The literature is surveyed to determine human tolerance to rapidly applied accelerations. Pertinent human and animal experiments applicable to space flight and to crash impact forces are analyzed and discussed. These data are compared and presented on the basis of a trapezoidal pulse. The effects of body restraint and of acceleration direction, onset rate, and plateau duration on the maximum tolerable and survivable rapidly applied accelerations are shown. Results of the survey indicate that adequate torso and extremity restraint is the primary variable in tolerance to rapidly applied accelerations. The harness, or restraint system, must be arranged to transmit the major portion of the accelerating force directly to the pelvic structure and not via the vertebral column. When the conditions of adequate restraint have been met, then the other variables, direction, magnitude, and onset rate of rapidly applied accelerations, govern maximum tolerance and injury limits. The results also indicate that adequately stressed aft-faced passenger seats offer maximum complete body support with minimum objectionable harnessing. Such a seat, whether designed for 20-, 30-, or 40-G dynamic loading, would include lap strap, chest (axillary) strap, and winged-back seat to increase headward and lateral G protection, full-height integral head rest, arm rests (load-bearing) with recessed hand-holds and provisions to prevent arms from slipping either laterally or beyond the seat back, and leg support to keep the legs from being wedged under the seat. For crew members and others whose duties require forward-facing seats, maximum complete body support requires lap, shoulder, and thigh straps, lap-belt tie-down strap, and full-height seat back with integral head support.

Human tolerance to rapidly applied accelerations: a summary of the literature (body restraints)

Dual-mechanism auxetic-core protective sandwich structure under blast loading

Shock waves are High pressure & Energy carrying transport media, Often Military Vehicles are subject to these shock waves. A Numerical analysis of floor-plate Armox-500T, an armoured grade steel for vehicle floorplate and occupants in the event of mine detonation under the vehicle cabin with Dynamic Explicit Finite Element Code LS-DYNA software was carried out, the shock wave from the mine was modelled approximately using Conwep and the vehicle driver was represented by using a Hybrid III dummy. The simulations found details of the model which includes, the displacement, the velocity, the acceleration, variation in the energy of the cabin's floor-plate, the stress the overpressure and the response of the dummy, obtained results were compared to experimental Results for validation

Lakshman Rao

Papers

Computatational Assessment of Protective Capabilities of Vehicle Floor, Seat and Occupant Response under Shock Loads