In-situ Characterization And Analysis Of Fabric Shape Retention Based On Mechanical Combination Test

As a kind of typical soft fibrous materials,fabrics can produce complex structural adjustment and material deformation even under low stress,which leads to morphological instability and plastic deformation of fabrics,resulting in surface wrinkles and buckling,which directly affects the aesthetic appearance,wearability and market value of textile materials.As an important index to describe the appearance performance of textiles,fabric shape retention is also an important test content in textile quality inspection and trade.Therefore,evaluating fabric shape retention objectively and efficiently has become an urgent need in industrial manufacturing,high shape retention product design and textile market.The existing characterization methods for evaluating fabric shape retention property mainly include appearance method,wrinkle recovery angle method,and image method based on appearance method and computer image recognition technology.However,the above methods belong to evaluation methods in visual principle,and thus the evaluation results of such methods are easily affected by complex texture and color of fabrics,showing some defects such as poor adaptability of categories.Therefore,it is still challenging to objectively evaluate the shape retention of fabrics.Based on this,our study pioneers the innovative characterization principle,i.e.in-situ mechanical combination method,to propose a testing method for characterizing the appearance characteristics of fabrics based on the intrinsic physical and mechanical properties of textile materials.By constructing multiple deformation modes of fabrics,this method simultaneously tests the physical and mechanical properties of fabrics under each deformation,and then completes the in-situ testing of the composite mechanical properties of fabrics in a limited time and space scale,which is conducive to revealing the inducing factors of fabric shape retention physically and realizing the objective and efficient characterization of fabric shape retention,which mainly includes the following contents:(1)The mechanical testing system for fabric shape retention(MST-FSR)was constructed,and the structural design and testing principle of the system were explained.Based on the analysis of the physical and mechanical components of the force-displacement curves,five characteristic indices related to the deformation properties were determined and extracted.Through the statistical analysis of the test results,it was proved that the system had strong stability(Repeated sample's CV ?2.28%)and high sensitivity(CV between samples?11.72%).(2)The internal relationship between ordered folding and mixed wrinkling of fabrics was studied,and it is proved by experiments that they obey the same structure-mechanics power law relationship(folding power law index ??1.1;Wrinkling power law index ??1.2),which indicates that the mechanical signals in the process of hybrid wrinkling can be captured from the orderly folding process,and lays a theoretical foundation for describing the non-hybrid wrinkling(i.e.,fabric shape retention)through the simple folding test(i.e.,MST-FSR test).(3)50 fabrics were selected for mechanical combination test,and the correlation between the extracted characteristic indices and subjective evaluation was analyzed.It was found that all five characteristic indices were significantly correlated with fabric shape retention at 0.01level(the correlation coefficients were-0.783,-0.810,-0.744,0.422 and 0.482,respectively).The prediction model was constructed based on five regression algorithms,namely Decision Tree(DT),Support Vector Machine(SVM),Random Forest(RF),Back Propagation Neural Network(BPNN)and Stepwise Regression Algorithm(SR).5-fold cross validation was used to compare and analyze the experimental results.According to the prediction performance,SR prediction model,which fits stably on the training set,was selected as the prediction model of fabric shape retention.The validity of the prediction model was verified by independent samples.The results showed that the evaluation results of the prediction model based on mechanical combination test were in good agreement with the subjective evaluation results,which indicated that the designed instrument and method provide a feasible and effective means to characterize fabric shape retention.(4)According to the prediction model of fabric shape retention,the influence levels of temperature,humidity and yarn surface friction properties on fabric shape retention were analyzed and discussed.It was found that under the condition of small external force,the conformal property of fabric treated with humidity was improved but the effect was not obvious,and the shape retention property of fabrics treated with temperature and plasma will become worse,which was consistent with the theory,further indicating that the prediction model can be applied to the comprehensive evaluation of fabric conformal property.Based on the above research work,this paper designed and developed a new mechanical test system for fabric shape retention,clarified the mechanical causes of fabric appearance wrinkling,and constructed an objective,intelligent and robust test method for fabric shape retention.By testing the fabric shape retention under different temperatures,humidity and yarn friction properties,the sensitivity of the test system to changes in fabric shape retention was further verified.This study provides a new test method for fabric shape retention,and is also conducive to promoting high shape retention design and research and development.