Recent Patents on Mechanical Engineering - Volume 7, Issue 3, 2014

With the advancement of digital signal technology, active noise control technique has gradually received more attention for the low-frequency noise in the vehicle. The active noise control apparatus and method have shortcomings in the theory and algorithm. Both acoustic devices researched on meeting the application requirements and adaptive active noise control algorithms are effective ways to improve the practicability of active noise control technique. The paper reviews various vehicle interior active noise control apparatuses in recent years. It has been found that the vehicle interior active noise control apparatuses can be classified as the extracting signal sources and the control strategy between cancelling signal and feedback signal. From review of the patents presented, it is found that there are many patents covering the active noise control method inside vehicle. However, there is a limitation in controlling speed and precision. Therefore, it is recommended that the development should be focused on the design of the control section of vehicle interior noise, which will improve the sound quality and save the space. Moreover, the cost of the new apparatus will be reduced by introducing intelligent controller.

The windshield wiper is among the main components of the vehicle. The windshield wiper system is composed of three major subsystems: one or more wipers and their arms, transmission assemblies and an electric motor. The paper reviews various patents of the wiper through adopting different structures and devices to attain new functions in recent years. Compared with the new structures, the traditional wiper has a limited wiped area. The function of the windshield wiper has been limited to clean the rain, frost, insects, thin snow, dust and other materials from the windshield, rather than the heavy snow or ice. Besides, it is not capable of adjusting its speed in respond to the change of the weather. Thus, several types of new structures of windshield wipers have been established to optimize these problems, such as the limited wiped area, the cleanup of heavy snow, the simplification of the structure, the reduction of noise, vibration, and harshness (namely NVH), the convenience of replacing the blade and the automatic control of the wiper. The new types of the windshield wiper are more compacted, reliable and especially suitable for use in various types of weather conditions whether they are moderate or severe. Moreover, the cost of the new machine will be reduced by introducing the new devices.

This paper reviews recent advances in the measurement of the contact-lubricant interfacial shear strength registered in patents. The proposed new measuring technology is based on the boundary slippage occurring in the (nominal) Hertzian zone of a cylindrical disc-plate contact in elastic, elastoplastic or fully plastic deformations under different loads. This technology may be useful for measuring the contact-lubricant interfacial shear strength in wide ranges of pressure and temperature. It involves the compound Young’s modulus of elasticity of two contact surfaces or/and the hardness of the softer contact surface. By solving a couple of equations for the contact friction coefficients under different loads, two characteristic parameters for the interfacial shear strength i.e. the interfacial shear strength-pressure proportionality and the extrapolated atmospheric interfacial shear strength can be obtained simultaneously. The interfacial shear strength under different pressures can then be calculated by using these two parameters. This measuring method is new, simple and of low cost. It may overcome some shortcomings in the classical measurement and provide us a new way to measure the contact-lubricant interfacial shear strength.

The paper introduces an advanced lubrication technology registered in patents by using the interfacial adsorption technology. This technology is applied for boundary lubrication occurring in the case of very low lubricating film thickness such as in a micro slider bearing. According to this technology, in the bearing inlet zone, the stationary contact surface is covered with a coating, to which the lubricant adheres significantly more strongly than to the remaining other bearing contact surfaces which are normal with no artificially covered coatings. By applying this technology, the loadcarrying capacity can even be generated between two sliding parallel smooth plane surfaces, where conventional hydrodynamic lubrication theory denies the lubricating effect.

In order to study the performance of 3D printing product, some relevant patents and researches are studied. A simulation approach for the static properties of 3D printing product with clearance bubble is presented. The processing procedure of 3D printing is described and a hierarchical model based on three premises is put forward. Moreover, the static balance model of bubble is proposed and gas equations under different conditions are elaborated. Finally, four simulation experiments are carried out. The compared results show that the properties and lifecycle of 3D printing product can be changed, or even destroyed with the change of external working conditions. The interaction among multi clearance bubbles can lead to more severe damages to the 3D printing product.

The present study describes a theoretical method of force estimation in frequency domain from field vibrations of a piping in a span with lumped masses. In an earlier study by Saha, the configuration of piping with uniform properties in a span without any concentrated mass has been considered. Inverse theory has been the mathematical framework in the study. This paper may be viewed as an extension of the aforementioned work. The modifications are in the basic formulation which includes lumped mass and in the structure of matrix system for the solution. After a recent literature survey, we have found a good number of patents in the area of vibration measurement and reduction. In this context, the works of Zens et al. are one of the latest developments in this field which are quite significant.

This paper presents a meta-heuristics algorithm of particle swarm optimization for solving the emergency resources distribution in disaster relief operations. An optimization mathematical model is established to achieve the objectives of the earliest emergency response time, and the lowest dispatch costs, considering the actual application environment in which the relief resources are consumed by the affected areas continuously and all available selected depots are called upon to transport commodities to the demand point at almost the same time. Furthermore, this proposed model highlights the real meaning of continuous consumption by adding the assumption that subsequent supplement is not allowed. The results of a numerical example indicate that the improved solution based on PSO algorithm is reasonable and feasible. The purpose of this study is to provide an effective approach by addressing recent patents and scholarly articles on the subject of engineering design and modeling.

This work presents the final patent (in a three-part series of patents) in the area of rifle operating group-based recoil reduction. As a realization of the future developments addressed in the author’s prior works, a gas-operated rifle design to reduce the recoil force transmitted to the user during operation is presented here. Like its patented predecessors, the operating group design presented here includes features to reduce the propellant gas moving internal component contributions to recoil force. Unlike its patented predecessors, the motion of the operating group design presented here is initiated by propellant gases only.

An improved response surface method (RSM) for the buckling reliability and sensitivity analysis of stiffened composite panels is presented in this paper. The proposed method can consider the nonlinear trend of limit state function (LSF), and overcome the weakness of classical RSM. A stiffened composite panel under axial compression load is analyzed. The results show that the accuracy and the efficiency of proposed method are both satisfactory. The number of random variables can be greatly reduced according to actual engineering, and uncertainties of geometry and Young's modulus E11 should be top-priority in the buckling reliability analysis of a composite stiffened panel. Recent patents on the reliability analysis of stiffened composite panels and RSMs are also addressed.

In order to improve the performance of a common differential, recent patents on various limited-slip differentials have been addressed. In this paper, another new automatic limited-slip differential is proposed. It could be locked or unlocked automatically according to the vehicle’s travelling condition. This function is realized by adding a set of locking and clutch mechanism to the common cone gear differential. To better understand its structure, the engagements of each component during working, are analyzed. At the same time, the torque distribution is discussed when a wheel slips on the low-µ muddy road. The analytic results show that torque distribution is associated with the ground adhesion condition when the differential’s structure is certain. Moreover, the larger additional torque could not exist even if the locking coefficient increases. The results could provide reference for the future development of limited-slip differential.

This paper aims to investigate the optimization of process parameters of micro holes machining in Electric Discharge Machining (EDM) for Stainless Steel grade 304 (SS 304) on the machining characteristics using the Grey Relational Analysis (GRA) method. Twenty seven experimental runs based on the Orthogonal Array (OA) of Taguchi method have been carried out. The multi-objective optimization of the process parameters such as Material Removal Rate (MRR), Tool Wear Rate (TWR), Diametral Overcut (DOC) and Taper (T) has been performed. The current is identified to be the most influential factor of the MRR, TWR and the T, and the pulse-off time has an impact on DOC. Furthermore, the analysis of variance (ANOVA) is carried out to identify the most significant factor. The experimental results also examined the influence of various process parameters through SEM micrographs. In this article, recent patents have been discussed.