TPMS-based Modeling Of Metal Fiber Porous Structure For Permeability Simulation

Porous metal fiber sintered sheet(PMFSS) is a new-style structural function material. With the features of complex network structure, high porosity, large specific surface area, etc., it has been increasingly applied in metallurgical machinery, petrochemical, national defense and other fields. The key techniques are thoroughly discussed aiming at the microscopic flat surface structure of PMFSS in this paper, including micro-structure information extracting through Micro-CT scanning and image processing, parameterized modeling for stratified random fiber network structure based on triply periodic minimal surfaces(TPMS), numerical simulation for its permeability, and coupling relation of structural function. The main contributions are as follows:1. TPMS method is introduced to describe the porous fiber structure and its flat surface feature. For the digital modeling, several morphology statistics are extracted through Micro-CT scanning and image processing method, including the type, length, and pose angle of per fiber segment. Then based on quantitative analysis on these morphology statistics, the fiber diameter and spatial orientation are effectively controlled through TPMS function parameters adjustment and geometric transformation. Finally visual TPMS modeling is achieved on Open CASCADE platform, which is provided to prepare for following permeability analysis.2. The permeability of PMFSS which has different 3D geometric structure is analyzed. Based on statistical data of metal fiber porous structural material, three-dimensional geometric models with various structure characteristics are built by changing the number of fibers, the deviation angle, and modulation surfaces. Some results can be obtained from simulation analyses of fluid properties, including that in-plane permeability of porous structure is higher than that of through-plane direction. And normally, material with higher density has a lower permeability. In-plane permeability has a negative correlation with deviation angle while through-plane permeability has a positive correlation. In additions, the permeability has a negative correlation with the smooth of fiber surface, which has a significant impact on in-plane permeability.3. The gradient composite structure of porous metal fiber is designed, and then its permeability is discussed. The gradient composite structure is generated by combining two different structural models. The simulation results reveal that structure with different gradient has better permeability than a normal structure does. The structure with gradient feature order that is from lower density to higher density, or large deviation angle to small angle, has a large permeability.