Applied Mechanics and Materials Vols. 813-814

Abstract: The study of the dynamic behavior of annular plates with circumferential cracks can find many applications in several machine components such as flywheels, clutch plates, compact discs etc. A crack on a structural member introduces a local increase of flexibility in that region then; this affects the static and dynamic characteristics. The effects of cracks on the dynamic characteristics of structures, especially on the natural frequencies and modes, were extensively studied. In this study, the natural frequencies of annular plates with circumferential cracks are investigated by using finite element method. The cracks were non-propagating and open. The annular plate with different cracks was subjected to different boundary conditions and final variation in the natural frequency was obtained, which was compared with the theoretical frequency and the change in the natural frequency was studied. The results of this study with improved elements are compared with the theoretical results in the literature. It is observed that the location and the number of cracks have various effects on the natural frequencies related to the vibration modes.

Abstract: The wheel of a vehicle plays a vital role to bear the load applies on it. Generally spokes acts as the supports between the wheel rim and hub. These spokes must have sufficient strength and stiffness to avoid the failure of the wheel. In present days these wheels are made up of aluminum alloy, magnesium alloy and steel. To reduce the weight of the wheel many wheel designs are implemented and applied for different vehicles. In this paper three different wheel designs are chosen, those are inclined spokes, curved spokes and Y shaped spokes made up of Al alloy, Mg alloy and Steel. Static structural analysis subjected to pressure on the wheel rim and free vibrational analyses are performed by using finite element analysis tool Ansys 12. The objective of the present work is to observe the best design which contains higher structural stiffness, specific structural stiffness with lower von mises stresses under static load conditions. It is observed that curve shaped spoke designs are better in for manufacturing of wheel in both static and dynamic point of view.

Abstract: This paper presents the theoretical study and analyzes the comparison of porous structures on the performance of a couple stress fluid based on rough slider bearing. The globular sphere model of Kozeny-Carman and Irmay’s capillary fissures model have been subjected to investigations. A more general form of surface roughness is mathematically modeled by a stochastic random variable with non-zero mean, variance and skewness. The stochastically averaged Reynolds type equation has been solved under suitable boundary conditions to obtain the pressure distribution in turn which gives the expression for the load carrying capacity, frictional force and coefficient of friction. The results are illustrated by graphical representations which show that the introduction of combined porous structure with couple stress fluid results in an enhanced load carrying capacity more in the case of Kozeny-Carman model as compared to Irmay’s model.

Abstract: The aim of this project is to fabricate an economical walking aid for Paralytic patients caused due to a stroke. The Paralysis caused due to stroke is referred as Hemiplegia or Hemiparesis. In general these patients walk with the assistance of another person. The patient first moves his unaffected leg as the assistant holds him firmly to give him support. Then the assistant pushes the impaired leg of the patient with his own leg while supporting him with his hands. In this way walking is achieved for the hemiplegic patient. To eliminate human assistance, the patient can also use a wheel chair to move from one place to another, especially the Autonomous Robotic Wheelchairs (ARW) that are being used these days. However, in order to gain back his motor capabilities, he should promote the use of hemi paretic limb during functional tasks. Active participation is critical to the motor learning and recovery. So designing a mechanism which enables movements on paralyzed body is crucial for functioning of other parts of the body as this prevents blood stagnation due to continuous rest given to specific parts. A DC motor along with some pulleys are used for actuating the leg and a telescopic tripod wheeled balancing support is used for providing counter-torque that helps the person from falling down on paralyzed side.

Abstract: Gearbox plays a vital role in various fields in the industries. Failure of any component in the gearbox will lead to machine downtime. Vibration monitoring is the technique used for condition based maintenance of gearbox. This paper discusses the use of machine learning techniques for automating the fault diagnosis of automobile gearbox. Our experimental study monitors the vibration signals of actual automobile gearbox with simulated fault conditions in the gear and bearing. Statistical features are extracted and classified for identifying the faults using decision tree and Naïve bayes technique. Comparison of the techniques for determining the classification accuracy is discussed.

Abstract: Braking system is important in any automobile. It is essential to decelerate the vehicle and stop it. Friction braking system is widely used system of braking. It makes use of frictional force to safely retard the vehicle. The temperature of the brake pad (stator) and disc (rotor) increases because of frictional force between them. Higher temperatures may lead to fading of brakes resulting in its failure. This paper briefly reviews published works on studying the wear and thermal characteristics of brake pads and on various available brake cooling methods. The microstructural changes in the brake pads are analyzed and reason for enhanced wear at higher temperatures is traced out. The various test results obtained using microscope (SEM), Friction assessment screening tests (FAST), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) are described in brief. A description of the available methods of enhancing the brake cooling and decreasing the wear rate is discussed. This work will be useful in planning further research in this important area of automotive field.

Abstract: The perception of Tolerance Analysis (TA)/Tolerance Stackup is imperative for every Design and Manufacturing Engineer because Tolerance is the criterion that should be compromised between the cost and function of a product. The literatures relevant to 15 methods of TA which are being used to determine Assembly Tolerance from Component Tolerances are collected and critically analyzed to gain an insight into the existing methods. Out of these methods, four major methods viz., Simulation Based Stack-Up Analysis, Second Order Tolerance Analysis, OpTol - Spatial Tolerance Analysis and Tolerance Analysis of 2D and 3D Assemblies are chosen for further study and comparative analysis. Based on the analysis and based on the identified merits and demerits of these methods, a framework for a new TA Method is developed. Based on the developed framework, a new TA Method using Artificial Neural Network (ANN) is developed and trained which can predict the value of Assembly Tolerance for the known Component Tolerances.

Abstract: Literature reported extensive work on the failure of Industrial power transmission systems, during their routine torque transmission, rotary motion etc. During transmission through gear drive the noise, temperature, stresses, vibration etc are important factors to be considered. When one or more of above exceed certain design limits, the drive and its accessories must be examined for the cause and a preventive maintenance is to be followed. The latest research work carried out, in above area is reviewed. The cause of failure and failure analysis is examined. An attempt is made in this paper, to systematically analyze the modes of failures, the reasons for the same, issues and challenges involved, there in, and measures to be taken for addressing them. This analysis is likely to help the researchers to proceed further in analyzing the failure and to suggest means to prevent failure of gear power transmission systems. The major contribution of present work is, to present the common modes of failure of gear teeth in power transmission systems, and measures to be taken to address the same. In general various additives in the lubricating oil help in controlling initiation of pitting. The present work involves controlling one of the additives namely sulphur in the lubricating oil to control pitting. The present work forms an excellent basis for identifying various other parameters affecting the pitting failure of gear teeth in a gear box.

Abstract: Over the years, designers have been developing various brake pedals in a bid to eliminate the operator’s risk of pressing the wrong pedal and to reduce his or her braking reaction time. One of the effective methods for reducing weight of trucks brake pedal is to change the design structure of it. The brake pedal is designed and analysed using Ansys 14.0. Different materials are used for the effective design of brake pedal with weight reduction of pedal and improved grip between foot and the pedal. The FEA results obtained and discussed herein confer optimum, cost effective design solution, easy to manufacture, and exhibits better grip.

Abstract: Modern industrial robots are designed according to the principal design rules to construct light and stiff. When the controllers are used in industrial robots, the problem arises due to the repetitive motion and technical aspects of the controller. In this work, we proposed an alternative electronics controller design for the robotic arm in order to withstand various load conditions. The PIC controller is used to control the robot motion and to reduce time delay of motion and to analyze the performance of the prototype on various load conditions. In this paper, a robotic arm that serves as a tool to lift an object from one place to another where it can be widely used in factory is developed. The main focus of this work is to design, develop and to implement robot arm with enhanced control with stumpy cost. The proposed system is actuated by 3 DC motors and the motion of the robot arm is controlled by PIC micro controller. The robot arm is designed with two degree of freedom and talented to accomplish accurately simple tasks, such as light material handling, which will be integrated into a mobile platform that serves as an assistant for industrial work force. The designed arm lifts up to 2 kg object.