Automated Fiber Placement And In-situ Consolidation Process Of CF/PEEK Lattice Structure

Composite lattice sandwich structure is a new generation of ideal structure integrating material,structure and function design,with many excellent properties such as light weight,high specific strength,high specific rigidity,and strong designability.However,the existing fabrication technology of the composite lattice sandwich structure has problems with complex fabrication process,high cost,low material utilization,and poor automation,which severely restricts the industrial application.Aiming at the high load-bearing efficiency and low-cost manufacturing of the thermoplastic composite lattice sandwich structure,the article proposes a new fabrication technology for CF/PEEK lattice sandwich structure based on automated fiber placement and in-situ consolidation process,develops the lattice structure manufacturing setup capable of automated fiber placement and in-situ consolidation of thermoplastic composite tape,and focuses on the influence of process parameters on the mechanical property and trajectory placement quality under the new fabrication technology,in order to choose the optimum parameters according to research,ensuring the performance of the final composite lattice sandwich structure.The article mainly involves the following aspects:A meso-scale lattice structure manufacturing setup capable of automated fiber placement and in-situ consolidation of thermoplastic composite tape is developed.For proposing the overall design plan of the setup,the working way and functional requirements of the setup are analyzed,and the design scheme and structure design of major modules including heating and pressurization apparatus are completed.And then the automatic placement prototype head of thermoplastic composites tape consisting of selected and manufactured relevant parts is installed on the three-axis movement platform.Movement platform can realize the movement of the automatic placement prototype head on a predetermined trajectory in space through the G code.The last is to debug the whole setup.The setup can manufacture CF/PEEK lattice cores and other specimens required for the process research of the subject based on automated fiber placement and in-situ consolidation process.The influence of automated fiber placement and in-situ consolidation process parameters on interlaminar bonding performance of meso-scale structure is analyzed,in order to ensure the mechanical property of final specimens.Taking the meso-scale thermoplastic composite laminate as a representative structure,aiming to improve its mechanical property,the meso-scale automated fiber placement and in-situ consolidation process is studied.Using interlaminar shear strength(ILSS)and micro morphology as characterization approach,design of experiments using a single factor approach and response surface approach is employed to investigate the influence of major automated fiber placement and in-situ consolidation process parameters including placement pressure,placement temperature and placement speed on the interlaminar mechanical property.A prediction model between parameters and mechanical property is established,obtaining the optimal combination of process parameters within the scope of the experiments.The influence of automated fiber placement and in-situ consolidation process parameters on curve trajectory placement quality of prepreg tape is analyzed,in order to improve the placement quality of the first layer of prepreg tape at corners of lattice core.Selecting transition round corner between the straight rod and the inclined rod of lattice cores as the research object,the maximum angle between the inclined rod of lattice core and the horizontal plane under the manufacturing constraints is explored.And the influence of major automated fiber placement and in-situ consolidation process parameters,that is placement pressure,placement temperature and placement speed,on curve trajectory placement quality at the concave-convex round corner of lattice structure is investigated.The fabrication procedure of the composite lattice sandwich structure based on automated fiber placement and in-situ consolidation process is proposed.And adhesive strength of two different connection method,that is the automated fiber placement and in-situ consolidation method and the glue method,is also compared.The influence of core process parameters such as number of layers of prepreg tape and placement sequence of prepreg tape at the cross node on flatwise compression performance of lattice sandwich structure is analyzed.And the flatwise compression performance and the failure mode of the lattice sandwich structure under different process parameters are also theoretically analyzed.The mechanical property of thermoplastic composite lattice sandwich structure manufactured by different fabrication process is compared,in order to evaluate the lattice sandwich structure fabrication process proposed in this article.