冷轧工作辊摩擦不稳定分析及其抑制对策

对冷轧机工作辊由于摩擦力引起的垂直、横向振动作了定性分析，指出了它们的危害，提出了预防措施。     

机载电缆作战损毁后智能化诊断系统

从技战术实际需要出发,给出了某型飞机作战损毁后机载电缆的智能化诊断系统的硬件结构框图。根据硬件系统模拟开关组件的原理,定义了电缆的连接矩阵、测量矩阵以及断口的映像矩阵运算,给出了断头查找的算法。计算表明,系统可在20 min内完成一个循环的断头查找并给出故障定位。     

Comparison of Skidding Performance of Small Track-type Experimental Prototype Skidder and J-50 Skidding Tractor

In this paper, field experimental comparison is made between a small track-type experimental prototype skidder and a J-50 skidding tractor. Experimental data, including skidding productivity, soil compaction on skidding trails, and damage rate of the residual trees, are analyzed. The results indicate that with the condition of scattered skidding area and low skidding volume per cycle, small track-type experimental prototype skidder has advantage on working and a higher skidding productivity. It makes lower soil compaction to the skidding trails in the depth of 0-5 cm, 5-10 cm, and 10-15 cm. Under the same work conditions, the damage rate of the residual trees made by small track-type experimental prototype skidder is only 1/5 of those made by J-50 type skidding tractor. The damage rate is reduced by 80%.     

Material surface layer damage estimation for cyclic loading conditions using the nanoindenting and nanoscratching techniques

The nanoindenting method is based on the automatic measurement and recording of the force acting on the indenter (10⁻²-5 N) and the depth of indentation (10⁻²-200 μm). The scratch hardness or nanoscratching method is based on the continuous recording of resistance forces to movement of the indenter impressed into the surface. __________ Translated from Problemy Prochnosti, No. 4, pp. 132–139, July–August, 2006.     

Residual strength prediction of multiple cracked stiffened panels

Prediction of the coalescence of adjacent cracks is critical for residual strength estimation of structures under multiple site damage conditions. A methodology successfully developed for the case of crack link‐up prediction of un‐stiffened plates, is extended for the case of typical cracked stiffened aircraft panels. The proposed link‐up criterion is based on the change in the magnitudes of elastic and plastic strain energies of the stiffened panel, before and after the cracks coalesce. The strain energy magnitudes of interest are calculated using non‐linear elastic–plastic finite‐element analysis. For the application and verification of the method, experimental results from the open literature are used. Residual strength values calculated by the proposed methodology are in good agreement with the experimental results. The present criterion provides superior results when compared to the existing and commonly applied link‐up criteria.     

Fatigue damage accumulation of cold expanded hole in aluminum alloys subjected to block loading

Fatigue damage accumulation of cold expanded hole in aluminum alloys used in land transportation components was investigated. Tests were carried out using pre-cracked SENT specimens and inserting an expanded hole at the crack tip. The degree of the cold expansion was chosen equal to 4.3%. Tests were performed in two and four block loading under constant amplitude. Two sequences were compared.The increasing and the decreasing magnitude were compared. The experimental results were compared to the damage calculated by the Miner's rule and a new simple fatigue damage indicator. This comparison shows that the ‘model of the damage stress’, which take into account of the loading history, yields a good estimation of the experimental results. Moreover, the error is minimized in comparison to the Miner's model.     

用于BaF2闪烁光慢成分抑制的膜系设计及制备

利用BaF2闪烁光快、慢成分处于不同波段的性质，设计出了具有特定带隙的膜系结构，用于抑制发射光谱中的慢成分。在保证快成分具有一定透过率条件下，实现了对BaF2闪烁光慢成分的全方向抑制，使晶体的快慢比得到很大提高。从膜系γ射线辐照损伤的结果可知：辐照对膜系透射带和截止带的影响不大，辐照后的膜系仍能满足抑制要求。     

双束强辐照对氧化物弥散强化铁素体型合金强化相稳定性影响

采用双束复合辐照装置,研究了He存在条件下,强辐照对长期时效后的ODS合金中强化相(Y2O3)的稳定性和辐照损伤特征的影响。实验结果表明:双束强辐照下,ODS合金中强化相不稳定,发生聚集长大并造成附近基体中Ti、Y浓度增高,导致空洞尺寸和空洞肿胀增加,并对这一结果从理论上进行解释。     

通风除尘电机轴承内套热损伤疲劳断裂分析

某炼钢厂LF炉外精炼炉通风除尘电机轴承内套在运行过程中发生断裂 ,断裂源位于轴承内表面。用光学显微镜和扫描电镜对断裂件进行宏、微观检验。结果表明 ,电机轴承内套是由于润滑失效产生的热损伤疲劳断裂     

A finite element formulation to identify damage fields: the equilibrium gap method

It is proposed to determine damage parameters in two dimensions (surface of a material) or three dimensions (in the bulk of a solid) by using full‐field displacement measurements. A finite‐element approach is developed to evaluate piece‐wise constant elastic parameters modeled by an isotropic damage variable. Two sets of examples are discussed. The first series deals with mechanical fields obtained by finite element simulations to assess the performance of the approach. The second series is concerned with displacement measurements performed during a biaxial test on a composite material. Copyright © 2004 John Wiley & Sons, Ltd.