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弹性针织物压力性能研究及测试系统的设计与开发

The Pressure Performance of Elastic Knitted Fabric and Measuring System Development

【作者】 王永荣

【导师】 张佩华; 冯勋伟;

【作者基本信息】 东华大学 , 纺织工程, 2010, 博士

【摘要】 弹性针织面料具有优秀的弹性和回弹性,广泛用于紧身衣,塑身衣,泳衣,弹力袜及医疗绷带等功能性压力服装产品,能让消费者及病患者得到更多的视觉、生理、功能上的满足。随着生活水平的不断提高,人们对压力服装的舒适性、功能性及安全卫生性提出了新的要求,从而引发了关于服装压力的热点研究。服装压力是评价压力服装舒适性和功能性的重要指标之一,因为服装压力大小直接影响人体运动与生理感觉。不适当的穿着压力服装会影响着装者的疲劳感和工作效率,且关系到人体的健康。因此,在压力服装设计及其功能性研究的过程中,服装压力的测试与评价尤其重要。本论文主要研究弹性针织物的静态服装压力性能和动态服装压力性能的测试与表征。设计与开发针织物三维变形接触压力测试系统、改进智能人体假人服装压力测试系统和研发柔性压力传感器分别用于针织物的静态、动态压力性能、假人上服装压力分布及人体上服装压力测试,并确立相应的表征指标,为完善服装压力性能的评价体系奠定了基础。本论文主要包括四部分工作:一、弹性针织物物理机械性能与服装压力关系选取广泛用于针织服装的16种弹性针织面料,分别采用YG061拉伸测试仪和KES-FB系统对针织物的拉伸性能、剪切性能、弯曲性能、压缩性能、表面特征及厚重特性等在内的16个物理机械性能指标进行测试和评价,并对比分析平针针织物的横向和纵向性能差异。通过灰色关联分析方法建立起针织物16个物理机械性能指标(比较序列)与服装压力值(参考序列)之间的关联度,发现服装压力与拉伸力、弹性模量、弯曲刚度及剪切刚度的关联度依次最高,说明这些指标对服装压力的影响最大。本文采用多元拟合方法确定了拉伸力、弹性模量、弯曲刚度及剪切刚度与服装压力之间的定量关系。二、弹性针织物三维变形下接触压力性能的测试与表征为了模拟测试压力服装及产品在穿着过程中的静态压力和动态压力,设计与开发了针织物三维变形下接触压力测试系统。该测试系统由压力测试装置、位移驱动装置和数据收集装置三部分构成。三个高精度的压力传感器嵌在一个顶压半球的预定位置,其数据传导线均埋在顶压半球内部,这样避免顶压半球在顶压针织物过程中引起针织物的额外变形而引起的压力值波动。三个高精度的压力传感器监测针织物在不同变形状态下施加给相应接触位置的压力。位移驱动装置控制顶压半球在垂直方向运动使针织物在一定范围内变形,数据收集装置实时把传感器记录的模拟信号转化为可识别的数字信号并通过电脑软件显示出来。针对这一测试系统,确定了测试参数(顶压深度、顶压速度、循环次数及预加张力)。在此参数下测试针织物在伸长率10%-40%的范围内的静态压力、动态压力及动静态压力疲劳性能。为了定量评价针织物的接触压力性能,建立了较为完善的评价体系,定义了新的动态压力性能表征指标,即动态压力刚度,以表征针织物单位变形时压力的变化量;静态压力疲劳度和动态压力疲劳度表征针织物在反复顶压变形后动静态压力的衰减程度。研究结果表明,可直接利用静态压力大小、动态压力大小及动态压力刚度构成针织物一次变形中接触压力性能的表征指标,静态压力疲劳度和动态压力疲劳度表征针织物在多次反复变形中接触压力的衰减程度,这两部分共同构建了针织物三维变形中接触压力性能的评价体系。为了验证指标的有效性,本文收集了24种弹性针织物,分别测试了针织物伸长率在10%-40%范围内的静态压力、动态压力及动静态压力疲劳行为,对比分析了不同纤维构成的弹性针织物、不同纱线细度的弹性针织物、不同氨纶细度的弹性针织物、不同氨纶喂入率及不同组织结构的弹性针织物的性能与特征。三、智能人体假人上服装压力的测试与客观评价本文进一步改进设计和完善智能人体假人系统(LLY-56A),8个压力传感器分布在右肩上、右胸部、左胸部、右背部、右肋间、左腰部、左臀部和左臀侧部,并分别嵌入到一个人体假人的体表,监测并记录穿着在人体假人上的压缩性服装产生的压力,并传输信号到数据收集与处理设备,转化成为可读取的数字信号。为了模拟压力服装在不同三维尺寸的人体上产生的压力,智能人体假人可以在其前中线和后中线处横向扩张,最大扩张量为5cm。采用相同款式的服装结构,针对12种弹性针织物在10%-40%的变形范围内,测试并分析其在不同变形率下的压力分布和在不同三维尺寸人体假人上产生的压力分布。并对不同纱线种类、纱线细度、组织结构及氨纶喂入率的面料的服装压力分布进行了对比与评价。本智能人体假人能逼真模拟人体形态,不仅可以很好的示范女性上装的着装效果并有助于对不同三维尺寸的真人服装压力预测,而且能使服装压力测试标准能尽可能客观和统一,为服装舒适性的进一步研究和企业的实际应用提供一个很好的信息载体和重要的技术平台。四、柔性压力传感器的设计与开发人体假人与人体的各部位结构与性能有一定的差异,且影响了服装压力的测试。因此,实验中实测人体服装压力也是必要的。但是,复杂的人体曲面及人体生理、物理变化,增加了服装压力测量困难,给其测试传感器提出了更高的要求。本章为了解决这一问题,设计与开发柔性压力传感器,此传感器既可以用于人体服装压力的测试也可以用于人体健康监护。此传感器采用PVDF压电材料,通过静电纺丝方法制备纳米纤维膜。每个传感器由三层结构构成,包括柔性上电极、PVDF纳米纤维膜和固定的下电极构成。上电极为铟锡氧化物(ITO)沉积在塑料膜上作为导电材料,塑料膜作为绝缘层保护整个传感器避免因为锤子的敲击而损坏。PVDF纳米纤维膜作为触觉感应单元,由导电银胶与上下电极相连。刚性的下电极也由两部分构成即铟锡氧化物层(ITO)和玻璃。首先把铟锡氧化物层(ITO)沉积在玻璃上作为下电极,玻璃作为基体材料支撑下电极和整个传感器。采用电子扫描电镜SEM观察静电纺PVDF纳米纤维的表面形态。采用室温的XRD光谱仪和红外透射光谱仪表征静电纺PVDF纳米纤维膜的结晶形态。最终,在自行搭建的测试设备上测试其压电信号,表明基于PVDF纳米纤维膜的压力传感器开发是可行的,并可以进一步拓展应用于人体健康的监护及触觉传感器等。本论文的研究结果首次比较系统而且清晰的表明,弹性针织物的物理机械性能与服装压力定性与定量关系,并建立了弹性针织物的评价体系,包括测试系统、测试程序与参数和表征指标,并针对不同纱线构成的针织物进行测试与分析,得出纱线种类、纱线粗细、弹性纱线粗细和组织结构等特征对服装压力的影响。本论文改进设计了人体假人,通过内嵌入8个压力传感器构成服装压力智能人体假人测试系统,用于测试人体上服装压力分布。通过机械控制可实现假人沿前中线和后中线的扩展,用于模拟不同三维尺寸的假人。最后,为了实现人体上服装压力的监测,本文中还尝试了柔性压力传感器的设计与开发,并完成了初步的信号测试,证实了其实现的可行性。

【Abstract】 Elastic knitted fabric with excellent elasticity and resilience is widely used in tight-fitting suit, swimsuit, stockings and medical bandages, etc. With the continuous improvement of living standards, consumers proposed higher requirement according to garment pressure comfort, functionality, safety and health, which leads to a research hotspot.Garment pressure is one of the important factors for evaluation of compression garment comfort, function, and security. The term "compression garment" refers to a garment which applies pressure to specific areas of the human body. An inappropriate compression garment will affect the energy, work efficiency, and health of the wearer. Insufficient pressure will limit the efficiency, and perhaps reduce the aesthetic appeal of the garment. Too much pressure will result in fatigue, reduce heart and lung functions, and perhaps cause serious damage to health. So the optional measurement methods and systems are crucial for its evaluation. In this thesis, developed pressure measuring system for compression fabric evaluation during its static and dynamic status; improved the smart mannequin system for pressure distributions; and developed flexible pressure sensor for pressure distribution. The content of this dissertation is mainly included four parts as following:1. The relationship between mechanical-physical properties and garment pressure for compression fabricsThe mechanical-physical properties of dozens of elastic knitted fabrics were measured using a KESF standard evaluation system and YG061 tensile evaluation system in laboratory with a controlled environment. Examined the structure characteristics and mechanical-physical properties, and to determine the influence of these properties on garment pressure performance, as well as to establish the quantitative relationships between materials mechanical-physical properties and corresponding pressure functional profiles. Grey system theory was used to identify the significance of the differences of individual mechanical characteristics of elastic fabrics. The developed relationships between pressure magnitude and material mechanical properties provided a rational and practical approach for assessing and predicting the performance of a compression garment.2. The static and dynamic pressure performance evaluation and characterizationA measuring system was developed for static and dynamic pressure evaluation, which is composed of three components, including pressure measuring device, displacement driving device, and data acquisition device. Pressure measuring device is composed of a rigid hemisphere, three high-precision pressure sensors, and sample-holding device. Three sensors are distributed on surface of hemisphere, sensing static pressure and dynamic pressure during hemisphere downward-upward motion. Displacement driving device is composed of main frame, a voltage/frequency converter and a driving motor. The hemisphere with sensors vertical moves to press on fabric sample at predetermined press depth, velocities, and standing time under control of the displacement driving device, the sample deforms to some extent and produces pressure on the surface of hemisphere. The data acquisition device is composed of a signal processor, data collection software, and PC. The pressure values are displayed simultaneously.In order to quantify the static and dynamic behavior of the compression fabric we establish the measure parameters such as press-depth, press-velocity, standing time and etc, also introduce three new indexes:the dynamic pressure stiffness index, static pressure fatigue and dynamic pressure fatigue. Stiffness is defined as the increment in pressure when the elongation increased or decreased by 1 cm. The stiffness of compression garment is important for their function. The static and dynamic fatigue can give information about pressure decay when fabrics undergoing repeated stretch and relaxation.Dozens of elastic fabrics are tested on the measuring system, their static, dynamic and pressure decay behaviors are evaluated in the extension range of 10%to 40%. The garment pressure performances are analyzed among fabrics with varied yarn fineness, Spandex fineness, structure, etc.3. Pressure distributions on a smart mannequin systemA smart mannequin with the dimension of a standard female body was improved for measuring garment pressure. The mannequin has a rigid internal layer and covered with a soft surface, and eight built-in pressure sensors are distributed on its surface. The sensors sense pressure imposed by wearing garment and fed data into an acquisition device simultaneously. The mannequin can extends transversely at the antemedial and postmedial line to the maximal level of 5 cm, which may imitate the dimensions of different human body. Dozens of compression garments made from elastic fabrics knitted were tested. Results show that the pressure distributions exhibit obvious difference among measuring points, also different at the same point while mannequin dimensions are varied, and the controlled Spandex feeding rate causes pressure variations among the specimens. This smart mannequin system provides a novel tool for evaluating the pressure performance of compression garments, and gives reliable data for functional product development.4. Flexible sensor for pressure measurementPVDF nano-fibrous membrane which was light weight, flexible, breathability, wearable, prepared by electrospinning technique. The electrospinning parameters such as the voltage, feeding rate, tip-to-collector distance, etc, were well controlled. More than 4 hours electrospinning time was needed for a certain thickness of PVDF nano-fibrous membrane.The morphology of PVDF nanofiber is determined by scanning electron microscopy (SEM), and crystal structure was evaluated by FTIR spectroscopy and X-Ray Diffractometer. The PVDF fibrous membranes were well designed and fabricated for tactile sensor. The sensor consists of three main parts, flexible electrode, PVDF fibrous membrane, and fixed electrode. The flexible electrode consists of ITO layer and plastic payer, ITO as the conducting polymer first was deposited on the plastic film as the top electrode, the plastic film as an insulator film protests the whole prototype avoiding destroy when the hammer hits. PVDF nano-fibrous membrane as the tactile-sensing element, connected with top and bottom electrodes by silver painter. The rigid electrode also consists of two layers, ITO and glass. ITO was deposited on the glass as the bottom electrode, the glass as a substrate for the bottom electrode and a platform supports the whole prototype. The deformation on PVDF fibrous membrane was applied by the tip of a load cell, which was bonded to a controlled hammer. The electric signals were obtained through home-made circuit and they were connected to an Oscilloscope. We found the feasibility of applying PVDF fibrous membranes prepared through electrospinning technology, to be flexible human-related tactile sensors.The results systematically and clearly show that the quantitative relationships between materials mechanical-physical properties and corresponding pressure functional profiles, the evaluation method for elastic knitted fabric function, including measuring systems, procedure, parameters and indexes.In this thesis, a smart mannequin was also improved, which 8 pressure sensors were distributed in fixed points for garment pressure measurement. The mannequin can extends transversely at the antemedial and postmedial line to the maximal level of 5 cm, which may imitate the dimensions of different human body. We found the feasibility of applying PVDF fibrous membranes prepared through electrospinning technology, to be flexible human-related tactile sensors.

  • 【网络出版投稿人】 东华大学
  • 【网络出版年期】2011年 08期
  • 【分类号】TS101.92;TS103.6
  • 【被引频次】10
  • 【下载频次】744
  • 攻读期成果
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