Advanced Materials Research Vols. 291-294

Abstract: This paper introduces a biological flapping micro air vehicle (FMAV) with four wings, instead of two wings, where wing clap-and-fling of real insects has been mimicked. The total weight is 2.236g. A spatial linkage is implemented in the flapping wing system, which is symmetry. This can prevent the flapping wing MAV from tilting toward the left or the right in the course of flight. By using the computational fluid dynamics (CFD), it has been confirmed that the flapping wing system can utilize the clap-and-fling mechanism, which is essential to enhance the lift and thrust in the insect flight.

Abstract: House, is a valuable asset in human’s life and is one critical and important setting in developing lives of human being. Therefore, as time goes by, people develop and wanting to improve the state and quality of their house so that they can live their lives towards better meaning parallel to their up growth. But, easy said than done, renovation is some work that needs thinking about. In fact, most of houses which are dwelled by modern Malay people in Malaysia nowadays did not evolve in synchronize to the Malay people’s needs. We could see lots of houses being renovated or extended by owners after the houses get dwelled in especially of those terrace housing in Malaysia. The renovations scenario upon these terrace houses is indeed one of the serious housing issues and problems in Malaysia. This writing thus will focus its investigation towards the phenomena of renovations upon selected double-storey terrace housing within Klang Valley, Malaysia. Investigations will be carried out by questionnaires, statistic analysis of findings from site visits, and interviews with the owners of the houses. Among those things that will be investigated are about the type of renovations that have been done and the factors which influence the act of renovating. Results show that the type of renovations varies, be it on a major or minor scale. Those renovations of houses involving numerous parts or sections of houses such as the kitchen, rooms, bathrooms, and so forth and were done because of many different factors or reasons.

Abstract: Aiming at calculating the natural frequency of roller chain drives, the software Catia was used for modeling the roller chain drives accurately and Ansys Workbench was applied to analyze the modal and harmonic response of the tension side chains, comparing the natural frequency and the theoretical calculation results of simplified model. The results showed that the deviation increased with the increase of the order of natural frequency and modal numerical simulation provides certain reference for engineering application.

Abstract: This paper considers the problem of semi-global decentralized output feedback control of large-scale systems with subsystems interconnected by nonlinearities which are functions of the measurable and immeasurable. The distinguishing factor of this paper is that the nonlinearities are allowed to have both higher-order and lower-order terms, to which the existing design schemes are inapplicable. Simulation results are given to demonstrate the validity of the proposed method.

Abstract: According to the current “Construction structure load standard”, in this paper, on the base of building a FEM of super high rise DTCS that with connected trusses and a single tower without connected trusses, the mechanical property of each was analyzed by using ETABS, a three- dimensional finite element software. The contrasted result indicates that with connected trusses the double-tower connected structures have better performance and higher structural effectiveness. This feature is more clearly seen with the increases of the truss’ rigidity. The stress of the truss shows certain regularity with the alteration of the truss’ stiffness and location.

Abstract: For the biggest top steel ring, the sampling device characteristic seriously influences on precision sampling. The simulation model was built in AMESim and certificated by experiments. Through simulation, the external load and the car interior are important factors in speed stability. It derived the calculation formula on external load and compared with experimental results. Under the load limit, the velocity will stable with load change. Above the load limit, the velocity will fluctuate violently. An overweight car prolongs the starting time and aggravates the braking vibration. Under a reasonable design specification, 300kg is optimum. These conclusions had been applied in this newly designed device effectively.

Abstract: Since last century, the exhausts of fossil fuel energy, excessive gas emission and global warming have been calling for the alternative methods to generate energy for vehicles urgently. The hybrid electrical vehicle (HEV), which is considered as a potential solution to solve this problem, has draw researchers’ attention. This paper mainly discusses the control strategy of HEV based on fuzzy logic. By using this control strategy, the work space and work efficiency of engine are optimized, which play a vital role on improvement of the operation performance of HEV. Meanwhile, the strategy has been applied to optimize the power balance of battery, which includes the characteristics of battery in the controller. Though the model based on Matlab/Simulink, the simulation results confirmed the excellent effectiveness of our control strategies, which optimized the fuel consumption of engine and the power balance of battery successfully.

Abstract: The discrete finite element (FE) model often cannot reflect structure characteristics accurately due to imply more idealistic assumptions and simplifications. Therefore, it is necessary to update FE model for structural damage identification, response calculation, safety evaluation, optimization design, and so on. This article will illustrate respectively three key steps of updating parameters selection, target function selection and optimization method in process of dynamic FE model updating of footbridge structures based on ambient excitation, and put forward a feasible updating method: combine empirical method with sensitivity analysis method to select updating parameters; joint natural frequencies, MAC and modal flexibility as target function; adopt optimization algorithm based on the optimization theory.

Abstract: The dynamic mechanics model was built up to analyze the contact-impact between drill string and wellbore according to the characteristics of contact-impact, based on non-linear finite element method and Lagrange method. The dynamic mechanics equations were deduced by the dynamic mechanics model. The stress and deformation field of drill string with different parameters of bottom hole were obtained and tested by experiments and numerical simulation respectively. And also, the propagation laws of stress wave generated by contact-impact in drill pipe were studied. The comprehensive results indicate that the numerical results agree well with the actual dynamic process of contact-impact. The stress waves generated by contact-impact cause the change of stress. The contact-impact between drill string and wellbore under air drilling is the main reason for early drill string failure.

Abstract: The joint has a significant effect on the dynamic characteristic of the mechanism, and the identification of the stiffness of the joints has become a key problem. In this paper, a method is presented for identifying the dynamic characteristic of joints. An experiment is designed to test the dynamic parameter of the bolted joints specimen; the identification method, based on experiment, has a high accuracy result. By taking a specimen to experiment and identify the dynamic characteristic of joints, the relationship between the preload on the bolts and the joints stiffness is acquired. In order to validate the accuracy of the result, the FEM software is used to simulate. There are only a small discrepancy between the results of identification and simulation.