| Flexible fabric keyboard switch as a king of smart textiles is made of flexible conductive yarns and insulated yarns.It not only maintains the softness and permeability of traditional textile,but also has the function of the control circuit on and off.It can be woven into apparel or household decoration materials for making phone calls,controlling lighting,playing music,etc.So fabric switch plays a pivotal role in the field of wearable textiles,and has a very broad prospects for development.With the flexible fabric keyboard switch gradually mature,and the use of more and more widely,followed by the flexible fabric keyboard switch performance requirements are getting higher and higher.In addition to improving its stability and taking,the fatigue life is also a measure of flexible fabric keyboard switch is an important factor.In recent years,all aspects of the fatigue properties of textile materials were studied by many scholars,which the life of the material structure and fatigue properties of materials to provide an important theoretical basis.However,there is little research on the fatigue life of flexible switch.The fatigue life of flexible fabric keyboard switch is studied in this paper.The elastic modulus and breaking strength of the polyester yarns were tested by the universal strength tester.The fatigue life curves of polyester yarns were obtained by tensile spring back testing at 50%,60%,65%,70%,75%,80%and 85%stress levels.The lifetime of the flexible fabric keyboard switch is tested by using the composite life tester,and the life expectancy is about 30000 times.Secondly,the finite element analysis software ANSYS Workbench was used to analyze and assume the structure of the flexible fabric keyboard switch.The geometric model of the three-dimensional flexible fabric keyboard switch was established.According to the fatigue experiment,the geometrical model is set up for material property,mesh division,boundary condition and fatigue module.The stress distribution and fatigue damage morphology of flexible fabric keyboard switch are calculated by the "SN-None" average stress level theory.Finally,the results of comparative experiment and finite element analysis,the finite element calculation of life of 45,000 or so,greater than the experimental results,because the test polyester yarn rebound times greater than the soft fabric keyboard switch in the number of presses,mainly due to the neglect of its force during the process of interaction between the yarn.The finite element analysis shows that the center area of the flexible fabric keyboard switch and the connection between the orifice part and the support part of they are larger and the rest area is smaller.In the finite element analysis,most of the model fatigue damage occurred in the central part of the orifice part,indicating that the region is the stress concentration,the first occurrence of fatigue damage after stress.The main failure modes of the yarns in the fatigue test results are yarn creep,most of which appear in the central area of the orifice part.This provides an important basis for the analysis of flexible fabric keyboard switch,which proves the validity of finite element analysis. |
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