Present study characterizes the propagation of harmonic plane waves in Eringen's non-local thermoelastic medium. Three phase lag (TPL) theory of thermoelasticity has been applied to account for the interactions between elastic and thermal fields. Two sets of coupled longitudinal waves (elastic and thermal) and one independent vertically shear wave have been achieved. Longitudinal waves are found to be dispersive and experience attenuation. All these waves are found to be influenced by the elastic non-local parameter. Further shear-type wave obtains a critical frequency while the coupled longitudinal waves may face critical frequencies conditionally. High and low frequency asymptotes of physical fields have been calculated. By considering an illustrative example, numerical results have been computed to explore the physics of the problem. The results for the TPL model have been compared with those for the dual phase lag theory. The study reveals that the distribution of phase velocities and attenuation coefficients for the TPL model are significantly different from those of the dual phase lag models with respect to the frequency as well as non-local elastic parameter. TPL theory is found to be capable in predicting better results as compare to the dual phase lag theory of thermoelasticity.

目前的研究表征了谐波平面波在艾林根非局部热弹性介质中的传播。三相滞后（TPL）热弹性理论已被用于解释弹性场和热场之间的相互作用。已经获得了两组耦合的纵波（弹性波和热波）和一个独立的垂直剪切波。纵向波被发现是分散的并经历衰减。发现所有这些波都受弹性非局部参数的影响。当耦合的纵波可能有条件地面对临界频率时，进一步的剪切型波将获得临界频率。高低频渐近线物理场的数量已计算出来。通过考虑一个说明性示例，已计算出数值结果以探索问题的物理原理。TPL模型的结果已与双相滞后理论的结果进行了比较。研究表明，就频率以及非局部弹性参数而言，TPL模型的相速度和衰减系数的分布与双相滞后模型的相差很大。与热弹性的双相滞后理论相比，TPL理论能够更好地预测结果。