【作者】 王东；

【导师】 杜赵群； 刘金抗；

【作者基本信息】 东华大学 ， 材料与化工（专业学位）， 2022， 硕士

【摘要】 间隔织物是一种三维立体织物,由上表面层、下表面层、以及连接上下表面层的间隔丝中间层组成。经编间隔织物具有优异的缓压性能,在其受到外力作用时,间隔丝可以产生较大的弯曲作用,受到的外部压力可以迅速扩散,可以避免应力集中现象的出现,因此适合于用作垫类材料,作为垫类材料时,压缩性能是其主要体现的性能。但是目前就间隔织物在压缩性能研究方面,主要集中于单层间隔织物的压缩性能研究,缺乏对于多层间隔织物压缩性能的探究。因此本课题主要的研究思路是首先对多层间隔织物进行平板压缩和球形压缩试验,提取平板压缩和球形压缩结果中的相关指标进行整理与分析,之后建立间隔织物压缩粘弹性力学模型,对间隔织物压缩性能进行模型分析,揭示内部相互作用关系,最后基于最优化模型探究间隔织物弹性模量的影响因素,并对主观舒适性评价分数与织物弹性模量建立联系。本论文主要研究内容与结论如下:(1)采用层合叠加方法研究了多层间隔织物的压缩性能。通过研究发现采用垂直叠加的方式抗压缩性能、压缩回弹性能以及耐使用性能更好;间隔织物叠层处理对织物整体的压缩率影响较大,随着层数的不断叠加,整体压缩率逐渐降低;随着间隔织物层数的叠加,织物整体的压缩功不断增加,说明其层数越多,间隔织物整体的抗压性能越来越强;平板压缩和球形压缩之间的压缩功、回复功、滞后功等指标之间具有很好的相关性,不同尺寸的球形压缩之间的压缩功、回复功、线性度等指标之间具有很好的相关性,彼此之间存在一定的线性关系,可以通过一种特征指标参数值来预测其他特征指标参数值。(2)基于间隔织物自身的粘弹性特性,建立多种粘弹性模型对其压缩行为进行分析。建立线性弹簧模型、Maxwell模型、Kelvin模型、改进的Maxwell模型和改进的Kelvin模型,对每种粘弹性模型的本构方程式进行推导,并对平板压缩的试验结果进行拟合分析,确定了最适合用来描述间隔织物弹性压缩阶段中内部作用关系的最优化模型—改进的Kelvin模型;无论是对单层间隔织物的试验曲线还是多层间隔织物的试验曲线,改进的Kelvin模型对其拟合程度R~2值均在0.99以上,可以认为拟合曲线与试验曲线完全一致,模型对间隔织物模量的预测值与模量标准值偏差率小,可信度高;改进的Kelvin模型可用于分析间隔织物的弹性模量值和弹性压缩阶段中的粘滞系数;改进的Kelvin模型本构关系式表明间隔织物的弹性压缩阶段本质上为非线性阶段;随着间隔织物层数的叠加,间隔织物层与层之间的摩擦耦合作用强度不断提升,织物界面间的相互作用强度不断提升;随着间隔织物层数的叠加,能量耗散的功即“无用功”占比在不断增大,使间隔织物发生形变的功即“有用功”占比在逐渐减小,因此间隔织物整体的压缩率会随着织物层数的增多而逐渐减小。(3)利用最优化模型探究间隔织物压缩弹性模量的影响因素。间隔织物垂直方式叠加时弹性模量更大,多层间隔织物的叠加顺序几乎不会影响织物的弹性模量,外部作用力强度越大,织物整体弹性模量越大;间隔织物层数越多,织物弹性模量越大,人体主观舒适度越高;随着织物层数的增加,织物弹性模量不断增大,但此时人体对于织物整体的舒适性评价分数前后相同,表明了当间隔织物层数叠加到一定程度的时候,人体感知到的舒适性差异就不是特别明显了;从消费者角度考虑,在实际购买间隔织物床垫的过程中,可以按需购买,选择合适的厚度,不一定非要选择层数多、厚度大的床垫,可以选择层数略少的床垫,也可以获得一致的舒适性体验,织物弹性模量对人体主观评价结果具有重要影响。更多还原

【Abstract】 Spacer fabric is a kind of three-dimensional fabric,which is composed of an upper surface layer,a lower surface layer,and a spacer wire intermediate layer connecting the upper and lower surface layers.The warp-knitted spacer fabric has excellent pressure-releasing performance.When it is subjected to external force,the spacer wire can produce a large bending effect,and the external pressure can be rapidly diffused,which can avoid the occurrence of stress concentration,so it is suitable for use as a pad.When used as a cushion material,the compression performance is its main performance.However,the current research on the compressive properties of spacer fabrics mainly focuses on the compressive properties of single-layer spacer fabrics,and lacks research on the compressive properties of multi-layer spacer fabrics and the comfort of multi-layer spacer fabrics.Therefore,the main research idea of this topic is to perform flat compression and spherical compression tests on multilayer spacer fabrics,extract relevant indicators from the flat compression and spherical compression results,organize and analyze them,and then establish a spacer fabric compression viscoelasticity model.The compressive performance was theoretically analyzed to reveal the internal interaction relationship.Finally,based on the optimization model,the influencing factors of the compressive elastic modulus of the spacer fabric were explored,and the relationship between the fabric modulus and the subjective comfort evaluation was established.The main research contents and conclusions of this paper are as follows:(1)The compressive properties of multi-layer spacer fabrics were studied by the lamination stacking method.Through research,it is found that the vertical stacking method has better anti-compression performance,compression resilience performance and durability.With the superposition of the spacer fabric layers,the overall compression work of the fabric keeps increasing,indicating that the more layers there are,the stronger the overall compression performance of the spacer fabric is;there is a good correlation between the compression work,recovery work,hysteresis work and other indicators between plate compression and spherical compression.There is a good correlation between indicators such as work and hysteresis work,and there is a good correlation between the compression work,recovery work,linearity and other indicators of spherical compression of different sizes,and there is a certain linear relationship between them.The parameter value of one characteristic index can be used to predict the parameter value of other characteristic index.(2)Based on the viscoelastic properties of the spacer fabric itself,a variety of viscoelastic models are established to analyze its compressive behavior.The linear spring model,Maxwell model,Kelvin model,improved Maxwell model and improved Kelvin model were established,the constitutive equations of each viscoelastic model were deduced,and the test results of plate compression were fitted and analyzed,and the most suitable model was determined.The optimal model used to describe the internal action relationship in the elastic compression stage of spacer fabrics—the improved Kelvin model;whether it is the test curve of a single-layer spacer fabric or the test curve of a multi-layer spacer fabric,the improved Kelvin model fits it The R~2 values are all above 0.99,and it can be considered that the fitted curve is completely consistent with the experimental curve.The model has a small deviation rate between the predicted value of the spacer fabric modulus and the standard value of the modulus,and the reliability is high;the improved Kelvin model can be used to analyze the elastic modulus value of spacer fabrics and the viscosity coefficient in the elastic compression stage;the improved Kelvin model constitutive relationship shows that the elastic compression stage of the spacer fabric is essentially a nonlinear stage;with the stacking of spacer fabric layers,the strength of friction between spacer fabric layers and the strength of interaction between fabric interfaces increases continuously;with the superposition of the spacer fabric layers,the proportion of energy dissipated,that is,"useless work",continues to increase,causing the spacer fabric to occur.The work of deformation,that is,the proportion of"useful work"is gradually decreasing,so the compression ratio of the spacer fabric decreases gradually with the increase of fabric layers.(3)Use the optimization model to explore the influencing factors of the compressive elastic modulus of the spacer fabric.When the spacer fabrics are stacked vertically,the elastic modulus is larger.The stacking sequence of the multi-layer spacer fabrics hardly affects the elastic modulus of the fabric.The greater the external force strength,the greater the overall elastic modulus of the fabric;the more layers of spacer fabric,the greater the elastic modulus of fabric,the higher the subjective comfort of human body;the elastic modulus of fabric increases with the increase of fabric layers,but at this time,the human body’s overall comfort evaluation score for the fabric is the same before and after,indicating that when the number of fabric layers is improved to a certain extent,the difference in comfort perceived by the human body is not particularly obvious;from the perspective of consumers,in the process of actually purchasing a spacer fabric mattress,you can purchase it on demand and choose the appropriate thickness.It is not necessary to choose a mattress with a large number of layers and a large thickness.You can choose a mattress with a slightly smaller number of layers,and you can also obtain a consistent comfort experience.The elastic modulus of the fabric has an important impact on the subjective evaluation results of the human body.更多还原