The Topology Optimization Of Permeability In Liquid Composite Molding

This issue is the source of the National Natural Science Foundation of "molding resin membrane infiltration and the quality control of non-isothermal simulation coupled Theoretical and Experimental Research." (No. 50573060).Liquid molding process (LCM) is a manufacturing complex shape of the components of the composite materials which are very effective methods of technology. LCM is closed casting process that the principle is the pre-molding into mold cavity with liquid thermosetting resin impregnated and the resin cured after released would be carried repairing products. Accurate description of the resin in the reinforcement of permeability, the optimization of mold design, mold filling process of numerical simulation to shorten the manufacturing cycle to ensure that product quality is essential. Pre-forming process LCM penetration rate is an important process parameters, which will directly impact on the flow of resin fiber and effectiveness of the process of infiltration. If the resin impregnated with prefabricated parts in the negative, it is easy to lead to defective products, such as air bubbles. Therefore, the pre-penetration properties to solve the LCM process as a result of infiltration and have a bad product defects guidance at the same time on the preparation of composite materials technology has a positive role in promoting. LCM in the process, the body of prefabricated resin in the flow is often seen as porous media flow of movement. Preform penetration rate is inherent attributes, and the porous material as a structure can be designed with nature.Stokes fluid homogenization theory is first introduced . Continuum in theory, the assumption by the cyclical structure of the macro-micro-structure in space from the accumulation of repeat, then the performance parameters of the structure of the macro-micro-structure are of the average performance. Macro-porous materials in the fluid flow to obey the law of Darcy, and micro-cell within the fluid flow to obey Stokes equation. Darcy's law of the permeability and flow of macro-micro-flow cell linked. Adopting uniform methods of cell analysis has been calculation of the equivalent permeability of expression.In this paper, the focus is on micro-structure of the prefabricated parts cyclical performance of permeability to optimize the design, to build the largest equivalent isotropic porous media permeability of the optimization model. Because of the micro-structure of the symmetrical distribution of materials, the equivalent of cross-permeability is much smaller than the main direction of permeability, that can approximate zero, so I chose to infiltrate the direction of the main factor weighting. Relaxation as well as the design variables will be Darcy flow regularization method to discrete optimization problem into a continuous optimization problem. Against the use of uniform design theory of solid material in the cell in the distribution of cell components made by the cyclical nature of the material has the largest equivalent isotropic permeability.In this paper, two-dimensional cell for example were different from the calculation of the initial distribution of the mesh as well as the solid material to be smaller than the corresponding topology.After validation example, the initial distribution, only to the cell of an impact topology, the cyclical nature of micro-structure to be the same. Grid is the thickness of fluid - solid interface of the smoothness of an impact. The finer mesh, the more smooth solid - liquid interface is. The different size than the solid material of the micro-structure to be more or less the same configuration, is just one of the empty area of the region in accordance with changes in fluid volume.