UFC newcomer Jessica Andrade ‘s bright smile hides a fierce martial arts competitor.  The only grin bigger than hers during an open workout in support of UFC on FOX 8 belonged to her opponent, recent bantamweight title challenger Liz Carmouche . But Andrade’s nickname is also “Bate Estaca,” which in Portuguese means “Pile Driver.” It’s an illegal move in MMA, and one that immediately prompts howls for point deductions.  Andrade, a blue belt in jiu-jitsu who lives in the city of Niteroi in the state of Rio de Janeiro, earned it during a grappling competition in which she faced a larger opponent. During their match, she was caught in an armbar, and in a panic, picked up the opponent and slammed her on her head.  She doesn’t believe in cheating, of course, but she’s kept the name throughout her 11-fight career because it just might serve a purpose in the UFC.  “I think it’s a cool nickname if it puts fear in the hearts of my opponents,” Andrade told MMAjunkie.com (www.mmajunkie.com).  Andrade (9-2 MMA, 0-0 UFC) and Carmouche (8-3 MMA, 0-1 UFC) open the main card of UFC on FOX 8, which takes place Saturday at Seattle’s KeyArena and airs live on FOX. Andrade steps up on short notice as a replacement for ex-Strikeforce champ Miesha Tate , who was tapped to coach “The Ultimate Fighter 18″ and fight champ Ronda Rousey when title challenger Cat Zingano was injured.  The 5-foot-3 Andrade walked away from five scheduled fights in six months to accept the bout with Carmouche, who returns to the octagon after a submission loss to Rousey in February.  The opponents share a background in jiu-jitsu, though Andrade also has cut her teeth against bigger and more seasoned strikers recently in her 11-fight career.  “I already fought Duda Yankovich , a boxing champion, and she was a lot bigger,” said Andrade. “I submitted her and won the fight