Manz, YannikYannikManzGerlach, AndréAndréGerlachHoffmann, NorbertNorbertHoffmann2026-07-132026-07-132026-06-23Journal of Sound and Vibration 642: 119967 (2026)https://hdl.handle.net/11420/63882In nonlinear dynamical systems, internal resonance is a well known phenomenon. Natural frequencies may change with vibration amplitude, becoming commensurable or close at certain energy levels. Nonlinear modes then interact based on their participating oscillators. Here, we investigate effects on the response curve of a system as neighboring oscillators are modified. This provides new insights into the relation of internal resonance and the frequency response of coupled nonlinear systems. We use methods of Harmonic Balance and a continuation algorithm to compute nonlinear frequency response curves and nonlinear normal modes for a model system. It is arranged as a chain of Duffing oscillators with separated natural frequencies. We demonstrate a kinking effect in the response curve once internal resonance emerges in the system’s forced response. The kink is observed as a shift to higher response levels, stretching the response curve. We also show how this kinking effect is modified by adapting the nonlinearities of neighboring oscillators. The system’s response branches kink vertically as an oscillator in the chain is made linear, stacking on top of each other. Multiple stable solutions at a certain frequency may then be observed. We show that these solutions correspond to varying degrees of vibration localization in the system. We expect our results to be valuable in system design. It should be possible to exploit the observed kinking effect, shaping the response curve by adding suitable oscillators of various characteristics. The engineer may thus be able to reach a target system response level at a certain frequency.en0022-460X2026Elsevierhttps://creativecommons.org/licenses/by/4.0/KinkingStackingNonlinear dynamicsDuffing oscillatorsFrequency spacingInternal resonanceResonance overlapTechnology::621: Applied PhysicsJournal Article2026-07-0910.1016/j.jsv.2026.11996710.15480/882.17470