大型塑料模具钢模块淬火工艺的有限元分析

采用有限元软件MSC Marc模拟大型P20钢模块在复杂淬火工艺下的冷却过程,通过分析淬火过程中的温度变化历程及最终组织分布,为厂方生产的P20钢模块制定合理的淬火工艺.     

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。     

面向注射成型工艺的多信号实时测试系统

介绍了测试系统的设计原理、测量方法与关键环节，利用温度—压力双功能传感器测量注射成型过程中高速变化的压力、温度信号，并采用所开发的测试软件采集、显示实时变化的多路信号。该系统实现了注射成型过程的多信号自动、实时测试，并能通过计算机对数据进行处理与分析。     

边界点集规划与注塑模具浇口位置的优化

根据平衡流动路径特点，提出了以理想流动模式为目标、基于制件边界几何信息的浇口位置优化选取的原则；并以平板制件单浇口注射成型工艺为例，研究了最佳浇口位置的描述方法并建立了相应的数学模型，给出了优化算法及制件边界特征点集的规划提取方法；根据所建数学模型和所选用优化计算方法，开发了相应的计算软件，经实例验证，算法和模型可靠。     

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。     

钢筋混凝土双向叠合板抗剪强度的极限分析

通过对８块无结合筋双向叠合板的试验研究，本文采用组合周界错动机构，锥面母线为直线与曲线的连线，按塑性极限分析的方法推导了抗剪强度计算公式。该公式与试验结果符合性良好。     

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.     

Comparison of corrosion behavior of zirconium bombarded with self-ion and molybdenum ion

In order to study the effects of zirconium and molybdenum ion bombardment on the aqueous corrosion behavior of zirconium, one group of specimens was implanted with zirconium ions with ions surface densities ranging from 1 × 10¹⁵ to 2 × 10¹⁷ ions/cm² at about 170 °C, using a metal vapor vacuum arc (MEVVA) source operated at an extraction voltage of 50 kV. The other group of specimens was bombarded with molybdenum ion with ions surface densities ranging from 1 × 10¹⁶ to 5 × 10¹⁷ ions/cm² at about 160 °C, using a MEVVA source operated at an extraction voltage of 40 kV. The valence states and depth distribution of elements in the surface of the samples were analyzed by X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES), respectively. Polarization curves measurement was employed to evaluate the aqueous corrosion resistance of the zirconium samples in a 1N H₂SO₄ solution. It was found that the aqueous corrosion resistance of zirconium implanted with 5 × 10¹⁶ Zr ions/cm² is the best in first group samples. For molybdenum ion implantation, the aqueous corrosion resistance of samples declined with raising ions surface densities. The natural corrosion potentials of zirconium samples bombarded with self-ions are more negative than that of the as-received zirconium. While, as for molybdenum ion implantation, the results are opposite. Finally, the mechanisms of the corrosion behavior of the zirconium samples implanted with zirconium and molybdenum ions are discussed.