Applied Mechanics and Materials Vols. 101-102

Abstract: A novel algorithm of analyzing the textural features of image is put forward for color difference classify of ceramic tiles. First the image of tile is pretreated. Then two level wavelet decompositions are used on the image, and the energy feature of each sub-graph is extracted. The energy contains color and textural features of image, which be used to classify tiles into different color. Tile under test is classified according to the similarity measurement, which is the similar distance between feature value of tiles under test and the one of standard tiles. Euclid distance is used as similarity algorithm. Experimental results show that this method can reflect spatial relationship of color more effectively, and improves the accuracy of the classification in the production line.

Abstract: In order to obtain higher accuracy and faster calculation speed of hysteresis model of the piezoelectric micro-positional stage, the traditional PI hysteresis model is improved in this paper. First, based on the fact of that the slopes of the first half of the initial loading curve for the piezoelectric micro-positional stage change much while the slopes of the second half change little, the PI hysteresis model of the stage is established by the non-equiinterval threshold value. Then, the established model is identified by optimizing the minimum L²₂-norm of the model errors. The results show that the maximum error and average error of the model are 0.71 μm and 0.23 μm in the displacement range of 22.75 μm, respectively.

Abstract: The present paper deals with the numerical solution of two-dimensional linear hyperbolic equation using the meshless reproducing kernel particle method (RKPM). A variational method is used to obtain the discrete equations and the essential boundary conditions that are enforced by the penalty method. The effectiveness RKPM for two-dimensional hyperbolic problems is investigated by two numerical examples in this paper.

Abstract: There is a problem with non-contact measurement and detection, which reduces its measurement accuracy. Methods developed for measuring and inspecting screw thread characteristic parameters usually using a camera, which is controlled to scan the projection of thread in the parallel optical field to obtain thread images. However, with the block of screw line on the projection of the real thread form, it is impossible to acquire the real thread form from images. The traditional way is adjusting the optical axis to a suitable angle with the thread axis to acquire the real thread form projection, which has some problems, such as time consuming, high skill of operator, high-precision equipment for adjustment, inaccuracy, and so on. Hence, a new method through digital image calibration is presented. The results of relevant simulation indicated the feasibility of this new method, which improves thread measurement and detection accuracy.

Abstract: Flexible laminated membrane coupling is a device which transmits torque by a group or groups of stainless steel sheet. The Relative displacements between the input shaft and the output shaft are absorbed by the flexibility of laminated material. The paper establishes a size transmitting torque mechanical model by analyzing the six-hole laminated membrane in new coupling with joint bearing, and obtains the analytical solution. At the same time, the paper compares the solution with the computed result from the ANSYS finite element method, and finds that the results are coincident in the load carrying capacity of lamination. The paper proves the accuracy of mechanical model and provides a theoretical basis for the design of the new six-hole joint bearing style laminated membrane coupling.

Abstract: There are two necessary qualifications applying the skills of reverse engineering to develop a new product, including detecting device, and information processing and modeling technology. However, it is difficult for small and medium-size enterprises to have both. Therefore, in this research paper a web-based reverse engineering service center is proposed, which effectively connects the businesses using the reverse engineering services and the businesses offering these equipments and technologies to develop products. The services that the reverse engineering service center can apply as well as the relevant key technologies are introduced and illustrated. The approach has been proven as feasible.

Abstract: Mu method is a flutter solution technique based on frequency domain mu-analysis, which directly applies perturbation to dynamic pressure in aeroelastic equation of motion. In a previous study, the dynamic pressure perturbation was modeled as a purely real uncertainty, which could not guarantee the continuity of mu. To improve the continuity of mu, a small amount of complex perturbation is added to the dynamic pressure in addition to the real perturbation. Thus the mu method is improved with this mixed real/complex perturbation. Formulations and algorithm of the improved method are presented and validated with sample test cases. It is demonstrated that the improved mu method is more feasible and conservative than the original mu method due to the mixed perturbation.

Abstract: Product development process modeling (PDPM) is one of the key techniques for product development (PD). The main aim of PDPM is to provide a product design chain (PDC) for PD. To increase the efficiency of PDPM, a project-driven e-design system is proposed in this paper. There are two modules in the system: task decomposition and product design chain construction. Additionally, key techniques for enabling the system are discussed. Finally, an example of steering oil pump design project is studied to demonstrate the system.

Abstract: In conceptual design of mechanical system, selecting an appropriate mechanical drive type that meets design requirements is a critical problem. To tackle it, a novel classification decision approach to drive type selection is presented, which employs LVQ neural network as classifier to recognize a satisfactory drive from a range of drive types. This recognition process includes five stages: (1) capturing linguistic expression values of character factor for typical drives; (2) digitizing linguistic expression values and extracting features of drives; (3) constructing the structure of a LVQ neural network; (4) training this network with the feature data of character factor set; (5) identifying an appropriate drive type according to the input data using the trained neural network. This proposed approach capitalizes on the benefits of LVQ neural network to acquire domain knowledge and implement classification and decision. Hence at some extent the process of conceptual design can be simplified and the rationality of the decision can be greatly improved.

Abstract: In order to express the pitch curve of non-circular gear conveniently in a uniform way, which would lessen the complexity of calculating the tooth profile of non-circular gear, the authors propose a curve fitting method of NURBS curve with the least data points based on the fitting of NURBS curve. This method is used to express the pitch curve of non-circular gear, and the specific solution model and detailed calculation procedure are presented. In addition, a method to select data points inhomogeneously and appropriately using non-uniform factor of selecting points is proposed. Two design examples are introduced to testify the validity of this expression method.