may also affect the generation of Chladni patterns. Using harmonic analysis in ANSYS, we confirmed that tones of similar frequency on the same plate can produce different Chladni patterns, thus greatly simplifying the previous problem of having to use multiple plates of different shapes and sizes in order to visualize most of the piano keys. Based on the graphical simulation of a single tone, we have successfully extended it to a melody. This result provides strong support for effectively helping the hearing impaired to learn to play musical instruments, makes it possible to present music in a visual form, and opens up new possibilities for the wider use of music education tools in the hearing-impaired community.

Enhanced Reverse-Engineering Method for Accurately Predicting Lamina Properties in Laminated Composites via Combined Static and Dynamic Finite Element Simulations

This study aims to ascertain the material characteristics that are intrinsic to the prepreg layer within a laminated composite structure. The elastic modulus of the lamina, a primary determinant of composite structural behavior, is the focal point of this analysis. This parameter has been assessed by employing reverse-engineering techniques on a composite composed of sequentially stacked prepregs. The investigation entailed simulating the behavior of the composite under static loads and conducting modal analyses to reflect both static and dynamic conditions. The findings indicate that the elastic modulus values derived from combined tensile and modal analysis simulations exhibit superior accuracy compared to those obtained through tensile simulation alone. Specifically, the maximum prediction error for E1 (the tensile-direction elastic modulus of one lamina sheet) decreased from 1.17% to 0.28%, and that of E2 (the transverse-direction elastic modulus of one lamina sheet) decreased from 12.01% to 7.30%. Further simulations incorporating fabrication error variances underscored the critical nature of precise E2 analysis. The proposed methodology evidenced a more accurate assessment of E2, underscoring its potential to enhance the reverse-engineering process in composite material design.

Design and Experimental Results of a Three-Dimensional Force Sensor for Shearer Cutting Pick Force Monitoring

The main focus of this work is the design and development of a three-dimensional force sensor for the cutting pick of a coal mining shearer’s simulated drum. This sensor is capable of simultaneously measuring the magnitude of force along three directions of the cutting pick during the cutting sample process. The three-dimensional force sensor is built based on the strain theory of material mechanics, and reasonable structural design is implemented to improve its sensitivity and reduce inter-axis coupling errors. The strain distribution of the sensor is analyzed using finite element analysis software, and the distribution of the strain gauges is determined based on the analysis results. In addition, a calibration test system is designed for the sensor, and the sensitivity, linearity, and inter-axis coupling errors of the sensor are calibrated and tested using loading experiments in three mutually perpendicular directions. Modal simulation analysis and actual cutting pick testing of the coal mining machine’s simulated drum are conducted to study the dynamic characteristics and functionality of the sensor in practical applications. The experimental results depict sensitivities of 0.748 mV/V, 2.367 mV/V, and 2.83 mV/V for the newly developed sensor, respectively. Furthermore, the cross-sensitivity error was lower than 5.02%. These findings validate that the sensor’s structure satisfies the measurement requirements for pick-cutting forces.

A dual oblique wing-based low-frequency FBG accelerometer

The low-frequency vibration measurement technology is significant in energy exploration, aerospace, geophysical activities, health monitoring of large engineering structures, etc. A low-frequency FBG accelerometer based on a dual oblique wing is proposed to address the issue of difficulty in accurately measuring low-frequency vibration signals in current fiber Bragg grating accelerometers. Firstly, the structure of this accelerometer was theoretically analyzed and dimension-optimized. Secondly, the static stress analysis and modal simulation analysis are carried out, and the accelerometer is developed. Finally, it is fixed on the vibration table, and the low-frequency vibration test system is built to test the performance. The experimental results show that the natural frequency of the accelerometer is 46 Hz, the working frequency band is 0.1–28 Hz, the sensitivity is 55.6 pm/g, the dynamic range is 48.94 dB, and the resistance to transverse interference of less than 5.62 %. The accelerometer designed in this paper provides a new idea for low-frequency vibration signal measurement.

Miniaturized fiber Bragg grating accelerator sensors for low-frequency vibration monitoring.

Acceleration monitoring is an important technical means of seismic monitoring, oil exploration, deep well observation, etc. A miniaturized fiber Bragg grating (FBG) acceleration sensor with three cantilever beams is proposed against the fact that it is difficult for fiber-optic sensors to meet the requirements for low-frequency vibration monitoring. First, the model of the FBG acceleration sensor was built and theoretically analyzed; second, the effect of structural parameters on sensor sensitivity and natural frequency was analyzed, and the sensors were subjected to static stress analysis and modal simulation analysis through the ANSYS finite element analysis software; finally, the real sensors were developed and subjected to performance tests with a low-frequency vibration test system. According to the result, the natural frequency of the sensor is about 64Hz, and its sensitivity is 201.3pm/g; favorable linearity is observed at the working frequency band of 0.1-40Hz, and the transverse interference is less than 2.51%. The research findings offer a reference for the development of like sensors and the further exploration of the lower limit of low frequency.

A novel short fiber Bragg grating accelerometer based on a V-type dual mass block structure for low- and medium-frequency vibration measurements

A novel short fiber Bragg grating (FBG) accelerometer based on a dual mass block structure is presented in this paper. The sensor is established on a solid, symmetrical design comprising a V-type beam. The configuration in the FBG accelerometer causes the FBG fiber to distort twice as much when subjected to external vibration. The theoretical research and optimization of the FBG accelerometer's natural frequency and sensitivity are performed using MATLAB software, while static structural stress and modal simulation analysis are examined using ANSYS software. An experimental test is applied to evaluate the implementation of the sensors. The natural frequency of the sensor is 880 Hz, and its stability frequency response is flat in the 20–340 Hz low- to middle-frequency range. The linearity of the average sensitivity is approximately 66.95 pm/g, and the transverse anti-interference of the FBG fiber is around 6.53%. This work proposes a suitable method to observe low- and medium-frequency vibration signals in large-scale applications.

Propeller's operational modal parameters identification based on Fiber Bragg Grating sensing

The propeller will generate a lot of harmful vibration and noise underwater. In order to effectively solve the problem of vibration and noise, it is of great significance to accurately obtain the modal parameters of propeller for the design and optimization of the propeller structure. Since it is difficult to measure the load of propeller when it is running underwater, only operational modal analysis (OMA) method can be used to identify the operational modal parameters of propeller. This paper is aimed at solving this problem by taking the metal propeller as the research object, an open-water test platform was built, and the Fiber Bragg Grating (FBG) sensors were used to obtain the underwater strain information of the propeller. Finally, the operational modal parameters of propeller are identified by the Stochastic subspace identification (SSI) method. In addition, the modal simulation analysis of propeller was carried out by using finite element simulation software, and the experimental results were compared with the simulation results. The results show that the stochastic subspace identification method can accurately identify the operational modal parameters of propeller.

Research on fatigue life of all-terrain vehicle control arm based on measured load spectrum

Background: All-terrain vehicles are mostly used in poor driving environments. A key part of the suspension mechanism of all-terrain vehicles, the lower control arm, bears various loads when the vehicle is driving. This component is prone to be fatigue and failure, which affects the performance of the entire vehicle. Therefore, in order to improve the performance of all-terrain vehicles, the fatigue life of the lower control arm was studied based on the measured force load spectrum. Methods: Firstly, the finite element model of the lower control arm is established, the free modal simulation analysis is carried out, and the experimental research is carried out by building a modal test system. Then combining the calculated modal and experimental modal results, the finite element model is verified. Next, through the road load spectrum acquisition test in the automobile proving ground, the force time history of the lower control arm is obtained, and the signal is processed and analyzed to verify the reliability of the force load signal. On this basis, the boundary constraints of the lower control arm are established based on the actual working conditions of the all-terrain vehicle, and the dynamics simulation analysis is carried out with the measured force as input. Finally, according to stress-strain signal in dynamic analysis results, combining the modified local stress-strain method and the Landgrave damage criterion, the fatigue life of the lower control arm is calculated. Results: The minimum fatigue cycle life of the lower control arm on the test roads is 3.56×105 km, and its fatigue life meets the design and use requirements. Conclusions: The result shows that based on the actual driving load spectrum, the actual driving fatigue life can be calculated and forecasted more accurately.

Numerical and Experimental Investigation on Safety of Downhole Solid–Liquid Separator for Natural Gas Hydrate Exploitation

Deep water shallow natural gas hydrate (NGH) is a kind of clean energy and has entered the commercial exploitation stage. However, it produces a lot of seabed sediment in the process of large-scale mining, which not only easily causes undersea natural hazards, but also leads to pipeline equipment blockage and high energy consumption in the mining process. A downhole solid–liquid separator can effectively separate natural gas hydrate from sand and backfill sand in situ, which can effectively solve this problem. In this paper, the safety of a downhole solid–liquid separator desander under torsion conditions is determined by a test method. A numerical simulation method was used to simulate the tension and pressure of the downhole solid–liquid separator, and a modal simulation analysis and erosion analysis of the downhole solid–liquid separator were carried out. The experiments showed that the downhole solid–liquid separator could withstand 30 KN/m of torque, and a numerical simulation analysis showed that it could withstand 30 MPa of pressure and 50 KN of tension. The results show that the maximum stress is 116.56 MPa, and the maximum allowable stress is 235 MPa. The modal analysis showed that the downhole solid–liquid separator produces resonance at a frequency of about 93 Hz, resulting in large deformation, which should be avoided as far as possible. Through the erosion analysis, the life of the downhole solid–liquid separator was determined to be about 2.3 years. Numerical simulation and experimental results show that the designed downhole solid–liquid separator for natural gas hydrate can ensure safety.

A new L-shaped rigid beam FBG acceleration sensor

Acceleration detection is an important technology in the fields of seismic monitoring, structural health monitoring and resource exploration. A FBG acceleration sensor with the combination of L-shaped rigid beam and spring structure based on bearings is proposed against the low sensitivity that predominates in the low-frequency vibration measurement by FBG acceleration sensors, where L-shaped rigid beam is utilized to amplify the vibration signal, and is fixed by the bearings at both ends to effectively suppress the transverse crosstalk. The effects of structural parameters on the sensitivity and natural frequency of the sensors were analyzed using Origin theory, and such parameters were optimized; next, static stress and modal simulation analysis was made using COMSOL; in the end, a test system was built to test the performance of the real sensors. According to the findings, the acceleration sensor, whose natural frequency is 57 Hz, is of a flat sensitivity response in the low frequency range of 1–35 Hz, with the dynamic range being 89.83 dB, the acceleration sensitivity being up to 1241.85 pm/g, the coefficient of determination R2 for the sensitivity fit is 0.9997, and the transverse crosstalk being -26.20 dB within the operating frequency band. The findings offer a reference for improving the low-frequency vibration measurement capability of FBG acceleration sensors.

AN INVESTIGATION OF ULTRASONIC VIBRATIONS EFFECT ON SURFACE ROUGHNESS IN ALUMINUM 7075 AND AISI 1045 CARBON STEEL DURING END MILLING AND SIDE MILLING OPERATION

Milling is one of the discontinuous machining methods which makes tools contact with workpiece continuously along with the regular change of shear force. Providing strong materials for fabricating the required pieces challenge machining and producing complex shapes. Therefore, operations intended for reducing machining forces as well as increasing the final surface smoothness are remarkably important of which using ultrasonic vibrations is one method. This study centers on ultrasonic vibration-assisted milling operation. The required ultrasonic vibrations are applied using a transducer to an AISI 1045 steel workpiece and a 7075 aluminum. Also, by using an arithmetic modal analysis simulation on the related workpiece and fixture, the designing process was performed in a way to equate the natural frequency of the whole set to that of the ultrasonic transducer. The resonant frequency obtained for the steel and aluminum workpieces was 19840 and 19757[Formula: see text]Hz, respectively, and the milling operation was done by applying ultrasonic vibrations to the workpiece. The results obtained from surface roughness measurement indicated that an increase in the ultrasonic intensity from 15[Formula: see text]W/cm2 to 22.5[Formula: see text]W/cm2 in the aluminum workpiece resulted in improved surface roughness ([Formula: see text] by 70%. In addition, an increase in the ultrasonic intensity from 15[Formula: see text]W/cm2 to 22.5[Formula: see text]W/cm2 improved the surface smoothness ([Formula: see text] by 72%. Moreover, concerning the steel workpiece while the tool is perpendicular to the direction ahead of the workpiece, it was clear that applying 22.5[Formula: see text]W/cm2 ultrasonic vibrations to the end-milled surfaces resulted in an approximate increase in the average and maximum surface smoothness by 53% and 45%, respectively. Furthermore, applying 30[Formula: see text]W/cm2 ultrasonic vibrations to face-milled surfaces, either perpendicular to or parallel to the tool, led to an approximate increase in the average and maximum surface smoothness by 35% and 25%, respectively.

Miniature FBG Vibration Sensor with High Performance and Low Angle Dependence for Two-dimensional Vibration Measurement

A miniature FBG vibration sensor with high performance and low angle dependence has been proposed and applied in the two-dimensional vibration measurement of a vibration isolation platform in this paper. Considering the bonding points with maxim replacement, the sensitivity and resonant frequency theoretical model of the elastomer and packaged small-diameter FBG were established. The genetic algorithm was utilized to achieve the globally optimized structure sizes under multiple constraints, while the modal simulation analysis was carried out to verify the result. A novel ‘figure of merit’ defined as the product of the resonant frequency, the sensitivity, and the inverse of package volume was proposed for the performance evaluation of the sensor in the unit space of its package. The first-order and second-order frequencies of its X/Y direction of 1105.4 Hz/1266.1 Hz, while the sensitivity is 127.861 pm/g and 116.668 pm/g, correspondingly. The cross-interference in the X/Y directions of the sensor is less than 2%. Moreover, the test results of the angle dependence of the sensitivity show that the sensor possesses consistent sensitivity in all directions of the 2-d plane, while the fitted sin functions in the X/Y direction have a high R <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> of 0.99851 and 0.99831, respectively. Finally, the 2-D vector vibration measurement capacity of this sensor was demonstrated on a rubber spring vibration isolation platform. The results show that this miniature 2-D vibration sensor is suitable for medium-high frequencies vibration vector measurement and has a bright application prospect for the monitoring of machines.

Research on vibration reduction test and frame modal analysis of rice transplanter based on vibration evaluation

The chassis of rice transplanter tends to vibrate severely in the severe working environment, causing a severe effect on the operational performance and driving comfort. In order to avoid this situation, this paper constructs a vibration evaluation system of the rice transplanter and carries out experimental analysis. According to the optimal acceleration sensor placement scheme, a test platform system was designed. Taking the high-speed transplanter chassis as the research object, this study carried out the experiments modal analysis and optimization on the chassis. The three-dimensional model of the transplanting machine chassis established by SolidWorks was imported into ANSYS Workbench for finite element modal simulation analysis. Comparing the two modal analyses, it is found that the results data of the two analysis methods were very close. After optimization, the length x1, the section width x2 and the thickness of the hollow beam x3 of the main load-bearing beam of the frame were as follows : x1=1641.5 mm, x2 =26.7 mm, x3=5 mm, respectively. The maximum overshoot of the low-level system was reduced by 28.57%. It has been verified that the vibration of the whole machine has been effectively reduced. Keywords: chassis, high-speed rice transplanter, vibration evaluation, modal analysis DOI: 10.25165/j.ijabe.20221504.7244 Citation: Jin X, Cheng Q, Tang Q, Wu J, Jiang L, Wu C Y, et al. Research on vibration reduction test and frame modal analysis of rice transplanter based on vibration evaluation. Int J Agric & Biol Eng, 2022; 15(4): 116–122.

Hinge-type FBG acceleration sensor based on double elastic plate

It is critical for the health monitoring of large-scale structures such as bridge, railway and tunnel to acquire the medium-frequency and high-frequency vibration signals. To solve the problems of low sensitivity and poor transverse anti-interference of the medium-frequency and high-frequency fiber acceleration sensor, a hinge-type Fiber Bragg Grating(FBG) acceleration sensor based on double elastic plate has been proposed, and the hinge and elastic plate are used as elastomer to realize the miniaturization and transverse interference suppression of the sensor. The MATLAB and the ANSYS are used for theoretical analysis and optimization of sensor sensitivity and resonance frequency, structural static stress analysis and modal simulation analysis, while the test system is built to test the sensor performance. The results show that the resonance frequency of the sensor is 1300 Hz; the sensor has a flat sensitivity response in the middle-high frequency band of 200–800 Hz; the sensitivity is about 20 pm/g, and the fiber central wavelength drift and acceleration have good linearity and stability, while the transverse anti-interference is about 3.16%, which provides a new idea for monitoring of medium-frequency and high-frequency vibration signals in large-scale structures.

Analyzing behaviour of a rail wheel assembly with alumino thermite weldment with modal analysis simulations in ANSYS

The Free vibration response of the Railway track is an important area in the design of the Rail and its joints to improve the ride comfort of the passengers. In this study, the rail weld considered is alumino thermite weldment used in majority of Indian Railways network. This paper aims at the study of the vibration response of rail wheel assembly having an AT weld on as a rail joint subjected to free vibration and to find the Natural frequencies of vibration and mode shapes. The geometric model of rail and weldment with wheel and axle components is modelled using Space-claim which is a part of ANSYS package and analysed using numerical simulation package ANSYS 2020 Workbench. In this work, free vibration analysis or modal analysis of the rail weld is carried out to extract the first few modes of vibration. The Natural frequencies obtained along with the corresponding mode shapes of the rail weldment show that they are within the permissible range specified by the standards of railway department also for better ride comfort of the passenger.

Modal simulation analysis based on vibration characteristics of Euler Beam

Taking the Euler Beam as the research object, the finite element models of beam structure under five support conditions, using solid elements, shell elements and beam elements respectively, are established for considering the influence of different boundary conditions. Based on the eigenvalue method, the first three natural frequencies of the beam structure under five kinds of support conditions are calculated. Through the contrast analysis of the theoretical value and simulation value, the most reasonable simulation constraints are given for different element types. Also, the selecting rules of the element numbers and element types for the Euler Beam are offered which provide the reference and basis for the beam structure modal calculation.