基于能量原理的等效静态载荷法及其在活塞动态优化中的应用

Method of Equivalent Static Loads Based on Energy Principle and Its Application in Dynamic Optimization Design of Diesel Engine Piston

针对位移等效静态载荷法在求解结构动态优化时遇到的等效关键时间点不合理、等效结果误差大等问题,提出一种基于能量原理的等效静态载荷法.该方法通过将结构动态响应解空间进行谱元离散,识别出结构的关键时间点,并在该时间点构建了基于能量等效的动态载荷静态转化数学模型.应用优化算法搜索得到了等效静态载荷集的最优解,从而将结构动态优化问题转化为静态优化问题求解.最后,通过在某柴油机活塞油腔结构的动态优化设计中的有效应用,验证了能量等效静态载荷法的有效性和工程实用性,拓展了等效静态载荷法的理论范畴,同时为复杂结构动态响应优化设计提供了一种新的思路.

Aimed at the problem of illogical time critical point and large error of the method of equivalent static loads based on displacement in structural dynamic optimization, an equivalent static loads method based on energy principle was proposed which could identify the critical time of structure by getting the spectral element discrete solution space of the structure dynamic response. The mathematical model of equivalent transformation was proposed based on the energy at the critical timer and the optimum solution of the set of equivalent static load was obtained using the global optimization algorithm. Therefore, the dynamic optimization problem could be transformed into a static structure optimization problem and solved. Finally, the effective and engineering practicability of the proposed method was proven by the effective application of the method in dynamic optimization design of a diesel engine piston oil chamber structure. The results expand the scope of the theory of equivalent static loads, providing a new way for the dynamic response optimization design of a complex structure.