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纬编针织物线圈的三维模拟及变形实现
Three-dimensional Simulation and Deformation Realization of Weft Loop
【作者】 赵磊;
【导师】 邓中民;
【作者基本信息】 武汉纺织大学 , 纺织材料与纺织品设计, 2011, 硕士
【摘要】 针织物的仿真技术已经得到了纺织领域的关注,对经、纬针织物的二维线圈及一些三维线圈的仿真已经有了一定的发展,但对三维线圈模型线圈与线圈之间的牵扯而产生力的表现形变的研究却很少。本文以Peirce经典纬编模型为基础,通过对纬编针织物的基本线圈单元(成圈、集圈、浮线、移圈)进行几何结构分析利用三角函数构建线圈曲线段的数学模型利用曲线段的组合来拟合线圈屈曲形态,以线圈模型为基础运用计算机图形学设计原理结合OpenGL(Open Graphics Library)图库利用二维网格模拟由线圈构成的部分织物并关将网格单元与线圈单元动态关联实现线圈受力变形模拟,通过用线圈结构图设计纬编织物实现了从数组到意匠图再到结构图的便捷而直接的仿真,使纬编织物的仿真更直观、快速、准确。本文首先将一段完整的线圈模型切分成若干以控制点为端点的曲线,用三角函数方程来建立曲线的屈曲形态并利用控制点将曲线以拟合成线圈,运用这种方法来绘制各种能满足纬针织物的线圈模型。利用二维数组的方法,将各种状态的线圈存储在数组之中通过数组排列实现对织物结构的基本模拟,将线圈与二维网格单元动态关联,利用改变矩形单元不同端点区域的位移拉扯矩形单元周围的单元来实现织物上线圈的变形。最终是利用OpenGL的图形工具结合以上原理,完成纬针织物三维动态仿真。本课题成功的表示了线圈形变的三维图形,使得通过改变线圈的屈曲角度、长度、尺寸以获得各种相互关联线圈互相拉扯而产生变形效果得以实现。当线圈发生形变,线圈周围将发生相应的形变,如果一个目标线圈被纵向拉伸那么纵向线圈将会相应的被拉伸,理论上目标线圈左右的线圈将会相应的变宽。这种对三维线圈模拟的改进理论使得下机织物线圈之间牵扯变形的效果得到提高,改善对针织物设计的可预见性,并且使得织物设计更加高效和准确,极大的缩短生产周期,节省生产成本。
【Abstract】 Simulation technique of knitted fabric structure has received much attentions in the textile community. Research and development has concentrated on the simple two-dimensional (2D) loops and some of the three-dimensional (3D) loops in warp and weft knitting structure. This paper on the foundation of Pierce model,make a analysis on the basic model loops(knit loop,tuck loop,float loop, loop transfer) employs the combination of trigonometric functions and lines to stimulate the flexing state of yarns. Based on loop model by using computer graphics design principle combined with OpenGL library using 2D grid simulation constitutes a part of the fabric of loop and close will mesh coil unit with dynamic correlative realize loop stressed deformation simulation, through using loop structure design weft basketwork realizes from array of loop-formed figure to chart to the convenient and direct simulation, make the simulation more intuitive weft basketwork, rapid and accurate.A unbroken loop has been divided into some curve,a 3D geometry of a series of weft knitted loops are specified which includes the required parameters of the number of loops, planar orientation angle of a loop at the point of connectivity to another loop and dimensions. All 3D geometrical transformations in this section use homogenou column-major 2×2 matrics for loop addtion, traslation, rotation and reflection. All geometrical transformation operators transform loop from model space to world space to position and orient a loop in relation to its parent loop. The weft knitted loop was trasformed from three dimensions to a flattened and segmentd 2D approximation with each loop assuming an trapezoid shape by four corner points and by modifying the four corner points to control the trasformation of this loop.The project have expressed coil deformation 3D graphics successfully, which made by changing the length of the coil Angle, buckling size to obtain various, interconnected coil mutual drag so the deformation effect can be realized. When the loop deformed the round of the loop are going about the corresponding deformation, if a goal loop by longitudinal extension so longitudinal loop will corresponding stretch, theoretically goals around loop winding will corresponding grows wider. This kind of 3D theoretically simulated improvement means loop can clearly see the fabric stressed deformation effect and improves the predictability of knitted fabric design, and make the fabric design more efficient and accurate, greatly shorten the production cycle, save the cost of production.
【Key words】 3D simulation; weft knitted fabric; computer aided design; coil model;