Key Engineering Materials Vol. 455

Abstract: The application of ultrasonic polishing and machining pulse electrochemical machining compound finishing is presented in the paper. The machining principle and experimental set-up of UPM-PECM compound finishing are introduced in the paper, discussing mechanism and model of the UPM-PECM in theory, and carrying on the experiment, which would co-act on hard-brittle metals in the machining. Furthermore, the material removal depth of UPM-PECM compound finishing is approximately proportional to the polishing time, and would decrease with the polishing time. This study indicates that machining velocity, machining accuracy and surface quality can be improved under UPM-PECM.

Abstract: The Large-grit bronze-bonded diamond grinding wheel was shaped employing a diamond dresser with elliptic ultrasonic vibration assistance, to solve problems such as high cost, low dressing speed and low accuracy. And the truing and conditioning performance of this new method was discussed for its effectiveness. Experimental results showed that the roundness error of elliptic vibration dressed diamond grinding wheel is less, and the bond tail was cut shorter and the chip capacity became larger than that of mechanical dressed one. The SEM observation showed for the present dressing method the material removal mechanism is ductile removal of bond material and micro breakup of gains and this method can perform truing of large-grit diamond grinding wheel as well as conditioning in one step.

Abstract: The process of Collaborative Product Development (CPD) comprises highly creative and knowledge-intensive tasks that involve extensive information exchange and communication among distributed teams. Traditional information management systems fail to provide adequate capability to support CPD, due to their inflexible data structures and hard-wired usage procedures, as well as their restricted ability to integrate process and product information. An ontology-based method of knowledge management is proposed to support CPD. The key idea hiding in the method is a flexible ontology-based schema with formally defined semantics that enables the capture and reuse of design knowledge. A part of CPD-oriented ontology library represented by UML is displayed.

Abstract: Hydraulic engine mounts (HEMs) are important vibration isolation parts in vehicle powertrain mounting systems, and the structural parameters of HEMs are the main factors which determine their vibration isolation characteristics. It is of great significance to discover the influences of the structure parameters on their vibration isolation characteristics in the design and study of HEMs. Firstly, the vibration isolation characteristics of HEMs are analyzed theoretically using a simplified lumped parameter (LP) model. Secondly, the HEMs with different rubber materials, lengths and cross-sectional areas of the inertia tracks are designed and manufactured, and their frequency response characteristics are investigated by experimental and analytical methods. Finally, the influences of these structural parameters on the vibration isolation characteristics of HEMs are educed. The analytical methods and conclusions are instructive for the design and tuning of the vibration isolation characteristics of HEMs.

Abstract: Based on linear three-dimensional piezoelasticity, an orthogonal polynomial approach is used for determining the elastic wave characteristics of piezoelectric spherical curved plates. The displacement components and electric potential, expanded in a series of Legendre polynomials, are introduced into the governing equations along with position-dependent material constants so that the solution of the wave equation is reduced to an eigenvalue problem. Guided wave dispersion curves for PZT-4 spherical curved plates are calculated. Corresponding mechanical displacement and electric potential distributions are illustrated. The influence of the ratio of radius to thickness on the wave characteristics is discussed.

Abstract: This paper is concerned with a synchronous control problem of distributed systems with wired and wireless hybrid communication network. A discrete tracking error mathematical model is established based on prediction model and non-memory state feedback controller. A sufficient condition for asymptotic stability of state tracking error between the master system and slave system is presented by constructing Lyapunov function, and a linear matrix inequality (LMI) approach has been employed to obtain the tracking controller gain matrix.

Abstract: In this paper, the edge quality of the nano-ZrO2 ceramics surface grinding was studied on experiments. Through the microscopic observation and measurement on the edge micro-step，and the white interference detection on the 3D surface profile of both sides of the edges, the edge quality traits are obtained，which lay a foundation for further study on the technology of the edge quality controlling and hard brittle material surface integrity evaluation.

Abstract: The brittleness, plasticity, super-plasticity and the removal mechanisms of critical fragmentation of the nano ZrO2 ceramics were investigated. The formula of critical ductile grinding depth of the common engineering ceramics was inapplicable to the nano-ZrO2 ceramics. A new formula of critical ductile grinding depth of the nano ceramics was established. The ultrasonic vibration grinding experiments showed that the critical ductile grinding depth of the ceramics was 15μm by conventional grinding, but the increment of the critical ductile grinding depth was 60 percent by ultrasonic grinding. The critical ductile grinding depth increased to 25μm. Analyzed by means of SEM, it was transgranular cracking during its cracking process. The nano-ZrO2 ceramics have high toughness so the critical ductile grinding depth increased. The shape, length, width and thickness of the grindings differed greatly from which obtained by conventional grinding.

Abstract: Laser tracker has widely been used in manufacturing industries, such as the industry of the large-scale machining tool, automobile, aircraft. So a high precision laser tracker is essential to satisfy the measuring requirements. In the paper the errors of laser tracker was analyzed and their calibration methods were discussed and studied. Then a calibration for laser tracker was carried on by using CMM and the measuring accuracy was verified. Finally, we demonstrate the application of laser tracker for detecting the large-scale machining tools. The measurement shows that the feeding straightnesses of tool rest in the two orthogonal directions are 0.0564 mm and 0.0309 mm in the working scope respectively. The results show the straightness of the body guide for the lathe meets the requirement, whereas the lathe tool workbench on the X axis direction does not and needs to be adjusted.

Abstract: Butterfly pivot is a large-travel rotational flexure pivot, which can provide elastic support for the rotational shaft in several ten degrees. Because of the complex structure, stiffness calculation of butterfly pivot is always completed by the method of Finite Element Analysis (FEA), which is not suitable for parameter design and optimization. The serial structure of four-blade isosceles-trapezoid (FBIT)is proposed to simplified the complex structure of the butterfly pivot. The FBIT is analyzed and the theoretical formula of stiffness calculation for rotation stiffness is derived in detail based on the essential theory of Mechanics of Materials. Design and optimization of rotation stiffness for each element can be achieved easily with the obtained the theoretical formula of rotation stiffness. The total rotation stiffness of the whole butterfly pivot is calculated and the rotation stiffness comparison between using the theoretical method and by the method of FEA is performed. The error between the theoretical rotation stiffness and the result of the FEA is less than 10%. It is acceptable and without any influence on the validity of the work and concept presented in this paper.