Numerical study of a welded plate instability using the subloading surface model

Instability in structural components has been widely studied to understand the elastic and inelastic behaviors of materials because of the risks associated with sudden failure of components under equilibrium conditions. However, most studies have been performed for various monotonic load configurations without considering the instability as a final step in a process induced by irreversible deformations that can arise even for small vibrations. This work investigates instability problems that may be caused by plastic strain during cyclic loading. This type of instability is difficult to study with conventional plasticity models because they fail in predicting irreversible deformation for changes in the stress state within the elastic domain. In contrast, unconventional theories abolish the distinction between plastic and elastic domains, allowing the material to exhibit a smooth elastoplastic response for every change in the stress state during a loading.