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Experimental study and comparative analysis of pitting fault in spur gear system

Research Article

By Kemajou Herbert Yakeu Happi, Bernard Xavier Tchomeni Kouejou, Alfayo Anyika Alugongo

This paper uses a dynamic six-degree-of-freedom model that considers torsional and lateral motions to predict the impact of pitting on vibration parameters in a spur gearbox for various operating speeds and torque loads. The study examines the dynamic characteristics of a gearbox with localized pitting damage on a single gear tooth using theoretical and experimental approaches. The research analyzes the forced vibrations of a single-stage spur gear system with pitting damage, which includes variations in mesh stiffness, damping, and gear error excitation, to identify symptoms of default. The equation of motion for the rotary gearbox system is established using the Lagrangian method in tandem with Short-Time Fourier Transform (STFT) and frequency-RPM map fault diagnosis. During real-time vibration monitoring, vibration signals are captured via accelerometers and processed in both the time and frequency domains using the LabVIEW data acquisition signal processing package to extract diagnostic information. The experimental findings demonstrate how vibration analysis combined with time-frequency processing can recognize machine conditions even in harsh operational conditions. Moreover, the experimental results indicate a significant similarity with the theoretical analysis and validate the effectiveness of the RPM frequency technique-based pitting detection method, which can be an asset in gear fault monitoring.

September 14, 2023

Vibration Engineering

A measurement method for zero-degree thermostat

Research Article

Thermocouple thermometers are widely used in laboratories and industry, the ice-water mixture is usually used as cold end compensation for thermocouple thermometer measurement. However, the ice-water mixture has disadvantages, such as complex manufacturing process, short use time, and unstable internal temperature field. The zero-temperature thermostat can replace the traditional ice water mixture to provide a stable temperature field environment. However, there is no suitable measurement method that can evaluate the zero-degree thermostat to meet the measurement requirements of thermocouple thermometer. Therefore, comparative experiments on temperature deviation, volatility, axial temperature field uniformity, radial temperature field uniformity, and load characteristics of the ice-water mixture and the zero-temperature thermostat are evaluated. In addition, the uncertainty of the zero-temperature thermostat and the ice water mixture is also proposed. The results reveal that the measurement results of temperature deviation, volatility, axial temperature field uniformity and load characteristic of the zero-temperature thermostat is smaller than that of the ice water mixture. Meanwhile, the uncertainty results also reveal that the zero-temperature thermostat is more stable than the ice water mixture. This study provides a comprehensive method for evaluating the performance of zero temperature thermostats, which can be used to verify the accuracy of the instrument and ensures the reliability of the thermocouple thermometers measurement, and promotes the development of zero temperature thermostat in temperature measurement field.

Applied Physics

Analytical determination of critical velocity and frequencies of beam with moving mass under different supporting conditions

Research Article

For a moving mass-beam system, the critical velocity of the moving mass is a key parameter that relates to the vibration stability of the system. In fact, the critical velocity obtained by the commonly used assumed mode method (AMM) differs from the actual situation. In this study, an analytical procedure is introduced to determine the critical velocity and frequency of the moving mass-beam system. The influence of moving mass is considered in the modal functions of the beam, and the frequency equations of the system were obtained through the modal analysis method and Laplace transform. And beams with four types of boundary condition were analyzed, which are hinged-hinged (HH) beam, clamped-hinged (CH) beam, clamped-clamped (CC) beam, and cantilever (CF) beam. By solving the frequency equations, the vibration frequencies of the system can be obtained, and the critical velocity can be determined. The results of the proposed method were validated by the finite element method (FEM). Through some examples, it was found that the natural frequency and critical velocity obtained by AMM is relatively high. And the critical velocities of the same moving mass-beam system under different supporting conditions ranked in ascending order are as follows: vcrHH

Vibration Engineering

Research and design of a small self-heating high-temperature lithium plugging meter system

Research Article

In the research of new reactors, lithium has become a research direction as a new coolant after sodium. Lithium working fluids introduce various metallic and non-metallic impurities such as oxygen, calcium, carbon, nitrogen, etc. to a greater or lesser extent during production, filling, and even operation. In addition, the processing, welding, and cleaning steps of the pipeline and equipment in the circuit during manufacturing inevitably result in residual dirt, grease, surface oxides, and moisture. These will have a certain impact on the performance of heat transfer and circuit safety through accelerated corrosion or plugging. Therefore, in high-temperature lithium circuits, the impurity concentration of lithium working fluid must be strictly controlled and purified before use. At present, the detection methods for impurity content in lithium working fluids can be divided into two categories: sampling analysis method and online measurement method. Sampling analysis is the most direct detection and analysis method, which can directly obtain the content of various impurities in lithium working fluids, and the results are relatively accurate; The online detection method can generally only detect non-metallic impurities, but it is relatively fast and simple, and is currently a commonly used measurement method on lithium working fluid devices. The plugging meter method has been studied and used as a rather convenient online detection method. This article introduces a small, self-heating, and mobile high-temperature lithium plugging meter system to meet the online detection of different points in the lithium circuit of system engineering.

Applied Physics

Strain modal response and vibration damping optimization of tower for wind power equipment

Research Article

The safety of wind power equipment under dynamic load is one of the key factors to ensure sustainable energy recovery. In order to effectively improve the reliability of tower structure, the damage identification of flange bolt fracture based on strain mode was studied, and the vibration control and optimization scheme was proposed and verified. The dynamic response of the tower to wind load was calculated using the theory of Davenport spectrum. Combined with computational fluid dynamics, the dynamic load change law of the tower was obtained. Based on ANSYS Workbench, the modal simulation and analysis of the tower were carried out. Under different bolt damage conditions, the distribution characteristics of the strain modal shape of the tower in the axial and radial directions were obtained. The vibration damper was applied to the inside of the tower, and the vibration and stress at different positions under wind load were compared and analyzed to verify the specific vibration reduction and optimization effect. The results show that the strain modal shape of the tower cylinder has a significant peak at the damage site, and the peak height is positively correlated with the damage degree, indicating that the strain modal shape is highly sensitive to the damage. In addition, the vibration and maximum stress of the flange and top position of the tower have been effectively reduced by the shock absorber. The average amplitude of tower top can be reduced by 22.5 %, and the peak stress at the bottom flange position can be reduced by about 38 %.

Applied Physics

Latest from engineering

Energy storage technologies and their combinational usage in micro/mini unmanned aerial vehicles: a review

Research Article

As the world population increases, energy consumption extensively increases in every field. Energy is a need in several applications, and depending on its importance, its production should be renewable and clean. In order to meet energy requirements sustainably nowadays various alternative energy resources and improvements are recommended in each sector. One of the environmental steps taken in the aviation industry is the improvement of the propulsion systems and the resources used. For this purpose, the use of electrical energy, a more sustainable option than the energy obtained from fossil fuels, is suggested. In order for electrical energy to be used efficiently, it must be stored. This article reviews energy storage technologies used in aviation, specifically for micro/mini Unmanned Aerial Vehicles (UAVs). Combinational energy storage technologies in hybrid propulsion system architectures and their individual usage in all-electric propulsion system architectures are examined. New-generation propulsion technologies are also evaluated and classified in detail.

The system for adaptive control of axial tool oscillations in vibratory drilling: description and experimental study

Research Article

Chips must be reliably segmented and evacuated from the cutting zone for effective deep hole drilling. Drilling with low-frequency axial vibrations ensures these useful effects because cutting edges periodically leave the cutting zone. Useful tool vibrations can be maintained using a special self-vibratory drilling head. The drilling head has an elastic element and ensures the self-excitation of vibrations due to the regenerative effect. However, high damping in the cutting zone suppresses axial self-vibrations and renders such a drilling head inexpedient for industry. This study develops a novel system of adaptive control for the vibration drilling process. The control objective is to maintain a specified peak-to-peak (PTP) value of vibration displacements. Due to the in-process adaptation of the feedback gain, the control system supplies additional energy if vibrations are not self-excited and removes energy if the PTP vibration displacements are greater than the specified value. To test the workability of the system, an experimental setup was made. In the setup, the actuator force acts on an elastically fixed workpiece. The dynamic properties of the setup are equivalent to those of the vibration drilling head. The algorithm of feedback gain adaptation was implemented with a microcontroller. A number of experiments for different drilling regimes revealed that the control system successfully maintains the specified PTP value of displacements. The developed control system can be implemented on a vibration drilling head because only an accelerometer is required for control and the required actuator force is under 100 N.

Vibration Engineering

A neural network simulator for educational purposes

Research Article

Artificial neural networks are inspired by biologic processes. Artificial neural networks are important because they can be used to deduct a function from observations, in other words artificial neural networks can learn from experience. Artificial neural network simulator to fulfill a need into the growing interest of neural network education is introduced in this study. NeuroQuick Laboratory simulator is implemented using object-oriented programming by Delphi programming and these classes can be used to create a standalone application with artificial neural networks. The NeuroQuick Laboratory Simulator is designed for a broad range of users, including beginning graduate/advanced undergraduate students, engineers, and scientists. It is particularly well-suited for use in individual student projects or as a simulation tool in one- or two-semester neural network-related courses at universities.

Industrial Engineering

Determinated area (DA) treatment goal when treating malocclusions with jaw functional orthopedics (JFO): Contribution to scientific evidence

Research Article

One of the goals of malocclusion treatment with Jaw Functional Orthopedics (JFO) is to obtain touch of the inferior incisors against the superior incisors in Determinate Area (DA). It is postulated that this touch would bring better stimuli and consequently faster results. Surface electromyographic study of the muscles was performed in Masseter, Temporal and suprahyoid muscles bilaterally from 159 patients undergoing malocclusion treatment with functional orthopedic appliances (FOA). To record muscle electric activity were used a conditioning signal module from Lynx Electronics Ltda with 8 channels, model EMG1000; software AqDAnalysis 4,18 from Lynx Electronics Ltda.; Software Lynx BioInspector 1,8r; passive surface electrodes (Ag/AgCl) from Noraxon Dual Electrodes (USA); dischargeable reference electrodes Kendall Meditrace (Ag/AgCl) – Canada. Frequency calibration was 2000 Hz, with 2048 sample by channel and time 1,024 seconds, and filters regulation was 20 Hz and 1000 Hz. The results found prove that there is a better electromyographic activity (bilaterally balanced) of the studied muscles when there is touch on DA. Conclusion. Touch in DA improves the neuromuscular response of patients treated with JFO. sEMG is a trustable tool to analyze masticatory muscles function for Diagnosis, Treatment and evaluation post treatment/gained objective.

Recently published

Research article

By Wanqing Huang, Yang Chen, Yongqi Chen, Tao Zhang

Recently published

Research article

By Regan Dunne, Dawood Desai, Stephan Heyns

71st International Conference on VIBROENGINEERING

Date

December 12-13, 2024

Submission deadline

November 4, 2024

Conference format

Hybrid

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A conversion guide: solar irradiance and lux illuminance

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Research Article

By Peter R. Michael, Danvers E. Johnston, Wilfrido Moreno

The standard for measuring solar irradiance utilizes the units of watts per meter squared (W/m2). Irradiance meters are both costly and limited in the ability to measure low irradiance values. With a lower cost and higher sensitivity in low light conditions, light meters measure luminous flux per unit area (illuminance) utilizing the units of lumens per meter squared or lux (lx). An effective conversion factor between W/m2 and lx would enable the use of light meters to evaluate photovoltaic performance under low solar irradiance conditions. A survey of the literature found no definitive and readily available “rule of thumb” conversion standard between solar irradiance and illuminance. Easy-to-find Internet sources contain conflicting and widely varying values ranging from 688449 to 21000 lx for 1000 W/m2 (1 Sun) of solar irradiance. Peer-reviewed literature contains Luminous Efficacy equivalent values ranging from 21 to 131 lx per W/m2. This manuscript explores the relationship and establishes a theoretical and laboratory measurement guide for the conversion between solar irradiance and illuminance. The conversion factor includes standards data, equipment calibration accuracy, and uncertainty estimates. Solar Irradiance of 1 Sun (1000 W/m2) for an LED-based solar simulator is (116 ± 3) klx and (122 ± 1) klx for outdoor sunlight.

December 4, 2020

Applied Physics

Design and calculation of double arm suspension of a car

Most downloaded

Research Article

By David Jebaraj B, Sharath Prasanna R

Suspension system is one of the challenging portions in designing a vehicle. The complete stability of the vehicle under dynamic conditions depends on the suspension system of the vehicle. Suspension system of a vehicle is interlinked with other systems such as steering, Wheels and Brakes. The main objective of this document is to provide complete guidance in designing and calculation of an independent suspension system with double control arms. The required parameters are calculated on considering a prototype vehicle with gross weight of 350 kg such as required stiffness of shock absorbers, Ride frequency, Motion ratio, Coefficient of damping etc. A CADD model was made with CATIA v5 r20 and SOLIDWORKS on the basis of calculations obtained and stress analysis was carried out for this model in various software such as Ansys. The complete assembled model was tested in LOTUS Shark and the result was obtained.

Industrial Engineering

Printed Circuit Boards (PCBs) are epoxy resin-impregnated and cured sheets of counter woven glass fabric (e.g. FR4) laminated between thin sheets of Copper. The nature of the PCB is inherently anisotropic and inhomogeneous but previous modal FEMs of PCBs have assumed isotropic, anisotropic (transversely isotropic and orthotropic) material properties and shown good correlation with test data for specific scenarios [1-3]. This paper details part of a research program aimed at gaining a better understanding of accurately modeling PCB’s dynamic behavior. New investigations into the impact of material anisotropy and, in particular, the effect of material orthogonal plane definition (Ex and Ey) on eigenfrequencies is analysed. A modal FEM of a JEDEC PCB is created, verified, and validated using well established theories by Steinberg and empirical data by others [4, 5]. The relative contributions of Ex, Ey and Ez on PCB eigenfrequencies is examined using a parametric modal FEM, analysing the role of material isotropy verses anisotropy. The impact of transversely isotropic material properties is also analysed for a typical JEDEC PCB. This analysis details the mesh density required for accurately modeling the PCB eigenfrequencies. The results show that a 100 % increase in Ez has only a 0.2 % difference in the eigenfrequency where as a 100 % increase in Ey has a 1.2 % difference in the eigenfrequency. The effect of orthotropic plane definition (alternating Ex with Ey) on the JEDEC PCB amount to a 7.95 % delta in eigenfrequency.

Capacitors with high voltage and capacity values are used in most induction coilguns that are designed and constructed. The fact that capacitors are quite bulky and slow in energy transfer and how a coilgun can be made without using capacitors is the study subject of this article. Two and four coil gun samples were made to find the essential components of an electric gun, and the results are reported in this article. The accuracy of the results is also confirmed by FEMM analysis for these models. The harmony of experimental and theoretical results shows that smaller and low cost portable electrical weapons can be a powerful alternative to firearms in the future.

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