Limit cycle bifurcations in a class of piecewise smooth systems with a double homoclinic loop

In this paper we consider a class of perturbed piecewise smooth systems. Applying the method of first order Melnikov function we give a lower bound for the maximal number of limit cycles bifurcated from a double homoclinic loop. As an application we construct a piecewise quadratic system with quartic perturbation, which has 11 limit cycles bifurcated from such loop.