Applied Mechanics and Materials Vol. 610

Abstract: This article is devoted to creation of mathematical models of overhead transmission lines (OHTL), taking into account the glaze. In the studying and designing of transmission lines is often necessary to construct mathematical model taking into account the influence of natural factors and all the basic physical parameters affecting or hindering them. The main difficulties arise when describing the equation of oscillations, as they nonlinear. Numerical experiments and comparative analysis with previously reported models was presented. The main setting is the critical velocity of the wind flow and its dependence on the angle of attack to OHTL.

Abstract: A numerical method integrating computational fluid dynamics and computational structural dynamics for predicating wing flutter in time domain is described. A strong coupling employing the dual-time method is adopted. The Newmark algorithm is used to solve flutter equation in modal spaces while the finite-volume algorithm for the Navier-Stokes equations is used to solve the flow. The computed flutter boundaries of AGARD wing 445.6 for frees-tream Mach numbers ranging from 0.499 to 1.141 agree well with the experiment than using the DLM.

Abstract: Pile hammer impact system is composed of hammer, pile cap and pile. Gravity field will produce uneven stress in the pile which is placed on a fixed rigid plane, and gravitational potential energy will increase the impact energy which is inputted to the pile during the impact process. These will influence dynamic response of collision process between pile hammer and pile. In this paper, a gravity field factor was added in the Simth difference equations which are based on One-dimensional Wave Equation. The numerical model of pile hammer impact system was established. A program was written to implement the numerical model. Simulation results indicated that the duration of collision, the peak and stable value of impact force and the effective impact energy would be affected by the gravity field.

Abstract: To reduce the computational resources, experimental design and response surface method (RSM) were employed to investigate the aerodynamic drag coefficient (C_D) and lift coefficient (C_L) of airfoils by using CFD methods. The selection of sample points, development and validation of response surface model and the effects of different sample points on approximation model were discussed. The results indicates that the number and distribution of sample points have a significant impact on model accuracy and optimize results. Also this method can greatly reduce calculation amount.

Abstract: Guide wheel crankshaft used in caterpillar tractor is analyzed under working condition. The crankshaft is made of 45Cr steel. Since the work conditions of the crankshaft are complicated, three dimensional finite element model of the crankshaft is built for strength checking of the crankshaft. Appropriate boundary condition is applied. The results show that the maximal stress of the crankshaft is 728MPa, which is less than the yield limit of 45Cr steel (835MPa). Therefore, the crankshaft can not be broken during the work of caterpillar tractor.

Abstract: Offshore platform rocking wall system and tuned mass damper are briefly introduced, and the paper integrates the advantages of these two kinds of seismic method, and the TMD is attached to the jacket offshore platform - rocking wall system, using the ANSYS for finite element analysis, and the analysis results are optimized. The results show that compared with the offshore platform - rocking wall system, additional TMD can give full play to the performances of the two kinds of seismic methods, which is remarkable.

Abstract: Steel structure is designed by limiting condition generally. Checking its stability is important in design. Calculating the effective length of the column is a key of stability checking. Some charts and formulas are written on Code for Design of Steel Structures, which is not applicable to the structural systems because of some assumptions. What is more, finding some values is not easy and the trend of the values is not obvious. In the paper the effective length of the column in the action of the fore with variable directions is derived by the equilibrium condition method and the effective length of the column chart is also drawn. Using these charts can quickly determine the effective length, and there is an intuitive tendency which the effective length varies with parameters.

Abstract: In this paper the elastic load-carrying capacity of the stability columns, which provide lateral support to leaning columns, is investigated. The solution to the effective length of the columns is obtained by using of differential equations. The influences of the leaning columns on the stabilizing columns are studied and the nomo-graphs for determining effective length of the supporting columns are made for practical using. The effective length of columns can be quickly determined by using the nomo-graph, which shows intuitively the trends of the curves in the nomo-graph owing to some relevant parameters.

Abstract: In the past ten years, the R&D of UAV (Unmanned Aerial Vehicle) is very popular and has the trend to replacing with the manned aerial vehicle due to its low-cost and high-mobility. According to the specifications, this project completes special contour and function of a mini-UAV design and passes the strict fabrication, prototyping, and aerial test processes. With the advantages of long flight endurance, speedy assembly/disassembly, simply contour, and portable, the developed mini-UAV has the capabilities of bungee launch and parachute recovery. Thus, it makes much progress in Taiwan’s mini-UAV area.

Abstract: In order to construct a simply structured alcolock device for autocar steering safety, the plunger solenoid with the conical face pole form is utilized to fabricate a electromagnetic actuating unit with double plunger solenoids. The unit can generate a electromagnetic actuation with long travel to complete the coverage of auto start-up lock hole and hence to stop the vehicle launch; the magnetic actuation is controlled by using a alcohol sensing system, and the shutting function for starting-up lock hole is generated by a baffle installed at the top of plunger solenoids as the actuating control is started up on the basis of an alcohol sensing signal. The plunger solenoid with conical face pole form possesses the output characteristic of long stroke and steady stroke force.