湿度对手机用纸浆模塑缓冲包装能量吸收特性的影响

Influence of relative humidity on energy absorption properties of molded pulp cushioning packaging for mobile phone

基于动态冲击试验,分析了纸浆模塑制品在冲击高度为30 cm、50 cm、80 cm及相对湿度为50%、65%、80%、90%条件下的荷载-位移数据,建立了名义应力-应变曲线和能量吸收曲线。结果表明:冲击高度一定时,随着相对湿度的增大,纸浆模塑制品的名义应力-应变曲线下移,弹性模量、屈曲临界应力明显下降,最佳能量吸收肩点向左下方移动,以RH=50%为基准,RH=65%、80%、90%时的平均第二屈曲临界应力分别下降14%、24%和42%;相对湿度一定时,随着冲击高度的增加,纸浆模塑制品的名义应力-应变曲线上移,弹性模量、屈曲临界应力明显提高,最佳能量吸收肩点向右上方移动,并且冲击高度的影响随相对湿度的增加显著增强;制品在承受冲击荷载时发生两次明显屈曲。

On the basis of impact tests,the load-deflection informations of molded pulp products were analysed under the impact height of 30cm,50cm,80cm and under the relative humidity （RH）of 50%,65%,80%,90%. Meanwhile the nominal stress-strains curves and the energy absorption curves were established.The experimental results show that：under a certain impact height,with the increase of relative humidity,the nominal stress-strain curves move downward,the elasticity modulus and buckling critical stress decrease,and the best energy absorption point offsets to the lower left.When the RH increases from 50% to 65%,80% and 90%,the average second buckling critical stress decreases by 14%,24% and 42% respectively.Under a certain RH,with the increase of impact height,the nominal stress-strain curves move upward,the elasticity modulus and buckling critical stress decrease,and the best energy absorption point offsets to the upper right,and this effect significantly enhances with the increase of RH.Under impact load,the molded products occur two obvious bucklings.