Applied Mechanics and Materials Vol. 394

Abstract: There are less topology optimization methods for bars structure than those for continuum structure. Bionic intelligent method is a powerful way to solve the topology optimization problems of bars structure since it is of good global optimization capacity and convenient for numerical calculation. This article presents a SKO topology optimization model for bars structure based on SKO (Soft Kill Option) method derived from adaptive growth rules of trees, bones, etc. The model has been applied to solve the topology optimization problem of a space frame. It uses three optimization strategies, which are constant, decreasing and increasing material removed rate. The impact on the optimization processes and results of different strategies are discussed, and the validity of the proposed model is proved.

Abstract: According to characters of auto covering parts such as large size, thin thickness, complexity in shape, low degree of standardization and expressed by model, etc. This paper put forward the drawing die design process of auto covering parts based on NX software. The assembly drawing of the auto covering part drawing die was shown in detail. In accordance to the mold design process, the digitized model was parametrically designed. The competitiveness of the auto covering part mold manufacturing enterprises was significantly improved with the application of 3D mold dynamic simulation s and automatic forming line simulation.

Abstract: Mould design is a complex process which mainly uses fixed design process or design approach. It has certain similarity or repeatability. In order to avoid duplication of effort and improve the efficiency of the mould design, present a mould design method based on NX knowledge reuse technology, establish the standard parts library, so as to realize the target of high-quality, short-cycle and low-cost in mould design. At last, the mobile phone shell mould design example is given to verify the feasibility and practicability of the mould design based on NX knowledge reuse technology.

Abstract: Business process and professional simulation process are closely relative and alternate together for complex product simulation. This paper presents a business-task coupled process management method, which can implement integration management of business process and professional simulation process. Business-task coupled process is controlled by a multilayer workflow engine based on workflow technology. When the business process executes a task activity, the responding task process will be driven. The workflow engine controls every simulation activity in the task process. A simulation activity invokes one specified simulation tool and transfers data through a simulation component. The application result shows the validity of the method.

Abstract: Aimed at multi-pulleys timing belt transmission system of automobile engine , programing parametric design software based on visual C++, set up timing belt and pulleys 3D model , Improve the design efficiency by design chart and data programmed processing .through comparison of conventional design result , verify the software feasibility and exactness.

Abstract: Property of transmission system will directly influence the performance and reliability of helicopters. Information exchange and sharing are difficult in transmission system life-cycle, which has complex product to fabricate and mass information to handle. To solve this problem, we establish a unified product data (UPD) to manage the information of research-development process for transmission system. In distributed collaborative environment, a single enterprise UPD is established by analysing transmission system development process and data flow. The theoretical frame of UPD and several key techniques are studied, including architecture, model, management, consistency, and mapping of data access control. Data integration and data access control model in development process is discussed in this paper. A UPD integration framework based on collaborative agent is presented, which shows the evolvement theory among PUPD, DUPD, SUPD and IUPD. Besides, task-role-based access control model is proposed, and dynamic right control process is given for UPD.

Abstract: The safety of agricultural tractors drivers is a very actual topic, especially when tractors operate on side slopes, such as in terraced vineyards. This work approaches the stability problem of articulated tractors by modelling, simulating and quantifying the safety of the driver with respect to both roll and pitch overturns. First of all, an articulated tractor has been modelled and simplified, after that a stability index has been defined and calculatedin several simulated slope conditions when the tractor travels along a circular trajectory; then, the obtained results have beencompared with respect to a conventional tractor. This work is a preliminary studyfor a tilting test platform for real vehicles, capable to reproduce real field conditions (slope, obstacles, roughness). Finally, some directives on how exploiting the obtained results for real-time safety devices have been formulated.

Abstract: The main goal of this work relies on implementing discontinuous quadratic elements on a previous existent optimization code. The existent code refers to problems of topology optimization using a standard Boundary Element Method (BEM) formulation. A Topological Derivative (D_T) is used for determining the domains sensitivity. The implicit cost function used for D_T derivation is based on the total potential energy. A fixed amount of material with less efficiency is progressively removed during the optimization process. It is expected that the quadratic elements implementation increases the accuracy of the final solution, since the previous code were implemented by using linear elements. Despite of this code is still under development the final topology presents a good agreement when compared with those presented in the literature.

Abstract: Surface Electromyographic (SEMG) signal is characterized by physiological noise contained,in order to eliminate inclusion noise. In wavelet packet analysis domain,after analysising the traditional soft-threshold and hard-threshold de-noising method of characteriscs,a new method which is μ rhythm threshold method is provided to improve threshold function. In Matlab7.0,the relevant procedures and simulation show that the method can not only solve the hard-threshold de-noising continuous problem,but also solve the detects before and after the threshold treatment of the soft-threshold wavelet coefficients constant deviation. Meanwhile,the application of the method in the wavelet analysis shows that wavelet packet μ rhythm threshold method de-noising significantly better than wavelet μ rhythm threshold method,and proves that the wavelet packet has remarkable capacity to de-noising.

Abstract: Accurately achieve the luminance of light sources at night images is significantly important to vision-based night visibility estimation. In this paper, we propose a practical night visibility algorithm. This algorithm contains two main parts, light sources recognition and edge extraction. Firstly, we give the model of vision-based visibility estimation, and propose the framework of algorithm. Secondly, we give the method to extract light sources from multiple potential targets by the prior knowledge of space information. Then, we analysis the features of light source image, and explain the expanded temple to cut sub-image of light source, and induce in PS level set to segment the edge. Experiments show that, the light source average recognition precision is approach to 0.95 at the condition of moderate breeze, and compared with the manual segment, the precision of light source segment is approach to 0.99 at the condition of real visibility larger than 500m.