ABAQUS standard and explicit???

What is the differences between ABAQUS standard and explicit?

This question is the one I hear all the time in my basic classes. To deeply understand the distinction of these solvers let’s make a clear definition of each one.

In an Explicit analysis, the matrixes is going to be updated at the end of each time step, and the new equations is solved directly and without iteration. In simple words achieving equilibrium state is not strictly enforced in an explicit analysis, as a result the accuracy of this method can be guaranteed only when the increments are small enough. The main advantage of this method is that it has no convergence difficulty.

On the other hand the basis of Implicit method is to satisfy the equilibrium of the system. In each increment the solver tries to iterate the equilibrium. However this method is generally more accurate but it might confront with convergence problems and is also more time-consuming.

All in all,  ABAQUS Standard is Stiffness matrix controlled method, which means stiffness matrix changes at every integration point.  ABAQUS Explicit is mass matrix controlled method, which means mass matrix changes during the analysis.

In many cases it is obvious which method (ABAQUS/Standard or ABAQUS/Explicit) is more suitable.  wave propagation for example must be simulated with an explicit analysis. on the other hand, for smooth nonlinear problems is recommended to use implicit solver. But for many cases you can use both methods. If your project is confronting with convergence difficulties with numerous iterations, using ABAQUS explicit is a good solution. Here I have recorded a free video lesson in which I explain these methods in a greater depth.