考虑织布弹性的软着陆气囊缓冲特性研究

Cushioning characteristics of a soft landing airbag with elastic fabric

对缓冲气囊模型进行合理简化,从能量守恒和热力学基本方程出发,计入气囊织布弹性势能的影响,建立了缓冲气囊的物理解析分析模型,同时采用LS-DYNA对其有效性进行了验证。并基于该模型,进行了水平圆柱式气囊缓冲特性的研究。研究结果表明对于带固定排气口的水平圆柱式气囊,忽略织布弹性,得到的最大冲击过载值要比弹性织布气囊低,若织布的弹性模量小于0.2 GPa时,织布弹性对缓冲性能的影响更加突出。初始充气压力以及排气口面积对此类气囊缓冲特性同样有显著的影响。增加初始充气压力可以降低气囊缓冲过程中的最大冲击过载,但是有效载荷触地速度有所提高。排气口面积过小,释能不充分,气囊将发生反弹,排气口面积过大,能量转化不够,有效载荷触地速度较高。

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 infla tion 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 limi tation because no enough impact energy is transferred to the airbag attenuation system.