Bi-directional porous beams under low-velocity impact: Made of carbon fiber reinforced PLA, fabrication with 3D printer and testing with impact equipment

In this article, two-dimensional functionally graded porous types <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mo>∧</mml:mo> </mml:mrow> </mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mo>∨</mml:mo> </mml:mrow> </mml:math> (2D-FGP <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mo>∧</mml:mo> </mml:mrow> </mml:math> and 2D-FGP <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mo>∨</mml:mo> </mml:mrow> </mml:math> ) are manufactured using a 3D printer. This is made feasible by technological advancements that have made it possible to make complicated parts that were before unattainable. The Polylactic acid reinforced with carbon fiber (PLA-CF) is fed into a 3D printer to create the beams. The low-velocity impact attributes of the beams, such as histories of contact force, impactor displacement, and absorbed energy, are extracted using drop-weight impact testing equipment. The 2D-FGP <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mo>∧</mml:mo> </mml:mrow> </mml:math> and 2D-FGP <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mo>∨</mml:mo> </mml:mrow> </mml:math> beams with varied hole diameters are tested in a variety of impactor initial energies till are broken. The significant findings indicate that the 2D-FGP <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mo>∧</mml:mo> </mml:mrow> </mml:math> distribution’s peak contact force is greater than the 2D-FGP <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mo>∨</mml:mo> </mml:mrow> </mml:math> distribution and that this trend is reversed for impact time, absorbed energy and peak impactor displacement. In both 2D-FGP <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mo>∧</mml:mo> </mml:mrow> </mml:math> and 2D-FGP <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mo>∨</mml:mo> </mml:mrow> </mml:math> scenarios, the beams break at a lower energy as the hole diameter grows. A non-linear polynomial equation that incorporates the inputs of hole diameters, impactor initial energy and hole type distribution is provided to forecast the peak contact force and absorbed energy.