Bruno Senna, after years of struggling to make an impact in Formula 1, is bowing out after being replaced at Williams by Valtteri Bottas. Senna, a nephew of the late F1 legend Ayrton Senna, has signed up with Aston Martin's world endurance sports car team for 2013.'ALWAYS HAD VICTORIES'The David Richards-led team said: "Senna will drive at each round of the WEC in 2013." The WEC is the FIA's world endurance championship, including the Le Mans 24 hours.Senna commented: "Until 2009 I always had victories and podiums in the categories I passed. Since then, through a series of circumstances beyond my control, I did not have the same chance in F1."The proposals offered to me this season also did not give me this possibility."