机载SAR天线座结构动力学建模及分析

该文对机载SAR天线座有限元建模及结构动力学特性进行了研究。文中基于结构动力学理论,建立了机载SAR天线座的有限元模型,指出了动力学分析的关键技术,并进行了模态分析和瞬态动力学分析。仿真结果表明:机载SAR天线座的动力学性能满足伺服控制系统带宽和结构强度需求。该文提供的有限元快速建模和分析方法可为机载SAR天线座的轻量化设计提供重要支撑。     

机载SAR天线座连接支架的拓扑优化设计

拓扑优化方法在雷达天线座的减重设计中具有突出优势,特别适合于大型精密雷达和机载雷达天线座的结构优化设计。文中建立了连接支架的拓扑优化模型,以单元密度为设计变量,体积分数上限为约束条件,加权应变能最小化为优化目标,对机载SAR天线座连接支架进行了拓扑优化设计。考虑到结构美观和制造性,添加了对称平面约束和拔模约束。结果表明:拓扑优化结果符合仿生学原理,在减轻质量的同时,也提高了结构性能。     

某新型仪器舱的拓扑优化设计

对某新型仪器舱的拓扑优化设计进行研究。使用HyperMesh建立仪器舱的拓扑优化模型,利用OptiStruct对设计空间进行拓扑优化求解,以减重70%为目标,得到基于加权刚度最大化的设计方案,并采用3D打印制造了仪器舱的聚乳酸树脂样件。对比试验表明,基于加权刚度最优的设计方案,在质量最轻的前提下,实测+X支架刚度和-X支架刚度达到最优,实现了初始设计目标。     

Analysis of thermal-mechanical coupled characteristics of vehicle twin-tube shock absorber

A comprehensive model that included mechanical dynamics of the shock absorber coupled with its thermal properties was proposed innovatively.Moreover a thermal-mechanical coupled model which reflected the closed-loop positive feedback system was established by using MATLAB/SIMULINK,and some curves of shock absorber temperature rising characteristic were obtained by simulation ＆computation under several operating modes and different parameters conditions.Research results show that：shock absorber design parameters,external excitations,and thermo-physical properties parameter,such as oil density have effect on the shock absorber temperature rising characteristic.However other thermo-physical properties parameters,such as oil specific heat,cylinder density,cylinder specific heat,and cylinder thermal conductivity,have no effect on it.The results may be used for studying reliability design of the shock absorber.     

Large deflection of annular throttle-slices in shock absorbers

A general analytical formula of large deflection for annular throttle-slices in shock absorbers was deduced.The Chien-perturbation method was used to derive the stiffness curve equation of a single throttle-slice in shock absorbers.The analytical formula of large deflection for superposed throttle-slices was deduced directly and generalized.The undetermined coefficients of analytical formula were obtained through the finite element method(FEM) and curve fitting.Numerical results show that the analytical formula has satisfactory accuracy.     

基于流—固耦合的汽车减振器动态特性仿真分析

对减振器的流—固耦合建模和求解技术进行研究。基于多求解器的流—固耦合方法,建立精度较高的阻尼阀流场网格模型和叠加阀片有限元接触模型,并联合有限体积法和有限元法对减振器流—固耦合模型进行求解和分析,获取了减振器的速度特性和示功图,对阻尼阀内部压力场、速度场进行详细分析,对叠加阀片非线性动力学特性进行分析。仿真结果表明:由于高速油液对阻尼阀壁面的冲击作用,阻尼阀核心区域的压力场急剧变化;阀片在开启和关闭瞬间,速度有一个跳跃,这使得节流通道迅速变化,具体表现为开阀点附近的速度特性曲线向下弯折。因此,阻尼阀核心区域的流场网格模型和叠加阀片的接触模型对仿真精度影响最大。计算中考虑了油液的湍流流动,阀片的接触滑移和大挠度变形,使得流—固耦合模型尽可能地贴近物理事实,仿真结果与试验吻合较好。     

双筒式液力减振器开阀前内部流场的CFD仿真分析

研究开阀前减振器内部流场变化对减振器阻尼特性的影响.采用CFD仿真软件Fluent对减振器内部阀系的节流作用进行了数值模拟.将阀系的节流缝隙分为两部分进行数值仿真,确定了阀系结构中各部分对阀系节流压差的影响程度.通过试验测试对数值模拟结果进行验证.最终确定了通过数值模拟方法得到减振器的阻尼力是可行的.