热定型过程弹力针织物热塑性应变模型研究

Study on thermoplastic strain model of elastic knitted fabric in the heat setting process

为了得到针织物在热定型过程中的应变理论模型,首先通过分析热定型过程中弹力针织物在常温拉伸、加热伸缩、冷却收缩阶段中热塑性和应变力学特性,推导出高弹应变模型和塑性应变模型。其次通过分析针织物定张力加热过程高弹形变时应变松弛时间、弹性模量及黏度,推导出针织物定张力加热过程的应变模型;结合热塑性和应变力学特性,进而得到加热过程针织物形变模型;最后通过分析冷却过程中的收缩率模型推导出纤维收缩形变模型,联合以上2个形变模型得到弹力织物经向与纬向热塑性应变模型。结合实际热定型工艺,由热塑性应变模型得到幅宽和面密度与热定型加工的温度、加热时间以及经、纬向拉伸量的热塑性机理模型。研究结果表明:用实际生产中的结果与模型计算结果进行对比分析,证明了该热塑性机理模型的准确性和有效性。

In order to obtain the strain theoretical model of the knitted fabric during heat setting process, the high elastic strain model and plastic strain models were derived firstly by analyzing the thermoplastic and strain mechanical properties of elastic knitted fabrics during normal temperature stretching, heating expansion and contraction, and cooling shrinkage. Secondly, the strain model of the constant tension heating process of knitted fabrics was derived by analyzing the strain relaxation time, elastic modulus and viscosity of high elastic deformation during the heating process of knitted fabrics. Finally, the fiber shrinkage deformation model was derived by analyzing the shrinkage model in the cooling process, and the warp and weft thermoplastic strain models of the elastic fabric were obtained by combining the above two deformation models. Combined with the actual heat setting process, the thermoplastic strain model was used to obtain the thermoplastic mechanism models of the width and surface density and heat setting process temperature, heating time and warp and weft stretch. The results show that the accuracy and effectiveness of the thermoplastic mechanism model are proved by comparing the results in actual production with the results calculated by the model.