Study On The Compression Property Of Spacer Fabric

Spacer fabric is one typical kind of three-dimensional structure, which consists of up and bottom surfaces and one spacer layer. The flexible and resilient three dimensional structures make spacer fabric having good permeability and moisture conductivity, compressive resilient etc., and it has been widely used for car decorative, functional clothing, gasket materials, healthcare, shoes, strap, filter and other fields. Currently, the researching works of the spacer fabric focus on the plane compression performance and the analysis of the influencing factors, but there is fewer studies about the mesoscale mechanical effect of the local area, especially in the application of mattress where the action and reaction between torso and spacer fabric can be assumed as an interaction between a certain curvature sphere and spacer fabric. It significantly relates to the sleep quality, comfort and physiological health friendly. So, the paper also studies the spherical compression of spacer fabric so as to provide theoretical basis for practical production.The paper mainly analyzed from the following two parts:one part is to analyze the qualitative relationship between the whole stretch and plane compression of spacer fabric and its up and lower surfaces and spacer filaments. The other part is to quantitatively analyze the contour shape and the surface deformation of the spacer fabric during the spherical compression. Based on the experimental results of the structure and properties of spacer fabrics and spherical compression behaviour, we can get the following conclusions:(1) Spacer fabric structure factors impacting on the mechanical properties:①The thickness of the spacer fabric. The experiment results show that the value of the whole fabric tensile force does not equal the sum of the two surfaces and the spacer yarns due to fabric thickness, which results in the two surfaces fracture at different time. The thicker the fabric is, the more obvious the phenomenon is. In the plane compression test, the results indicate that if the fabric is thicker, and it causes more obvious "prone suppressing phenomena". It is disadvantageous for the fabric to release pressure. So we should determine the best thickness of the spacer fabric based on the working principle of the Euler beam.②the surface structure of the spacer fabric. The tensile experiments depict the fracture asynchrony of the two surfaces, especially for the fabric with less interlocking points reducing the tensile performance of the whole fabric. So we should try to make the structure structures of both surfaces are consistent so as to have the same strain. The plane compression experiments express that the surface density structure of the spacer fabric influences the compression performance. The reason is that during compression fabric the surface structure influences the boundary conditions of the spacer yarn. The tighter the surface structure is, the greater forces the spacer yarns suffer from both ends.③The spacer yarn. Through the tensile experimental analyses, we can see that the spacer yarns’ main stress form includes the torsion and bending and tensile because of the surface tensile deformation. In plane compression test, the spacer yarn bears all the force. Moreover, we assumed the spacer yam to be the Euler beam through the analysis, finding that the length and thickness of the spacer filament have great influence. The bigger the ratio between the length and the diameter is, the more easily the spacer filament bends. By testing the bending modulus of the spacer yarn as support materials, the bigger the modulus is, the better the press performance is.(2)In this experiment, we use the resin to solidify the surface contact profile of the spacer fabric compressed. Then through the image acquisition and experiment verification, the circular form fitting correlation coefficient reaches as high as0.9998and the maximum coordinates relative error is less than6.5%, indicating that there are significant linear relationship and proving the contact profile curve of boundary shape between the ball and the spacer fabric approximately being circular. The correlations between the compress strain at the lowest point of the spacer fabric based on four different curvature balls (including18cm,16cm, and12cm and8cm) are analyzed, indicating that the bigger the ball diameter is, the smaller the lowest point strain is. The correlation coefficients are all greater than0.98, showing the good consistency between the stress and the strain under different diameter ball compression. In addition, we establish a theory mode of spherical compression through the spherical compression theory analysis. We analyzed the errors between the measured and theoretical results under8cm diameter ball compression tests with the same compression strain, finding that the biggest error is7.5%, which indicates that measured and calculated results have good consistency and prove the feasibility using the plane compression of the spacer fabric to analyze the spherical compression performance and provide a theoretical basis for the spacer application on the mattress.(3)The measurement method of the average surface tension is tested on spacer fabric by implanting conductive yarns, and the relationship between surface tension and overall compression force of the spacer fabric is measured with the spherical indenter diameter of18cm,16cm,12cm and8cm, respectively, under the strain of81%. Test results show that the bigger the diameter is, the greater the pressure is. In addition, the correlations coefficients between compression forces and average surface tension forces are all greater than89%and the highest linear relationship is99.9%, which means that it is feasible and effective to test the surface deformation of the spacer fabric through the surface resistance method. Moreover, this study also tests the dynamic surface morphology deformation of the spacer fabric through the glass ball experimental method during spherical compression, and the preliminary test shows that the experiment is feasible.This researching works provide experimental foundation and theoretical basis for the analysis of the interaction process between the spacer fabric used as mattress material and the different t radius ball used to simulate different parts of the human body. The researching works also provide scientific guidance for optimizing mattress production technology, and has important theoretical and applied significance.