连续纤维热塑性预浸丝材拉挤制备过程中纤维弯曲变形与损伤阈值的流固耦合研究OA

During the multi-die pultrusion of continuous fiber-reinforced thermoplastic prepreg filaments for additive manufacturing,fibers are prone to buckling and damage under the combined effects of high-viscosity resin flow and mold constraints,which in turn affects forming stability and mechanical properties.Aiming at the unclear coupling mechanism of non-Newtonian resin flow,heat transfer,and fiber mechanical behavior in the multi-die pultrusion process,a multi-physics fluid-structure interaction numerical model coupling the temperature field,flow field,and stress field is established based on the finite element method and Carreau viscosity model to analyze the influence of processing parameters on fiber forming behavior.A one-way fluid-structure interaction strategy is adopted to transfer resin flow loads to the fiber structure,and numerical simulations are carried out under different pultrusion speeds,mold temperatures,and mold structural parameters,combined with prepreg filament fabrication experiments and mechanical property tests of the corresponding filaments.High-performance prepreg filaments with a tensile strength of 1 047.7 MPa are stably prepared.On this basis,the critical bending deformation range for fiber damage is determined,and an equivalent elastic strain of 1.078×10-3 is proposed as the fiber bending deformation threshold for continuous and stable production,which provides a quantitative basis for the optimization of multi-die pultrusion process parameters and the design of mold systems.