核电反应堆用芯部材料的核物理性能

核物理性能是核电站反就堆芯部结构材料的首要技术条件。本文概述合金材料核物理的有关问题，以及核截面的计算方法。     

程潮铁矿大断面采准巷道稳定性数值模拟研究

针对武钢程潮铁矿采准巷道净断面尺寸增大，巷道稳定性下降的状况，采用数值计算方法对程潮铁矿巷道支护方案进行优化计算，并给出合理的支护方案。     

Nonparametric estimation from length-biased data under competing risks

A new model for cross-sectional lifetime data is presented. The model is based on the length-bias assumption, and it is adapted to situations in which several types of censoring may occur. The NPMLE of the survival function is derived. An EM-algorithm to approximate the NPMLE is devised. The performance of the introduced estimator is investigated through simulations. A real set of data collected as part of a study on unemployment duration in Spain is used for illustration purposes.     

非概率可靠性理论在机械臂架设计中的应用分析

以轮式起重机六边形箱形截面臂架为对象,对1 0 0吨汽车起重机椭圆截面臂架进行非概率可靠性优化,使其强度、刚度和稳定性满足非概率可靠度的条件下,重量最轻;并对椭圆截面中的大圆直径、顶边长度和圆心到顶边距离三者关系进行了分析,得出三者协同变化及独自变化时对臂架重量和可靠度的影响,为设计者提供了有力的参考依据。     

椭圆截面工件车削加工

通过对工件椭圆截面的分析,提出了一种新型的椭圆截面车削加工的方法,在比较了目前的椭圆插补算法的基础上,设计了一种采用极坐标的、适合于车削系统使用的新型的椭圆插补算法。     

集聚纺车间地沟均匀吸风设计方法探讨

探讨集聚纺车间地沟均匀吸风设计方法。介绍了地沟均匀吸风的设计原理和实现均匀吸风的措施;分析了变风量系统对均匀吸风性能的影响;介绍了变风量均匀吸风系统的设计;计算分析表明:回风沟道应采用变截面分段设计法,吸风口采用条缝型形高速自适应风口,吸风口面积之和与沟道截面积之比不大于0.4,前后吸口的吸风不均匀程度可以控制在15%以内。认为:采用支沟道变截面分段设计能较好地控制吸风的均匀性,可以保证集聚纺车间气流均匀稳定。     

基于STL文件的实体分割算法研究

由于快速成型机加工尺寸的限制,难于制造尺寸较大的零件。针对这一问题本文提出一种基于STL文件格 式的实体分割算法,对STL文件分割过程中的关键问题进行了详细地论述,包括:截面轮廓的生成,截交三角面片的 处理和截面轮廓的三角化算法;通过对STL文件的分割处理,提高了快速成型系统对大尺寸零件的制造能力。     

三维物体的任意方向二维断面图像提取

医学三维数据场可视化是当前科学计算可视化应用的重点。在Visual C＋＋平台下,结合可视化工具包VTK,对DICOM格式的CT图像序列进行三维重建。用VTK对CT图像序列进行处理,使其在屏幕上能够显示任意方向的二维断面图像,并且可以用鼠标对断面图像进行缩放、平移、旋转等实时交互操作,从而弥补了CT不能按任意角度扫描的缺憾。     

Non-linear curling of wide single-flange steel panels

An original analytical model to study the non-linear flange curling in wide single-flange panels is presented in this paper. Flange curling phenomenon is the tendency of the wide thin flanges (in compression or tension) to move towards the neutral axis, when thin-walled members are subjected to bending. Despite the simplicity of the formula developed in earlier works of Winter to account for the flange curling effects, which is used in current steel codes, recent work has showed that this expression is rather restrictive and does not apply for all cases. The analytical expressions reported here are rather general since they (i) consider the restraining effect provided by the web, (ii) account for the shift of the neutral axis due to curling, (iii) incorporate the decrement of the second moment of area due to curling, and (iv) are fully analytical, thus avoiding iterative techniques. The analytical model is applied to study the curling behaviour of profiled steel decks and cassette-wall panels and is validated by means of comparisons with experimental results available in the literature. Since the EC3 rules state that the tensioned wide flange in liner trays should be reduced if the curling displacement is higher than 5% of the web height, approximate expressions to evaluate the reduced width of the wide thin flange under curling are proposed.     

Comparative study of analytical and numerical algorithms for designing reinforced concrete sections under biaxial bending

This paper presents a comparative study of different integration methods of stresses (both analytical and numerical) for concrete sections subjected to axial loads and biaxial bending. Such methods are applied to circular and rectangular sections. The constitutive equation used is a parabola-rectangle from the Eurocode-2. The comparison was performed with regard to the accuracy and the computational speed of each method. The objective of the paper is to determine which of the integration methods compared is more efficient in computing the interaction surfaces for rectangular and circular sections. The analytical method proposed by Barros et al. [Barros MHFM, Barros A, Ferreira C. Closed form solution of optimal design of rectangular reinforced concrete sections. Eng Comput 2004;21(7):761–76] for rectangular sections is compared with the numerical method termed “modified thick layer integration” proposed by Bonet et al. [Bonet JL, Romero ML, Miguel PF, Fernandez MA. A fast stress integration algorithm for reinforced concrete sections with axial loads and biaxial bending. Comput Struct 2004;82(2–3):213–25] and with the well-known fiber method. Furthermore, two new methods are proposed for circular sections: one analytical and one numerical based on the Gauss–Legendre quadrature. The results of both methods are compared with the classical layer decomposition method.