TY - JOUR T1 - Approximation of the Duffing oscillator frequency response function using the FPK equation JO - Journal of Sound and Vibration PY - 2011/01/01 AU - Cross EJ AU - Worden K ED - DO - DOI: 10.1016/j.jsv.2010.08.034 VL - 330 IS - 4 SP - 743 EP - 756 Y2 - 2025/07/16 ER -