Homoclinic solutions for Swift-Hohenberg and suspension bridge type equations

We establish the existence of homoclinic solutions for a class of fourth-order equations which includes the Swift Hohenberg model and the suspension bridge equation. In the first case, the nonlinearity has three zeros, corresponding to a double-well potential, while in the second case the nonlinearity is asymptotically constant on one side. The Swift Hohenberg model is a higher-order extension of the classical Fisher Kolmogorov model. Its more complicated dynamics give rise to further possibilities of pattern formation. The suspension bridge equation as studied by Chen and McKenna (J. Differential Equations 136 (1997), 325-355): we give a positive answer to an open question raised by the authors. (C) 2002 Elsevier Science (USA).