Tunable pull-through energy attenuator and decelerator devices is disclosed which provide for variable force-time profiles, deceleration and kinetic energy attenuation of moving objects so as to prevent damage or injury to impacting objects, vehicles or persons. The device employs either consumable inelastic or reusable, viscoelastic deforming elements, such as tubes, rods, plates or strips, which absorb substantial amounts of energy through repeated inelastic or viscoelastic deformation when the deforming element is pulled-through a tunable array of rigid pins having a variety of configurations and settings. The disclosed devices provide for variable force-time profiles which control the cumulative deformation and thereby the amount of energy absorbed and rate of deceleration of impacting objects. The device may be readily adapted and deployed as highway vehicle guardrails, road barriers or crash cushions for frontal and side impacts and as load attenuators for crash-resistant aircraft seats, spacecraft landing pods, crash-resistant aircraft landing gear, aircraft and vehicle passenger restraint harnesses, cargo tie-downs, vehicle bumpers and collapsible vehicle steering columns.