Based on the static compression experiments, the compressive stress-strain curve of multi-layer corrugated boards is simplified into three sections of linear elasticity, sub-buckling going with local collapse and dens...Based on the static compression experiments, the compressive stress-strain curve of multi-layer corrugated boards is simplified into three sections of linear elasticity, sub-buckling going with local collapse and densification. By considering the structure factors of multi-layer corrugated boards, the energy absorption model is obtained and characterized by the structure factors of corrugated cell-wall. The model is standardized by the solid modulus and it is universal for corrugated structures of different basis material. In the liner-elastic section, with the increase of the load, the energy absorption per unit volume of multi-layer corrugated boards gradually increases; in the sub-buckling section going with local collapse, the compression resistance of multi-layer corrugated boards goes on under a nearly constant load, but the energy absorption per unit volume rapidly increases with the increase of the compression strain. It is shown as an ascending curve in the energy absorption diagram. In the densification section, the corrugated sandwich core has no energy absorption capability. A good consistency is achieved between theoretical and experimental energy absorption curves. In designing the cushioning package, the cushioning properties can be evaluated by the theoretical model without more experiments. The suggested method to develop the energy absorption diagram for corrugated boards can be used to characterize the cushioning properties and optimize the structures of corrugated sandwich structures.展开更多
针对退火后的2195铝锂合金在变形温度为400~490℃、应变速率为0.01~10 s^(−1)条件下进行等温热压缩实验,对获得的真应力应变曲线进行摩擦力和温升效应的修正,并基于修正后的真应力真应变建立材料的本构关系。结果表明:实验值和预测值的...针对退火后的2195铝锂合金在变形温度为400~490℃、应变速率为0.01~10 s^(−1)条件下进行等温热压缩实验,对获得的真应力应变曲线进行摩擦力和温升效应的修正,并基于修正后的真应力真应变建立材料的本构关系。结果表明:实验值和预测值的相关系数R为0.99584,平均绝对误差(AARE)为3.698%,表明所建立的本构模型能很好地预测2195铝锂合金在不同变形参数下的流动应力值;基于修正后应力应变数据,通过将流变失稳图(传统热加工图)(conventional hot processing map,CHP)与变形激活能值Q耦合,建立了激活能加工(activation energy processing,AEP)图,优化出合金的热加工窗口为:应变速率<0.4 s^(−1),温度475~490℃。展开更多
基金Funded by the National Natural Science Foundation of China (No.50905120)
文摘Based on the static compression experiments, the compressive stress-strain curve of multi-layer corrugated boards is simplified into three sections of linear elasticity, sub-buckling going with local collapse and densification. By considering the structure factors of multi-layer corrugated boards, the energy absorption model is obtained and characterized by the structure factors of corrugated cell-wall. The model is standardized by the solid modulus and it is universal for corrugated structures of different basis material. In the liner-elastic section, with the increase of the load, the energy absorption per unit volume of multi-layer corrugated boards gradually increases; in the sub-buckling section going with local collapse, the compression resistance of multi-layer corrugated boards goes on under a nearly constant load, but the energy absorption per unit volume rapidly increases with the increase of the compression strain. It is shown as an ascending curve in the energy absorption diagram. In the densification section, the corrugated sandwich core has no energy absorption capability. A good consistency is achieved between theoretical and experimental energy absorption curves. In designing the cushioning package, the cushioning properties can be evaluated by the theoretical model without more experiments. The suggested method to develop the energy absorption diagram for corrugated boards can be used to characterize the cushioning properties and optimize the structures of corrugated sandwich structures.
文摘针对退火后的2195铝锂合金在变形温度为400~490℃、应变速率为0.01~10 s^(−1)条件下进行等温热压缩实验,对获得的真应力应变曲线进行摩擦力和温升效应的修正,并基于修正后的真应力真应变建立材料的本构关系。结果表明:实验值和预测值的相关系数R为0.99584,平均绝对误差(AARE)为3.698%,表明所建立的本构模型能很好地预测2195铝锂合金在不同变形参数下的流动应力值;基于修正后应力应变数据,通过将流变失稳图(传统热加工图)(conventional hot processing map,CHP)与变形激活能值Q耦合,建立了激活能加工(activation energy processing,AEP)图,优化出合金的热加工窗口为:应变速率<0.4 s^(−1),温度475~490℃。
