duplicate SAMPLE db in db2
The SAMPLE database is usually created with the db2sampl command (documented here for DB2 LUW 10.5). You can tell db2sampl to create another SAMPLE database under a different name with the -name option (note: this command must typically be run by someone with SYSADM privilege in the instance, e.g. by the db2inst1 user). For example, on a Linux box:

someuser@myserver:~$ sudo su - db2inst1
[sudo] password for someuser:
db2inst1@myserver:~$ db2sampl -name SAMPLE2