Time dependent low-velocity single and multiple impact response of functionally graded (FG) untwisted and pretwisted conical shells are analysed considering porosity factor. A modified Hertzian contact law which accounts for permanent indentation is considered for the low velocity impact problem. An eight-noded isoparametric shell element is used for the finite element formulation while Newmark’s time integration algorithm is used to solve the time dependent equations. The effects of porosity considering even and uneven porosity factor, initial velocity of impactor (VOI), mass of the impactor and twist angle of FG conical shell on the transient impact response of the conical shell are examined and analyzed. The contact force and indentation increase with increase of VOI and mass of the impactor while the contact duration decreases for both the occasions. Twist angle has a significant effect on contact force but has marginal effect on contact duration. Contact force for perfect (porosity free) FG conical shells is higher than that of porous FG conical shells. Lower contact force is observed for higher porosity factor. Even porous FG conical shell predicts lower contact force and higher shell displacement than that of an uneven porous FG conical for a given porosity factor.

考虑孔隙率因素，分析了功能梯度（FG）未加捻和预加捻的锥壳随时间变化的低速单次和多次冲击响应。对于低速冲击问题，考虑了修正的赫兹接触定律，该定律考虑了永久压痕。八节点等参壳单元用于有限元公式，而纽马克（Newmark）的时间积分算法用于求解时间相关方程。考察并分析了考虑均匀孔隙率和不均匀孔隙率，冲击器的初始速度（VOI），冲击器的质量和FG圆锥壳的扭转角对圆锥壳瞬态冲击响应的影响。接触力和压痕随着VOI的增加而增加两种情况下，接触时间都会缩短，冲击器的重量和质量也会降低。扭转角对接触力有显着影响，但对接触持续时间却有很小的影响。完美（无孔）FG锥形壳的接触力高于多孔FG锥形壳的接触力。对于较高的孔隙率因子，观察到较低的接触力。对于给定的孔隙率，甚至多孔FG圆锥形壳也比不均匀的多孔FG圆锥形具有更低的接触力和更高的壳位移。