Applied Mechanics and Materials Vol. 680

Abstract: In terms of structure design for transmission towers, early because of restricted by calculation method, are generally will tower inner force analysis that was decomposed into several pieces of plane truss. This method omits truss space effect, is a kind of approximate calculation method. Later adopted a more accurate method of space truss, considering the relations between the deformation coordination of bar of tower structure and the mechanical equilibrium conditions, can reflect the actual situation of the tower stress relatively and accurately. The above calculation method, both plane truss method and method of space truss all nodes are assumed to be the ideal of articulated point, ignoring the interaction of the influence of secondary moment and torque to the structure. In recent years, with the rising of power grids, high voltage, large capacity of transmission lines construction become the trend of the development of the grid technology. Gradually to develop in the direction of high, long-span transmission tower, component cross section increases gradually, the second-order stress effect on the structure is becoming more and more important. The truss method in some special structure and the adaptability of complex working conditions should be tested by experiment and other finite element calculation software review.

Abstract: With the operation of the power engineering, such as west-east electricity transmission, the outside sending of the three gorges, areas network and so on, many large span engineering emerged in different part of China. And among it, the key point of the whole subject is the design of the structure. This essay aims mainly at introducing the history and modern application of steel tube tower. Meanwhile do the analysis comparison for the modeling of the transmission tower according to angle steel tower and steel tube tower under the working condition of high winds. Steel tube tower is better because it is smaller in shape factor of wind load than angle steel tower, so it can reduce the tower weight and fundamental effort, the economical advantage is great.

Abstract: Considering width and thickness of large width angle steel, the section area of large width angle steel is larger than that of normal angle steel. Application of large width angle can increase bearing capacity of the member. Therefore it is feasible that large width angle steel replaces double combined angle steels. Taking the tower for ±800 kV DC transmission line from Jin ping to south Jiangsu Province, under the same design conditions, large width angle steel and double combined angle steels are used respectively in the main members of the tower to modeling finite element analysis.The results indicate that the stiffness variation is more uniform, causing rod end bending bar additional stress is about the axial stress of about 2%~3%.

Abstract: Magneto-rheological (MR) damper is a semi-active control device, which takes advantage of both the reliability of passive devices and the adaptability of fully active control devices and is widely used on many kinds of machines and civil works. But there are some particular problems when the MRD is used on transmission tower-line system.This article is aimed to introduce the technological means to these problems such as :choose sant colony algorithm as the suitable semi-active control algorithm; consider adopting Self-Powered/Self-Sensing structure to Increased general OS stability;

Abstract: The uplift behavior of rigid pedestal pile is affected by the geometry, which is not totally same with plate anchor. A series of uplift tests of relatively large scale pile models with various dimensions in silt soil have been conducted to investigate the influence of angles of enlarged base, ratio of base and shaft diameters and embedment ratios. The whole trend is that uplift capacity will decrease with the increase of angle of enlarged base. The maximum difference of ultimate uplift load for various angles of enlarged base is within 20%. Soil surrounding pile base can be mobilized when ratio of base and shaft diameters is no less than 2.0, otherwise the part of enlarged base will not take effect fully. A gently curved rupture surface emerged from the edge of enlarged base to soil surface when embedment ratio is no more than 3. For deep rigid pedestal pile, a balloon-shaped rupture surface occurred. The height of whole rupture is 2.7D.

Abstract: Compared with the intrusion detection based on pattern matching, the method which is based on model checking can detect the complex attacks. But all of the existing algorithms are only used to detect some specific types of attacks. To solve this problem, we firstly use the Linear Temporal Logic with Past Construct (LTLPC) formulae to set up formal sub-models for the five kinds of attackers, the four kinds of attack processes and the eight kinds of attack effects. According to their universal relationship and the semantic relation of variety of LTLPC operators, we obtain the above sub-models together, thus, the universal models described by LTLPC formulae for universal attacks are formed. On this base, we implement an intrusion detection method based on LTLPC for detecting all types of attacks. Compared with the existing methods, the detecting ability of the new method is more comprehensive.

Abstract: Basing on the basic attributes of the green machine product, the article put forward the main principles that should to be abided, when construct the synthesis evaluate index system. Then use the AHP method in analyzing the choice approach of the green machine product`s design scheme. Green machine product means that in its whole life process (including material gaining, designing, manufacturing, packing, transiting, using, recycle, reusing or refilling), we can economize the energy, do little or minimum damage to the environment, protect the worker well. It has four characteristics including technology advancement, economic, resource saving and environment friendliness. Green machine product design is to make sure that it can influence the environment less and keep its basic functions, service life and quality. Its green degree play an important role in judging whether or not it can meet the green product’s basic requirements and improving its design project and produce technology.

Abstract: In the solution of trust region subproblem within the classical trust region algorithms, the centre of sphere is the current interaction point and one step-size is the upper bound. Considering that only with the negative gradient direction to acute angle may reduce the function value, we introduce the parameter to control of the centre of sphere and the radius. Based on the numerical experiments, obtains the value range of the parameter. The numerical evaluation demonstrates the validity of the new trust region algorithms.

Abstract: Virtual Sensei Lite (VS Lite) is an inexpensive user-friendly motion analysis system. As an alternative motion capture system, it is a must for VS Lite’s user to assess the accuracy of the measurement system capability. To date, such analysis to observe the reliability and accuracy of VS Lite has not been reported. Therefore, this study proposes a procedure for assessing the accuracy and capability of the Virtual Sensei Lite using ANOVA Gage Repeatability and Reproducibility (Gage R&R) designed experiments. In this procedure, a gage R&R study is conducted to obtain replicate measurements on nine parts by three operators. The total variation due to measurement error is then observed to identify the accuracy of measurement. The study able to demonstrate on the accuracy of VS Lite as the value of total variation due to measurement error is within 10%-30%.

Abstract: Compared with the Intrusion Detection (ID) based on pattern matching, the model-checking-based methods can find the complex attacks. But their rates of missing report are still high. To solve this problem, we firstly use the Interval Temporal Logic with Past Construct (ITLPC) formulae to describe some signatures for network attacks. And then, we can use some automata to establish models of audit logs. On the basis of it, automata, i.e., attack models, and ITLPC formulae, i.e., signatures, constitute the two inputs of the ITLPC model checking algorithm. Therefore, a new model-checking-based ID algorithm is obtained by calling the ITLPC algorithm. Compared with the existing methods, the new method is more powerful, as shown in the experimental simulations.