Introduction

The explicit dynamics method efficiently handles numerous small-time steps. 

The explicit dynamics method is well-suited for analyzing high-speed dynamic events, but its advantages also extend to the analysis of slower (quasi-static) processes. A good example is sheet metal forming, where contact plays a dominant role in the solution, and local instabilities, such as wrinkling of the sheet.

It utilizes an explicit central-difference time integration scheme, where each step is relatively low-cost (in comparison to direct integration dynamic analysis) because it does not require solving a system of simultaneous equations.

Benefits of the Explicit Dynamics Method

The use of small-time steps, determined by the stability limit, is beneficial because it allows the solution to proceed without the need for iterations or forming tangent stiffness matrices. Additionally, it simplifies the handling of contact.

Unlike Linear Steps, where results are automatically checked for accuracy (using the half-increment residual), explicit dynamics analysis does not perform such checks. 

However, this is typically not a concern because the stability condition forces a small-time step, ensuring that the solution changes only slightly during each increment, which simplifies the incremental calculations.

Although the analysis may require a very large number of increments, each one is relatively inexpensive, making it a cost-effective solution. It is not uncommon for Explicit steps to require over 105 increments for an analysis. This method is computationally attractive for problems where the total dynamic response time is only a few orders of magnitude longer than the stability limit, such as in wave propagation studies or certain "event and response" applications.

For Output

The element output available for a dynamic analysis includes stress; strain; energies; and the values of state, field, and user-defined variables. The nodal output available includes displacements, velocities, accelerations, reaction forces, and coordinates. All of the output variable identifiers are outlined in Explicit Step output variable identifiers.