平压单瓦钙塑瓦楞纸板本构模型

为得到由纸面板和钙塑瓦楞夹芯结构复合而成的钙塑瓦楞纸板的力学行为,基于单瓦钙塑瓦楞纸板平压准静态和碰撞冲击试验,得到并分析了钙塑瓦楞纸板准静态应力-应变曲线及半正弦脉冲激励下的应力-应变曲线,结果表明钙塑瓦楞纸板应力-应变曲线呈线弹性区域、波动式上升屈服区域和压实区域;对比准静态和动态应力-应变曲线可知,钙塑瓦楞结构几乎不受应变率的影响,这是由于钙塑瓦楞的材料特性决定的。根据测试数据的三个特征与考虑粘滞性的因素,建立了钙塑瓦楞纸板的静态、动态非线性本构关系,成功识别出模型中的参数。所用的碰撞冲击试验方法为表征缓冲材料的力学行为提供了一个新的方法,同时得到的动态模型可直接应用于考虑钙塑瓦楞复合纸板箱缓冲作用的产品跌落冲击响应与优化设计。     

预压缩多层钙塑瓦楞纸板隔振性能研究

目的对不同预压程度下多层钙塑瓦楞纸板隔振特性进行研究。方法通过对不同预压程度下的钙塑瓦楞纸板进行振动试验,发现压缩率为50%的钙塑瓦楞纸板有很好的隔振效果。然后基于材料的粘弹性理论建立压缩率为50%钙塑瓦楞纸板的本构模型,并用最小二乘法识别参数,根据车辆运输包装系统建立基于1/4车辆运输模型条件下的含易损件的二自由度非线性产品包装系统模型,得到动力学方程并数值求解,并通过一个算例说明该模型可直接用于包装隔振设计。结果无量纲加速度值一般随着隔振材料面积的增大而减小,随着材料层数的增加呈现先增大后减小的变化。结论为进一步研究钙塑瓦楞纸板的隔振性以及相关包装设计提供一定的理论基础。     

组合瓦楞纸板缓冲衬垫的力学性能研究

本文研究了3A型、3B型、BAB型组合瓦楞纸板缓冲衬垫的抗弯性能和平压性能。抗弯试验结果表明,组合衬垫的载荷一挠度曲线可分为4个阶段,依次为瞬时弹性变形阶段、延迟弹性变形阶段、弹塑性变形阶段和屈服塑性变形阶段;从抗弯性能方面考虑,在对瓦楞纸板进行粘接使用时,可以将A型或B型瓦楞自行组合,但最好不要将B型或A型瓦楞与AB型瓦楞组合。平压试验结果表明,在3A型、3B型及BAB型组合瓦楞纸板缓冲衬垫的静态压缩曲线均存在三个峰值,且峰值与瓦楞纸板层数一一对应,各层按照屈服强度从小到大的顺序依次屈服、破坏;从静态压缩性能方面考虑,BAB结构的抗压性能最好,3B结构次之,3A结构最差。根据静态压缩试验绘制的瓦楞纸板缓冲系数-最大静应力曲线,为采用组合瓦楞纸板衬垫进行缓冲包装设计提供了依据。当采用该曲线进行缓冲包装时,应根据产品特性及流通环境特点,尤其是产品或包装件可能给予缓冲衬垫的静压力范围,合理选择衬垫的组合型式。     

基于静态压缩试验的缓冲包装材料性能对比分析

聚苯乙烯和聚丙烯缓冲包装材料都是粘弹性材料.通过对这2种材料在不同约束(不同加压速度,不同压缩次数)条件下进行静态压缩试验,研究这2种材料的静态特性.试验得到的数据运用Matlab软件,采用最小二乘法进行曲线拟合,得出材料的应力-应变曲线和缓冲系数-最大静应力曲线.最后分析这2种材料的静态压缩特性,并比较它们的异同点.     

空气柱衬垫缓冲性能研究

目的对空气柱衬垫的缓冲性能进行分析研究。方法通过动态压缩试验和应力-能量法得到空气柱衬垫最大加速度-静应力曲线,研究其动态缓冲性及承载力。结果得到了空气柱衬垫在不同跌落高度不同厚度的动态压缩试验曲线。结论材料缓冲性和承载能力均随着厚度增大而加强,跌落高度增大,包装件所受冲击载荷也随之增大。研究结果为进行合理缓冲包装设计提供计算依据。     

发泡聚乙烯缓冲材料的静态压缩缓冲曲线研究

本实验是模拟缓冲材料在大型包装件中的使用情况.对比并研究了EPE缓冲材料在预压缩前后所表现出的力学性能和缓冲性能.通过应力-应变曲线描述了EPE缓冲材料的静态压缩力学性能,从转化后的缓冲系数-最大应力曲线中获得最小缓冲系数及所对应的最大应力值.将对使用EPE进行缓冲包装设计起到一定的指导意义.     

丝瓜络材料静态缓冲性能试验及分析

目的 -研究得到丝瓜络材料的静态缓冲系数与最大应力曲线,为应用丝瓜络作为缓冲材料的计算提供理论依据与实验数据。方法 -参考GB 8168-1987包装用缓冲材料静态压缩试验方法,在电子万能实验机上测试不同分组样件,研究受力方向、尺寸、湿度、结构等因素对缓冲性能的影响,以及该材料与其他缓冲材料(聚脂海绵、瓦楞纸板)静态缓冲性能的对比。结果 -得到了丝瓜络材料力-位移曲线与应力-应变曲线,并计算得到了缓冲系数-最大应力曲线。结论 -丝瓜络是缓冲性能优越、环保的自然材料,可完全降解。完整的丝瓜络圆柱体纵向受压时的缓冲性能与瓦楞纸板结构以及蜂窝纸板结构类似,丝瓜络单层外壁材料可重叠横向受压,其缓冲性能与聚脂海绵类似,在大载荷情况下优于聚脂海绵。去除内芯的丝瓜络缓冲性能优于完整的丝瓜络圆柱,丝瓜络代替其他缓冲材料完全可行。     

层合方式和压缩方向对层合瓦楞纸板压缩性能的影响

目的研究层合方式和压缩方向对层合瓦楞纸板压缩性能的影响。方法通过静态压缩对平齐式和交错式等2种层合瓦楞纸板的3个方向进行实验,得到相应的应力-应变曲线,运用能量效率法对其峰应力、平均抗压强度、总吸能和比能量吸收进行对比分析。结果 2种层合方式的瓦楞纸板在x,y,z方向的应力-应变曲线走势大致相似,峰应力、平均抗压强度、总吸能和比能量吸收均为x方向最大,y方向次之,z方向最小。在x,y,z各个方向上,平齐式层合瓦楞纸板的峰应力、平均抗压强度、总吸能和比能量吸收均高于交错式层合瓦楞纸板。结论不同层合方式和压缩方向对层合瓦楞纸板压缩性能的影响较大,设计重型缓冲包装时可以优先选择平齐式层合瓦楞纸板的x方向,可以更好地达到提高缓冲效果和节约材料的目的。     

丝瓜络材料静态缓冲性能试验及分析

目的研究得到丝瓜络材料的静态缓冲系数与最大应力曲线,为应用丝瓜络作为缓冲材料的计算提供理论依据与实验数据。方法参考GB 8168—1987包装用缓冲材料静态压缩试验方法,在电子万能实验机上测试不同分组样件,研究受力方向、尺寸、湿度、结构等因素对缓冲性能的影响,以及该材料与其他缓冲材料(聚脂海绵、瓦楞纸板)静态缓冲性能的对比。结果得到了丝瓜络材料力-位移曲线与应力-应变曲线,并计算得到了缓冲系数-最大应力曲线。结论丝瓜络是缓冲性能优越、环保的自然材料,可完全降解。完整的丝瓜络圆柱体纵向受压时的缓冲性能与瓦楞纸板结构以及蜂窝纸板结构类似,丝瓜络单层外壁材料可重叠横向受压,其缓冲性能与聚脂海绵类似,在大载荷情况下优于聚脂海绵。去除内芯的丝瓜络缓冲性能优于完整的丝瓜络圆柱,丝瓜络代替其他缓冲材料完全可行。     

泡沫塑料/瓦楞纸板组合结构的缓冲性能

目的分析比较不同种类缓冲材料组合结构的缓冲性能。方法将EPS和EPE分别与单、双瓦楞纸板进行叠合,获得4种组合结构件,对上述缓冲材料进行静态压缩试验。结果得到不同材料的应力-应变曲线及缓冲系数曲线。结论泡沫塑料/双瓦楞纸板的应变能大于泡沫塑料/单瓦楞纸板;EPE/双瓦楞纸板的缓冲性能相对于EPS/双瓦楞纸板来说更为优异;泡沫塑料/双瓦楞纸板的最小缓冲系数低于相对应的泡沫塑料。     

Effect of initial pre‐compression of corrugated paperboard cushions on shock attenuation characteristics in repetitive impacts

The use of paper as a cushioning material is motivated by its environmental advantage over polymeric materials such as expanded polystyrene. Various studies have been conducted to investigate the capability of corrugated paperboard (CPB) to act as cushioning materials for protective packaging. The studies have normally focused on performance of cushions and effects of climatic conditions on the shock attenuation in the first drop. However, no information is available to show that CPB can be engineered to produce a cushioning element with good shock attenuation in repetitive impacts. This study investigates the deterioration of the shock attenuation characteristics of CPB cushions in consecutive impacts. A series of cushion‐test style experiments on multilayer cushion pads made entirely from CPB were conducted. Each cushion was first subjected to 20 impacts, followed by simulated warehousing in a climatic chamber, and then the additional 15 impacts. The effect of initial pre‐compression strain introduced in the process of making cushion pads is discussed and demonstrated. The performance of cushions was judged not only by the maximum acceleration of shocks. Entire recorded shock pulses and calculated corresponding shock response spectra were analysed and are presented as 3D maps in order to reveal trends that occur when a cushion is subjected to multiple drops. The paper shows that the level of pre‐compression has an important effect on the degree of deterioration of cushion performance after multiple drops. As an example, the maximum acceleration for a pad pre‐compressed to 95% strain increased by less than 20% between the 1st and the 35th drop. In contrast, for 80% pre‐compression, the increase was 300%. It was found that the selection of optimum static stress should be made in conjunction with the expected number of impacts in order to optimize the cushion performance. Copyright © 2009 John Wiley & Sons, Ltd.     

预压缩对蜂窝纸板能量吸收的影响

目的探究相同温湿度环境条件下,不同程度的预压缩对不同型号蜂窝纸板缓冲性能的影响。方法利用电子材料试验机对材料进行压缩,进而通过Matlab软件绘制出应力-应变曲线、静态缓冲系数曲线以及能量吸收曲线。结果预压缩限制在线弹性阶段,对蜂窝纸板各项性能无明显影响;当预压缩进入弹塑性阶段,蜂窝纸板的各项性能产生较为明显的下降;当预压缩进入塑性坍塌阶段,蜂窝纸板的各项性能显著下降,甚至丧失缓冲特性。结论随着预压缩程度的增加,蜂窝纸板静态压缩性能、静态缓冲性能及能量吸收性能都会降低。     

Enhancement of cushioning performance with paperboard crumple inserts

This paper introduces a novel approach to using multi‐layered corrugated paperboard to provide improved protection against severe mechanical shocks and drops. Conventionally, cushion design requires the determination of the maximum expected shock levels or drop heights as well as their probability of occurrence. These are usually determined from statistical analysis of original field measurements or published drop height distribution data. With this approach, it is acknowledged that the cushioning element will provide adequate protection for statistically likely events but not for extreme, statistically unusual, events. A multi‐layer cushioning system made entirely of corrugated paperboard, designed to extend the cushioning protection range to include these extreme events, has been investigated. The main feature of the cushion is the inclusion of a corrugated paperboard crumple element designed to provide the necessary energy absorption for high compression stress levels. The effect of the complex deceleration produced by the crumple element on the product is analysed by means of the shock response spectrum. Experiments have shown that the paperboard crumple insert dramatically extends the protection range of the cushioning system by generally lowering the shock response spectrum, thus extending the cushion curve static load range. This results in a significant increase in the allowable drop height for a limited number of extreme events. Although this approach may be extended to a combination of conventional cushioning materials, the benefits of providing product protection with recyclable paperboard material are significant. Copyright © 2005 John Wiley & Sons, Ltd.     

Corner Foam Versus Flat Foam: An Experimental Comparison on Cushion Performance

Most cushion structures used in the industry are end caps, edge or corner foam. The bearing area and thickness of the cushioning obtained from cushion curves apply, in principle only, to flat foam because the specimens used to develop the cushion curves are flat foam samples. This study is aimed at finding the difference between the two foams in stress–strain relationship and dynamic impact. A hysteresis cycle compression test, in conjunction with digital image correlation techniques, and a shock cushion test were performed to assess the static stress and strain, energy dissipated and maximum acceleration of flat and corner foams. The study found that the static stress of the corner foam that occurred during the compression testing is 23% higher in average than the flat foam, depending on the compression speed. The shock cushion curve of the corner foam showed a similar pattern as the flat cushion curve but was shifted horizontally to the right as a result of the increased static stress. This study recommends that the conventional cushion curve should be shifted to the right horizontally by about 23–35% in order for a packaging designer to apply it for corner foam. Copyright © 2014 John Wiley & Sons, Ltd.     

Evaluation of Static and Dynamic Cushioning Properties of Polyethylene Foam for Determining Its Cushion Curves

A comparison of static and dynamic cushioning properties of polyethylene foam is discussed in this paper. A dynamic factor function is defined and obtained from the analysis on the experimental data from compression and cushion tests. The deformation energy per unit volume is taken into consideration to make an estimate of the maximum strain and dynamic stress data in an impact, and the peak acceleration can be predicted from the compression data corrected for the dynamic effects by the dynamic factor function. Then, the cushion curves at almost every test condition, such as different drop heights or thickness of cushioning material, can be approximated by a specially developed computer code using Matlab. This research can assist in determining the accuracy of cushion curves for all variants of a particular cushioning material from the dynamic factor function and compression test data. This new procedure will greatly simplify the experimental process for determining cushion curves. Copyright © 2014 John Wiley & Sons, Ltd.     

B楞双层瓦楞纸板衬垫平压缓动态性能建模

根据B楞双层瓦楞纸板衬垫静、动态平压的测试数据,归纳出瓦楞纸板平压缓冲性能的三个基本特征及其它特点。在构造静态模型的基础上,首次建立了能较全面反映瓦楞纸板衬垫在不同条件下连续多次平压冲击时动态响应的非线性粘弹塑性模型。该模型的建立及其参数的成功识别,不仅解决了瓦楞纸板衬垫的平压动力学计算问题,为缓冲包装优化设计创造了条件;也解决了测试工作量庞大的问题,通过少量测试,识别出模型参数,便可全面掌握瓦楞纸板平压的缓冲性能。     

缓冲材料静态压缩试验数据处理辅助软件的开发

针对使用电子式包装件压力试验机测得的缓冲材料静态压缩试验数据存在的缺陷,结合缓冲包装设计的需要,运用Visual Basic编程语言开发了专门用于缓冲材料静态压缩试验数据处理软件,输入试验机测得的数据,即可方便的得到缓冲材料的应力应变曲线、缓冲系数应力、缓冲系数应变曲线,精度较高,有效的提高了数据处理和绘图的效率.     

EPE泡沫塑料在多次冲击下的缓冲性能

目的预测并分析多次冲击下EPE缓冲材料的缓冲性能。方法应用应力-能量法得到并分析多次冲击下的缓冲曲线,评价EPE缓冲材料的缓冲性能变化。结果 EPE试样在经受多次冲击后,厚度会减小,缓冲性能会下降。结论在缓冲包装设计中,要充分考虑环境因素,根据物流环境条件适当增加缓冲垫厚度,使产品得到充分防护。     

柱形空气垫静态压缩几何模型研究

目的 研究柱形空气垫静态压缩缓冲性能,将理论几何压缩模型进行试验验证,证明可行性。 方法 根据柱形空气垫受压变形特征,推导出几何压缩模型理论公式,对不同宽度、不同充气压强的柱形空气垫进行静态压缩试验,用拓色法计算理论面积,将试验曲线与理论曲线进行对比。结果 随着压缩位移的增加,接触面积曲线的理论值与试验值呈线性关系,在宽度相同的情况下,充气压强的增大导致接触面积曲线的理论值与试验值吻合程度下降;相同宽度、不同压强的柱形空气垫载荷位移曲线很接近,显示出规格才是影响柱形空气垫缓冲性能的主要因素。结论 所提出的柱形空气垫静态压缩几何模型可行。     

A new method for the determination of cushion curves

A new method for the measurement of shock‐absorbing characteristics of cushioning materials and determination of ‘cushion curves’ is discussed in this paper. The method not only significantly reduces testing time but also improves the accuracy of the estimate of a cushion curve. Cushion curves are determined from the material's static compression characteristics and the impact data (static load/peak acceleration) obtained from a small number of impacts on a cushion tester. However, the method is capable of producing a cushion curve from the measurement of just a single impact. The process involves an iterative least mean squares (ILMS) minimisation of the discrepancy between peak acceleration values predicted from a theoretical model and measured in the impact tests. The algorithm of the ILMS method, examples demonstrating its application and the dynamic effect in impacts of various materials such as the EPU, the EPS and corrugated fibreboard are presented. Copyright © 2000 John Wiley & Sons, Ltd.