In this model, the dual optical drive is located at the top, and the two hard disks are placed at the bottom of the chassis. The hard disk is fixed to the cage space enclosed by steel plates. The way the hard disk is fixed on the chassis is mainly divided into screw fixing and screwless toolless disassembly design. The screwless design facilitates maintenance and upgrades, greatly improving user experience, but it also poses a huge challenge to the design and simulation of the rack. Figure 1 Schematic diagram of the hard disk and fixing method In this paper, the hard disk cover is fixed by the plastic hard disk frame, and the hard disk frame is fixed in the cage hard disk frame by assembling and clamping, and then connected to the whole machine by riveting and screw fixing. The setting of the plastic hard disk frame is of great significance for isolating the hard disk vibration and facilitating the disassembly. As a sheet metal assembly, the chassis is a typical shell structure. Therefore, the shell unit is mainly used. The original 3D design image file is used to extract the neutral surface and mesh the mesh. 1.1 Abaqus/Standard Analysis Settings In order to consider the structural mechanical properties of the chassis as much as possible in the finite element analysis, the calculation can be simplified and the calculation speed can be improved. The following assumptions and treatment methods are introduced: The graphics card and the motherboard use PCB material. The power supply and hard disk only need to consider the quality. Therefore, it is defined as a rigid body and given a certain density. At the same time, the ABAQUS automatically calculates and adjusts the reference point to the centroid function to establish a reference point to define. As a sheet metal assembly, the desktop chassis has a large number of riveted and bolted parts. In frequency analysis, there is no perfect theory to accurately describe various connection methods and contact pairs in frequency analysis. This is also the frequency analysis. Difficult, for this reason, combined with the experience of analysis, the various contact behaviors such as riveting, screw fixing, assembly coordination, etc. are processed separately. In the establishment process, the surface-based constraints are defined according to the master-slave formula, and the materials are generally soft and The mesh is denser to the subordinate surface. Abaqus provides three methods for solving vibration modes: Lanczos method, Subspace method and AMS (automatic multiple substructure) method. Each of the three methods has its own advantages and disadvantages. The default Lanczos method is used in the analysis. Its advantage is its feasibility and Efficient and support sparse matrix methods. Bakelite Material,Bakelite Plastic,Bakelite Made From,Bakelite Synthetics WENZHOU TENGCAI ELECTRIC CO.,LTD , https://www.tengcaielectric.com
1 model establishment