基于压电陶瓷动态信息的结构裂纹识别方法

利用压电陶瓷的动态特性和压电系统的动态信息,对铝梁的裂纹损伤进行了分析研究。随着梁裂纹尺寸的增加,压电陶瓷片的导钠幅值下降,且系统固有频率减小。利用导钠幅值的变化和系统的动态信息,可以对裂纹的位置和尺寸大小进行识别。实验证明该方法的有效性。     

住宅设计的分析与研究

总结了住宅设计的发展,概括了住宅各个功能区的特点。通过设计的实例说明了各不同功能区的设计,成果可供进一步的研究参考。     

“锲而不舍 金石可镂”——上海秀派公司2．45GHz有源RFID标签技术的成功之路

上海秀派公司坚持自己的技术长项——2．45GHz有源RFID,充分发扬该种RFID的特长,记者采访该公司时了解到了开发方面的很多细节、成功案例和实施经验。我们不但非常推崇该公司的“锲而不舍”的意志,而且还意识到如果秀派公司的成功经验一旦辐射到中国的RFID行业中,一定会把这项在国外诞生的技术更好地植根于中国的土壤,使之更加适合中国的实用环境。     

基于可靠性评价的含缺陷核压力管道疲劳寿命预测方法

含缺陷压力管道经缺陷评定合乎使用后,其疲劳寿命的估计具有重要的工程意义。将整个含缺陷压力管道作为一个整体,分析了含缺陷压力管道的疲劳裂纹扩展特点,提出了相应的含缺陷压力管道疲劳寿命的计算过程,并在基于可靠性评价的基础上,给出了核压力管道的可接受失效概率,最终得到了含缺陷核压力管道疲劳寿命预测方法。     

工业管道测厚的几点问题探讨

超声波测厚在腐蚀监测上应用越来越广泛,为让这项检测技术更准确、更可靠,充分发挥功效,文章就工业管道测厚中测厚数据处理、测厚点选择、高温问题以及其它影响因素等几个方面进行了探讨。     

On the corrosion fatigue crack initiation model and expression of metallic notched elements

In the present study, attempts are made to extend the application of the mechanical model for the fatigue crack initiation (FCI) and the FCI life formula of metallic notched elements in laboratory air to those in the corrosive environment. The test results and analysis of the corrosion FCI (CFCI) life of aluminum alloys and Ti---6A1---4V show that the expression of the CFCI life obtained by modifying the FCI life formula in laboratory air can give a good fit to the test results of the CFCI life. The salt water (3.5% NaCl) environment has no effects on the CFCI resistant coefficient compared with the FCI resistant coefficient in laboratory air. However, 3.5% NaCl environment greatly decreases the CFCI threshold of aluminum alloy, but has little effect on the CFCI threshold of Ti---6A1---4V. The loading frequency ranging from 1 Hz to 10 Hz has no appreciable effect on the CFCI life, and thus, the CFCI threshold of aluminum alloys investigated. Hence, the expression for the CFCI life of metallic notched elements proposed in this study is a better one, which reveals a correlation between the CFCI life and the governing parameters, such as, the geometry of the notched elements, the nominal stress range, the stress ratio, the tensile properties and the CFCI threshold. However, this new expression of the CFCI life needs to be verified by more test results.     

STRESS INTENSITY FACTORS AND WEIGHT FUNCTIONS FOR SEMI-ELLIPTICAL SURFACE CRACKS IN FINITE-THICKNESS PLATES UNDER TWO-DIMENSIONAL STRESS DISTRIBUTION

Abstract— A Fourier series approach is proposed to calculate stress intensity factors using weight functions for semi-elliptical surface cracks in flat plates subjected to two-dimensional stress distributions. The weight functions were derived from reference stress intensity factors obtained by three-dimensional finite element analyses. The close form weight functions derived are suitable for the calculation of stress intensity factors for semi-elliptical surface cracks in flat plates under two-dimensional stress distributions with the crack aspect ratio in the range of 0.1 ≤ a/c ≤ 1 and relative depth in the range of 0 ≤ a/t ≤ 0.8. Solutions were verified using several two-dimensional non-linear stress distributions; the maximum difference being 6%.     

提高自蔓延高温合成陶瓷内衬钢管性能的研究

在概括了自蔓延高温合成陶瓷内衬钢管的制备原理基础上，从降低陶瓷层孔隙率，减少陶瓷层裂纹和提高陶瓷层结合强度等方面，论述了提高自蔓延高温合成陶瓷内衬钢管性能的措施，对自蔓延高温合成陶瓷内衬钢管的应用现状及展望进行了评述。     

The effect of a solid additive on rolling fatigue life

Behaviour of a series of lubricant oils and the effect of a non stoichiometric inorganic compound, as solid extreme pressure additive, on rolling fatigue life are studied using the rolling four-ball accelerated service simulation test proposed by Barwell and Scott. The results show, in all tested cases, the remarkable efficacy of this type of additive. The Total Acidity Number (tan) was found to increase with performance time for the case of the base lubricant, while for the oils with additives, it remained at its constant low value. This led to a proposal of a possible mechanism of the additive performance in the rolling process.     

Microscopic and Macroscopic Growth Rates of Fatigue Cracks in Steels and Alloys under the Influence of Crack Closure

On the basis of the experimental data, we show that the difference between the macroscopic and microscopic fatigue crack growth rates in the second section of the kinetic diagram of fatigue fracture is caused by the effect of crack closure within the limits of its existence. We establish the relationships between the macroscopic and microscopic fatigue crack growth rates and the structure of the material in the second section of the diagram for various values of the load ratio with regard for the effect of crack closure and propose a procedure of examination of the fracture processes in structural materials based on the analysis of microscopic and macroscopic fatigue crack growth rates.