Anisogrid lattice structure in thermoplastic composite by filament gun deposition

A new method to manufacture thermoplastic composite parts has been used to produce anisogrid lattice structures. Filament gun deposition consists of a hot-melt gun loaded with narrow thermoplastic prepreg tapes. Anisogrid lattice structures have been prototyped with 3 different geometries and 5 different numbers of layers (from 4 to 8) by using a metallic pattern and E-glass/polypropylene prepregs. Scanning calorimetry and bending tests of multi-layer samples have been used to characterize thermoplastic prepregs. Anisogrid lattice structures have been tested under tensile loads. A finite element model has been used to predict mechanical stiffness of these structures by using material properties coming from the sample characterization. Numerical models have been developed with a batch-type parametric approach to rapidly evaluate the combined effect of geometric and material parameters. A good agreement has been found between experimental and numerical data with an average difference about 4%.