Quasi-static full penetration tests were investigated on sandwich panels with graded polyurethane foam core and aluminum face-sheets. Results showed that the panels with decreasing foam core density (HL) create more contact force and its amount is 1.5 times the force required to penetrate into panels with increasing foam core density (LH). Also, the indenter needs the highest energy to penetrate into sandwich panel with decreasing foam core density (HL), and its value is 1.32 times the energy required to penetrate into panel with increasing foam core density (LH).
