The Development Of Automatic Test And Evaluation For Silk Cohesion Based On Virtual Instrument

The evaluating and testing system of raw silk cohesion based on virtual instrument and the objective evaluation of raw silk cohesion are studied in this thesis. The main contents covered by the thesis are the design of testing method for inspecting cohesion of raw silk, the suitable choice of the abrasion mechanism, the method to avoid wearing down the knife-edge unevenly and making the surface of the knife-edge serrated, the development of the main parts of the mechanism to deliver the raw silk at constant speed, the stability of the delivering mechanism is demonstrated properly based on the analyzing the structure of the delivering mechanism, the design of the interface, the design of the software of the evaluating and analyzing system, the method of the objective evaluation of raw silk cohesion according to the change of the structure of raw silk, the correlation between the results of objective evaluation and the results of subjective evaluation inspected by Duplan tester, and etc, The following is a brief introduction of the content for each chapter. In foreword the background of topic selection of this thesis is described briefly. In chapter 1 a brief account of the recent progress in the world of studies on the test and evaluation of raw silk cohesion is presented, and the characteristic and progress of the testing devices for raw silk,other fibers,filaments and fabrics are also introduced. The deficiencies of the cohesion tester and the subjective evaluation are given out emphatically. In chapter 2 the development of the measuring method for raw silk cohesion is discussed. The correlation between raw silk structure parameters and raw silk cohesion and key structure parameters affecting raw silk cohesion are analyzed. The characteristic of raw silk cohesion,how the raw silk structure and the processing affect raw silk cohesion,what the raw silk cohesion are working on the weaving and the quality of fabrics and the friction and wear mechanisms of raw silk are discussed in detail, which provides the foundation of the measuring method for cohesion. In chapter 3 the abrasion mechanism is selected and it is introduced how to maintain the knife-edge even and smooth. The main contents include as follows: the features of the friction loads of weaving and the key friction loads are elaborated, as the abrasion mechanism for cohesion testing the abrasion head of Duplan is reasonable and feasible, the reciprocating parts are designed to change the abrasion zones continuously and keep the surfaces of the knife-edges consistent, and the micro -breadth oscillation of the abrasion head is analyzed. In chapter 4 the development of the main parts of the mechanism to deliver the raw silk at constant speed is elaborated. And the mode to drive the raw silk to overcome friction forces and move at a constant speed, the figure and size of the transmission mechanism, the material of which the parts of the mechanism are made are also analyzed in detail. The silk tension, the feasibility of the transmission and the stability of the constant-speed traveling silk on the mechanism are discussed theoretically. The measured silk tensions are presented and compared with the results of the theoretic analysis. The transmission mechanism is considered properly according to the feasibility of the transmission and the stability of the constant-speed traveling silk on the mechanism. In chapter 5 the characteristics and realization of VI, data transmission between hardware and interface, and LabVIEW (Laboratory Virtual Instrument Engineering Workbench) are introduced particular. Virtual instrumentation technology integrates the computer, the sensor and the testing mechanism and completes the evaluating and analyzing system of raw silk cohesion. The whole system is friendly interface, convenient operation and comprehensive function. In the chapter 6 it is discussed that the structure of raw silk is changing under the abrading according to the friction and wear mechanisms of raw silk, the size of raw silkvaries with the abrasion, the increment of raw silk diameter has relation to abrasion and depends on the thickness of sericin, the physical and mechanical capability of sericin such as the adhesive strength. And so the cohesion of raw silk can be evaluated in terms of the diameter increment. Different testing methods for raw silk size are introduced, which provides the foundation of and selecting sensor assessing cohesion objectively. The experiments show that the diameter of raw silk increases with abrasion and the diameter increment depends on abrasion speed and yarn tension. Under the test condition of constant abrasion speed, yarn tension, for raw silks of the same linear density, diameter increment can be exclusively determined by cohesion, that is to say, the cohesion of raw silk can be evaluated in terms of the diameter increment. The assessed results of raw silk cohesion by Duplan tester and by the evaluating and analyzing system of raw silk cohesion based on virtual instrument are presented. The correlation between cohesion assessed by skilled person and that by the evaluating system is -0.837. In chapter 7 a summary is made to describe the main contributions of the present work to the objective evaluation of raw silk cohesion and the problems need to be further studied. The future work is also prospected.