Is there any differences between send and dsend in SimGrid, except except blocking/ non-blocking function?
dsend is a non-blocking detached send. If you look for a non-blocking send, then that's isend. The difference is that where you absolutely have to do MSG_comm_wait() or MSG_comm_test() to finish a communication that were started with isend (the data transfer will not occur unless you do so), you cannot interact with the communication started with dsend.
The concept of detached communications is inspired from detached threads, so it may help to read about it on the Internet.