准静态压缩下的蜂窝纸板承载性能实验研究

对蜂窝纸芯和纸板准静态压缩实验,测定分析面纸、孔径比、厚度对蜂窝承载性能的影响.结果表明:蜂窝纸板压缩呈非线性特征,其压缩变形过程经历黏弹性、黏弹塑性、塑性坍塌3个阶段;面纸、厚度、孔径比不同程度影响蜂窝纸板的承载性能.随厚度、孔径比增大,承载力降低,面纸对承载力的影响减小;原纸定量增大,抗弯性能增强,纸板纵向弯曲强度大于横向弯曲强度.     

聚氨酯蜂窝纸板动力学性能及其本构模型

将聚氨酯填充到蜂窝纸板的孔隙中制作了聚氨酯蜂窝纸板复合材料,进而对其进行落锤冲击实验。通过落锤实验得到聚氨酯蜂窝纸板复合材料的应力-应变曲线,对影响其动力学性能的复合材料孔径、厚度、横截面尺寸及冲击速率四个因素进行了分析。结果表明:复合材料的动态屈服强度和动态弹性极限随着蜂窝纸芯的孔径、复合材料厚度和横截面积的增大而减小,随着冲击速率的增大而提高。在实验数据的基础上拟合了复合材料的动态本构方程,并对本构方程与实验数据进行了比较,拟合效果较好。     

蜂窝纸板静态缓冲性能的影响因素分析

分析了影响蜂窝纸板静态缓冲性能的3个因素:蜂窝纸板厚度、蜂窝孔径和蜂窝纸芯定量。根据静态压缩试验所得的应力-应变曲线,得出了3个影响因素对临界应力和临界应变的影响趋势,为缓冲包装中蜂窝纸板的选材提供一定的设计依据。     

纸蜂窝结构平压性能的实验研究

通过对蜂窝纸芯和纸板平压强度的测试，分析孔径比、犀度对蜂窝纸芯平压强度的影响以及纸芯和纸板平压强度的差异，探讨了生产工艺对蜂窝纸板平压强度的影响。     

蜂窝纸板压痕折叠方法探讨

针对目前蜂窝纸板难以折叠成型的问题,分析了蜂窝纸板压痕困难的原因,以及实现折叠的可行性和前提条件,讨论了蜂窝纸板制作缓冲衬垫可能的压痕折叠方法,提出了搭接蜂窝纸板和改变蜂窝芯结构的方法,为解决蜂窝纸板压痕折叠问题提供参考依据。     

蜂窝纸板面内平台应力表征

面内平台应力是评估蜂窝纸板面内承载性能的重要指标,且蜂窝纸板性能极易受环境湿度的影响.该文试验分析蜂窝纸板厚度、芯层和面层对其面内平台应力的影响;基于不同相对湿度条件下蜂窝原纸的纵向屈服强度,建立了相对湿度影响的蜂窝纸板面内平台应力模型,并与试验实测数据进行比较验证.结果表明:纸板厚度和面纸性能对蜂窝纸板面内平台应力有较大影响,芯层性能对其影响较小;所建立模型能较准确地反映环境相对湿度对纸蜂窝结构材料面内平台应力的影响.借助该模型,无需大量的试验,即可估算其考虑相对湿度的面内平台应力,为蜂窝纸板的配纸和合理选用提供理论依据.     

瓦楞纸板和蜂窝纸板的性能比较

<正>将面纸、芯纸相同,用纸量相同,芯层与面纸之间粘合的胶也相同的瓦楞纸板和蜂窝纸板做性能测试,测试结果如下:(1)蜂窝纸板的平压强度远高于瓦楞纸板,而且在耗材量一定的情况下,蜂窝纸板的平压强度随着孔径的增大而减少。     

蜂窝纸板静态压缩试验研究及其模拟分析

对4种不同厚度的蜂窝纸板进行了静态压缩的完全加载和二次加载实验,结果表明:完全加载过程有4个明显的阶段;最大压力都为屈服力的2~3倍;30 mm厚度的蜂窝纸板其屈服阶段占厚度的百分比最大;二次加载的实验曲线分为3个阶段,可以有效消除蜂窝纸板的屈服强度峰值,改善蜂窝纸板的缓冲特性。AN-SYS软件模拟分析表明:距离面纸1/5~2/5处的蜂窝纸芯最容易屈服变形;粘结处变形比各面上变形量大;中间部位易产生向内变形,而两端易产生向外变形。     

纸蜂窝夹层板主共振频率的影响因素

目的 研究芯层结构因素和静应力因素对纸蜂窝夹层板-质量系统主共振频率的影响。方法 采用正弦振动试验测试纸蜂窝夹层板-质量系统的振动传递特性,分析不同静应力作用下不同蜂窝芯的纸蜂窝夹层板-质量系统的主共振频率变化规律。结果 纸蜂窝夹层板-质量系统的主共振频率在150~350 Hz之间;蜂窝芯结构及芯层材料影响纸蜂窝夹层板的刚性,从而影响系统的主共振频率;载荷质量变化引起静应力的变化,也会影响系统的主共振频率。主共振频率均随蜂窝胞元边长、纸板厚度、芯纸定量及静应力的增大而降低。结论 可为纸蜂窝夹层板的振动传递特性研究提供基础,有助于不同材质蜂窝夹层板的优化设计。     

一种新型蜂窝纸板包边工艺及其制品性能研究

目的 为实现蜂窝纸板包边工序的机械化和自动化, 提出一种新型蜂窝纸板包边工艺, 并对其制品的侧面载荷性能, 即侧面戳穿的承载状况进行研究。方法 提出了包含压溃、 压痕、 上胶、 折边和侧面压紧等5个关键工序的新型包边工艺, 并与现有手工包边工艺生产的蜂窝纸板进行对比实验, 测试和分析了2种包边工艺生产的4种不同厚度蜂窝纸板, 在侧边受集中载荷下戳穿所需的最大载荷。结果 手工包边生产工艺的蜂窝纸板侧面受集中力时, 最大戳穿力只与包边纸的性能有关系, 蜂窝纸板厚度对其没有太大的影响; 新型包边工艺生产的蜂窝纸板在侧面受集中力时, 最大戳穿力与包边纸的性能有关, 同时蜂窝纸板厚度对其也会产生较大影响; 新型包边工艺生产的同种规格蜂窝纸板侧面戳穿所需的最大载荷大于手工包边方式生产。结论 新型包边工艺大大提高了蜂窝纸板的侧面载荷能力, 同时可实现机械化和自动化加工, 极大地提高了蜂窝纸板后道工序的生产效率和产品质量。     

Creasability testing by inclined rules — a base for standardized specification of paperboard

In die cutting manufacture of paperboard it is necessary to apply the correct creasing conditions, e.g. neither too small nor too big a rule height, in order to achieve sufficiently low folding resistance without any cracks along the folding lines. The most appropriate rule height for a given paperboard is usually determined by trying different rule heights in a series of very time consuming and costly trial and error tests. And, in practice, this procedure must be repeated for each major change in board quality. This report shows that an inclined crease rule, i.e. a rule having a gradually increasing rule height, can be used advantageously to rationalize such tests and to achieve much greater reliability. A folding line produced by such an inclined rule contains both the upper limit for the rule height, i.e. where cracks start to appear, and the lower limit, i.e. where the rule height is obviously too small, and the technical range for achieving a good creasing result is thus clarified in one single test. Illustrative data for two types of paperboard are given as well as some theoretical aspects of the concept of creasability. Considering that the described method not only rationalizes the testing work but also enables more reliable observations to be made than have been possible in the past, the method opens new potentials for effective research and development in the fields of converting, convertibility, die form design, etc. © 1997 John Wiley & Sons, Ltd.     

Influence of Low‐Intensity Repeated Impacts on Energy Absorption and Vibration Transmissibility of Honeycomb Paperboard

Packaging products in logistics typically will receive multiple low‐intensity repeated impacts, fewer moderate to high‐intensity impacts and vibration. As a result of low‐intensity repeated impacts, local buckling and fold will be formed in honeycomb paperboard, and its cushioning performance will be weakened. This paper investigates the influence of low‐intensity repeated impacts on the cushioning performance of honeycomb paperboard. The low‐intensity repeated impacts with dropping height 5 cm were conducted at first. Then, the moderate‐intensity impact with dropping height 80 cm and vibration experiment were, respectively, conducted. The results show: (a) honeycomb paperboard absorbs the energy produced by low‐intensity repeated impacts through layer upon layer folding of honeycomb structure. The highest buckling peak turns up in low‐intensity impact, followed by a series of buckling in intact honeycomb paperboard. However, the buckling is not obvious in repeated impacts; (b) the load carrying capacity of honeycomb paperboard after low‐intensity repeated impacts declines significantly. Three deformation stages are observed in the load–displacement curve. Most of impact energy is absorbed in the plateau stage. The absorbed energy of damaged honeycomb paperboard under moderate‐intensity impact decreases with the increasing of low‐intensity impact repetitions; and (c) the low‐intensity repeated impacts have an obvious influence on the resonance frequency of packaging product and stiffness of honeycomb paperboard. To confirm vibration properties of product using honeycomb paperboard cushioning, it should be considered in a designing process that honeycomb paperboard changes soften more in logistics. Copyright © 2016 John Wiley & Sons, Ltd.     

蜂窝纸板异面动态冲击性能的实验分析

目的以六边形蜂窝纸板为研究对象,研究厚度对其异面冲击性能的影响。方法通过动态冲击实验来分析接触力、最大接触力、最大位移、最大应变、吸收能与单位厚度冲击能之间的关系,研究厚度为30,40,50和60 mm等4种蜂窝纸板的异面冲击力学性能。结果当冲击能一定时,随着蜂窝纸板厚度的增加,接触力逐渐减小,接触时间逐渐变长;当单位厚度冲击能一定时,厚度与最大位移和吸收能成正比例关系,厚度与接触力、最大接触力、最大应变成反比例关系;对于任一厚度的蜂窝纸板,最大接触力、最大位移、最大应变、吸收能随单位厚度冲击能的增加而增加,且与其呈线性关系。结论当冲击能相同时,不同厚度蜂窝纸板的吸收能几乎相同,可知蜂窝纸板吸收能量的能力与蜂窝纸板的厚度无关,取决于冲击能量的大小。     

内含气体对蜂窝纸板静态缓冲性能的影响

目的研究蜂窝纸板的内部气体对其静态缓冲性能的影响规律。方法通过静态压缩实验,研究在不同孔隙率的条件下蜂窝纸板的缓冲性能。结果通过静态压缩实验,得到了应力-应变曲线,对比不同孔隙率条件下的应力-应变曲线,可以观察到孔隙率越大,蜂窝纸板在压缩过程中的静态峰应力越小,蜂窝纸板越容易被压变形,并且形成的密实层越薄,其中孔隙率为0与孔隙率为100%时的应力-应变曲线变化明显,且气体泄漏不受厚长比和孔径尺寸的影响。结论在静态压缩过程中,蜂窝纸板内的气体使蜂窝纸板所能承受的应力明显增强,并且通过理论推导,得出了内含气体影响下蜂窝纸板在静态压缩过程中各个阶段的应力理论公式,为其缓冲性能的研究提供了一定的理论方法。     

Experimental quantification of differences in damage due to in-plane tensile test and bending of paperboard

Creasing is an essential process to convert paperboards into packages since it enables folding along well-defined lines. The creasing process relies on purpose-made damage that is initiated in the paperboard structure: delamination. However, creasing might also cause in-plane cracks, which must be avoided. In this laboratory study, three paperboards were creased at six different depths, respectively. Two mechanical tests were performed to characterize the creases at standard climate (23°C and 50% RH): 2-point folding, to examine the bending force and short-span in-plane tensile test to evaluate the strength. The results were normalized with the values for the uncreased boards, which gave the relative strength ratios: relative creasing strength (RCS) and relative tensile strength (RTS). When the relative strengths were evaluated against the normative shear strains, a creasing window was formed. This window has an upper limit given by the RTS values, corresponding to the in-plane cracks, and a lower limit given by the RCS values, corresponding to the delamination damage initiated in the paperboard during creasing. It was observed that both the RCS and RTS values exhibit a linear relation against normative shear strain. From this, it was concluded that performing tests at two creasing depths might be sufficient to estimate the lower, and upper, limits for the creasing window in future studies. Finally, the effect of moisture was investigated by creasing, folding and tensile testing at 23°C and 90% RH, which showed that moisture had no clear effect on the RCS or the RTS values.     

夹层结构纸板的力学性能测试方法概述

为了使相关人员能对夹层结构纸板的力学性能测试方法有较为全面的理解和认识,研究了瓦楞纸板、蜂窝纸板和瓦楞复合纸板的力学性能相关测试标准,阐述了各种力学性能的测试原理,分析了各测试标准之间的差异,并介绍了改进夹层结构的剪切性能测试装置的相关研究成果。通过分析可知,瓦楞纸板、蜂窝纸板和瓦楞复合纸板的不同力学性能测试标准的要求不同,且各种力学性能测试标准还需要改进和更新,3种纸板的力学性能测试需根据具体的应用环境选择合适的测试标准和方法。     

折叠型瓦楞纸蜂窝芯及其缓冲性能研究

折叠型瓦楞纸蜂窝芯的静态压缩应力应变曲线经历线弹性、屈曲平台和密实化三阶段,用同样材质同样重量的七层瓦楞纸板分别制作成折叠型瓦楞纸蜂窝芯和多层瓦楞纸板,对其进行准静态压缩实验,结果表明折叠型瓦楞纸蜂窝芯的承压性能远远高于多层瓦楞纸板,但其回弹性能比多层瓦楞纸板差一些,因此折叠型瓦楞纸蜂窝芯的缓冲效率高于多层瓦楞纸板的缓冲效率,它特别适合于大型机电产品的缓冲包装.     

内含气体对蜂窝纸板异面动态冲击性能的影响

目的以六边形蜂窝纸板为对象,研究内含气体对其异面冲击性能的影响。方法通过动态冲击实验分析内含气体对接触力、最大接触力、最大位移、最大应变和吸收能的影响,得出不同孔隙率时,蜂窝纸板的接触力-时间曲线,最大接触力、最大位移、最大应变、吸收能与冲击能曲线和吸收能-孔隙率曲线。结果在给定冲击能的情况下,最大接触力与吸收能随着孔隙率的增大而减小,最大位移及最大应变随着孔隙率的增大而增大。在孔隙率一定时,最大接触力、最大位移、最大应变和吸收能随冲击能线性增大。此外,冲击能越大,接触力达到峰值的时间越短,接触持续时间越长。结论在动态冲击实验中,内含气体使蜂窝纸板吸收冲击能的能力明显增强,并且当冲击能一定时,孔隙率越大,蜂窝纸板越容易被压变形,吸收能越少。