基于典型鸟类翅膀特征的小型轴流风机叶片仿生设计与试验

基于提取的雀鹰、长耳鸮翅膀的表面特征对小型轴流风机的叶片进行仿生优化,以求提高风机的气动性能。设计出8种仿生风机模型,通过CFD计算选出最优的仿生风机模型进行性能试验验证,并与原型风机进行了对比。对比试验流量-静压曲线发现,仿生风机气动性能明显好于原型风机,最大质量流量提高了6.1%,最大静压提高了7.0%,并发现V型截面好于圆弧型截面。本研究为叶片仿生参数的进一步优化提供了前期基础。     

载能电刀仿生防粘表面技术

微创手术具有创伤小、疼痛轻、恢复快等优点已逐渐成为外科手术主流。微创手术组织的切割、止血常采用载能手术器械如电刀、电凝钩来完成,组织粘刀严重,会引起结痂、粘刀撕裂,造成二次创伤引起医疗事故。如何解决载能手术刀粘刀是微创手术器械面临的重要技术难题,本研究师法自然,从自然中汲取表面超滑防粘创新灵感,在揭示猪笼草湿滑防粘机制的基础上,提出液膜式防粘新策略,研究了仿生防粘表面结构高温防粘机理以及制备工艺方法。通过软组织载能切削试验测试了仿生防粘表面防粘性能、以及组织热损伤与耐久性,试验结果证实了仿生防粘表面的防粘效果得到显著提升,组织粘附力降低80%、组织粘附量降低88%、创口损伤面积减小82.6%、热损伤面积减小71%,满足了载能微创手术器械防粘技术要求。     

薄板结构弹塑性大挠度样条有限条分析

根据固体力学大变形增量理论,拓展了结构分析有限条法,建立基于Updated-Lagrangian法的弹塑性大挠度样条有限条法,编制了相应的C语言程序包FSMAP(Finite Strip Method Analysis Program),用于薄板结构大挠度问题的分析.数值算例表明,本文计算结果与有关文献解吻合较好,该方法计算稳定,处理边界条件灵活.     

仿生表面形态对齿轮动力学性能的影响

为了实现齿轮的参数化建模,在Pro/e中建立渐开线直齿圆柱齿轮轮齿模型,以工程仿生学和有限元理论为基础,运用MSC.Nastran对普通齿轮和仿生表面形态齿轮进行了瞬态频率响应分析,并通过激光雕刻技术将仿生表面形态加工在齿面上,进行实际的台架试验.试验和有限元模拟结果表明:在相同的内部激励作用下,普通齿轮和仿生表面形态齿轮的响应情况不同,其中仿生表面形态齿轮的形变量最小,可以有效地改善齿轮的动力学特性,提高齿轮的可靠性.     

Gas-solid erosion on bionic configuration surface

A three levels orthogonal table-L9(34) was used,namely,impact angle,rotating speed,erodent size,and surface configuration were considered.The three bionic surface configurations are pit,groove,and ring.The experimental results indicate the experiment factors affecting erosive rate are,in their sequence of contribution,erodent size,impact angle,configuration,and rotating speed;the erosive rate increased with increase in rotating speed,erodent size;the erosion resistance of the sample with ring structure is higher than that of the other two samples.Based on this result,regression orthogonal experiment was carried out to select the optimal erosion resistance condition with respect to the ring bionic surface configuration.Regression equations between erosive rate and experimental factors of ring surface configurations were obtained.     

多道次直缝焊管连续成型有限条分析

采用基于Updated-Lagrangian法的大变形样条有限条法,分析直缝焊管多道次连续成型过程的纵向薄膜应变和位移。模拟结果表明,变形带材的边缘是变形剧烈的部位,必须严格控制带材边缘纵向应变。多道次连续成型时,带材变形应先逐渐增大,然后逐渐减小,以保证成品质量。     

激光处理非光滑凹坑表面耐磨试验的均匀设计研究

本文采用试验优化技术中的均匀设计方法 ,实施了影响凹坑非光滑表面耐磨性的多因素复杂试验。通过用统计分析软件SPSS(StatisticalPackagefortheSocialSicence)处理试验数据 ,得出了激光处理仿生非光滑凹坑表面耐磨的多因素回归方程 ,发现速度、负荷、时间的凹坑圆周方向的距离对耐磨性有显著影响 ,凹坑轴向之间的距离对耐磨性影响不大     

Numerical Simulation on Flow Control for Drag Reduction of Revolution Body Using Dimpled Surface

Numerical simulation on the flow fields near the dimpled and the smooth revolution bodies are performed and compared by using SST k-ω turbulence model, to explain the reasons of friction and base drag reductions on the bionic dimpled surface and the control behaviors of dimpled surface to boundary layer near wall of the revolution body. The simulation results show that the dimpled surface reduces the skin friction drag through reducing the velocity gradient and turbulent intensity, and reduces the base drag through weakening the pumping action on the flow behind the revolution body caused by the external flow; the low speed rotating vortexes in the dimples segregate the external flow and the revolution body; and the low speed rotating vortexes forming in the bottom of dimples can produce negative skin friction.