Applied Mechanics and Materials Vol. 160

Abstract: The rotor system balance design is always one of the main concerns in scroll fluid machinery dynamics, as it affects the scroll mechanical reliability, safety and life. According to the scroll fluid machinery working principle and structure, combined with the dynamic balance theory, four kinds of balance weight design philosophy were proposed in this paper and verified by a specific example, in which the bearding loads were calculated using four design methods and compared. The results show that the balance design philosophy will have a significant effect on fluid dynamic characteristics. The result is helpful for optimizing the rotor balance design of scroll fluid machinery and improving the mechanical properties.

Abstract: Fixtures play a great role in manufacturing, and the quick changes in modern life lead to high need for changes in fixtures. The reconfigurable Pin-type Fixtures with Vacuum-suction-cup (PFV) developed broadly with the quickly progress of industrial technology. This paper mainly describes the design principles and main differences included in PFV. The characters of ideal PFV are drawn in line with the researches have been done in patents, companies and colleges. According to the actual needs of industry for fixture and the development of computer-aided-fixture-design technology, the trend of PFV in the next several decades is concluded in this paper.

Abstract: This paper introduced and analysis the various components of switched reluctance motor driver system, built each part of the simulation model in Simulink and described the functions and working principle of them. Connecting each simulation model of the system constituted a simulation model of SRD. The system uses dual-loop control, the speed loop with PI control, current loop with angle position and current chopped control methods. It ensures that we can get a satisfactory performance when SRM in the low-speed or high-speed. Simulation results showed the effectiveness of PI regulator error-free speed adjustment.

Abstract: According to the article, the various digital modeling techniques in architecture and civil engineering are extensively discussed. 7 main methods for modeling which are geometry, polygons, displacement texture creation, digital sculpture, plug-ins, vector scanning, and GIS are contrasted and analyzed. To provide reference service for digital modeling in architecture and civil engineering, the research includes their working principles, features, running environments and fields of applications.

Abstract: Considering the requirements for efficiency and precision in the forklift styling, the authors developed the forklift optimizing system for its styling based on the interactive genetic algorithms (IGA). The system includes parameter optimization, color optimization and part combination three modules. The parameter optimization module can find the user defined parameters of the forklift 3D models and generate new models. Color optimization module can group the model surfaces and render the groups with different color. New color plans are generated through random changing of the colors in each group. The parts combination module divides forklift into several parts and build lib for each part. The module can pick parts from the lib and assemble them into a whole forklift and demonstrate them. The thesis developed a protosystem on the Solidworks platform with VBA programming tools. Interactive genetic algorithms are applied to realize the three module’s function.

Abstract: The free vibrations of a stepped Euler-Bernoulli beam are investigated by using the Adomian decomposition method (ADM). The stepped beam consists two uniform sections and each section is considered a substructure which can be modeled using ADM. By using boundary condition and continuity condition equations, the dimensionless natural frequencies and corresponding mode shapes can be easily obtained simultaneously. The computed results for different boundary conditions are presented. Comparing the results using ADM to those given in the literature, excellent agreement is achieved.

Abstract: The ubiquitous network and it provides the high quality wireless service, all depends on the wireless communication system network security level. Safety algorithm for wireless communication system constructed in different network reliability. In this paper, based on the wireless communication system to study on information security technology, as the development of information security provides a theoretical basis.

Abstract: The unsteady viscous flow fields of dual flapping airfoils in tandem configurations are simulated by a Navier-Stokes Solver based on dynamic deformable hybrid meshes. Aerodynamic interactions of three motion models are studied including flapping fore airfoil with fixed aft airfoil, two airfoils flapping in phase and out-of-phase. The results indicate that the aft airfoil in the wake of the flapping fore airfoil has great influence on the aerodynamic performance. When the fore airfoil flaps with a fixed aft airfoil, the thrust generation and thrust propulsive efficiency were enhanced by 65% and 44% respectively, compared to that of single flapping airfoil. When the two airfoils stoke in phase, the thrust generation is twice over that of single flapping airfoil. However the out-of-phase stroking has relatively much lower thrust.

Abstract: In this paper, modal characteristics of self-compacting concrete (SCC) beams were studied through experiment. 3 self-compacting concrete beams were gradually damaged and then subjected to vibration test in free-free boundary conditions after each load step. From analysis, eigenfrequencies could indicate the existence of damage but it could not represent the damage locations. Modal Assurance Criterion (MAC) is lesser reliable to indicate crack damage compare to eigenfrequencies. Next to these, capacity for damage detection and localization of Coordinate Modal Assurance Criterion (COMAC) and the flexibility matrix method are also examined and compared. This paper introduces in detail the dynamic properties and damage localization methods in SCC, which provide basal databases of damage diagnosis for SCC structures and promote the popularization of SCC in civil infrastructures.

Abstract: Support Vector Machine is a powerful machine learning technique based on statistical learning theory. This paper investigates the potential of support vector machines based regression approach to model the strength of cement stabilized soil from test dates. Support Vector Machine model is proposed to predict compressive strength of cement stabilized soil. And the effects of selecting kernel function on Support Vector Machine modeling are also analyzed. The results show that the Support Vector Machine is more precise in measuring the strength of cement than traditional methods. The Support Vector Machine method has advantages in its simple structure，excellent capability in studying and good application prospects, also it provide us with a novel method of measuring the strength of cement stabilized soil.