集中供热热管太阳能集热器系统的研究

在原有铜铝复合板的基础上,试制了一种适合多层建筑的集中供热太阳能供热系统,克服了原有的平板式及真空管式集热系统的易炸管?易冻?易结垢?单管损坏后整个系统失效等问题.利用集热板价格低的特点,结合多层建筑,充分利用楼层的集热面积,集体安装,其结构体现了集中供热的特点,其热量可以互为补充.     

钨极氩弧焊温度场三维动态模拟及红外测温

焊件温度场快速加热和冷却过程中的正确描述是进行组织转变和焊后接头力学性能分析的前提条件,文中建立了电弧运动下的三维焊接温度场的动态有限元计算模型,利用有限元分析软件Ansys编制了APD I程序,针对铝合金钨极氩弧焊焊接动态过程进行了模拟仿真.采用双椭圆热源模型进行计算,分析中考虑了材料热物理性能随温度的变化,以及辐射、对流、相变对温度场的影响.采用红外测温仪SAT-HY6800对焊接过程进行测温,加装滤光镜排除电弧辐射对红外测温的影响,实现了对焊缝区域温度的采集.将测量温度与计算结果进行了比较,两者基本吻合.     

冷切边模堆焊工艺的研究

文中研究的冷切边模堆焊工艺是以普通低碳钢为基体 ,通过在刃口部位堆焊高硬度合金钢制造冷切边模 ,代替传统的切边模制造工艺 通过工艺性能实验 ,分析了工艺参数对焊接质量的影响以及堆焊质量的关键因素稀释率对堆焊层硬度的影响 ,从而选取了适当的工艺参数并制订了堆焊法制造切边模的工艺 对堆焊过程中出现的刃口塌坡、气孔、裂纹等焊接缺陷提出了预防和解决的措施 堆焊的刃口平均硬度在HRC58.5以上 ,且具有一定的冲击韧性 利用此工艺笔者成功的堆焊制造了一批冷切边模和冷冲模 ,其性能达到或超过传统工艺制造的切边模 ,同时该工艺还是修复冷冲模、冷切边模等模具的行之有效的方法     

Variations in defect substructure and fracture surface of commercially pure aluminum under creep in weak magnetic field

Commercially pure polycrystalline aluminum of grade A85, as a test material, is investigated. Using scanning and transmission electron microscopy the aluminum fine structure and fracture surface are analyzed. Fractures are studied in the regime of creep with and without a simultaneous effect of 0.3-T magnetic field. It is found that the application of a magnetic field in a linear stage of creep leads to substructure imperfection increasing. Furthermore, the magnetic field effect on aluminum in the process of creep causes the average scalar density of dislocations to increase and induces the process of dislocation loop formation to strengthen. Fractographic investigation of the fracture surface shows that in the fibrous fracture zone the average size of plastic fracture pits decreases more than twice under creep in the condition of external magnetic field compared with in the conventional experimental condition. In a shear zone, the magnetic field causes the average size of fracture pits to decrease. Experimental data obtained in the research allow us to conclude that the magnetic field effect on aluminum in the process of creep leads to the fracture toughness value of the material decreasing, which will affect the state of defect substructure of the volume and surface layer of the material. The influence of the magnetic field is analyzed on the basis of the magneto-plasticity effect.     

焊接热应力模拟及基于VC的二次开发

建立了基于Ansys的简单TIG焊温度场、应力场模型,并采用Windows通用软件开发平台VC 6.0结合Ansys分析过程开发了焊接热应力有限元分析程序.研究了利用VC和Ansys参数化设计语言APDL进行二次开发的技术,开发的程序主要包括用户界面模块、Ansys计算模块、VC调用接口模块和VC后处理模块等.模拟结果表明,所开发的程序能实现VC和Ansys软件的交互调用和结果显示,拓展和丰富了进行焊接过程模拟的方法及软件交互性.