Journal of Engineering and Thermal Sciences
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Dynamic analysis of towing operation with military tracked recovery vehicle
Get PDFThe present work is focused upon development of multi-body dynamic (MBD) models of a military tracked recovery and towed vehicles in Adams Tracked Vehicle (ATV) toolkit, and carrying out the dynamic analysis of towing operation with the vehicles. Towing is one of the important recovery operations for the military recovery vehicle, which is generally carried out on plain terrain conditions. However, it is also desired to tow another vehicle of similar weight class over certain gradients as well. In this regard, it is required to assess the structural rigidity of the tow bar assembly, while negotiating the gradients. The finite element models of the tow bars have been developed in Abaqus/CAE, from which the modal information is extracted. The finite element models of the tow bars have been integrated with the MBD model of the recovery and towed vehicles in ATV through Adams/Flex. The dynamic analyses of towing operation with the existing tow bar assembly, have been carried out over different gradients, based on which required design modifications have been proposed to minimize the relative angular motion between the tow bars while descending the gradient. With an objective of further weight reduction and enhanced gradient climbing capability, suitable recommendations have further been provided to modify the tow bar assembly design. Dynamic simulations were carried out with the modified tow bar assembly design, through which higher gradients could be negotiated with reduced tow bar assembly weight. The above dynamic analyses have provided a base platform for arriving at the standard operating procedure of carrying out the towing operation in practice. The analyses have also established a framework for future design of tow bar assemblies under the influence of a three dimensional vehicle dynamic environment
Fault diagnosis method of gear based on lifting wavelet packet and combined optimization BP neural network
Get PDFAiming at the problem of weak signal signature recognition of gear faults, a gear fault diagnosis method based on lifting wavelet packet and combined optimization BP neural network is proposed. The initial non-sampling prediction and update operators are calculated by Lagrange interpolation subdivision based on the principle of lifting wavelet, and the adaptive redundancy lifting wavelet packet decomposition and reconstruction algorithm is constructed. The network parameters of the number of hidden layers and the quantity of nodes, initial weights and thresholds of BP neural network are optimized by genetic algorithm (GA). The Levenberg-Marquardt (LM) algorithm is used to improve the search space of the network. Through experimental analysis, the results show that the gear fault diagnosis method proposed in this paper not only has high diagnostic accuracy, but also increase efficiency
Hyperparameter optimization for enabling multi-level feature classification in a wind turbine gearbox
Get PDFMajority of the previous research investigations on fault diagnostics in a wind turbine gearbox are limited to binary classification, i.e., either detecting the type of defect or severities of defect. However, wind turbine gearbox consists of multiple speed stages and components, therefore performing the binary classification is not adequate. In the present study, a multi-level classification scheme which is capable of classifying the defects by stage, component, type of defect and severity level is proposed. Experiments are performed and the response is recorded through vibration, acoustic signal and lubrication oil analysis. Later, an integrated multi-variable feature set is achieved by combining the statistical features of the above mentioned individual condition monitoring strategies. Further, the obtained integrated multi-variable feature set is subjected to multi-level classification using various machine learning models and the learning model that best suits for carrying the multi-level classification is investigated. Finally, the hyperparameters of the learning models are optimized by an iterative process of reducing the objective function. It is observed that, optimized support vector machine model has yielded favorable results when compared to other machine learning models with the overall classification accuracy of 82.52 % for the four-level classification
Study on applicability of end corrections of extended inlet and outlet of expansion chamber hydraulic noise suppressor
Get PDFAt present, a study on the end corrections of extended inlets and outlets of expansion chamber gas mufflers is relatively mature. However, such a research for an expansion chamber hydraulic suppressor has not been made yet. A coaxial and a non-coaxial expansion chamber configurations were introduced into hydraulic systems in this paper, and one-dimensional (1D) analytical approach was used to construct mathematical models of these structures and to verify it by experiments. After that, combined with the finite element method (FEM), researches on whether end corrections of the structures are applicable or not were studied
Strength determination of wagon bearing structures made of round pipes at railroad ferry transportation
Get PDFThe article presents the results of strength simulation of the bearing structure of freight wagon bodies made of round pipes during railway ferry transportation. In order to reduce the cost for manufacturing freight wagons, the introduction of round pipes in the supporting structure was proposed. In order to ensure the possibility of transportation of the designed structures of wagons on railway ferries, it was proposed to install on their draw bars an assembly unit for fixing with regard to decks. The value of the dynamic load which acts on the supporting structures of the bodies of the main types of freight wagons transported on the railway ferry was determined and the strength was calculated. It was established that the maximum equivalent stresses are within admissible values. The obtained results will enhance the efficiency of the operation of freight wagons through international transport corridors
Analysis of gearshift processes in an automatic transmission at low vehicle speeds
Get PDFThe increase in the number of speeds in automatic transmissions of vehicles leads to a convergence of gear speeds between adjacent gears. At low vehicle speeds, periodic changes in external driving conditions (for example, hilly or winding sections of roads) can lead to loop shifting between adjacent gears. To simulate this process, a dynamic transmission model is proposed, which can be used in the development of shift control systems and for calibration of the engine and automatic transmission at various operating modes and vehicle conditions
A breeze energy harvesting of vibration caused with a cantilevered piezoelectric beam
Get PDFThe researches of wind energy harvesting have been more and more popular in recent years. In the paper, a vibration energy caused by a breeze is harvested with a cantilevered beam using a piezoelectric patch. When a swaging fan applies a breeze environment, the alternating voltage generates from the piezoelectric patch. Moreover, by designing a full wave rectifier, the alternating voltage from the piezoelectric patch is transformed as a DC voltage. Through some experiments, the amplitude of the alternating voltage is about 2.70 V and its frequency is 2.60 Hz (the first natural frequency of the cantilevered beam). And the gained DC voltage is about 2.45 V and can be made a luminous diode be on. These experimental results indicate that vibration energy caused by the breeze can be harvested with a full wave rectifier
Experimental investigation of photovoltaic module system coupled with solar panel cleaning system
Get PDFSolar energy is a non-conventional source of energy. Solar panels generate electrical output by absorbing solar radiation. The performance of photovoltaic (PV) module often depends on environmental factors like dust, humidity, hail and temperature. Installation elements like altitude, installation site, tilt angle also affects the efficiency of solar energy output. The objective of this research work is to clean the dust deposited on PV panels using the minimum amount of water and energy. To regularly clean the dust, a semi-automatic self-cleaning mechanism has been designed and fabricated, which cleans the deposited dust on the solar panel automatically. Therefore, the process turns out to be reliable and faster and it leads to increased power output of the solar panels. An experimental investigation has been done at Bennett University, Greater Noida dated 15 October to 21st October 2019. An increase in efficiency by 1.2 % to 3 % was reported in this experimental study
Measurement of damping properties of beeswax and cosmetic wax using Oberst beam method
Get PDFDamping treatment is a standard practice in many industries for controlling excessive vibration at resonance. Different damping materials are available for various engineering applications. Wax is one of them, and it’s mostly used in musical instruments. There are two types of wax are available namely beeswax (natural wax) and cosmetic wax. The aim of the present study is to measure damping properties of these two types of wax using Oberst Beam Method (OBM). The effects of damping material’s thickness and bare sample on damping loss factor are studied
Design and real time implementation of nonlinear sliding surface with the application of super-twisting algorithm in nonlinear sliding mode control for twin rotor MIMO system
Get PDFThis paper proposes the design of a nonlinear sliding surface based on the principle of variable damping concept for 2-degree of freedom Twin Rotor Multiple input Multiple output System (2-dof TRMS). The implementation of the designed nonlinear sliding surface in real time is demonstrated. Super-twisting algorithm is applied in nonlinear sliding mode control. The nonlinear sliding surface enables the system trajectory to be highly robust and with the application of super-twisting algorithm in nonlinear sliding mode controller (SMC), the designed controller has minimized the problem of chattering considerably. The system is modeled in such a way that it includes all nonlinearities and coupling effects. A decoupler is designed to nullify the coupling effect. This scheme is capable of reducing both the settling time and peak overshoot simultaneously for 2-dof TRMS. The scheme also reduces the chattering. The proposed method is compared with the design using PID controller. The applicability of the designed nonlinear sliding surface and nonlinear SMC with super-twisting algorithm have been tested both in simulation and in real time. This research paper is mainly dealing with the modeling of Twin rotor MIMO system by including all nonlinearities and coupling effects, the decoupler design for 2-dof TRMS, the design of nonlinear sliding surface for 2-dof TRMS and application of super-twisting algorithm in nonlinear sliding mode control for 2-dof TRMS