针对全机疲劳试验约束点动态载荷超差导致约束部位结构疲劳失效的问题，研究了试验中约束点动态不平衡载荷产生的主要因素，分析了多通道协调加载控制激励-响应曲线和结构动态载荷响应过程，揭示了控制系统激励-响应相位差与结构动响应耦合是导致约束点动态不平衡载荷的主要原因。基于粘滞阻尼控制基本原理，提出了弹性阻尼约束方法，设计了弹性阻尼约束装置，从强度性能、流场分析、瞬态动力学仿真分析等证明了方法的可行性，并给出了关键参数的取值范围。在某型飞机全机疲劳试验中开展了应用验证，验证结果表明弹性阻尼约束可有效降低试验过程中的动态不平衡载荷，在节流阀25%开度下，最大动态冲击载荷降低60%至3100N。研究结果可广泛推广至其它型号全机疲劳试验。

To address the problem of structural fatigue failure at the constraint locations caused by dynamic loads exceeding toler-ance limits at the constraint points in full-scale aircraft fatigue tests, the main factors contributing to dynamic load imbal-ance at the constraint points were studied. The excitation-response characteristics of multi-channel coordinated loading control and the structural dynamic load response process were analyzed, revealing that the coupling between the excita-tion-response phase difference of the control system and the structural dynamic response is the primary cause of the imbal-anced dynamic load at the constraint points. Based on the fundamental principle of damping control, an elastic damping constraint method was proposed, and an elastic damping constraint device was designed. The feasibility of the method was demonstrated through analyses including structural strength analysis, transient dynamic simulation, and the optimal ranges for key design parameters were determined. The method and device were validated in the full-scale fatigue test of a certain aircraft model. The results show that the elastic damping constraint effectively reduces the dynamic load imbalance during testing. At a 25% opening of the control valve, the maximum dynamic impact load is reduced by 60% to 3100 N. The re-search findings are widely applicable to the full-scale fatigue tests of other aircraft models.