Nonlinear visco-hyperelastic tensile constitutive model of spray polyurea within wide strain-rate range

• Published in: International journal of impact engineering Vol. 163; p. 104184
• Main Authors: Chen, D, Wu, H, Wei, J S, Xu, S L, Fang, Q
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.05.2022; Elsevier BV
• Subjects: Constitutive models; Deformation effects; Drop hammers; Finite element method; Genetic algorithm; Genetic algorithms; Hammers; Hardening rate; Impact tests; Mathematical models; Mechanical properties; Modulus of elasticity; Multi-objective optimization; Multiple objective analysis; Nonlinear visco-hyperelastic model; Optimization; Parameters; Polynomials; Polyureas; Prony series; Protective coatings; Protective structures; Retrofitting; Spray polyurea; Strain rate; Strain-rate effect; Tensile deformation; Tensile properties; Tensile stress; Tensile tests; Nonlinear visco-hyperelastic model; Multi-objective optimization; Genetic algorithm; Spray polyurea; Strain-rate effect
• ISSN: 0734-743X; 1879-3509
• DOI: 10.1016/j.ijimpeng.2022.104184

•Tensile stress-strain curves of SPUA within a strain-rate range of 10−3–103 s−1 are experimentally derived.•Dependences of the elastic modulus, tensile stress, fracture strain on strain rate are formulated.•Nonlinear visco-hyperelastic model and parameter determination approach of SPUA are proposed and validated. Spray polyurea (SPUA) is widely used as a protective coating material for structures subjected to the intensive impulsive loadings, attributed to its prominent large tensile deformation capacity and strain-rate hardening effect. This paper aims to study the tensile properties of SPUA within a wide strain-rate range both experimentally and theoretically. Firstly, by reasonably designing the geometry and dimension of specimens, a series of quasi-static and dynamic uniaxial tensile tests were carried out, and the nonlinear stress-strain curves corresponding to the strain-rates ranging from 10−3 s−1 to 103 s−1 were obtained. It showed that the mechanical properties of SPUA are sensitive to the strain-rate, i.e., the elastic modulus and tensile stress increase with the rising of the strain-rate, while the fracture strain is linearly negatively correlated with the logarithm of strain-rate. Then, a nonlinear visco-hyperelastic (NVHE) constitutive model composed of a 3rd-order polynomial hyperelastic model and seven Prony series terms describing the viscoelastic properties were established, and the corresponding twenty-three model parameters were calibrated through a multi-objective optimization based on genetic algorithm. Furthermore, based on the finite element program ABAQUS/Explicit, the validations of the proposed NVHE model and the parameters determination approach are verified by the present tensile test and existing drop hammer impact test. This work could provide a helpful reference for the retrofitting design of the protective structures.