内燃动力包隔振参数灵敏度分析及优化设计

Sensitivity analysis and optimization design of parameters of vibration isolation for power pack

为减少内燃动力包隔振参数优化设计中优化变量的数量并提高优化设计效率,将全局灵敏度分析引入动力包隔振参数优化设计中。首先,建立动力包双层隔振系统18自由度数学模型,基于新型快速显式数值积分法求解动力包隔振系统振动响应,并推导动力包机组振动烈度及系统隔振效率的函数表达式;其次,运用Sobol法对动力包隔振参数进行全局灵敏度分析,确定对动力包系统隔振性能影响较大的参数,并将其作为系统隔振性能主要影响参数;第三,将动力包隔振性能主要影响参数作为优化变量,以机组振动烈度与系统隔振效率为优化目标对动力包隔振参数进行多目标优化设计,获得最优的参数方案;最后,进行动力包地面台架实验,并对动力包隔振性能实验与仿真结果进行对比。研究结果表明:对机组振动烈度与系统隔振效率而言,灵敏度较大的参数为横垂比(隔振器横向刚度与垂向刚度比值)、纵垂比(隔振器纵向刚度与垂向刚度比值)、框架与车体相连的4个二级隔振器垂向刚度及机组与框架相连的3个一级隔振器垂向刚度;优化后的动力包在各个运行工况下系统的隔振性能指标都得到了较大程度改善,特别是在转速为1 000 r/min(空载)工况下,动力包机组振动烈度降低12.00%,系统隔振效率提升29.61%;所有工况下的机组振动烈度都为B级或A级,而且动力包系统隔振效率也均在85%以上,满足工程要求,验证了本文内燃动力包隔振系统模型的准确性及优化设计方法的合理性。

To reduce the number of optimization variables and improve the efficiency of optimization design, the global sensitivity analysis was introduced into the optimization design of vibration isolation parameters for the power pack. Firstly, a power pack system mathematical model with 18 degrees of freedom was proposed, and the new rapid explicit numerical integration method was used to compute the vibration response of the power pack vibration system. The function expression of unit’s vibration intensity and vibration isolation efficiency of the system was derived. Secondly, the global sensitivity analysis of the vibration isolation performance of the power pack was carried out by using the Sobol method. The parameters which have great influence on the vibration isolation performance of the power package system were determined and taken as the main influencing parameters of the vibration isolation performance of the system. Thirdly, the main parameters that affect the vibration isolation performance were taken as the optimization variables of the suspension parameter optimization design of the power pack. The vibration isolation efficiency and the unit’s vibration intensity were taken as the optimization objectives to carry out the multi-objective optimization design for the suspension parameters of the system, and the comprehensive optimal parameter scheme was obtained. Finally, the power pack ground platform experiment was carried out, and the test and simulation results of vibration isolation performance were compared. The results show that the parameter sensitivity of lateral vertical ratio(the ratio of lateral stiffness to vertical stiffness of the vibration isolator), longitudinal vertical ratio(the ratio of longitudinal stiffness to vertical stiffness of the vibration isolator),vertical stiffness of the four secondary vibration isolators and the vertical stiffness of the three primary vibration isolators, is much larger than other parameters. The vibration isolation performance of the optimized power pack is improved to a great extent, especially at no load of 1 000 r/min, the vibration intensity decreases by 12.00% and the unit’s vibration isolation efficiency of the power pack increases by 29.61%. In addition, the vibration intensity of the unit is at level B or level A under all working conditions, and the vibration isolation efficiency of the system is also above 85%. The designed power pack system meets the engineering requirements, which verifies the accuracy of the model and the rationality of the optimization design method.