Study On Influencing Factors Of Tensile Properties Of Low - Elastic Weft - Knitted Reinforced Materials

In recent years, the weft knitting reinforced material in the composite material world attention, since it has good extensibility and high production efficiency, as textile composites reinforced body gives the composite good formability, impact resistance and lower production costs. Meanwhile, the knitting flexible, it can produce the surface forming reinforced material with surface stress uniformity and overall good formability. Currently, the textile reinforcement materials have been widely used in many industrial fields of aviation, marine, automotive, medical and so on. Therefore, the study of textile reinforcements increasing cause for concern, while the weft knitting reinforced material also will be concerned, in particular, its surface formability research has aroused great interest.Extensive literature review of previous studies and for understanding and analysis, found that with the rapid development of the textile composite materials, knitted reinforcing material research more and more as a reinforcement of textile composite. But compared with other textile reinforced material, weft reinforced material research is relatively less, and the depth is also insufficient, basically concentrated in weft axial structure reinforced composite materials research, and based on coil geometry model common weft-reinforced composite theoretical analysis of mechanical properties, based on the coil geometry model and ordinary weft of theoretical analysis for the reinforced composite materials mechanics performance. The paper aims at the structure of the weft reinforced material selection, improvements in tensile properties and surface forming knitting provide theoretical and experimental reference.This paper is mainly based on as textile reinforced composite material reinforcements of weft knitted structures can be woven, structure selection, the tensile properties and surface forming woven research. Through analyzing different woven materials, spun yarn in the computer more easily than filaments knitted on flat knitting machine, and good mechanical properties is filaments; of different reinforced structure analysis, and according to the requirements of a reinforced composite reinforcements, choose suitable reinforced structure are Milano rib, double Milano rib, interval structures, purl stitch; In the process of test weaving, determined knitting parameter. Use Origin and Design - expert software analysis of reinforced material tensile test data, from the enhanced structural perspective, the most suitable as reinforcement of the textile composite material as follows:interval structures, double Milano rib, purl stitch, Milano rib; from the perspective of the woven material, form of yarn and mechanical properties are the decisive factors affecting the tensile properties of reinforced material, polyester yarn better than cotton yarn, filaments better than yarn; while the combination yarns and knitting stiches affecting the reinforcing material tensile properties are nonlinear, the four low elastic weft reinforced material horizontal and longitudinal stress response value for the response surface analysis, it is concluded that the structure of the optimum parameters of the woven respectively:Milano rib stitch 85, combination yarns 5; double Milano rib stitch 80, combination yarns 5; interval structures stitch 80, combination yarns 5; purl stitch’stitch 88, combination yarns 4.To expand the application areas weft reinforcing materials, eliminate plane weft reinforcing materials used for surface formed produce stress at the problem of uneven, so for the study of surface forming knitting process. By improving the method of 3D surface expands to a 2D plane and amendments to the calculation formula, the weft surface forming materials effect forming materials better, but there can’t put too much knitting needles and when knitting the Milano rib reinforcing material widening joint hole problems. Through the needles with release after, it so that the new needles can hook yarns and put numbers is not limited, so the surface can be freely shaped design, without affecting the process of knitting; by reducing the Milano rib between the lapping distance, so that the Milano rib surface forming widening joint hole eliminated, to enhance the stress of materials more uniform.Research said on the research of the factors effect tensile properties and surface forming knitting of weft knitting reinforced materials, to promote the weft knitting reinforced materials in the textile composite have practical significance.