Applied Mechanics and Materials Vols. 365-366

Abstract: In order to identify design defects in mechanical product quickly and accurately, geometric constraints relationships between mechanical parts are formulated as critical functions, assembly constraint relationship (ACR) matrix is established based on encoding of geometric constraints between mechanical parts. Directed graph is employed to describe constraint relationship of ACR matrix, the node in directed graph denotes parts number, data structure of node stores the design parameters of mechanical parts, weights of directed graph arcs represents geometric constraint type. Weights of directed graph arcs are treated as antigen, design defects for mechanical parts are treated as antibody, mutation rules such as trimming, splicing and replacement is employed to identify design defects of antigen gene. Identification example of spherical mechanism demonstrates effectiveness and accuracy of above methodologies.

Abstract: Topology optimization of thermo-elastic structures using the hybrid cellular automata method is investigated in this paper. The objective is to minimize the mean compliance of a structure with a single material volume constraint. The hybrid cellular automata method is used to solve the optimization problem. The local change in the design variable is determined by a local rule based on the proportional control law. The numerical example is presented to show the feasibility of the present approach.

Abstract: This paper focused on the area of simulation of man-machine applications, using JACK ergonomic software, and have a detailed analysis of sight of domain, and comfort of human-computer design factors to achieve a auxiliary design. The paper combines the emergency communications vehicles emergency communication vehicle cabin man-machine design examples to verify the effectiveness of the proposed method.

Abstract: With the advance in 3D body scanning technology, it opens opportunities for virtual try-on and automatic made-to-measure in apparel products domain. This paper proposed a novel feature-based parametric method of human body shape from the cloud points of 3D body scanner [T². Firstly, we improved the skeleton construction through adding and adjusting the position of joints. Secondly, automatic extraction approach of semantic feature cross-sections is developed based on the hierarchy. According to the unique distribution of cloud points of each cross-section of each body part, the extraction method of key points on the cross-section is described. Thirdly, we presented an interpolation approach of key points which fit cardinal spline to cross-section for each body part, in which tension parameter is used to represent the simple deformation of body shape. Finally, a connection approach of body part is proposed by sharing a boundary curve. The proposed method has been tested with our virtual human model (VHM) system which is robust and easier to use. The process generally requires about five minutes for generating a full body model that represents the body shape captured by 3D body scanner. The model can be imported in a CAD environment for application to a wide variety of ergonomic analyses.

Abstract: The rapid sample preparation equipment has been designed for the detection of the chemical composition of textiles, the device can rapidly and quantitatively sample preparation, to meet the needs of modern detection. Firstly, introduced the design requirements and design process, and the equipment is designed based on SOLIDWORKS software platform, then check interference. finally, analysis the mechanical properties of the equipment using SOLIDWORKS Simulation Xpress module. The results verify the feasibility and rationality of the design for the automated detection of reference fabric.

Abstract: Knowledge-based Engineering (KBE) should be introduced into the field of mechanical part modeling. The knowledge-based and featured mechanical part modeling is proposed based on the two layers of knowledge base. Features and process planning rules for mechanical parts are integrated and explicit knowledge and tacit knowledge are involved in this model. Explicit knowledge includes basic information, shape feature, precision feature, material feature and assemble feature, and tacit knowledge includes process rule-based reasoning and process feasibility analysis. The model proposed will help to the following process planning and play a very important role to improve the success rate of design mechanical parts. Finally a case study is conducted.

Abstract: The reverse engineering takes the products as prototype, through improving the CAD models to get new products models, which achieves the original design of product. The reverse engineering provides a convenient and fast tool for improvement design of the products,which is very important for shortening the development cycle and improving enterprise competitiveness. Therefore, it is necessary to research the reverse engineering. In this paper, the three-dimensional data scanner is used to measure the point cloud data of physical sample, by means of reverse engineering software Geomagic Studio to achieve the reverse modeling of parts and error detection analysis of digital model.

Abstract: Parameter mapping method was put forward, through the skull restoration design and manufacture based on user demand. Considering the cost, time, resource utilization rate and feasibility, the conversion of the skull prosthesis design parameters and mapping between the design parameters of user needs were realized. The effectiveness of the method was verified through the example analysis, which provided a basis for the design and scheme of the skull restoration.

Abstract: The molding quality of plastic injection products are affected by such factors as mold structure and molding technology in the forming process. If the products have any quality problem, every forming process will have to be reviewed, which will intangibly lead to an increase in workload for mold-related staff and in the costs of production. Based on an example of molding defects warping in the practical production of a PBT plastic injection product, this essay analyzes the molding defects by using Moldflow software, with the aim of optimizing molding scheme and the molding quality of injection products and finally improving the social and economic benefits.

Abstract: This study is based on a real fire accident that occurred in Keelung City, Taiwan. The fire site was situated in an old five-story building that was renovated for recreational purposes. When the fire broke out, a stack effect formed instantly because the fire source was gasoline, the initial location of the fire was the stairway, and the fire burned rapidly with a cut-off downward evacuation exit. Customers were unfamiliar with the escape routes and fire-extinguishing equipment, leading to the loss of five lives. This study applies the Fire Dynamics Simulator (FDS) to develop a computer numerical model and simulate the actual conditions of the fire accident. The major fire dynamic behavior parameters are computed to evaluate the transport of flames, smoke particles, and toxic gases within the enclosed building. Recommendations for fire safety in this type of architectural structure are provided to reduce the reoccurrence of similar disasters.