crash simulation

hello everybody,

i am doing a simulation of the crash of a square tube crashed by a solid plate.

i am interested in the reaction force by the tube throughout the crash distance.

i am using LSdyna solver...

i used the ascii output RCFORC but the result is not found as expected.

and i was suggested to use SECFORC as my output result.

can anyone please help me find out the difference of RCFORC and SECFORC.

thanks

sharad