Research On In-plane Stiffness’s And Strength’s Prediction Model Of Stitched Composite Laminates

Stitched composites strengthens the Z-direction mechanical properties by add stitches in thethickness direction, overcoming the weak impact resistance, damage tolerance and low defects inthickness direction of the traditional laminate, which has a wide range of applications in engineeringpractice. Accurately predict the mechanical properties of stitched composites, is a prerequisite for itsapplication and development. In this paper, the proposed prediction model of composite Laminatesin-plane stiffness and strength was established based on the stitched composite microstructure. Mainlyincludes the following contents:Based on the meso-scale structure of stitched laminates, the parametric suture laminate finiteelement model of a single cell was established for different diameters and different densitiestoughened, considering the impact of the suture causing thickening shelves across the fiber volumecontent. By introducing additional periodic boundary conditions, developing stitched proposedcomposite single plate finite element stiffness prediction model。Based on the ANSYS, finite elementstiffness prediction progressive for the stitched and unstitched composite materials and laminatedplate is established. The error between prediction results and document’s results is less than10%.Based on the flow around the column-suture analogy model with considering any direction offlow around the column to resin surrounding any direction elliptical cross-section stitches improvedthe flow around45°column-suture analogy model,and based on that fluid numerical analysis withfinite element analysis based on unit cell modeling method and the theoretical solution of fluid withfinite element analysis based on the theory of fluid unit cell modeling method was established,assessed the accuracy and efficiency of stiffness analysis method established in this paper.Based on the prediction method of monolayer plate’s stiffness,Introduceing the strength failurecriterion, established gradually cumulative damage analysis method and gradually damage analysismethod based on overseas model of stitched composite’s strength,which compared with theexperimental results of the literature, verified the effectiveness of the method to establish the strengthanalysis. Based on the ANSYS, a simulation program of the model is written, progressive failureanalysis of a single cell under drawing loads is simulated, and the failure mechanism.isanalyzed.,prediction results are in good agreement with literature results.