Applied Mechanics and Materials Vols. 26-28

Abstract: In CNC machining, the constant following error was caused by the uniform motion of feed drive, which could induced contour error in the multi-axis movement, and the contour error would affect machining accuracy. In this paper, the produce principle of following error is analyzed, as well as the influences of following error on contour of linear and circular interpolation. The following error was compensated by velocity feedforward controller, and a new method for identifying coefficient of velocity feedforward controller is presented, based on the actual observed values of following error. The following error was eliminated after compensating with the proposed method.

Abstract: The risk model with interclaim-dependent claim sizes is studied in the presence of a linear dividend barrier and stochastic interest. An integro-differential equation for some Gerber-Shiu discounted penalty functions is derived. We show that its solution can be expressed as the solution to the Gerber-Shiu discounted penalty function in the same risk model with the absence of a barrier and a combination of two linearly independent solutions to the associated homogeneous integro-differential equation.

Abstract: Calculating stress intensity factor is an important task of fracture mechanics, specially in the thick walled cylinder with inner pressure, which has macro crack. The value of KІ is crucial for safety life. The software ANSYS was used to calculate the stress intensity factors of the walled cylinder in this paper. Crack along the axis in the inner face of the tube can be predigested a long plate with a center crack. According to the symmetry of this model, the calculated model was built. The results show that the relative error is under 5% and the method is available to satisfy the precision engineering requirements. In addition, the error and how to reduce it were analyzed.

Abstract: A new design method for fire protection, based on analytic hierarchy process (AHP), was put forward, to explore an economic and secure strategy for fire protection of steel staggered-truss structure (SSTS). The chords and web members of SSTS were classified into different important grades by AHP according to the influence which components make on the stability of structure at elevated temperature. And the components are protected by different levels based on the important grades. Furthermore, a comparative investigation was conducted in order to appraise the economic and practical performance of the provided new fire protection method with traditional fire protection. The results indicate that the proposed fire protection strategy for SSTS based on AHP could achieve higher security with the same volume of fire retardant coatings.

Abstract: Aiming at the situation that feature extraction of image defects is slow, the accuracy is not high, this paper proposes a new super-fuzzy defect classifier based on self-adaptation, in which defect classification can be judged and determined intelligently according to different image windows feature. Firstly, a specific model of adaptive super-fuzzy classifier is given. Then, this algorithm is applied to defect recognition of fabric image for algorithm effect checking. Results show that this adaptive super-fuzzy classifier has some characteristics, such as high speed, simple calculation, no membership degree calculation, and the accuracy and threshold of defect classification can be made intelligent estimation according to different cases with this classifier.

Abstract: In this paper, powder spreading property in Wood-Plastic Composite(WPC) Selective Laser Sintering(SLS) rapid prototyping(RP) process is studied. WPC is more suitable for make parts by SLS according to its advantages, such as low-cost and green biological etc.. But as wood power is mainly composed of wood fiber and wood fibers have irregular shapes, easy to aggregate and block power spreading process, spreading powder uniformly on bed by leveling roller is difficult, resulting in bad shape quality of parts. In order to further improve powder spreading property of RP process, with optimal design of components, viscosity reducer calcium is added into WPC. Finally, as result of better powder spreading property, shape quality of the parts made by WPC is improved greatly and have good as well as with good laser sintering properties.

Abstract: This paper presents a modified Ant Colony Algorithm(ACA) called route-update ant colony algorithm(RUACA). The research attention is focused on improving the computational efficiency in the TSP problem. A new impact factor is introduced and proved to be effective for reducing the convergence time in the RUACA performance. In order to assess the RUACA performance, a simply supported data set of cities, which was taken as the source data in previous research using traditional ACA and genetic algorithm(GA), is chosen as a benchmark case study. Comparing with the ACA and GA results, it is shown that the presented RUACA has successfully solved the TSP problem. The results of the proposed algorithm are found to be satisfactory.

Abstract: With the global financial crisis happened, companies and investors pay more attention to development expense. Development costs mainly include design cost at the design stage. We analyze the design process and extract many design factors in order to estimate design cost at the conceptual and embodiment design stage. A number of process-based design features that impact the design cost are considered. These design factors include: 1) the number of performances and constraints, 2) sub-functions level and relationships, and 3) solutions at the conceptual design stage. At the embodiment of the design stage the design factors include: 1) the number of parts and their relationships, 2) the types of materials, 3) load resources, and 4) the number and types of tolerances. We use relative cost to estimate design cost by comparing the number of design factors among designs. To demonstrate the relative design cost estimation in practice, Kodak single-use cameras are used as example products. Use of these methods proves beneficial in estimate design cost in the design process.

Abstract: Photoelectrochemical (PEC) degradation of Procion Red MX-5B was investigated in aqueous Na2SO4 solution. Higher electrolyte concentration resulted in higher current between the electrodes due to increased conductivities of the solutions. UV irradiation could obviously raise the current, and the differences became larger in accordance with the increase of the applied potentials. The pH declined in the first 30 minutes and became constant for the prolonged reaction time during both PEC degradation and photocatalytic oxidation. The applied potential could only slightly improve dye decolorization. Although a potential of 8 V was applied to 0.3 mol/l Na2SO4 solution, TOC removal efficiency of PEC degradation was almost as the same as that of photocatalytic oxidation.

Abstract: In order to solve the typical soldering defects in lead-free wave soldering, the Design of Experiment(DOE) was conducted to optimize the process parameters. Based on the printed circuit board(PCB) experimental results, the method of Analytic Hierarchy Process(AHP) was employed to analyze the experiment results quantitatively. Then the influential weights of each factor in different levels were obtained. It is concluded that the influential sequences of the four main process parameters in lead-free wave soldering are track speed, flux quantity, soldering temperature and preheat temperature; the optimal process parameters are as follows: flux quantity 40mL•min-1, preheat temperature 110°C, track speed 1.6m•min-1, soldering temperature 265°C. Furthermore, the reasons of solder bridging and missing weld defects were discussed systematically according to the analysis results. This paper reveals the key direction to optimize the process parameters and provides an effective measure to improve the soldering quality in lead-free wave soldering.