Advanced Materials Research Vols. 243-249

Abstract: For lack of flexible description and the increasing complexity of data input, traditional modeling methods can not meet the demand of fast modeling for complicated bridge structures. Traditional methods are classified into the data based modeling and the graphic based modeling, and their disadvantages are discussed. On this condition, a new modeling method based on design drawings of AutoCAD is presented in this paper, which could fulfill the requirement of fast modeling and reflect the mechanic properties and internal relation of the structures. Especially, it can draw data from the AutoCAD lines automatically for analysis. The efficiency and reliability of the method has been proved by our software system WXQ developed for curved-skew bridges through a practical project.

Abstract: Constructing a building electricity laboratory needs much fund because relevant equipment is developing fast. The virtual building electricity laboratory based on virtual reality technology and network technology seems to be a possible way to instruct students in electricity experiments when most colleges can not afford to expensive and constant-upgrade equipment. It studies the possibility of virtual building electricity laboratory in technology, constructs basic structure of virtual laboratory operational system, and researches electricity experiment system module functions.

Abstract: For the research of beam’s deformation, material mechanics uses equation of small deflection curve which neglects 1^st order derivative of deflection and regards bending moment M is merely a function of abscissa x, and then gets the approximate solution of vertical displacement. However in some case, small deflection curve isn’t efficacious, so two methods come up in this paper to solve the accurate differential equation of beam’s deformation. This paper takes a slightness beam from temperature controlling device as an example and shows detailed process of mathematical modeling and solving. For iteration, firstly governing equations are founded, then an initial value is put into it to work out a new value, next see the new value as a new initial value and calculate again, by doing the operation repeatedly steady-state solution will be got in the end. For functional analysis, deflection equation is assumed as a kind of function containing some undetermined coefficients, then make it satisfy all the boundary conditions, and establish residual fonctionelle, by partial derivative operation to make the fonctionelle minimum, undetermined coefficients are estimated and deflection curve is got. At the end, impacts of gravity and axial deformation are discussed.

Abstract: A modeling method of tower crane flexible attachments based on ANSYS is researched for more practical crane. Form-finding is used to model and analyze flexible attachments and the analytic equations for typical example are derived. Comparing the analytic solutions with ANSYS solutions, the biggest relative error is 0.45% which is the foot moment relative error while cantilever beam top transverse force is 5×10⁵N. The results show that the form-finding method accords with engineering practice, and is reliable and suitable for structural analysis of flexible attachment tower crane.

Abstract: With the rapid development of computer technology, more and more finite element analysis software is applied to the field of structural analysis. However, for ordinary shelf designers, in a short time learn to use finite element analysis software are still some difficulties. Through mapping algorithm of node coordinates and programming using VB6.0 to achieve the second development on SAP84. This system has a friendly, convenient and easy to use interactive interface which for the rational design of the shelf provides a theoretical basis.

Abstract: In order to analyze the behavior of building structures in a real fire, a numerical method is proposed, which employs fire zone model to simulate the fire growing and the temperature distributions in a firing room. Two computer programs are developed to predict the thermomechanical response of the structures, one for thermal response analysis, and another for structural analysis. The structural analysis program contains a fiber beam element and a layered shell element. These elements, validated against data from experimental tests, can be used to predict the response of beam/column and slabs in fire conditions. Based on these programs, a system for analyzing the behavior of structures under fire is developed on MSC/PATRAN platform. The behavior of building structures under fire can be simulated with this system and the results can be used as the reference for the fire safety analysis and assessment of general building structures under fire.

Abstract: The joint between all plains in unit sheet aluminum curtain wall which is hanged on main body architecture is plugboard combination. The change of ambient temperature and wind load generates the change of expansion joints, which are the performance index of curtain wall required gas and water tightness, among curtain walls and suspension members. Thus obtained value of expansion joint among curtain walls is very important to guide the curtain wall’s installation. Here, an assemble structure model of curtain wall has firstly been established, the changing law of expansion joints among curtain walls has also been obtained under all kinds of work conditions based on previous model and the ANSYS software’s application. Some better suggestions have been also provided associating the construction technical specification. It can provide future protection for revised this technical specification, and accelerate the scientific normalization of the design in construction curtain wall.

Abstract: Concrete is a mainly and commonly good combined construction material, and is consisted of many well-defined components, so mechanical properties of concrete are very complex. the compressive strength of the concrete is a main criterion in producing concrete, but the test on it is complicated because test components of concrete must be kept in the special condition an tested after 28 days. To simplify the procedures and obtain a reasonable data, the paper presents a method using the system of BP neural network predicting the strength of concrete. the system is trained and tested by using many data of strength of concrete in the past ,the test result shows that the value of the strength of concrete predicted is approximate to the experimental value, and the method presented is very efficient and reasonable in predicting the compressive strength of concrete .

Abstract: This paper presents an evaluation of accuracies of a plastic hinge (PH) beam element and a spread plastic (SP) beam element for structural material nonlinear analysis. The cases of beam sectional material behavior under hardening and softening are investigated. The result shows that post-yielding response of member nodal force and deformation presented by the PH element is strongly influenced by the preset hinge length. The refined mesh of the SP element should be employed to obtain the accurate post-yielding response of member nodal force and deformation. The SP element fails to present consistent and rational evaluation of the post-yielding response of member nodal force and deformation in the case of section under softening. The two elements present consistent response of section force and deformation but different maximum curvatures.

Abstract: According to the hydraulic driven system working principle of crawler bulldozer, the simulation model of electro-hydraulic proportional control driven system was established by using AMESim, and the simulation was carried out. The simulation result indicates that using feedback regulation in control of hydraulic motor of driven system, the system pressure stay in a relatively stable state, which is conducive to the efficient operation system. As the load increasing suddenly, the system pressure volatile during the volume of hydraulic motor changing. However, steady state can be quickly restored.