摘要
应用INSTRON 9250HV型落锤冲击试验系统和有限元技术研究了不同湿度下纸浆模塑制品的冲击压缩过程、承载能力、能量吸收特性。结果表明:纸浆模塑材料的弹性模量和屈服应力均随相对湿度的增高显著下降,90%相对湿度下纸浆模塑材料的弹性模量和屈服应力分别仅为50%环境湿度下的弹性模量和屈服应力的44.5%和37.6%;有限元分析得到的纸托制品含有湿度信息的冲击压缩载荷-变形曲线、能量吸收曲线与相应实验结果一致;纸浆模塑制品的冲击承载能力和吸能性能随着湿度的增大显著下降,90%相对湿度下纸托制品第一次和第二次的屈曲载荷分别仅为50%相对湿度下的屈曲载荷的44.8%和47.9%;纸托制品设计时应以下层支撑结构冲击压溃为设计限度,下层支撑结构压溃时的名义应力值和能量吸收值即为纸托制品设计的最佳吸能点(吸能设计限值)。
The impact of molded pulp products is investigated by using the INSTRON 9250HV impact experiment system and finite element method,and the impact compression process,load carrying capacity and energy absorbing characters are obtained for molded pulp products under different humidity conditions.The elastic modulus and yield strengths of the molded pulp materials decrease remarkably with the increasing of the relative humidity,for example,under the 90% humidity condition they are 44.5% and 37.6% respectively to those under the 50% humidity condition.The impact load-deformation curves and energy absorbing curves of the molded pulp trays are obtained by using the finite element method under the different humidity are consistent with those by the experimental tests.The impact load carrying capacity and energy absorbing of molded pulp products decrease remarkably with the increasing of the relative humidity,and the first and second buckling loads under the 90% humidity condition are respectively 44.8% and 47.9% to those under the 50% humidity condition.For the two layer structure,the impact response of the molded pulp tray exhibits the two buckling processes phenomena.The first buckling is corresponding to the collapse of the underlayer supporting,and the second buckling is corresponding to the collapse of the uplayer supporting.The impact collapse of the underlayer supporting should be taken as the safety design limit in the design of the molded pulp trays,and the nominal stress and energy absorbing of the collapse of the underlayer supporting form the best point of energy absorbing（the limit of energy absorbing） for practical design.
出处
《应用力学学报》
CAS
CSCD
北大核心
2013年第4期593-597,650-651,共5页
Chinese Journal of Applied Mechanics
基金
国家自然科学基金项目(50775100)
中央高校基本科研业务费专项资金项目(11612456)
关键词
纸浆模塑制品
冲击压缩
有限元
能量吸收
相对湿度
molded pulp products
impact compression
finite element method
energy absorbing
relative humidity.
