三维正交机织复合材料力学性能研究进展

总结三维正交机织复合材料力学性能的研究现状与发展趋势。介绍了纱线截面对三维正交机织复合材料弹性模量的影响;阐述了三维正交机织复合材料几何结构的数值表征特点;总结了国内外三维正交机织复合材料的准静态力学性能和动态力学性能研究成果。认为:三维正交机织复合材料细观结构的分析已较为成熟,但应在所建模型中考虑实际的纱线状态;研究纱线与基体的界面性能也很重要,尚待加强相关研究。     

多轴向经编复合材料预制件的几何模型

为更好地了解复杂多轴向经编复合材料预制件的细观结构,在对多轴向经编复合材料预制件结构特征进行研究的基础上,通过合理假设,从细观几何角度出发,建立了带有短切毡的多轴向经编复合材料预制件单元结构模型.利用这个模型推导几何结构特征参数和加工工艺参数之间的关系,得出多轴向经编复合材料预制件理论纤维体积分数公式.以不同规格的多轴...     

正交-准正交复合三维机织复合材料力学性能

为弥补单一结构三维机织复合材料在性能方面的不足,研究正交-准正交复合三维机织复合材料的力学性能。以高强涤纶长丝为原料,分别织造四层正交和准正交三维机织结构作为预制件,依据均衡对称准则设计4种复合结构,选用双酚A环氧乙烯基脂为基体,制备正交、准正交及复合三维机织复合材料,并对制得的复合材料进行经向拉伸和弯曲性能测试。结果表明:准正交三维机织复合材料的经向拉伸和弯曲性能均优于正交三维机织复合材料;在复合三维机织复合材料中,复合顺序对复合材料性能的影响大于复合比例;正交结构位于材料表层时复合材料可以获得更优异的力学性能。     

三维正交机织圆管织物的试织及其单胞模型

探讨三维正交机织圆管织物单胞模型的建立方法。通过分析三维正交机织圆管织物经向、纬向和法向断面显微照片,建立了织物细观单胞模型,利用几何模型公式推导建立了织造工艺参数与几何结构特征参数之间的理论关系;计算了每层经纱的厚度、织物层数、织物厚度以及纤维体积含量,并与织物参数实际值进行了对比。结果表明:计算结果与实际值间有良好的一致性。认为:所建三维正交机织圆管织物单胞模型较为合理、有效。     

三维纺织技术发展现状

本文综述目前国内外生产三维结构复合材料预制件的三维纺织技术的发展。分别介绍三维编织技术、三维机织技术、三维针织技术及三维正交非织造技术。     

基于一元二次函数的层联机织预制体细观结构表征

织物预制体结构参数之间的相互关系是高性能复合材料设计需要解决的关键问题。为建立层联机织预制体的细观几何关系,通过显微观察和结构分析提出基于一元二次函数的抛物线凸透镜形纬纱横截面、抛物线形经纱路径等假设,通过研究典型的多层平纹层间联锁结构层联机织预制体,建立预制体全厚度单胞模型,推导其细观结构参数的几何表达,获得纱线横截面变异系数、预制体厚度和纤维体积含量的计算方法,从而实现预制体结构的细观设计。通过实测值和理论预测值的对比,验证了该细观模型的有效性和合理性,并确定了层联机织平纹预制体的纱线填充因子取值区间为0.73~0.87。     

三维正交机织复合材料力学模型研究进展

文章针对细观结构和理论模型进行了综述和回顾,重点介绍了三维正交机织复合材料的分析模型,以期待为今后的研究工作提供借鉴。     

用于复合材料增强的机织物

简述复合材料用机织预制件的分类、结构、生产设备及其各方面的最新进展，分析机织预制件对复合材料力学性能的影响。     

三维多向编织复合材料T型梁抗弯应力分析

针对三维多向编织复合材料结构件承载细观结构优化设计的问题,以三维编织复合材料T型梁为对象,对其抗弯性能进行模拟分析。基于细观结构单胞模型,采用刚度体积平均法计算具有不同编织角的三维四向、五向和六向编织复合材料的弹性常数;利用有限元软件Patran/Nastran计算T型梁承受弯曲载荷的应力与应变,分析纤维束交织结构和细观结构参数对T型梁抗弯性能的影响。结果表明,纤维体积含量一定时,三维六向较三维四向、五向编织复合材料的弹性性能更接近各向同性,同时选择比较大的编织角,可提高T型梁抗弯的承载能力。此方法可为异型三维编织复合材料构件细观结构的选型与参数设计可供参考。     

基于气缸的三维机织增强体织造系统设计

为在经纱方向引入贯穿织物厚度的接结纱从而提升机织增强复合材料层间性能,以三维正交无卷曲机织增强体为对象,设计了一种窄幅三维机织织造系统。采用气缸作为开口、引纬和打纬的主要驱动部件,实现多重综框的独立开口运动与管状多剑杆机构的多层梭口同时引纬运动,并在可编程控制器上实现各机构协调运作,使经纬纱垂直平铺,接结纱与纬纱交织并贯穿织物起到层间约束作用。通过显微镜观察三维机织增强复合材料各个切面(分别沿经纱、纬纱和接结纱),并测量纱线卷曲度、横截面积、组织单元尺寸等关键几何参数。测量结果表明,这种三维机织系统可实现三维正交无卷曲机织增强体的织造。     

Multiaxis three‐dimensional circular woven preforms – “radial crossing weaving” and “radial in–out weaving”: preliminary investigation of feasibility of weaving and methods

The aim of the study is to develop new preform structures and processes to use in the technical textile and composite industries. Multiaxis and orthogonal three‐dimensional (3D) circular woven preforms and weaving methods have been developed. The multiaxis structure has five yarn sets as (±)bias, axial, circumferential, and radial yarns whereas the orthogonal structure has three yarn sets, axial, circumferential, and radial yarns. Two weaving methods, radial crossing and radial in–out weaving were introduced to form the structures. An experimental rig was constructed to evaluate the methods. Basic process and structure parameters have been identified. The preliminary studies showed that the multiaxis 3D circular woven preforms and methods seemed feasible.     

Generalized geometric modeling of three-dimensional orthogonal woven preforms from spun yarns

Through the thickness mechanical properties of composites have been improved with the advance of 3D woven preforms incorporating through-thickness reinforcement element compared to 3D woven composites from stack of 2D fabrics. In this study, a generalized geometric model considering non-jammed and jammed constructions of 3D orthogonal woven preforms from spun yarns was developed to predict fiber volume fraction (FVF) of structure constituents, preform thickness, preform areal density, and minimum thread spacing (x-, y-, and z-yarn spacing) to achieve jammed construction in terms of weave factor, number of layers, and constituents’ variables (y- and z-yarn sequence, linear densities, packing factor, and fiber volumetric density). Numerical results are presented to demonstrate the generalized model potential as a design tool to achieve broad range of constituents FVF that controls composite performance.     

Finite element analysis of monofilament woven fabrics under uniaxial tension

Mechanical behavior of woven fabrics under tensile load is complex because their deformation could result from the combined effects of tension, compression, bending, and shear. In this study, the tensile behavior of woven fabrics is simulated using finite element method. The input parameters are the mechanical properties of constituent yarns obtained from tensile and friction coefficient tests and the geometry of woven fabric repeating unit. First, a 3D geometric model of the repeating unit based on Pierce’s model was built using computer-aided design tools. Then, finite element analysis which incorporates material properties, frictional contact, and periodic boundary conditions was implemented using ANSYS. A non-linear mechanical behavior was defined. Frictional contact algorithm for the cross-sectional zone of the repeating unit and periodic boundary conditions to the contour of the repeating unit was implemented. Numerical simulation data and experimental data were compared, which showed good agreement.     

三维正交机织物织造及复合材料成型工艺研究

详细阐述三维正交机织物的结构特征、织造原理及织造工艺,以三维正交机织物为增强体、环氧树脂为基体,采用真空辅助树脂传递模塑(VARTM)工艺成型,制成复合材料,并分析其内部结构。结果表明:由普通织机改造的多综眼多剑杆织机可以织造三维正交机织物,成型后复合材料内的纱线形状和位置未发生明显变化,树脂较好地渗透到织物内部,复合材料具有较高的纤维体积分数。研究结果为进一步研究三维正交机织复合材料的力学性能及应用奠定了基础。     

A novel structure of woven composite pressure pipes and its multi-scale analysis

A novel structure of woven composite pressure pipes (WCPP) is designed in this paper. Based on the overall geometry structure of woven preform, the representative volume unit (RVU) is established. The effective elastic constants and the mechanical properties of the woven composite layer are predicted by a multi-scale method, and the failure properties are simulated. Compared with filament-wound pressure pipes (FWPP), the WCPP can effectively improve the overall mechanical properties of the composite pressure pipes, and it can promote the further application of composite pressure pipes.     

Production principles for a T-shaped 3D woven nodal structure (T-3DWNS)

The integrated three-dimensional (3D) woven nodal structure (3DWNS) is regarded as one category of 3D textile structure, and it has potential applications for creating lightweight composite truss structures. The conventional weaving technology has been adapted for the manufacture of a variety of 3DWNS’s. This allows the production, in the woven fabric plane, of either a two-dimensional (2D) flat solid form, or a 2D-shaped woven preform. Once the woven 2D form is removed from the tensions of the loom enables the transition from 2D into a 3D woven structure (2D-to-3D). This article introduces an innovative approach based on the conventional weaving principles for creating a fully integrated 3DWNS in a T-shape (T-3DWNS). This fabrication method provided the forming of a node point without distortion, whilst maintaining the circumference of the adjoining child strut to a main/parent strut. This eliminated the need for further joining processes to bond the truss structure together, providing a fully integrated and lighter textile truss structure for composites engineering. This article defines the design parameters and range of specifications for the production of the T-3DWNS and introduces derivative configurations for future development.     

Mechanical properties improvement of silane addition epoxy/3D orthogonal woven composite material

In this study, the influence of silane addition on mechanical properties of epoxy/3D orthogonal glass fiber woven composite was studied. The KH560 silane modification composite specimen reinforced with 3D orthogonal woven fabric/epoxy was manufactured by means of Resin Infusion under Flexible Tooling. The mechanical properties of the epoxy/3D glass fiber woven composites were characterized by tensile and bending tests. The tensile and bending properties of silane-modified 3D orthogonal woven glass composite in warp and weft directions were compared with the pristine or epoxy/glass composite material not coupled using silane. The results show that the tensile and bending properties in warp and weft directions have been improved due to the silane addition. The bonding strength between the fiber and matrix was improved and the delamination and debonding between fiber and matrix was retarded and shifted to cohesive failure of the matrix due to the silane modification. Electron microscopy of the fracture and failure modes of the test specimens were used to support the results and conclusions.     

An Experimental Investigation into the Structure and Mechanical Properties of 3D Woven Orthogonal Structures

An experimental investigation is reported on the relations between the structure and mechanical properties of 3D woven orthogonal structures, one of the major types of textile constructions used for composite reinforcements. Tests for mechanical properties relating to tensile, shearing, and bending forces are discussed, and potentially useful information is provided towards the design and application of such textile structures. This paper also shows that satisfactory 3D orthogonal structures can be woven by using conventional looms.     

组合式3D机织物复合材料的拉伸性能

采用正交和角联锁结构进行组合设计,并使用玻璃纤维试织了2种不同结构的组合式3D立体机织物,经与树脂复合制成增强复合材料,对其拉伸性能进行了测试。结果表明,组合式3D机织物增强复合材料具有接近正交3D机织物增强复合材料的弹性模量和抗拉强度。