A Study On Shear Properties Of Fiber Materials

The fibers are flexible materials.It is easy for them to subject to shear deformation because of their small diameter and great flexibility.However,the shear deformation in fabrics is both viscose and elastic at the same time,so it is difficult to study.For the fiber material,the shear properties are of great research value,which can directly affect the shear strength and material properties of the fiber composites.Therefore,this thesis intends to conduct an in-depth study of the shear properties of flexible fiber materials,which is different from the previous studies on the relationship between fiber shear properties and fiber types,the density of fabric yarns,and the structure,etc.,but focuses on the shear strength of the fiber material itself.Judgment and modeling of the shear properties of fibers and fabrics are made.Aiming at fiber materials,six kinds of fiber materials such as nylon conductive yarn,polyester,basalt fiber,ceramic fiber,glass fiber and black conductive fiber were selected as the main research objects.First,the fiber shear clamp was designed to perform shear experiments to measure Shear strength of fiber materials,compare the shear strength and tensile strength of different fabrics,judge the fiber breaking characteristics,and then observe the fracture surface morphology of the fiber for verification.Then the modeling study of small deformation shear behavior of fiber fabric.First,the viscoelastic shear deformation of the fabric was modeled using rheological mechanics theory.The parallel and series connection of Newton stick pot,friction element and Hook spring was used to simulate the friction and viscoelastic force of the fiber fabric.The strain relationship leads to two indexes that can characterize the shear performance,shear stiffness and shear lag moment.Then through the KES-FB1 shear test,the shear lag curve,measured shear stiffness,and shear lag moment are obtained.Substituting the measured data into the model,the theoretical values ??of the shear stiffness and the shear lag moment are obtained and compared with the actual values,so as to judge the validity of the model.The comparison results show that the theoretically calculated shear stiffness and shear lag have small deviations from the measured values,so the model can be initially proved to be effective.The analysis process and research method for the shear properties of fiber materials in this paper is a very effective theoretical method for studying the mechanical properties of fabrics,which is conducive to understanding the mechanical nature of fabrics.