基于ABAQUS的三原组织机织物拉伸力学性能模拟

为更好地了解平纹、斜纹和经面缎纹3种基本组织纯棉机织物抵抗外力拉伸变形的能力,在实际测量织物结构参数的基础上,提出一种评价和预测机织物拉伸性能的方法;借助专业纺织建模软件Texgen建立织物三维细观模型;利用有限元软件ABAQUS,依据织物拉伸环境设置材料属性、相互作用和边界条件等计算模型数值解;通过织物拉伸强力测试实验验证数值模拟结果的有效性。结果表明:平纹织物、斜纹织物和经面缎纹织物拉伸应力、应变模拟结果与实验测试结果差异率均在6%以内;在原料、经纬纱密度和捻度、织物经纬密都相同的条件下,平纹织物抵抗外力变形的能力更强。     

三原组织织物拉伸力学性能有限元仿真

为使织物在设计前就可预估其拉伸性能,对织物拉伸过程进行了有限元模拟和试验验证。通过超景深数码显微镜对织物试样的细观照片进行尺寸测量,得到纱线的几何结构参数,借助AutoCAD绘图软件建立了三原织物单胞物理模型;基于纱线拉伸试验和织物周期边界条件理论,利用有限元分析软件ANSYS研究了三原织物的拉伸性能;并将有限元仿真结果与拉伸试验结果进行对比。结果表明：织物经向拉伸时,经向平均应力、经向平均应变、纬向平均应变和泊松比的有限元模拟结果与试验结果的差异均在5%左右;经向弹性模量的有限元模拟结果与试验结果的差异也在10%以内;证明有限元仿真的可行性。     

基于有限元方法的不同集聚纱织物拉伸力学性能分析

为了在设计织物时可以依据不同集聚纱纱线性能来估算织物的拉伸性能,提供了一种预测织物拉伸性能的方法。以一种普通棉织物为例,对织物拉伸力学性能进行了有限元模拟和实验验证,基于有限元软件ABAQUS仿真织物拉伸性能理论数值结果的有效性,采用显微图像法实测织物结构,借助纺织建模软件Texgen建立织物细观模型,利用有限元法模拟织物拉伸并计算数值解,给出全聚纺、全聚赛络纺、紧密纺、紧密赛络纺这四种集聚纺纱方式所纺单纱交织平纹织物的拉伸力学性能。结果表明:紧密赛络纺单纱交织织物拉伸性能最好,而全聚纺单纱交织织物拉伸性能最差。     

真丝和涤纶仿真丝织物的拉伸性能有限元仿真

为了在织物设计时可以依据织造原料的纱线性能来估算织物的拉伸性能,以预测、优化织物的拉伸性能,对织物的整个拉伸过程做了有限元仿真和试验验证。选用规格相近的涤纶仿真丝和真丝织物,借助超景深数码显微镜VHX-5000测量织物试样,获得纱线的几何结构参数,运用AutoCAD软件构建织物三维系统的有限元模型;并运用有限元软件Ansys,设置载荷和边界条件,求解拉伸载荷的仿真数值结果;最后将有限元模拟结果与试验结果相对比。结果表明:织物拉伸模拟曲线与实验曲线基本相同,证明有限元仿真的可行性;涤纶仿真丝和真丝织物的拉伸曲线在拉伸初始阶段和断裂阶段有明显差异。     

基于ABAQUS的筒状纬编针织物拉伸力学性能模拟

为更好地了解筒状纬编针织物抵抗拉伸变形的能力,基于对织物试样尺寸测量得到的几何结构参数,借助Rhino 3D建模软件建立了纬编针织物线圈模型和筒状纬编针织物模型;同时利用有限元分析软件ABAQUS在单位线圈和筒状织物2个方面研究了筒状纬编针织物的纵向拉伸性能;对织物拉伸过程进行有限元模拟和实验验证,并对针织物拉伸过程中...     

热轧非织造材料力学性能有限元分析*

利用同轴反射光显微镜拍摄热轧非织造材料的多层图像,结合多聚焦图像融合技术,得到材料的清晰图像和纤维位置信息;再通过python编程构建热轧非织造材料几何结构有限元模型,运用ABAQUS程序实现材料力学拉伸性能模拟,获得不同模型参数条件下应力-应变曲线。对比不同参数条件下有限元模型所得的应力-应变曲线发现：材料中热黏合点可以视为弹性体;在应变为0．38时纤维性能对整体材料应力的影响为30％,而热轧辊温度、生产速度和纤网面密度等因素对整体材料的应力影响为70％。     

机织间隔织物压缩性能有限元分析

为研究机织间隔织物的力学性能,建立机织间隔织物的力学分析模型,以采用特殊工艺生产的机织间隔织物为研究对象,通过对机织间隔织物的成型原理与结构进行分析,利用ANSYS分析软件建立机织间隔织物的有限元模型。由于间隔织物在使用过程中压缩性能是最主要的力学性能,对机织间隔织物的压缩性能进行了模拟分析,得出了反映机织间隔织物压缩过程中受力变形情况的应力与变形云图和应力与应变曲线。与实验结果进行的对比分析表明吻合较好。     

超高分子量聚乙烯平纹织物的穿刺冲击模拟与响应分析

运用有限元方法对带刃刀具刺穿超高分子量聚乙烯平纹织物的冲击过程进行数值模拟,并通过准静态实验验证有限元模型的有效性。通过给出布面刺破效果的数值仿真模拟,对织物刺穿过程中的纱线的应力应变分布进行分析,得到冲击系统的能量变化规律。数值模拟结果指出:刀刺织物过程中,刀具的能量主要转化为织物的弹性应变能,其余为塑性耗散能和摩擦耗散能;纱线破坏以剪切断裂为主;平纹织物的弹性回复性能有助于抵抗刀具的冲击,增强其抗剪切性能是提高防刺性能的关键。     

双向载荷下双轴向经编柔性复合材料有限元模拟

柔性复合材料在日常使用过程中不仅常常受到双向及多向拉伸载荷的作用,而且在有小裂缝的情况下还会继续使用。为更好地了解双向载荷下双轴向经编柔性复合材料拉伸和开缝撕裂性能,为材料性能评价及预测提供理论参考。本文利用有限元方法对双向载荷下双轴向经编柔性复合材料拉伸和开缝撕裂的应力应变曲线进行模拟,特别对三种不同加载比率下双向拉伸和双向载荷下开缝撕裂的应力应变曲线进行计算模拟。结果表明：有限元模拟的双轴向拉伸及开缝撕裂的应力应变曲线与试验结果在弹性阶段的拟合精确度很好,但材料屈服后拟合值偏大;不仅可以模拟现在试验可以测试的1：1加载比率下材料的应力应变曲线,而且可以模拟目前试验无法完成的其它任意载荷比下的应力应变曲线。     

低屈服钢拉伸试验与数值研究

为了了解低屈服钢的拉伸性能,开展拉伸试验并进行数值研究:采用圆棒试件进行单轴拉伸试验,分析试件的力-位移曲线、延展性以及断裂模式等;基于幂强化法和加权平均法计算材料颈缩后的真实应力-应变数据;采用扩展有限元方法对圆棒试件的拉伸、颈缩以及断裂过程进行数值模拟。通过与试验数据的对比发现:加权平均法可以得到与实际相吻合的颈缩后的真实应力-应变数据;扩展有限元方法可以对低屈服钢的拉伸、颈缩与断裂过程进行有效的仿真。     

Finite element modelling the mechanical performance of pressure garments produced from elastic weft knitted fabrics

Compression garments mainly produced from elastic knitted fabrics have attracted many attentions due to their medical care performances. Components’ characteristics of the pressure garments such as yarn and fabric structure affect significantly the pressure applied on the human body. In this paper, it is aimed to simulate the effect of yarn’s mechanical properties as well as fabric structure on mechanical performance of the compression garment. For this purpose, a precise geometrical model for fabric structure is needed by which the pressure applied to the body could be predicted. Accordingly, double jersey knitted fabrics containing elastane weft yarns were produced on an electronic flat knitting machine and the fabric tensile properties were measured in course direction. Using equations governing the fabric structural unit-cell, a real geometric model was created in a finite element software environment. Considering the linear visco-elastic properties for elastane weft yarn, stress-strain curve was extracted. The results obtained from numerical simulation were compared with the experimental data in order to validate the proposed geometrical model. The findings demonstrate a good agreement between experimental and simulation results.     

二维织物冲击响应模拟计算与分析

为说明织物在弹体冲击过程中的抗冲击能力,运用有限元软件ABAQUS模拟分析的方法,考察一种典型二维芳纶织物的抗冲击性能。绘制并分析弹体的速度曲线、能量变化曲线、应力在织物中的传播以及弹体冲击织物的过程,揭示这种织物抵抗冲击的性能与行为。二维织物在不足以将其击穿的弹体的冲击作用下,整个冲击过程被分为2个阶段,且冲击过程中主要发生系统动能与内能的相互转化。所作研究为防冲击织物的设计提供了一种有效的预测方法,同时也可将其扩展应用于其它结构材料的防冲击分析。     

Finite element analysis of penetration force for needle during tufting process

Tufted carpet is one of the most used carpets. The penetration force of needle is an important factor in tufting process. Few know how to calculate the penetration force during the tufting, although the principle is one of the least understood processes. This paper presents our research on using finite element method (FEM) to study the penetration force of needle during tufting. In this study, the model is developed using ABAQUS software, and the material properties of nonwoven fabric are approximately modeled by linear elastic orthogonal anisotropic continuum. The required engineering constants were obtained from experimental test. A user-defined subroutine VUMAT for characterizing the constitutive relationship of the orthogonal anisotropy nonwoven fabric and the damage evolution was compiled and connected with a commercial software package ABAQUS/Explicit to calculate the penetration force. At the same time, needle penetration force was tested by sensor mounted on needle bar of tufting machine. It was found that there is an approximate agreement of the penetration force between FEM calculations and experimental results. The reasonable agreement proves the validity of finite element analysis model, which could be used to calculate the impact response of the needle penetration stress precisely. The finite element model has been verified experimentally and can be used to study the influence of the key tufting parameters such as the backing material properties and the needle geometry on penetration force, which is vital for designing needle and driving mechanism.     

三维机织增强复合材料弹道冲击边缘部分有限元分析

利用有限元软件ABAQUS建立基于三维机织增强复合材料的单胞模型,探讨子弹在三维机织增强复合材料中应力波的传播发生过程,对比分析子弹冲击后边缘部分的实验结果和模拟计算的结果,并对三维机织增强复合材料的最终破坏模式与常用的层合板进行了比较。结果表明：子弹在三维机织复合材料中的应力峰值随入射速度的增大而增大,并来回发生反射,弹头从三维机织增强复合材料下表面射出后其增强纱线的断裂较入射上表面粗糙,分层现象在三维机织增强复合材料内部没有发生,而实际观察的破坏孔洞与采用有限元软件模拟后的图形基本吻合。     

Finite element analyses of tensile impact behaviors of co-woven-knitted composite from unit-cell approach

This paper reports finite element analyses of tensile impact behaviors of co-woven-knitted (CWK) composite from a unit-cell model. A unit-cell model was established to characterize the microstructure of the CWK composite. A vectorized user-defined material subroutine was written and connected with commercial finite element analysis (FEA) software package ABAQUS to calculate the tensile failure of the CWK composites. The FEA results were also compared with the experimental results of the CWK composites under high strain rate tension obtained from the split Hopkinson tension bar apparatus. The comparisons indicate that the FEA results agree well with the experimental results. The failure mechanisms of the CWK composite under the different strain rates are also discussed.     

An investigation into the effects of fiber architecture on the mechanical behavior of woven preforms

This study attempts to analyze the behavior of different types of woven composite preforms (i.e. plain, twill, and satin) under distinct loading conditions. To this end, fabric elements are modeled using discrete finite element approach. Different loading scenarios such as intra-ply shear, in-plane tension, and simultaneous intra-ply shear and in-plane tension loads are applied to the fabric elements. TexGen software is utilized to develop the geometric model of the fabric elements. Subsequently, the geometric model is exported to ABAQUS FE package and mechanistic analyses are conducted. The FE results reveal that under the same loading conditions, the in-plane tensile stress induced in plain weave elements has the minimum value compared to twill and satin elements. Having said that, the intra-ply shear resistance of the plain element is larger than the other weave types. What’s more, the behavior of the fabric elements under simultaneous intra-ply shear and tension loading scenarios are studied that discloses almost the similar response for all weave types.     

织物成型性顶球评价方法

 为有效地选择服装和箱包用衬布及复合材料用基布,在综述国内外织物成型性研究成果的基础上,提出了一种简便、有效、全新的织物成型性顶球评价方法。这种方法可根据试样贴服球体表面的状态和起皱程度评价织物的成型性。研究结果表明,顶球法记录的作用力-位移曲线与织物的力学性能及成型性有密切的关系,可用于表征织物的成型性。大量测试表明,这种方法具有较好的重现性和区分度。同时还阐述了织物成型性的表征方法,并分析影响织物成型性的因素。为有效预测织物的成型性,运用有限元软件abaqus对顶球法进行了模拟,得到的作用力与位移曲线和实测结果基本一致,为基布的开发提供了新的思路。