Applied Mechanics and Materials Vols. 457-458

Abstract: Mode is the natural vibration characteristics of the mechanical structure. Each mode has the specific natural frequency, damping ratio and modal shape. These modal parameters can be obtained by the calculation and experimental analysis. A calculation or test analysis process is called modal analysis. The analysis process is achieved if calculated by the finite element method, is called the analysis of calculating mode. The spindle mode of driving roll was analyzed in this paper. If clear structure in one easy frequency affected range of each order main modal characteristics through modal analysis method, it can predict the vibration response of this band structure of external or internal variety under the action of vibration. Therefore, the modal analysis is an important method for fault diagnosis of structure dynamic design. Comparing theory results with finite element results indicated that the error was less than 10 percent. The accuracy on the shaft modal analysis finite element method was improved.

Abstract: With two upper and nether piezoelectric vibrators to provide excitation in the same time, vertical double driven piezoelectric feeder (vertical double driven feeder for short in the paper) has smaller piezoelectric ceramics (PZT), and lower driving voltage to prolong the lifetime of the PZT, meanwhile, its carrying capacity gets stronger, compared with vertical single driven piezoelectric feeder (vertical single driven feeder for short in the paper). Vibration analysis was carried out on the feeder system, and the affection factors on the system natural frequency and feeder tray amplitude were received. Based on the modal analysis, the system theoretical resonant frequency was got as 135.95Hz. In the end, the prototype was tested to analyze the relationships among the feeding speed, feeder tray amplitude, driving voltage and driving frequency.

Abstract: This paper introduces a set of new design for the tandem wing airship, which the angular position between the front wing and tail wing are at 0o and 45o. Through the Wind Tunnel Platform test on the scaled models, lift-drag force for each configuration at different speed and mooring point was obtained and the aerodynamic performance and stability properties were analyzed. The results indicate that the tandem wing models have considerable higher aerodynamic characteristic and maintain a better stabilizability. The effect on longitudinal and yaw moment are relating to the mooring point, angle and position of the tandem wing. Result of this study could provide a new approach in designing an efficient tandem wing airship.

Abstract: Over these years, that many real estate developers, business organizations and other companies all start to invest the development of the commercial real estate becomes the hot topic and also receives enormous attention. However, the exploitation of the commercial real estate has high risk in our country because of the complexity of operation and the blindness of investment. This article applied ISM theory to analyze the investment risk of the commercial real estate among operation stages to build the ISM model of the commercial real estate risk, and proposed some measures and recommendations.

Abstract: This paper mainly describes and introduces the various types of city passenger rail vehicle doors as well as the advantages and disadvantages of them. It pays more attention to describe and introduce a new type of internationally advanced Sliding Plug Door100% low-floor passenger car doors from ministry of science and technology.

Abstract: In order to solve the problem that the management of water-supply operation is still backward and the phenomenon of water resources wasting is exceedingly serious, this paper introduce some advanced technologies such as computer, frequency transformer, programmable logical controller (PLC) and so on into water-supply network, the constant pressure water supply system is devised to achieve the variable-frequency speed control by making use of the electric controlling system composed of S7-200PLC, MM440 frequency transformer, miniature circuit breaker, AC contactor, thermal relay, DC power supply, miniature electro-magnetic relay, sorts of indicator lights and host command devices.

Abstract: This paper mainly describes the characteristics of the utilization of thermistor resistance changes with temperature. When temperature is too low or too high, the thermal resistance values change correspondingly. This causes its associating sensor voltage signal changes. The changes of the voltage signal will lead to the subtraction proportional operation and dual comparator threshold voltage change correspondingly. This appearance enables the double threshold voltage comparators output highly, so that the multivibrator starts emitting diode conduct. Therefore the alarm circuit works.

Abstract: This article in view of the situation of highway automobile rear-end collision accident frequency, designed and developed based on the ultrasonic ranging car anti collision warning system, its main purpose is to get the driver more parking time, thereby reducing the occurrence of accident. The design on the basis of the minimum safety distance model, and puts forward the system solution: by ultrasound to measure the distance of the two cars, using this system as the control core, for the analysis of all kinds of information, when driving distance less than the minimum safety distance control will alarm and stop the car.

Abstract: Different error requirements on different surfaces are necessary in many situations. If the registration between the measured dataset and the nominal surface is performed ignoring these differences, an inaccurate result could occur due to the surfaces which have low precision. An improper registration even results in false verdict. So the differentiated registration is of significance in precision engineering. In this paper, a new registration method taking into consideration of the different error requirements is proposed. Firstly surfaces are classified based on different error requirement. Then, appropriate weight factors are iteratively given to these surfaces. Based on the change relationship of error and weight factors, the algorithm controls the error distribution by optimizing the weighted least squares. Our method has the great flexibility in distributing the error, which is suitable for engineering applications. The experiment demonstrates the validity.

Abstract: The optimization of scheduling is an important aspect of the construction project plan, the paper proposes applying improved ant colony optimization to solve the public construction projects scheduling optimization problem under limited resource condition and constructs the mathematical model of the project construction schedule optimization. Further verify the validity of the model and the improved ant colony optimization on the schedule of the optimization problem solving has universal applicability.