Dynamic response and failure of CFRP Kagome lattice core sandwich panels subjected to low-velocity impact.

• Fiber fracture, matrix crack, delamination of face sheets, rib inclining/fracture of lattice core, and debonding are the active failure modes of sandwich panel. • The sandwich panel struck by the flat impactor nose has the highest energy absorption among three impactor noses. • The large impactor nose size brings about the high peak load, the long response time and the high energy absorption. • The energy absorption of andwich panel struck at interlace point of lattice core is highest among four impact positions. Dynamic response and failure of carbon fiber reinforced plastic (CFRP) Kagome lattice core sandwich panels subjected to low-velocity impact were investigated experimentally and numerically. The geometrical shapes of the impactor noses are flat, hemispherical, and conical. The active failure modes of fiber fracture, matrix crack, delamination of face sheets, rib inclining/fracture of lattice core, and debonding were observed in experiment. The impactor nose shape has significant influence on the failure modes of sandwich panels. The energy absorption of sandwich panel increases with increasing impact velocity. The sandwich panel struck by the flat impactor has the highest energy absorption among three impactor noses. Finite element (FE) simulations implementing a user-defined material subroutine (VUMAT) of Hashin criterion and progressive degradation were performed and agree well with the experimental results. It is shown that both dynamic response and energy absorption of the sandwich panels are sensitive to the impactor size and impact position. [ABSTRACT FROM AUTHOR]