Applied Mechanics and Materials Vols. 148-149

Abstract: The prediction of flatness is researched based on the simulation of virtual NC manufacture process. In this paper, a new interpolation-regression model is proposed, which is based on the simulation method of the finite element analysis and depends on MATLAB to realize the calculated algorithm of flatness error. In the model, on the premise of that the workpiece is completed the simulation, the information of numerous discrete points is acquired from the virtual workpiece. A new surface which is much closer to the workpiece morphology is generated by interpolation theory with statistics toolbox of MATLAB. The assessed datum of flatness is concluded by the theory of the multivariate linear regression. Synthesizing the original points and the created datum, the work calculates the flatness error and develops the flatness predicted system of virtual workpiece. The system can realize the vivid man-computer interaction in MATLAB.

Abstract: A robust trajectory control problem for an underactuated AUV with parameter uncertainties and external disturbances was considered. The trajectory control was decomposed in the horizontal plane and vertical plane. Based on the robust theory, the AUV model for heading control was proposed, and the heading controller was designed. The simulated results show that the method can effectively overcome disturbances of constant ocean currents to ensure the precision track.

Abstract: Wind power is an important direction of new energy, which has no pollution, no consuming fossil fuels, and no producing waste, which is widely used at this stage of clean energy. The small stand alone wind power has been paid more and more attention due to its low cost, flexible installation, strong adaptability. This paper introduces the mechanical and electrical structure, which are used in KW level stand alone mode wind turbine automatically track and yaw system. The motion rules and control strategies of the tracking and yaw system are discussed and then the control program flow is provided. The PIC16F873 chip is used as controller for this part in this system. It can fully meet the design requirements, which will reduce costs and increase the system's control ability. This system can automatically track and yaw, according to the wind direction and wind power.

Abstract: This paper introduces a solar powered automatic controlled advertising light box system functioning box rotation and poster cycling displaying of each panel, which overcomes the disadvantages of ordinary advertising light boxes of humdrum displaying and high energy consumption. The system includes three parts which are box rotation system, poster scrolling system and single-axis sun tracking system which can improve the solar energy efficiency and reduce energy consumption. Sun tracking system which effectively combined the sun angle tracking and photoelectric tracking method can automatically switch between the work mode and hibernate mode according to time and weather condition so as to maximize energy efficiency. A hierarchical control strategy which contained main control system and sun tracking system is adopted to control light box rotation, panel displaying and sun tracking at the same time. The solar advertising light box system was verified by tests that with the hierarchical control strategy the power generated by solar panel increased 38.2% than fixed panel. Experiment results show that the light box works stably and has potential to apply under the situations where cable laying is not convenient.

Abstract: Wireless Sensor Network is receiving more widely appreciate because of its great prospect. But a variety of sensors need a unified mobility management platform. This paper considers this problem, proposes and implements a wireless sensor management platform which can control a variety of sensors and transfer the collected data by using wireless technology. Then a testing wireless network is built to test the performance of this mobile platform. The test result proves that this platform has the ability of manage sensors, and has the advantages of mobility and portability.

Abstract: Using a biometric as an identity has the advantage that identities are unique if the underlying biometric is of a good quality, such as fingerprints, faces, irises. Since biometric measurements are noisy, the existing identity-based encryption systems cannot be used directly to construct IBE scheme. The error-tolerance property of Fuzzy-IBE allows for a private key to decrypt a ciphertext encrypted with a slightly different measurement of the same biometric. Based on this property, a new biometric identity based encryption scheme is proposed. Our scheme is constructed in the standard model and achieves a selective identity security. In addition, the security of our scheme is reduced to decision bilinear Diffie-Hellman(BDH) assumption instead of other strong assumptions.

Abstract: Due to extremely low thermal conductivity, high modulus, high toughness, light weight and non-combustible property, ultrafine glass wool can be widely used as glass fiber reinforcements in composites, thermal insulation materials, acoustic insulation materials, engineering materials, construction, infrastructure and environmental protection projects and so on. In particular, as a insulation material, glass wool exhibits unique advantages. The predominant process of glass wool is centrifugal blowing process. This paper describes a study of the relationship between the diameter of ultrafine glass fiber and thermal conductivity. The thermal conductivity of ultrafine glass wool decreases with the decrease of average diameter.

Abstract: In this paper, a static pressure calibration device is designed and the method of static calibration with piezoelectric pressure sensors is discussed. According to the theory of PASCAL law, the static calibration device is developed, whose stress ratio is up to 1:25. And this device has been accredited by the authorities. To ensure the consistency of pressure calibration, the improvements on calibration device’s output are made. As a result, we can calibrate up to four sensors at the same time. By means of the pressure calibration device, the calibration method of pressure sensor, the calibration theory, system components and calibration procedures is given. As the test results shown, the corresponding sensors’ static calibration linearity is 0.05%, and its uncertainty is 0.42%. It’s practicable and reliable to make static calibration to sensors by the pressure calibration device.

Abstract: Crane load spectrum is the basis data of the evaluation of fatigue life, obtaining the large samples data need to consume large amount of time and finance. For exploring and initiating a new way of obtaining and predicting the crane load spectrum, the present essay uses Support Vector Machines (SVM) to establish the non-linear mapping relation between this type of crane's work cycles and different rated weights and lifting loads, namely equivalent load spectrum of crane. The Engineering example demonstrates: it is feasible to construct the equivalent load spectrum for some type of crane using SVM. Meanwhile, the equivalent load spectrums of the typical or future crane in this type could be obtained and predicted through the trained SVM model. It has provided the reliable data for the reliability analysis and fatigue life prediction of crane.

Abstract: The influence of hot-pressing parameters on formaldehyde and other volatile organic compounds (VOC) were studied in this paper. The particleboard of larix gmelinii and UF resin were used as main raw materials. Orthogonal design was adopted to analyze the influence of hot-pressing temperature, time, resin and density on the concentration of formaldehyde and other VOC. The results showed that the emission of formaldehyde and other VOC were significantly affected by hot-pressing temperature, time, resin and density. The emission of formaldehyde and other VOC were obviously decreased in usage with the increasing of hot-pressing temperature, press time and the decreasing of density. Taking formaldehyde and other VOC emission into account, the optimized condition was hot-pressing temperature of 180°C, press time of 5 min, resin content of 11%, board density of 0.6g/cm³. The emissions of optimized particleboard satisfied the national standard GB18580-2001.