Additive manufacturing (AM) is a novel technology which allows fabrication of complex geometries from digital representations without using any tooling. In addition, this technology results in low material waste, short lead times and cost reduction especially for low-quantity parts production. Although metal AM technology is already in use for the production of load bearing metallic components, additively manufactured polymers and polymer matrix composites can find only limited usage currently. Major applications of polymers and polymer composites are in rapid prototyping of objects where mechanical loading is minimal.  We have recently shown that (Celik et al, Additive Manufacturing Journal, 2020) short fiber reinforced thermoset composites can be additively manufactured in highly complex geometries and these structures possess mechanical properties exceeding those of their metallic counterparts. In this reference study, we reinforced epoxy thermoset matrix with highly loaded (up to 46% by volume), short carbon fibers and used direct write additive manufacturing technology to fabricate composite structures with unprecedented mechanical performances.

In this current work, we investigate the application of direct write additive manufacturing technology for the fabrication of sandwich panels. Additive manufacturing of fiber reinforced sandwich panels possesses tremendous potential in terms of combining design flexibility, high strength and light weigh performance compared to the traditional engineering materials. A sandwich panel can be defined as an engineering structure which is made of a thin skin covering a low-density core on both (top and bottom) sides. Sandwich panels are commonly used in various applications where high structural rigidity and low weight are both required.

Current additive manufacturing processes developed for thermoplastic sandwich panels suffer from an unavoidable weak mechanical performance and low thermal resistance. To overcome these limitations, emphasis is paid in this study on identifying the potential of AM technology for short carbon fiber‐reinforced sandwich panels composites using direct write additive manufacturing. Sandwich panels using different infill densities with unprecedented strength (>107 MPa), and high short carbon fiber volume (46%) were attained successfully. In parallel to high level of strength enhancement, lightweight composites (0.72 g/cc3) in the form of sandwich panels were obtained. The mechanical performance of the created sandwich panels was examined and compared to unreinforced, base ink structures by performing compression tests. Successful fabrication and characterization of the additively manufactured thermoset-based carbon fiber reinforced sandwich panels in this study can open doors for wide range of applications that require lightweight structures, high mechanical performance as well as the desired component complexity.


Direct Write Additive Manufacturing of High-Strength, Short Fiber Reinforced Sandwich Panels

Division / Sponsors: 
Aerospace, Bioengineering, Applied Mechanics, Design Engineering Division, Advanced Energy Systems, Manufacturing Engineering Division, Noise Control and Acoustics, Nondestructive Evaluation, Diagnosis, and Prognosis (NDPD), Nuclear Engineering Division, Process Industries Division, Fluids Engineering, Heat Transfer, Materials, Microelectromechanical Systems, Safety Engineering and Risk Analysis, Computers & Information in Engineering


Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2020/volume/84478

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