Abstract: In this paper, the creep and stress relaxation tests of high stitch density biaxial warp knitted fabric reinforced PVC were carried out, and the action law of tensile rate and initial stress level on the viscoelastic behavior of the material was investigated. The relaxation modulus and creep compliance were obtained and their curves as a function of time were drawn. The test results show that the high stitch density biaxial warp knitted fabric reinforced PVC has typical viscoelastic behavior; the membrane has reached the steady-state relaxation stage in the test period, and the stress level has a significant effect on the static viscoelasticity of the PVC membrane. In particular, the creep phenomenon occurs with the increase of the initial stress level, and the tensile rate plays a role in the stress relaxation behavior of the sample, but it is not obvious. By comparison, the long-term transformation relationship between creep and stress relaxation of high stitch density biaxial warp knitted fabric reinforced PVC deduced by the principle of aging creep and time effect force relaxation of metal materials is deviated from the experimental results.

Key words: reinforced PVC membrane, creep test, relaxation test, viscoelastic constitutive relation