基于ADAMS的垂直摇臂式喷头多体动力学建模与优化

以Nelson SR100型垂直摇臂式喷头为对象,针对现有垂直摇臂式喷头动力学性能的研究存在忽略摩擦因素、过于简化模型等问题,基于虚拟样机软件ADAMS建立了垂直摇臂式喷头的动力学仿真模型,综合考虑摇臂与转轴、喷管与水管密封等部位实际的摩擦情况,以试验数据确定各部件之间的实际摩擦因数。针对垂直摇臂式喷头的垂直上下摆动、水平左右步进旋转这两个主要动作,运用STEP函数构建一个完整周期非自由与自由运动时间段内喷头导流器所受水平与垂直力的模拟函数进行动力学仿真。最后通过换向仿真,模拟实际摇臂在换向过程中,摆动杆对限位板的接触碰撞力的大小。以接触碰撞力最大值最小为目标函数,对上述接触碰撞力最大值进行优化,将影响换向顺利程度的换向杆长度等因素作为约束条件,优化后的最大碰撞力较优化前减少了55.9%。其动力学仿真结果可以为垂直摇臂式喷头的结构强度分析与疲劳寿命优化等相关动力特性的进一步分析及喷头动力学特性的设计提供基础。

Dynamic Simulation and Optimi zation of Vertical Impact Drive Sprinkler by Considering Friction Coefficeint

As to the problems of over-simplification to the friction coefficient and impact between parts of vertical impact drive sprinkler.Taking Nelson SR100 vertical impact drive sprinkler as research object , the actual friction conditions be-tween swing arm and spindle or effuse and pipe seal were comprehensively considered.A dynamics simulation model of vertical impact drive sprinkler was established based on virtual prototype software ADAMS.The coefficient of friction be-tween different parts is defined by the test data acquired.The horizontal and vertical force simulation functions of deflec-tor were constructed by STEP function in a complete cycle including free and non-free moving period.Two major ac-tions:vertical hunting and horizontal stepping of the sprinkler were simulated.The last reversing simulation was conduc-ted to test the magnitude of impact force.Taking the magnitude of impact force as target function and the reverse rod length or other factors as constraints, the magnitude of impact force was optimized based on the parametric modeling and optimization function of the software.The maximum of impact force optimized was reduced by 55.9%.The results of the optimization can be used to analyze the structural strength or the fatigue life of the sprinkler.