On new nonlinearity in third-order elastic modulus for vibrational analysis of FG porous beam based on nonlocal strain gradient and surface energy by modified homotopy perturbation method
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Eur. Phys. J. Plus, 137 4 (2022) 468
Published online: 15 April 2022
DOI: 10.1140/epjp/s13360-022-02650-6