物理属性驱动的多层次针织结构云仿真模型研究

As a focus of the Internet plus textiles, much attention has been paid on 3D simulation of multi-layer knitted structure for drawing knitted products in virtual display, online e-commerce，animation and films. Due to massive loops and complicated structures, traditional fabric simulation methods cannot make accurate calculation of microscopically physical interactions and real-time response to massive data processing. Based on physical factors influencing structure form such as yarn property, structural and technique parameterization, Cardinal interpolation spline curve and minimum rotating frame are used to establish multi-layer interlaced loops geometry. To simulate the complex nonlinear mechanical behavior of these multi-layer interlaced loops, traditional mass-spring plane is improved as a 3D cuboid by adding numerous mass meshes and linking springs whose performances are decided by structural physical properties. Differential equations of moving particles are solved by using the explicit Euler algorithm. Unreasonable loop penetration caused by excessive displacement is avoided with a collision detection method based on contact detection and OBB bounding box. Massive data storage, calculation and processing are all carried out on a simulation platform under cloud server to ensure the real-time simulation performance. The research will provide model foundation and technical support for virtual design, virtual testing and virtual display of knitted products.

针织结构的三维仿真是实现针织产品虚拟展示、在线电子商务和游戏影视场景的基础，是“互联网+”纺织技术研究的重点。由于线圈数量繁多、层次串套复杂，传统仿真方法无法实现微观物理交互的精确计算和海量数据处理的实时响应。课题从影响多层次针织结构形态的纱线、结构、工艺等物理属性出发，采用Cardinal插值样条曲线和最小旋转标架建立多层次线圈串套的几何模型，改进传统质点-弹簧模型为多层次体型系统，增加若干质点网格层和弹簧，模拟线圈串套和层次间联动的非线性复杂力学行为，并用显式欧拉算法求解线圈质点的运动微分方程。为避免线圈运动位移过大造成的不合理穿透，采用基于接触检测的OBB包围盒判断碰撞并作出响应；仿真过程中海量数据的存储、计算与处理均在基于云计算的仿真平台中进行，保证模拟的实时性。研究将为针织产品的虚拟设计、虚拟测试和虚拟展示等提供模型基础和技术支持。

多层次针织结构因其独特性能被广泛用于航空航天、生物医疗、交通建筑、服用家居等领域，其结构的三维仿真是实现针织产品逆向设计、性能模拟预测和产品虚拟展示的重要依据，是“互联网+”纺织技术研究的重点，需攻克线圈数量繁多、层次串套复杂的难题。项目从针织物成形的物理属性出发，在全面分析多层次针织结构特征基础上，围绕织物设计参数化数学模型、线圈集合体三维几何模型重建、织物内线圈交互的力学行为等方面进行了研究。采用Cardinal插值样条曲线和最小旋转标架建立了多层次线圈串套的几何模型，基于线圈集合体内的层次关系设计了三维质点-弹簧系统，并用显式欧拉算法求解了线圈质点的运动微分方程，并针对线圈运动位移过大而造成的不合理穿透问题进行了基于接触聚类的碰撞检测，在云仿真模块中实现了复杂针织结构的三维可视化。研究将为针织产品的数字化设计与开发提供理论和模型基础，为针织产品虚拟仿真教学提供技术支持。