Generation of cumulative second-harmonic ultrasonic guided waves with group velocity mismatching: Numerical analysis and experimental validationYanxun Xiang, Wujun Zhu, Mingxi Deng, Fu-Zhen Xuan and Chang-Jun LiuEPL, 116 3 (2016) 34001DOI: https://doi.org/10.1209/0295-5075/116/34001