Abstract
Quasi-static and dynamic compression experiments were performed to study the influence of liquid nitrile rubber (LNBR) on the mechanical properties of epoxy resin. The quasi-static experiments were conducted by an electronic universal machine under strain rates of 0.0001/s and 0.001/s, while a Split Hopkinson Pressure Bar (SHPB) system was adopted to perform the dynamic tests for strain rates up to 5600/s. The standard Zhu-Wang-Tang (ZWT) nonlinear viscoelastic model was chosen to predict the elastic behavior of LNBR/epoxy composites under a wide range of strain rates. After some necessary derivation and data fitting, a set of model parameters for the tested materials were finally obtained. Meanwhile, the incremented form of the ZWT nonlinear viscoelastic model were deduced and implemented into the user material program of LS-DYNA. A simulation-test contrast had been performed to verify the validity and feasibility of the algorithm. The results showed that the viscoelastic behavior of epoxy resin can be effectively simulated.
Highlights
High strength, electrical insulation and chemical stability enable the epoxy resins to be widely used in many fields, including military and civilian industries
The results showed that the tensile elongation, mode I fracture toughness, impact strength and energy absorption capability of the modified epoxy were elevated compared with the pure epoxy resin
The standard ZWT nonlinear viscoelastic model was chosen to predict the elastic behavior of liquid nitrile rubber (LNBR)/epoxy composites under wide ranges of strain rates and a set of model parameters for the tested materials were obtained based on the integral form of ZWT constitutive equation
Summary
Electrical insulation and chemical stability enable the epoxy resins to be widely used in many fields, including military and civilian industries. The mechanical behavior of the epoxy resins can be changed through the manufacturing process. It has been reported that the thermal treatment can help to modify the mechanical behavior of the polymeric materials. Post-curing and thermolysis are two competitive processes during temperature exposure [1]. The former one refers to the heat treatment above the glass transition temperature of a cured polymer, which can increase the degree of crosslinking by about 20–30% and elevate the stiffness as well as strength of the material. Mlyniec et al [1] presented a structurally based constitutive model, which took the influence of the post-curing as well as thermolysis process on stiffness of epoxy adhesives into account
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
