Applied Mechanics and Materials Vol. 418

Abstract: In this paper, compression behavior and energy absorption of aluminum alloy AA7005 tubes in T6 with and without holes are investigated numerically. True stress-plastic strain curves from the tensile test are used in the static simulation of AA7005 tubes. The deformed modes from the numerical simulation are compared between tube with and without holes. Energy absorption values and peak loads with and without holes are compared to develop the understanding on the size of hole to be used in tube for energy absorption control.

Abstract: According to the measured gas content in power transformers, we use BP neural network to accomplish the pattern recognition of transformer fault. The recognition effect of BP network pattern was studied from the aspects of adding over-fitting operation and genetic algorithm. Four kinds of neural network models, BP model BP & over-fitted identification model GABP model and GABP & over-fitted identification model, were constructed respectively, making the pattern recognition effect further enhanced.

Abstract: In the previous study on PPS race-PTFE retainer Hybrid polymer bearings, the relationship between thrust load, rotation speeds and wear loss under dry condition was investigated. It was found that the wear loss obviously changed under the thrust load ranging from 400N to 500N at the rotation speeds of 450rpm and 600rpm. The object of this study is to observe the friction coefficient at the rotation speeds ranging from 450rpm and 600N under thrust load of 400N. Rolling contact fatigue tests were performed and it was concluded that friction coefficient decreases with the rotation speeds.

Abstract: Studies of strain gradient plasticity theory have achieved considerable achievements in recent years. However, the combination of the mechanisms of the pressure-sensitive yielding and the size dependence of plastic deformation still remains an open challenge, especially in the relevant numerical simulation. In this paper, the finite-element formulation based on the flow theory of MSG plasticity for pressure-sensitive materials is set up. The elastic indentation response of the single crystal copper is computed using a user-defined eight-node isoparametric element through the USER-ELEMENT interface supported by the commercial software ABAQUS. The results of the numerical simulation show that the indenter load and the hardness have been slightly enhanced when the strain gradient is taken into account, compared to the results obtained from the CAX8R element.

Abstract: As needed by Taiwan industry upgrade, international competitiveness became a mutual goal for domestic traditional industries. Therefore, TPM equipment management strategy drew much attention from domestic industry. However, the current TPM promoters are mainly large scale industry since the introduction will put a huge amount of manpower and resources. Hence the study aimed to explore how to modify or reconstruct the proper models and procedures of TPM introduction to meet the needs of traditional industries. With this model, it is hoped that it could be used as a reference for proprietors in the process of implementing TPM, thus to reduce their exploration costs. It is also hoped that the study gains can be smoothly implemented in TPM activities in Taiwan traditional industries, thus enhance domestic competitiveness of traditional industries.

Abstract: In order to improve the smoothness of electronic cam motion,an electronic cam trajectory generation algorithm based on global optimal control points of quintic non-uniform B-spline is prop-osed. This algorithm solves the problem of non-global optimization in existing approaches caused by transferring kinematic constraints into control point constraints to avoid the semi-infinite constraints problem. The interval ranges of the reserved free control point variables are calculated first, followed by partitioning and checking the subinterval with the property of the objective function and kinemat-ical constraints repeatedly until finding the global optimal control point. Compared with the existing control point constraints algorithm, the object function is optimized further and the electronic cam trajectory is smoother. Finally an practical example of electronic cam proves the effectiveness of the proposed algorithm.

Abstract: This paper aims at finding the optimal parameters of the servo drivers and controller for a machine tool in order to improve machining accuracy and reduce machining time. Firstly, the backlash and pitch error of a transmission device were compensated by means of the controller. The control factors of the drivers include the ratio of load inertia moment to servo motor, speed loop gain, and integral time constant of the speed loop. The control factors of the controller are the acceleration/deceleration constant of feed rate and position loop gain. Each factor was classified into three levels and each experiment was repeated three times. The experimental data were converted into the signal-to-noise (SN) ratio to obtain the response tables of the SN ratio. Finally, the grey relational method was applied to find the optimal parameters. We compared the difference of the experimental results by employing the optimal parameters and default values of the drivers and controller of the CNC machine tool. Experimental results show that machining accuracy and machining time can be improved. Therefore, the results demonstrate the effectiveness of the proposed scheme.

Abstract: MTConnect is a technical standard recently proposed to facilitate the organized retrieval of process information mainly from numerically controlled machine tools. In this paper, core components such as agent, client, adapter etc are overviewed. Considering the difference in manufacturing devices openness and capabilities, different application schemes of agent and adapter are designed according to MTConnect protocol. Agent is designed for data acquisition in different situations and different ways to use Adapters are mainly discussed. Finally, the client, a software function in the application is developed by using C#. And the application is applied to a NC machine tool. In terms of data request, collecting, transmission and detection from a working NC machine tool, the proposed architecture in this paper is verified successfully.

Abstract: A detailed study on the calculating of planar mechanism degree of freedom-including gear pair was carried out in detail. By the analysis of the basis concept of constraint, the constraint type of bogus higher pair was introduced. Based on the constraint type, the classical Grübler-Kutzbach formula of planar mechanism degree of freedom is beyond doubt. In addition, the correct-ness and practicality the method for the calculation of the freedom of planer mechanism was proved. It is believed that the work will provided instructive guidance for the calculating of planar mecha-nism degree of freedom and design of planar gear-link mechanism.

Abstract: Two-step growth method was used for CuInGaSe₂,(CIGS) absorption layer in this study. The layer was first deposited by thermal evaporator to use indium and gallium sauces at a vacuum of 5 × 10^-6 torr and secondly, the deposited thin film was enclosed in a quartz cartridge for the first selenization. The second selenization process was coated by copper and then annealed again in a furnace. Finding best precursor for thin film solar cells was analyzed by scanning electron microscope (SEM), X-ray diffraction analyzer (XRD) and energy dispersive spectrometer (EDS).