Fig. 2

Schematic diagram of creep element model with joint damage, where \(E_{0} ,E_{1} {\text{ and }}E_{2}\) are the elastic modulus of the elastic element and Kelvin model element. \(\sigma_{0} ,\sigma_{{\text{s}}} ,\sigma_{1} {\text{ and }}\sigma_{2}\) are the stress of the elastic element, viscous element, and Kelvin model element. \(\eta_{1} ,\eta_{2} {\text{ and }}\eta_{3}\) are the viscosity coefficient of the Kelvin model element and viscous element. \(D_{t}\) is the joint damage.