在役加氢反应器材料损伤分析

基于随加氢反应器运行 5a的试验试块 ,研究了加氢反应器运行 5a后筒体材料 2 .2 5Cr 1Mo钢的损伤。进行了化学成分分析、拉伸和冲击试验、脱氢和脱脆试验以及断口形貌分析。结果表明 :反应器运行 5a后筒体母材及其焊缝金属的拉伸性能未发生明显变化 ,而冲击韧性明显降低 ,且焊缝金属损伤程度较母材严重。经分析 ,材料的损伤主要是加氢反应器长期使用过程中高温回火所致     

抗地震结构的服役费用函数及其建立方法

讨论了服役工程结构的经济性问题 ,包括 :抗地震结构在服役过程中为完成预定功能所需要的经济花费、这些花费同结构抗震可靠度的函数关系以及它们的建立方法。形成的服役费用函数可以作为决策结构最佳抗震设防标准的依据。     

Experimental habitat scenting inhibits colonization by beaver,Castor canadensis

Unoccupied beaver (Castor canadensis) sites in New York State were for two years experimentally scented with a mixture of beaver castoreum and anal gland secretion. These sites were colonized less often than unscented control sites. The beaver is the first mammal to have been shown experimentally to use intraspecific odor cues when settling in vacant habitat. Territorial pheromones may be useful as repellents for beaver or other rodents.     

混凝土内钢绞线的蚀坑形状及分布特征

为研究预应力钢筋的锈蚀特性,在自然气候条件下,采用内掺盐的方式,进行了混凝土内钢绞线的锈蚀实验．实验结果表明：钢绞线的蚀坑形状可抽象为2种典型形状,即椭球形和马鞍形;随着锈蚀率增大,蚀坑总个数增大,椭球形蚀坑出现的概率呈先增后减趋势;马鞍形蚀坑出现概率呈先减后增趋势,但变化幅度都不大;蚀坑的长度、宽度、深度都较好地呈对数正态分布．     

有机固相沉积对储层的损害

定性分析有机同相沉积对储层的影响,定量研究有机固相沉积后储层的损伤情况.利用岩石-毛细管模型描述地层孔隙空间,并用孔隙度、渗透率与比面等的相互关系推导出有机同相沉积量与储地层参数的变化关系式.     

Sensor placement for structural damage detection with modal data

A new method is presented for prioritizing sensor locations for structural health monitoring (SHM). In view of the needs of SHM and damage detection,sensor locations are optimized for the purpose of both sensitivity for local damages and independence of the target mode. However,the two different optimization criterions lead to an inconsistency of the optimal result. Considering the structural response changes that result from damage,the relationship between the structural response and damage is deduced from the structural motion equation by a quasi-analytical mode. Based on the harmony between damage identifiability and mode observability,an object function is set up,including the information of mode independence and damage sensitivity. Utilizing the technique of singular value decomposition,an interior algorithm for the optimum sensor placement is proposed with the multiple objective criterions of minimizing the condition number of coefficient matrix and maximizing the fisher information matrix. A numerical example shows that this approach can effectively avoid the contradiction between the two different optimization criterions. Comparing with the result of single object,the result of damage detection from the optical sensor locations is much more accurate.     

结构损伤识别的残余向量法及数值仿真

为了找到对小损伤较敏感的参数,在结构自由振动微分方程基础上,利用广义逆和矩阵投影定理,导出了识别效果很好的残余向量投影范数.确定了损伤单元,计算了该损伤单元的损伤因子.算例分析发现,该参数对结构损伤非常敏感,能识别出结构中的微小损伤,而且不受损伤位置的约束,仅需要结构的前几阶模态就能达到很好的效果.     

等效剪切刚度的框架结构损伤识别方法

为研究有别于现有侧重于研究结构具体构件(梁、柱及支撑等)的建筑结构损伤识别方法,提出应直接从整体开展框架结构损伤识别方法.将框架结构转换成"等效剪切型"结构,数值分析表明,结构具体构件出现损伤(即刚度发生退化)时,会引起受影响层的等效剪切刚度发生变化,因此,可以采用层等效剪切刚度变化率与层抗侧刚度作为指标来进行结构损伤定位与损伤程度评定.通过大量的框架结构数值模拟计算,归纳出了一套能将损伤定位到结构层及从整体来评定结构损伤程度的方法.     

Fabrication of high nitrogen austenitic stainless steels with excellent mechanical and pitting corrosion properties

A series of high nitrogen austenitic stainless steels were successfully developed with a pressurized electroslag remelting furnace. Nitride additives and deoxidizer were packed into the stainless steel pipes, and then the stainless steel pipes were welded on the surface of an electrode with low nitrogen content to prepare a compound electrode. Using Si3N4 as a nitrogen alloying source, the silicon contents in the ingots were prone to be out of the specification range, the electric current fluctuated greatly...     

Damage and deterioration mechanism and curing technique of concrete structure in main coal cleaning plants

Concrete structures in main coal cleaning plants have been rebuilt and reinforced in the coal mines of the Shanghai Da-tun Energy Sources Co. Ltd., the first colliery of the Pingdingshan Coal Co. Ltd. and the Sanhejian mine of the Xuzhou Mining Group Co. Ltd. In these projects, the operating environment and reliability of concrete structures in the main plants of the three companies were investigated and the safety of the structures inspected. Qualitative and quantitative analyses were made on the spe-cial natural, technological and mechanical environments around the structures. On the basis of these analyses, we discuss the long-term, combined actions of the harsh natural (corrosive gases, liquids and solids) and mechanical environments on concrete structures and further investigated the damage and deteriorating mechanisms and curing techniques of concrete structures in the main coal cleaning plants. Our study can provide a theoretical basis for ensuring the reliability of concrete structures in main coal cleaning plants.