Comparison of various loose fill cushioning materials based on protective and environmental performance

This paper compares various loose fill packaging materials based on the amount of material required for a given level of protection. A methodology developed to evaluate and compare package cushioning materials on the basis of environmental concerns relative to disposal and recycling is used to compare seven different loose fill materials. The materials compared include recycled expanded polystyrene (EPS), starch and paper based materials, wood shavings and popcorn. The shock level G was related to the amount of cushion material needed both by weight and by volume. The results show that starch-based loose fill materials (Naturpack and Eco-Foam) and Fiberflow showed the best protective performance and minimum material utilization by volume. 100% recycled EPS showed the best performance in terms of percent weight utilization. Other materials tested, like popcorn and wood shavings, showed poor material utilization.     

Evaluation of Two Simplified Methods for Determining Cushion Curves of Closed Cell Foams

Because of the negative environmental impact of using traditional polymeric materials for cushioning in protective packaging, the interest in optimization of cushion design resulting in replacement or reduction of the amount of cushioning materials has increased in recent years. It has been generally accepted that the shock absorbing characteristics for cushioning materials are presented as the so‐called cushion curves, i.e. graphs of peak acceleration of shocks versus the corresponding static stress, presented over a range of static stress conditions for a specific material thickness and at a specific drop height. The cushion curves are mainly used to design and optimize cushion packaging. This information is specific to each packaging manufacturer, particular chemical formulation and manufacturing process. The traditional method to obtain cushion curves of a specific material is described in ASTM D1596, but this method requires enormous amounts of test data, is time consuming and expensive. For this reason, cushion curves provided by manufacturers are rarely updated and often are obsolete. In recent years, alternative methods have been developed to obtain cushion curves in a significantly shorter time required for testing. To achieve a wide use of these methods, it is necessary to know their accuracy in comparison with the ASTM D1596 method. The objective of this paper is to compare two of those alternative methods with the standard ASTM D1596 method, by applying them to obtain the cushion curves of two typical cushioning materials. More specifically, the single compression data method developed by Sek et al. and the stress–energy method (dynamic stress versus dynamic energy) developed by Burgess were applied to obtain cushion curves for expanded polystyrene with density 15 kg/m³ and for polyethylene Ethafoam® (Modisprem S.A. Zaragoza, Spain) with density 29 kg/m³ and are presented in this paper. The effectiveness of these alternative methods for developing cushion curves and their advantages, disadvantages and limitations are discussed. Copyright © 2011 John Wiley & Sons, Ltd.     

基于不同防护材料易碎品运输可靠性结构设计

目的研究易碎品在运输包装过程中不同防护材质缓冲包装结构的防护性能。方法通过Ansys Workbench中的模态分析(Modal)和随机振动分析模块(RandomVibration),对模型进行模态和随机振动仿真分析,得到易碎品的各向应力、位移、总应力等,分析对比2种防护材质的仿真结果,选取最优的缓冲方案,并进行随机振动和跌落实验。结果 2种防护材质下缓冲结构都具有良好的防护性能,选择设计的EPE缓冲结构更具有经济环保性,且在随机振动和跌落试验中,包装件没有发生变形和损坏,内容物完好。结论为易碎品低成本、高可靠性的结构设计提供了思路,也为产品性能的预测和运输方案的检测提供了一种分析手段。     

松散填充材料的缓冲性能研究

松散填充材料可以用于对任意规格尺寸及形状的产品进行缓冲包装和固定,具有包装作业的方便性和适用性。松散填充材料的载荷能力、缓冲包装性能及对产品的固定作用,决定了这一材料的包装保护功能。通过对4种结构形状的松散填充材料在静态压缩、动态冲击和迁移性方面的测试与评价,分析了各种松散填充材料的包装性能,并与纸浆模制松散填充材料进行了比较,说明了松散填充材料单体结构形状对其缓冲性能和固定作用的影响。     

某型包装箱的低密度聚乙烯缓冲结构设计与分析

目的 基于低密度聚乙烯材料设计一种包装箱的缓冲结构,以满足冲击加速度的设计要求。方法 采用低密度聚乙烯材料对应的最大加速度-静应力曲线进行理论计算,设计出包装箱缓冲结构的初始模型,运用Ansys Workbench有限元仿真软件对包装箱整体进行水平跌落仿真,并对仿真结果进行分析。结果 当缓冲垫设计厚度为75 mm时,包装箱整体跌落后受到的最大冲击加速度低于40g,满足设计要求。结论 基于低密度聚乙烯材料设计的缓冲结构能够对包装箱提供有效的缓冲防护,缓冲性能满足要求。     

电饭煲运输包装设计及跌落仿真分析

为研究电饭煲在流通过程中运输包装的缓冲性能,选择了环保型的缓冲材料发泡聚乙烯(EPE)为缓冲衬垫、AB型瓦楞纸板为外包装箱进行缓冲包装设计。根据电饭煲的规格和缓冲要求,对缓冲衬垫和外包装箱的结构进行了计算和设计,并利用Solidworks软件进行建模,并将其导入ANSYS中,设置各层缓冲包装材料的参数后,进行了自由落体跌落仿真试验;通过分析电饭煲运输包装件与地面接触瞬间的应力分布云图和最大应力曲线,发现在跌落过程中的最大应力出现在外包装箱与地面接触位置,最大应力小于电饭煲材料ABS的极限应力。因此,所设计的运输包装满足产品的缓冲要求,达到了保护电饭煲的目的。     

溶解浆纤维增强缓冲材料的制备及其性能研究

随着日益增长的环保要求,来源于植物源的可降解缓冲包装材料的使用和开发引起了广泛的关注。鉴于此,本文以3种不同植物源的商业溶解浆为原料,基于其在NaOH/尿素水溶液中的溶解,通过模塑成型-再生进行了溶解浆纤维增强缓冲包装材料的制备研究。通过模塑成型材料干燥前后径向与厚度方向尺寸的测量,比较了不同助剂制备的缓冲材料的径向收缩率与厚度方向的收缩率,借助扫描电镜观察了制备的材料的断面形貌,通过拉伸试验绘制应力-应变曲线来分析浆纤维缓冲材料的力学性能,通过振动缓冲性能测试比较了制备的材料的振动缓冲性能。结果表明在7%NaOH/12%尿素水溶液中溶解和在99.5%CH3COOH中再生制备的材料比较柔软、再生容易。另外阔叶木溶解浆纤维制备的缓冲材料较硬,针叶木溶解浆纤维制备的缓冲材料和添加淀粉的竹溶解浆纤维制备的缓冲材料具备一定的振动缓冲性能。添加淀粉制备的竹溶解浆纤维缓冲材料的径向收缩率和厚度方向收缩率都是较小的,且有35%的延伸率。     

Monitoring the Evolution of Damage in Packaging Systems under Sustained Random Loads

The ability of protective packaging systems to withstand dynamic loads during transportation is an important consideration when it comes to selecting a suitable material. The performance characteristics of packaging systems are best determined by subjecting the systems (such as cushioning materials and containers) to sustained random loads under controlled conditions. It is during these fatigue endurance tests that the loss of structural integrity of a material or an element needs to be quantified. The research presented herein uses two recently developed continuous structural integrity assessment techniques to evaluate variations in the mechanical properties (namely stiffness) of typical packaging elements. The first technique is based on the short‐time Fourier transform, and the other uses an adaptive digital finite impulse response (FIR) filter technique developed by the authors. The effectiveness and the limitations of the techniques were evaluated by undertaking selected controlled experiments during which damage was simulated by varying the length of a single degree‐of‐freedom vibratory system subjected to random base excitation. The materials used for the controlled experiments include steel, aluminium, acrylic and carbon fibre. Results show that, although both methods are capable of identifying the level of damage and the time at which it occurs, the FIR technique is generally more sensitive and better able to detect small changes in stiffness. Finally, the ability of integrity assessment techniques to monitor the progression of damage in real packaging elements, such as biodegradable air cushions and corrugated paperboard containers, was established. The analysis of real protective packaging elements subjected to random loads using both structural integrity assessment techniques yielded positive results. Generally, the adaptive FIR technique was found to be more sensitive in detecting small changes in system characteristics, even when the estimates were obtained with relatively coarse temporal resolution. Overall, the results presented in this study indicate that the adaptive FIR technique can be a practical and effective tool for establishing the ability of materials and structures to withstand sustained random loads. Copyright © 2011 John Wiley & Sons, Ltd.     

两种缓冲材料并列组合的包装设计

提出了一种利用线弹性体材料的力学数据进行缓冲包装结构设计的方法,进行了详细的理论推导,得到了计算两种线弹性缓冲材料并列组合时结构尺寸的关系式。并对组合条件下的缓冲效果进行了讨论。     

面向绿色缓冲包装的包装教学

介绍了绿色缓冲包装的内容,分析了一些缓冲材料的环保特点,结合两种新型缓冲材料,探讨了新型缓冲材料对包装教学的新要求.论述了缓冲包装教学的学科方向,提出一些包装教学的改进对策.     

聚乙烯缓冲材料多自由度跌落包装系统优化设计

在测试基础上,依据粘弹性力学理论,建立发泡聚乙烯缓冲材料动态非线性本构模型,并成功识别了模型参数;应用此模型在一定高度跌落冲击下,建立了多自由度包装系统动力学方程;依据物品响应加速度小于许用值及材料用量最小化两个原则,进行多自由度系统缓冲包装优化设计并获得最优解;基于最优解结构尺寸,测试了发泡聚乙烯缓冲系统的加速度响应值,数值算例及试验的结果表明理论值与试验值的平均相对误差都在0.8%以内。利用此设计方法可有效地避免欠包装和过度包装,克服了最大加速度-静应力曲线不能设计多自由度缓冲包装设计的弊端     

缓冲包装用明胶-淀粉泡沫的性能研究

目的以明胶和预胶化淀粉为原料制备具有缓冲效果的生物质可降解泡沫材料,为缓冲包装用生物质泡沫提供一种新的选择。方法通过对不同明胶-淀粉质量比、固含量、十二烷基硫酸钠(SDS)用量进行实验研究,并进行结构表征及静态压缩性能测定对泡沫材料进行综合评价。结果得到了明胶-淀粉缓冲泡沫材料的最优条件,固含量(用质量分数表示)为20%,表面活性剂质量分数为0.75%,明胶-淀粉质量比为70∶30。在此最优条件下的明胶-淀粉缓冲泡沫材料发泡倍率为5.14倍,表观密度为0.064 g/cm³,弹性模量为36.64 kPa,50%抗压强度为2.49 kPa。结论以明胶和预胶化淀粉为原料制备的复合泡沫材料具有表观密度低、缓冲性能较好的特点。单因素实验结果表明,预胶化淀粉对泡沫的力学性能有增强作用。     

基于计算智能的包装件非线性特性识别研究进展

将人工神经网络方法,模糊自适应控制技术与进化计算应用于包装件缓冲垫层非线性特性的识别问题,可以给出一种为评价、论证与设计缓冲包装提供理论依据的新途径,概述了有关该问题的若干进展情况,讨论了存在的问题并指出了有关的研究发展方向。     

泡沫塑料包装衬垫缓冲性能建模

本文从非线性粘弹性物质的多重积分型本构方程出发,引入塑性应变,推导了粘弹塑性物质的微分型本构方程.进一步考虑材料的损伤特性,建立了泡沫塑料包装衬垫的缓冲性能模型.根据在一种跌落高度、衬垫厚度和静态应力组合条件下的国产可发聚苯乙烯沫泡塑料的连续多次跌落冲击试验数据,识别了其缓冲性能模型参数.动力学计算与试验结果的比较表明,该模型能较好地反映可发聚苯乙烯泡沫塑料包装衬垫在连续多次跌落冲击过程中的加速度、速度、位移变化,冲击能量的吸收性和塑性变形等基本特性.并且仅根据在一种组合条件下的试验数据所识别的这一模型,在其它组合条件下其缓冲性能与试验结果也吻合较好.     

蜂窝纸板/EPE组合材料的动态缓冲性能

对发泡聚乙烯、蜂窝纸板及其组合材料进行动态压缩试验,测试这些材料的动态缓冲性能,目的是考察组合后材料缓冲性能的变化,以及组合方式对缓冲性能的影响。测试结果表明:组合结构兼有两者的优点,对可变载荷的缓冲与防振具有一定的自适应性能力;采用厚度较大的蜂窝纸板有利于提高组合材料对大载荷的缓冲性能;采用一定厚度的发泡聚乙烯可较大幅度地提高组合材料的缓冲性能。     

正切型弹性体材料的缓冲包装设计

提出一种利用正切型弹性体材料的力学数据进行缓冲包装结构设计的方法,对这种方法的原理进行详细的理论推导,得出计算缓冲垫结构尺寸的关系式。该关系式简单实用,设计出的缓冲衬垫具有最佳的理论缓冲效率。     

空降携行装备缓冲包装设计与分析

目的为了提高携行装备的可靠性,对空降携行装备缓冲包装设计方法进行研究。方法通过理论计算获得开伞过载和着陆冲击过载估值,判断空降携行装备缓冲包装设计输入;通过合理选择缓冲包装材料和准确设计缓冲衬垫的厚度,以优化缓冲包装设计方案,并通过地面试验验证设计方法的可行性和有效性。结果通过优化设计,对装备进行缓冲包装防护后,某型空降携行装备着陆冲击由48.7g降至17.7g,能保证空降携行装备着陆后的完好和正常使用。最大过载计算值与实际测量最大过载值差距较小。结论所用计算方法可用于空降携行装备缓冲包装设计,缓冲包装设计不仅可保护装备,而且对其携行具减重具有重要的现实意义。     

温湿度对缓冲材料静态特性的影响

通过静态压缩试验所得的数据,分析了温度、湿度、密度对聚苯乙烯泡沫塑料、聚乙烯泡沫塑料、聚氨酯泡沫塑料等常用的缓冲包装材料的应力-应变曲线、缓冲系数-最大应力曲线和静压残余应变等静态特性的影响。     

小麦秸秆缓冲包装材料的力学性能研究

目的研究小麦秸秆缓冲包装材料的力学性能。方法分别对小麦秸秆缓冲包装材料进行静态压缩、松弛蠕变以及动态压缩试验,采用L-M非线性拟合法曲线以及遗传算法识别模型参数。结果得到静态性能曲线和动态性能曲线,以此建立小麦秸秆缓冲包装材料的力学模型。结论小麦秸秆缓冲包装材料的力学性能曲线开口向上,呈凹谷状,且只有一个极值点,具有明显的非线性及粘性特征。动态缓冲特性曲线近似呈U型,过了最低点后,曲线急速上升,反映材料被压实。     

蜂窝纸板的隔振缓冲性能测试

为了保护产品在流通过程中不因受到振动和机械冲击而破损,必须对产品施行隔振缓冲包装,所以,研究隔振缓冲材料的动态力学特性是非常必要的.本文通过不同厚度的蜂窝纸板的隔振和静态压缩性能测试,获得了动态缓冲曲线和振动传递率曲线,为蜂窝纸板在隔振缓冲包装中的应用提供了基本数据,为隔振缓冲包装设计提供有用的依据.