Cushioning characteristics of a soft landing airbag with elastic fabric

Base on the energy conservation principle and thermo-dynamics equations, an analytical model of a soft landing airbag considering the elasticity of fabric was presented and validated by LS-DYNA. Then, this model was used to investigate the deceleration characteristics of a horizontal cylinder airbag. A series of simulations were conducted to find out the influence of fabric elasticity, initial inflation pressure and venting orifice area on cushioning properties. Numerical results showed that the maximum deceleration of payload in creases with decrease in fabric elasticity modulus; especially, when the elasticity modulus is lower than 0.2Gpa, the influence of fabric elasticity on cushioning properties will become more obvious; the initial inflation pressure also is a key parameter to affect the cushioning properties, and the maximum deceleration decreases with increase in initial inflation pressure, but at the same time the ending velocity of the payload will have a tiny increase; during design of a soft landing airbag, the size of the venting orifice of the airbag needs to optimize; if the venting orifice area is too small, the airbag will rebound because the impact energy can not be released in time; but if the venting orifice is too large, the ending velocity of the payload will exceed the limitation because no enough impact energy is transferred to the airbag attenuation system.