This video lesson shows that in some cases, when the object under analysis is very stiff and strong, we can simplify the problem and minimize its solution time by ignoring the stiffness matrix in the equation of motion. The explicit time integration method is best for such rigid body systems. This lesson is part of the Ansys Innovation Course: Time Integration. To access this and all of our free, online courses — featuring additional videos, quizzes and handouts — visit Ansys Innovation Courses at https://www.ansys.com/courses.