一种光敏树脂结构的力学性能

新设计三维打印光敏树脂结构,其主要用在减震隔震组合结构中作为阻尼元件.首先利用微机控制电子试验机对其进行静力加载试验,得到静载下载荷-位移特性曲线,并计算得到特定点处等效弹性模量,利用疲劳机进行动力加载试验,得到结构件在从5 Hz到20 Hz不同频率下滞回曲线,并计算出相应等效阻尼系数.基于有限元法,建立光敏树脂结构有限元模型,并以和实验相同的工况进行静力学和动力学计算分析,并对试验数据和数值计算结果进行对比,得到计算结果与实测结果吻合良好,从而验证有限元模型的可行性.在此基础上通过有限元计算方法,研究不同几何参数缝隙宽度、内弧半径、外弧半径、厚度对光敏树脂结构特定点等效弹性模量以及等效阻尼系数的影响.此结构受力时,纵向保持刚度输出,维持小变形,横向位移放大,具有良好的减振和抵抗变形的能力.     

轧辊温度场热交换系数的一种简便确定方法

轧件与轧辊之间的传热系数和冷却液的对流换热系数是研究轧辊温度场的难题之一。本文通过联立求解轧辊与轧件的热平衡方程，提供了一简单实用的计算方法。     

绝热层结构等效有限元模型的研究及应用

为了简化绝热层的有限元计算模型,提出了等效换热系数的概念,将绝热层和热交换介质的传热过程简化成等效热交换,并由此给出了平壁和圆筒壁传热的等效换热系数计算公式。该方法不仅极大地简化了热力学中的有限元模型,而且顺利解决了一些由于模型过大导致的问题。仿真结果表明:该方法准确可信,将其应用于鼓风站管道的有限元计算中,取得了令人满意的结果。     

大型管道绝热层结构等效有限元模型的简化研究及应用

为了简化大型管道绝热层的有限元计算模型,本文给出了等效换热系数的概念,将绝热层和热交换介质的传热过程简化成等效热交换,并由此给出了平壁和圆筒壁传热的等效换热系数计算公式。该方法不仅极大地简化了热力学中的有限元模型,而且顺利解决了一些由于模型过大导致的问题。仿真结果表明:该方法准确可信, 将其应用于鼓风站管道的有限元计算中,取得了令人满意的结果。     

离子交换树脂法可能成为一种提取金,银的主要方法

本文简介了离子交换树脂法的优点，工艺特点、树脂的种类和应用的研究、新型树脂的研制。指出树脂法有可能成为一种提取金、银的主要方法。     

一种三维源磁场的求解算法

提出了一种求解三维空间中已知电流源所产生的磁场分布的有限元算法.在数值实验中通过与毕奥萨法尔定律计算的结果相比较,验证了该算法的正确性.     

基于巴西圆盘实验的金属粉末压坯力学性能研究

采用圆弧型加载方式的巴西圆盘实验对2种成分相似的水雾化铁粉(Hgans ASC 100.29和Hgans Distaloy AE)压坯的力学性能进行研究。综合考虑实验装置、压坯的几何特征及材料属性对压坯抗拉强度的影响,引入系数C对巴西圆盘经典抗拉强度公式进行修正,以更加准确地描述压制过程中压坯的力学性能变化。采用高清摄像机进行实时拍摄,对粉末压坯从变形到完全断裂破坏的全过程进行详细的分析描述,利用实验不同阶段获取的数据及巴西圆盘的位移解析解,分别计算压坯的抗拉强度和弹性模量,同时拟合出抗拉强度与相对密度以及弹性模量与相对密度相关的幂函数方程,并将其用于基于广义塑性力学的金属粉末成形数值模拟;此外,将详细的实验图像和数据进一步用于压坯断裂性能的分析。     

2014055一种树脂吸附法生产的次品镓的提纯方法

本发明涉及一种树脂吸附法生产的次品镓的提纯方法。其特征在于其处理过程采用金属重熔结晶的方法进行结晶提纯。该提纯方法,与现有技术相比操作简单易行,有效地降低了成本,有效解决了次品镓问题,增加了镓的成品率。     

丙烯酸树脂用作超薄型钢结构防火涂料基料的研究

研究了以丙烯酸树脂为基料、P—C—N为膨胀体系、纳米Mg（OH）2为阻燃剂的超潭型钢结构防火涂料的防火性能。合成了丙烯酸树脂，研究了引发剂用量、滴加单体时间、溶剂用量等因素对丙烯酸树脂耐火性能的影响，得出合成丙烯酸树脂的最佳条件：引发剂用量为1．3g。滴加单体时间为120min，溶剂用量为65g。探讨了纳米Mg（OH）2对耐火时间的影响。IR谱图研究了丙烯酸树脂的结构，XRD分析、TGA—DTA分析研究了纳米Mg（OH）2的微观结构和防火涂料的热稳定性。制备的防火涂料在涂膜厚度为1．30mm时，耐火极限可达到106min。     

Mechanical properties and structure of age-hardened Ti-Cu alloys

The room temperature tensile properties of age-hardened Ti-Cu alloys, 0.9 and 4 at. pct Cu, were investigated. The results were correlated to the microstructure and to the observed interaction mechanism between moving dislocations and precipitated particles. Two types of precipitates were observed upon aging between 400° and 500°C. One type was identified as a metastable, ordered precipitate coherent with the matrix. The other type was the stable Ti₃Cu phase which was partially coherent with the matrix. Both types of particles were precipitated from a martensitic microstructure which resulted from the β → α transformation. Although the martensitic microstructure contributed to the high flow stress, the elongation to fracture was principally determined by the dislocation-particle interaction mechanism. The maximum elongation to fracture was obtained by inducing a dislocation by-pass mechanism in a structure containing homogeneously distributed, partially coherent Ti₃Cu particles. The tendency of the Ti₃Cu particles to precipitate preferentially on boundaries was minimized by low temperature aging. Formerly Assistant Professor Materials Research Laboratory, Rutgers University, New Brunswick, N.J.     

Mechanical and tribological properties of wear-resistant hot-compacted steels with a heterogeneous structure

Institute of Materials Science Problems, Ukrainian Academy of Sciences, Kiev. Translated from Poroshkovaya Metallurgiya, No. 3(363), pp. 42–46, March, 1993.     

以不同酚醛树脂制备的C/C-SiC复合材料的力学性能

选用热固性酚醛树脂A和热塑性酚醛树脂B分别与短炭纤维、石墨粉、硅粉、碳化硅按一定比例混合后,采用温压-原位反应法,制得具有不同树脂炭基体的C／C-SiC复合材料的试样1和2,并对其力学性能进行研究,以期优化该复合材料的成分配方和进一步提高其技术性能。结果显示：试样1在垂直于纤维层方向的压缩载荷及弯曲载荷作用下,未出现纤维拔出、脱粘等现象,界面结合较强,呈现脆性断裂,压缩强度σ⊥=60．7MPa,弯曲强度σb=34．5MPa;而在平行于纤维层的压缩载荷作用下,纤维与基体存在剪切作用,出现纤维脱粘,呈现韧性断裂,σ∥=52．6MPa。试样2由于纤维的分散性不好,大量聚集在一起,在压缩和弯曲载荷作用下,均存在纤维的拔出和脱粘现象,界面结合较差,材料呈现韧性断裂,强度较低,σ⊥=45．8MPa,σ∥=19．4MPa,σb=16．1MPa。     

Mechanical properties of 0.40 pct C-Ni-Cr-Mo high strength steel having a mixed structure of martensite and bainite

A study has been systematically made of the effect of bainite on the mechanical properties of a commercial Japanese 0.40 pct C-Ni-Cr-Mo high strength steel (AISI 4340 type) having a mixed structure of martensite and bainite. Isothermal transformation of lower bainite at 593 K, which appeared in acicular form and partitioned prior austenite grains, in association with tempered marprovided provided a better combination of strength and fracture ductility, improving true notch tensile strength (TNTS) and fracture appearance transition temperature (FATT) in Charpy impact tests. This occurred regardless of the volume fraction of lower bainite present and/or the tempering conditions employed to create a difference in strength between the two phases. Upper bainite which was isothermally transformed at 673 K appeared as masses that filled prior austenite grains and had a very detrimental effect on the strength and fracture ductility of the steel. Significant damage occurred to TNTS and FATT, irrespective of the volume fraction of upper bainite present and/or the tempering conditions employed when the upper bainite was associated with tempered martensite. However, when the above two types of bainite appeared in the same size, shape, and distribution within tempered martensite approximately equalized to the strength of the bainite, a similar trend or a marked similarity was observed between the tensile properties of the mixed structures and the volume fraction of bainite. From the above results, it is assumed that the mechanical properties of high strength steels having a mixed structure of martensite and bainite are affected more strongly by the size, shape, and distribution of bainite within martensite than by the difference in strength between martensite and bainite or by the type of mixed bainite present. The remarkable effects of the size, shape, and distribution of bainite within martensite on the mechanical properties of the steel are briefly discussed in terms of the modified law of mixtures, metallographic examinations, and the analyses of stress-strain diagrams.     

Mechanical properties of nitrogen-ferrite

Homogeneous formation of nitrogen-atom clusters (nitrogen GP zones) on{001} matrix planes during aging of an Fe-0.08 wt pct N alloy at 23 °C produces exceptional increases in the room temperature strength of the quenched solid solution. Overaging the zones at 100 °C to form the intermediate precipitateα″-Fe₁₆N₂ results in a decrease in strength but an increase in ductility of the material. Electron metallography on quenched, aged, and deformed structures suggests that dislocations shear the nitrogen-atom clusters during deformation. Formerly with the Wolfson Research Group for High-Strength Materials, Crystallography Laboratory, The University, Newcastle upon Tyne, United Kingdom