The ASCII file “RCFORC” contains the incremental forces contributed by contact algorithms. Due to the nature of the contact-impact interactions, the raw output tends to be very noisy and is of little value. To eliminate the inherent noise in the contact force output, LS-DYNA averages the force magnitude over the preceing output interval which results in a smoother and useful time history of the contact forces. The averaging is performed for all values between two output states as shown in the following figure. For more information, please read Remark #5 under the *DATABASE keyword in the LS-DYNA Keyword User’s Manual.
(Click image to enlarge)