Constitutive modelling on the whole-life uniaxial ratcheting behavior of sintered nano-scale silver paste at room and high temperatures

Uniaxial ratcheting and fatigue behaviors of low-temperature sintered nano-scale silver paste at both room and high temperatures were studied in the authors' previous work. The deterioration of sintered silver pastes under cyclic loading which manifest itself as decrease in elastic modulus is addressed by introducing a damage variable as represented by θ function. Then, the damage variable is coupled into a visco-plastic constitutive model, based on the Ohno-Wang and Armstrong-Frederick (OW-AF) nonlinear kinematic hardening rule. In addition, the temperature-dependent ratcheting behavior are also captured by incorporating the Arrhenius power-law model into the flow rule. The whole-life ratcheting behaviors of low-temperature sintered nano-scale silver paste are simulated and are in well agreement with experimental data.