2018 Volume 5 Issue 1 Pages 17-00087
The effects of the point angle of a metal anchor and the angle between the target and the plane perpendicular to the direction of travel of the anchor (target angle) on the docking state of the anchor in a satellite structure were experimentally and numerically evaluated. Projectile experiments were conducted using test plates at target angles of 0°, 30°, 45°, and 60° and two metal anchors with conical tips with different point angles (60° and 90°) to investigate the effects of the anchor point angle and the target angle and determine the minimum penetration velocity in each case. The experimental results indicate that the minimum penetration velocity increases as the target angle increases. Because of the limitations of the experimental equipment, performing experiments at certain target angles is difficult; thus, an accurate numerical simulation model was developed based on the experimental results to enable a more detailed investigation. The simulation results obtained using a bilinear isotropic hardening model and three Johnson-Cook models with different sets of parameters were compared with the experimental results to evaluate their applicability. Besides, the applicability of the numerical simulation model are also evaluated by experiments with different metal anchor shape and target plate thickness. It was confirmed that Johnson-Cook models can be used to effectively simulate the docking state and minimum penetration velocity of a metal anchor projection at different target angles. The effects of the point and target angles on the docking state of the metal anchors were investigated more quantitatively through numerical analysis. The numerical analysis results indicate that the minimum penetration velocities of the metal anchor with the smaller point angle (60°) are smaller than those of the metal anchor with the larger point angle (90°) when the angle of attack, which is the angle complementary angle to the target angle, is larger than half of the anchor point angle. When the angle of attack is smaller than this critical value, the metal anchor passes through the target at the minimum penetration velocity, and the conditions are not suitable for docking. The experimental and numerical simulation results indicate that a metal anchor with a smaller point angle can more easily penetrate a target plate and the angle of attack should be larger than half of the anchor point angle to achieve an adequate docking state.