Mechanical Vibration Characteristics Research Articles

Simulation Study on Mechanical Vibration Characteristics of GIS Bus Misalignment

Abstract Gas-insulated switchgear (GIS) has been widely used in power grid systems. The busbar is a crucial element within a GIS system, responsible for facilitating electrical connections between different GIS components. Any defects during manufacturing or improper installation procedures can lead to busbar misalignment, resulting in abnormal vibrations within the GIS. This study focuses on analyzing the mechanical vibration characteristics of GIS bus misalignment using a simulation model based on the finite element method for a 252kV GIS. When the busbar is misaligned and the conductor experiences an unbalanced force, it undergoes Coulomb forces at double the voltage frequency. Under normal or misaligned conditions, the conductor exhibits forced vibrations at the power frequency of 100Hz. However, when misalignment occurs, there is a coupling effect between electrodynamics and vibrations, causing the shell to display integer frequency vibration components.

Inherent resonance of carbon and graphene-based nanocomposite coupled single-span arch beams

In recent decades, there has been a significant rise in the utilization of composite materials for various engineering applications. These advanced materials offer the potential to improve the mechanical properties and vibration characteristics of structural components. This particular study is dedicated to enhancing the vibration performance of coupled curved-curved beams that feature a linear elastic mid-layer, achieved through the incorporation of carbon nanotubes (CNTs), graphene nanoplates (GNPs), and graphene oxide powder (GOPs). The governing equations of the system are solved using the generalized differential quadrature (GDQ) method. While previous research primarily focused on the use of CNTs to enhance the vibration behavior of coupled-curved beams, this study delves into the utilization of multiple nanofillers for this purpose. An essential aspect of modeling composite materials lies in determining their equivalent mechanical properties. This research undertakes a comparison between the rule of mixture (RoM) and Halpin-Tsai methods for calculating these properties, revealing that frequencies derived from the RoM method are higher than those obtained through the Halpin-Tsai approach. Additionally, the study highlights that systems incorporating GNPs demonstrate higher frequencies at lower nanofiller volumes, with CNTs and GOPs following in ranking. However, this hierarchy shifts at higher nanofiller volumes. The arrangement of nanofillers within the system is influenced by its boundary conditions, with the curvature of the bottom beam playing a significant role in affecting vibration behavior. Increasing the radius of the bottom beam (R2) leads to higher system frequencies, which subsequently decrease with higher R2 values.

Effect of various weaving architectures on mechanical, vibration and acoustic behavior of Kevlar-Hemp intra-ply hybrid composites

Due to the benefits of including high stiffness, low density, low cost, ecologically benign nature and abundant availability, natural fibers are employed as reinforcement in composites. These fibers however have a few shortcomings, including poor moisture resistance and incompatibility with most matrices. Therefore, the goal of this research is to combine the benefits of natural fiber (hemp) with synthetic fiber (kevlar) to develop a hybrid composite. Hemp and Kevlar yarns were handloomed to form fabrics with different architectures such as plain, twill and basket. These hybrid fiber epoxy composites were fabricated using compression molding and the samples were subjected to mechanical testing, free vibration and acoustic emission characteristics. Hemp and Kevlar fiber composites were also fabricated for comparison purpose. The results revealed that the twill and basket weave intra ply hybrid composites exhibited the better mechanical properties when compared with the plain weave hybrids. Whereas, the free vibration results showed that the all the hybrids exhibited better performance that the mono-fiber composites. Acoustic behavior of the basket weave hybrid was found to have the highest sound transmission loss value of 13.7 dB in the higher frequency range. On the other hand, the hemp-epoxy composites exhibited the highest sound transmission level of 6.3 dB in the lower frequency range.

Digital Twins and Data-Driven in Plant Factory: An Online Monitoring Method for Vibration Evaluation and Transplanting Quality Analysis

The plant factory transplanter is a key component of the plant factory system. Its operation status directly affects the quality and survival rate of planted seedlings, which in turn affects the overall yield and economic efficiency. To monitor the operation status and transplanting quality of a transplanting machine in a timely manner, the primary task is to use a computerized and easy-to-use method to monitor the transplanting units. Inspired by the latest developments in augmented reality and robotics, a digital twin model-based and data-driven online monitoring method for plant factory transplanting equipment is proposed. First, a data-driven and virtual model approach is combined to construct a multi-domain digital twin of the transplanting equipment. Then, taking the vibration frequency domain signal above the transplanting manipulator and the image features of the transplanting seedling tray as input variables, the evaluation method and configuration method of the plant factory transplanter digital twin system are proposed. Finally, the effect of the transplanter is evaluated, and the cycle can be repeated to optimize the transplanter to achieve optimal operation parameters. The results show that the digital twin model can effectively use the sensor data to identify the mechanical vibration characteristics and avoid affecting transplanting quality due to mechanical resonance. At a transplanting rate of 3000 plants/h, the transplanting efficiency can be maintained at a high level and the vibration signal of the X, Y, and Z-axis above the transplanting manipulator is relatively calm. In this case, Combined the optimal threshold method with the traditional Wiener algorithm, the identification rate of healthy potted seedlings can reach 94.3%. Through comprehensively using the optimal threshold method and 3D block matching filtering algorithm for image threshold segmentation and denoising, the recognition rate of healthy seedlings has reached over 96.10%. In addition, the developed digital twin can predict the operational efficiency and optimal timing of the detected transplanter, even if the environmental and sensor data are not included in the training. The proposed digital twin model can be used for damage detection and operational effectiveness assessment of other plant factory equipment structures.

Free Vibration Analysis of Composite Cylindrical Shell Reinforced with Silicon Nano-Particles: Analytical and FEM Approach

Previous research presented the effect of nanomaterials on the mechanical properties of composite materials with various volume fraction effects; in addition, their research presented the effect of nanomaterials on the same mechanical characteristics for a composite plate structure, such as vibration and thermal buckling behavior. Therefore, since the use of shell structures is for large applications, it is necessary to investigate the modification of the vibration characteristics of its design with the effect of nanomaterials and study the influence of other reinforced nanoparticle types on its features. Therefore, in this work, silicon nanoparticles were selected to investigate their effect on the vibration behavior of a shell structure. As a result, this work included studying the vibration behavior by testing the shell structure with a vibration test machine. In addition, after manufacturing the composite material shell with various silicon volume fractions, the mechanical properties were evaluated. In addition, the finite element technique with the Ansys program was used to assess and compare the vibration behavior of the shell structure using the numerical technique. The comparison of the results gave an acceptable percentage error not exceeding 10.93%. Finally, the results evaluated showed that the modification with silicon nanomaterials gave very good results since the nanomaterials improved about 65% of the shell's mechanical properties and vibration characteristics.

Mechanical Vibration Characteristics Analysis of a Counterblow Hammer Press in the Forging Process

Mechanical Vibration Characteristics Analysis of a Counterblow Hammer Press in the Forging Process

Experimental investigation on mechanical properties and free vibration characteristics of epoxy‐based glass/flax laminates

AbstractIn the present study, an attempt is made to replace the synthetic glass fiber used in the FRP structures in terms of natural flax fibers without much sacrifice on static and dynamic stability of the structure. Three types of glass/flax hybrid composite laminates were prepared with different fiber volume fraction of glass and flax fibers. For better understanding purpose, a dedicated glass and dedicated flax laminates were also fabricated. All the laminates were fabricated by vacuum bag molding method with uniform laminate thickness. The mechanical properties of the fabricated laminates, such as tensile strength and flexural strength, were evaluated in accordance with ASTM standards. The impulse excitation technique was used to assess the free vibration characteristics of glass/flax laminates such as modal frequency and material damping. Based on experimentally evaluated mechanical and vibration characteristics a suitable fiber volume fraction for the preferred laminate thickness was suggested to achieve optimum static and dynamic stability.

Improvement of the mechanical and damping behavior of nylon by integration of nanoclay platelets

Abstract Nylon is used as a gear material thanks to its beneficial characteristics, such as self-lubrication, noiseless and fail-safe operation. Poor resistance to heat, dimensional stability, shock and impact loads are major drawbacks of nylon when used in engineering applications. The addition of a nanofiller to a nylon matrix can enhance its mechanical and vibrational properties. Montmorillonite nanoclay (Cloisite 15 A, Cloisite 20 A and Cloisite 30B) modified with ammonium salt was incorporated into the Nylon 6 matrix by solution mixing and melt mixing. Nanoclay with 1, 2 and 3 wt.-% were added to the nylon matrix and the resulting mechanical and free vibration characteristics were determined. The experimental results of the mechanical and free vibration behavior were compared with the ANSYS results. Tensile strength, modulus of elasticity, specific strength, specific stiffness, natural frequency and damping factor were found to increase as the weight percentage of the nanoclay in the nylon matrix increased. Cloisite 30B nanocomposite shows better mechanical and free vibration characteristics when compared with pure Nylon 6, Cloisite 15 A and Cloisite 20 A nanocomposites. The Cloisite 30B nano-composite was prepared with 2 wt.-% shows maximum mechanical and free vibration performance.

Characteristic Analysis and Experimental Verification of Electromagnetic and Vibration/Noise Aspects of Fractional-Slot Concentrated Winding IPMSMs of e-Bike

In this study, we performed the electromagnetic and mechanical characteristic analyses of an 8-pole 12-slot interior permanent magnet synchronous motor (IPMSM). Permanent magnet synchronous motors are classified into surface permanent magnet synchronous motor and interior permanent magnet synchronous motors according to the type of rotor. The IPM type is advantageous for high-speed operation because of the structure where the permanent magnet is embedded inside the rotor, and it has the advantage of having a high output density by generating not only the magnetic torque of the permanent magnet, but also the reluctance torque. However, such a motor has more vibration/noise sources than other types, owing to changes in reluctance. The sources of motor noise/vibration can be broadly classified into electromagnetic, mechanical, and aerodynamic sources. Electromagnetic noise sources are classified into electromagnetic excitation sources, torque pulsations, and unbalanced magnetic forces (UMFs). Vibration and noise cause machine malfunctions and affect the entire system. Therefore, it is important to analyze the electromagnetic vibration source. In this study, the electromagnetic characteristics of an IPMSM were analyzed through the finite element method to derive the UMF. Vibration and noise analyses were performed by electromagnetic–mechanical coupling analysis, and vibration and noise characteristics based on electromagnetic noise sources were analyzed.

Study on Vibration Damping Mechanism of Shoe Sole with Alternating Lattice Structure Using Vibration Level Difference

As one of the media of the ground and feet, the design of footwear products has lately received great attention, and the cushioning performance of the sole has become a key factor for the comfort and sportiness of the foot. In this paper, a new type of middle sole sports shoes with an alternating gradient lattice structure was proposed. The dynamic response of the structure was analyzed by ABAQUS software, and the model was validated by modal analysis. The effects of different kinds of alternating lattice and uniform lattice sole models on vibration isolation were analyzed by using the vibration level difference as the evaluation index of vibration characteristics. The analysis results are as follows: (a) We found that the mean of the vibration level difference of the alternating gradient structure is higher than that of the uniform lattice structure, which confirms the feasibility of the alternating gradient arrangement and its excellent buffering performance. (b) Two kinds of vibration stage drop values of the 24-series alternating lattice structure model are analyzed, and “C-G-X″ structure has the highest vibration stage drop value. In addition, the comprehensive analysis of the alternating gradient lattice structure of the soles shows that the four types of structures have good cushioning performance, and the C-series structure in the frequency range of 0–140 Hz vibration level difference value is higher than other series. The results show that the evaluation index of vibration level difference based on mechanical vibration characteristics can accurately analyze the response of different structure soles to vibration, which also provides a method for the future design of vibration reduction and exploration of the biomechanics of footwear.

Mechanical and free vibration properties of Phoenix sp. fiber reinforced epoxy composites: Influence of sodium bicarbonate treatment

AbstractIn this research work, the Phoenix sp. fiber‐based epoxy composites were fabricated using compression molding technique and investigated their mechanical and free vibration characteristics by varying the fiber length and content. The test results indicated that the fiber length and content influence the properties of composites significantly. The composites showed higher mechanical and free vibration properties than the neat epoxy due to increased composite stiffness. In particular, the composites reinforced with 20 wt% of 15 mm length fiber offer better overall properties. In addition, an effort was made to improve the properties of the optimized composites by reinforcing the sodium bicarbonate treated Phoenix sp. fibers. The treatments showed a positive impact on the composite properties, especially the 120 h treated fiber reinforced composites offered highest mechanical and free vibration properties than the other composites investigated. This could be attributed to increased fiber‐matrix interfacial bonding and the existence of small protrusions on the fiber surface that act as a mechanical interlocking mechanism, and the same was confirmed through morphological analysis. The experimental results showed that the sodium bicarbonate treatment is efficient in increasing the properties of Phoenix sp. fiber composites, as well as being less harmful to the environment after disposal.

Design and performance exploration of a cymbal piezoelectric energy harvester under the excitation of power transformer vibration

With the rapid application of internet of things technology and wireless sensor in transformer station, the demand for stable and reliable power source becoming increasingly stronger. Power transformer operates with high energy density vibration, which provides a suitable energy source for health monitoring sensors. A cymbal piezoelectric transducer is designed to harvest the energy of vibrationwhich is made of cymbal end cap and piezoelectric ceramic to convert mechanical energy to electricity. Also, the power circuit is designed to realize the transmission and storage of electric energy. Then, the performance of the cymbal piezoelectric energy harvester is explored by FEM and experiment. The influence of mechanical vibration characteristics on the charging power of piezoelectric transducer is studied, including amplitude, frequency and preload. The experimental results show that the cymbal piezoelectric energy harvester can provides stable and reliable power, which allows the possibility of large-scale application of wireless sensor in transformer station. The present work provides a new design concept for developing the novel cymbal harvesters used in large-sized vibratory equipment, such as power transformer, to harvest vibration energy.

Evaluating the influence of mechanical system vibration characteristics on servo motor efficiency

In this study, the influence of mechanical vibration characteristics on the efficiency of a servo motor was experimentally investigated. For this purpose, a dedicated apparatus comprising two servo motors connected to a coupling was used. The efficiency of the motor was investigated by first considering the signals of voltage and current; then, the mechanical power was calculated from the acquired torque and angular velocity supplied by the motor. Subsequently, working conditions involving different angular velocities and loading torques were investigated to generate a motor efficiency map. To clarify the influence of the vibration characteristics on the motor efficiency, two types of couplings differing in torsional stiffness and damping characteristics were considered—Type A and Type B. The efficiency was calculated for eight vibration conditions imposed via the selection of the velocity control gain settings for both types. Resultantly, the manner in which the efficiency is affected by the vibration conditions was clarified. Moreover, coupling in the case of better vibration damping characteristics was confirmed to yield a higher motor efficiency for all gain settings. Furthermore, motor working conditions corresponding to high and low motor efficiencies were evaluated, and the motor thermal behavior was investigated. Overall, a lower motor efficiency was confirmed to be associated with increasing temperatures. These results suggest the importance of the vibration characteristics of mechanical systems for achieving high efficiency.

Experimental investigation on mechanical and vibration characteristics of Flax/CNSL composite laminates

Natural fiber reinforced composite materials are most increasingly used as sustainable structures in engineering industries due to their vast availability and eco-friendly nature. In this regard, an emphasis is given in the present work to the use of natural fiber in structural composite material in place of synthetic fibers for structural applications. In the present study, the mechanical properties and free vibration characteristics of a pure green composite laminate were experimentally evaluated. For complete understanding of the behaviour of green composite material, a second laminate is prepared using synthetic resin. Two types of composite laminates were fabricated by hand layup method. In the pure green laminate, natural flax fiber is embedded in cashew nut shell liquid (CNSL) resin and for the second laminate epoxy resin is used as matrix. The flax fiber is preferred due to its high mechanical strength among all the natural fibers. Alkaline treatment is done for the natural flax fiber before fabrication to remove impurities and also improve the surface adhesion. Both the laminates were tested for mechanical properties and free vibration characteristics according to ASTM standards. The experimentally evaluated tensile, flexural properties and modal frequency values of two types of laminates are reported and discussed.

Dynamic Mechanical Properties and Free Vibration Characteristics of Surface Modified Jute Fiber/Nano-Clay Reinforced Epoxy Composites

Untreated and treated jute fiber and nano-clay in various ratios were used to fabricate jute/nano-clay/epoxy hybrid composites through compression molding method. The dynamic mechanical and free vibration behaviours were evaluated by varying the concentration of NaOH (2.5%, 5% and 7.5%) and wt.% of nano-clay (1, 3, 5 and 7 wt.%). Experimental outcomes disclosed that the storage and loss modulus, damping factor and natural frequency are influenced by concentration of NaOH solution and nano-clay content. A positive shift (towards higher temperature) in glass transition temperature and enhanced natural frequency of the composites after NaOH treatment and nano-clay addition confirmed that superior interfacial bonding exists between the jute fibers and epoxy matrix. Finally, the composites incorporated with 5% treated fiber and 5 wt.% of nano-clay is suggested for low strength structural applications in construction and automobile industries.

Effects of microfluid in the veins of the deployable hindwings of the Asian ladybeetle on flight performance

The deployable hindwings of certain coleopterans are their major flying components, and the veins supporting their hindwings play a significant role during flight; this knowledge is critical for designing bioinspired deployable micro air vehicles (MAVs). Therefore, the effects of microfluid (hemolymph) in the veins of beetle deployable hindwings are investigated in this paper. Microstructures are derived from hindwing cross sections and the nanomechanical properties of the hindwings and veins of the Asian ladybeetle Harmonia axyridis (Coleoptera: Coccinellidae). Based on these microstructures, three three-dimensional coupled models are established, including solid veins, hollow veins, and hollow veins filled with hemolymph. Then, the mechanical properties and vibration characteristics of the models are investigated. The torsional veins are affected more significantly by hemolymph when bending. This work will be helpful in designing new biomimetic deployable MAVs.

Effect of Adding Methylcellulose on Mechanical and Vibration Properties of Geopolymer Paste and Hybrid Fiber-Reinforced Geopolymer Composite

AbstractThe effect of methylcellulose, an organic admixture, on the mechanical properties and vibration characteristics of newly developed geopolymer paste (GP) and hybrid fiber-reinforced geopolym...

Numerical analysis of vibration characteristics and mechanical properties of polyoxymethylene/cloisite polymer nanocomposites

Polymer nanocomposites plays a vital role in engineering applications like automobile, aerospace, marine, transportation, electrical, medical and chemical industries. The properties of polymers are increased and improved by nanoclays. The polymers are highly used in engineering application especially in vibrating materials. In such that the mechanical properties and vibration characteristics of the polymer nano composites are analyzed in this work. The polymer nanocomposite was prepared with Polyoxymethylene POM as polymer and cloisite as clay (C20A, C25A & C30B) by melt mixing method. The tensile strength and elongation of (POM + Cloisite 20A) combination has higher value than other combinations. The vibration studies are carried out using ANSYS and the (POM + closite20A) combination was found to have better vibration characteristics than other combination of the polymer nanocomposites. The mechanical properties were also analyzed using ANSYS and compared with experimental results. From the experimental and analytical results the deviation is within the range of 2.5–4%.

Design and analysis of an ultrasonic tactile sensor using electro-mechanical analogy

This paper proposed a hybrid design approach of a vibro-concentrator, a vital component of an ultrasonic tactile sensor, by using electro-mechanical analogy. Lab experiments on soft materials with elastic modulus from 14 kPa to 150 kPa were conducted using the tactile sensor installed with the vibro-concentrator to verify the performance of the design. Various mechanical and electrical parameters, such as resonance frequency shift and equivalent conductance, were discussed, focusing on their feasibility as new stiffness indicators.As a variant of tactile sensors, ultrasonic tactile sensors have the advantage of high sensitivity and minimal contact with the object over traditional tactile sensors based on force-displacement principle. They detect the changes in mechanical vibration characteristics, mostly resonance frequency shift of the sensor, as an indicator of the mechanical properties of the object. A vibro-concentrator has been frequently adopted to improve the performance an ultrasonic tactile sensor, but its design has yet been systematically considered. We propose a hybrid design approach based on electro-mechanical analogy for both mechanical and electrical analyses. Mechanically, impedance analogy was adopted to design an ultrasonic vibration concentrator for the sensor to localize the contact and reinforce the vibration behavior at ~40 kHz. Electrically, we used mobility analogy to derive electrical parameters from the tactile sensing tests in lab environment. The competence of the design was demonstrated by mechanical and electrical characteristic tests. By investigating various electrical parameters from tactile sensing tests, the equivalent conductance determined by the electro-mechanical analysis was found to have almost perfectly linear relationship (R2 = 0.9998) with the samples’ elastic modulus ranging from 10 kPa to 70 kPa, and showed its potential as a new stiffness indicator for soft materials. Further analyses suggested that the electrically determined series resonance frequency shift, parallel resonance frequency shift, and maximum phase angle frequency shift also had excellent linearities (R2 = 0.9947, 0.9842, and 0.9935, respectively) with sample’s modulus and can be considered as indicator candidates.

Modeling and Mechanical Vibration characteristics analysis of a Quadcopter Propeller using FEA

Quadcopter is a mechatronic device that has four arms and each arm having a D.C. motor with a propeller. These four propellers provide the thrust to quadcopter, furthermore difference in the angular speed of these propellers is responsible for roll, pitch and yaw motion. The propeller of the quadcopter is subjected to the dynamic loading and vibration during the flight. The present study investigates the vibration characteristics of quadcopter propeller. To investigate the vibration behaviour, three different type of material are analyzed for result comparison. The solid model of propeller was designed in Creo 2.0 and Ansys 16.2 was used for analysis. Modal analysis was performed to find the First 6 natural fundamental frequencies and their mode shape. The frequency variation describes the failure and safe region through colour couture scale under different loading condition. The obtained results are compared and validated with the previous studies.