含通孔损伤变截面钛合金蜂窝壁板拉伸性能研究

针对飞行器结构采用的钛合金蜂窝壁板,采用试验研究和有限元分析相结合的方法,研究了通孔损伤对变截面钛合金蜂窝壁板拉伸性能的影响.其中,有限元模型采用参数化建模方法建立,包含蜂窝芯体细节和斜角区细节结构.研究结果显示,斜角区是变截面钛合金蜂窝壁板的薄弱部位,无损伤试验件的破坏模式为沿斜角起始区域内蒙皮倒圆处横截面断裂;对于...     

Correction to: Determining the Relative Cratering Ages of Regions of Psyche’s Surface

Space Science Reviews - Analysis of Homestake, Gallex and GNO measurements reveals evidence of variability of presumed solar-neutrino-flux measurements. Analysis of Super-Kamiokande neutrino...     

Balloon altitude studies of southern hemisphere hard X-ray sources by the Imperial College-University of Tasmania-INPE collaboration

Hard X-ray balloon altitude measurements with a 1600 cm² phoswich array are described. Data from observations on Sco X-1, GX1+4, GX5−1, Nova Oph. 1977, SMC X-1, SS433, IC 4329A and MR 2251-178 are presented. The role of Comptonisation in X-ray production for Sco X-1 and GX1+4 is discussed.     

同轴度误差的矩阵计算机法

用矩阵法建立了同轴度误差最小二乘评定数学模型,给出了一组采样数据、微机数据处理程序和同轴度误差值。     

Observations of diffuse galactic positron annihilation radiation

The Galactic plane was scanned nearly three times by the UCSD/MIT Hard X-Ray and Low Energy Gamma-Ray Experiment on HEAO-1 from August 1977 through September 1978. Its Medium Energy Detectors were of the NaI/CsI phoswich type and operated over the 100 keV to 2 MeV range, with a 17° FWHM field of view and a 9% energy resolution at 511 keV. Sky maps for each epoch of observation were constructed in several energy bands. After subtraction of known point sources, a component associated with the galactic plane remains, whose spectrum is consistent with a power law and a positron annihilation spectrum. In the 333 to 583 keV energy band the flux is concentrated within ±35° of the galactic center, and the ratio of flux/radian (anticenter) is high, with a 2σ lower limit of 13. The parameters of the galactic center region's annihilation spectrum are positronium fraction of 0.9±0.1 and 511 keV flux of (2.0±0.7)×10⁻³ photons/cm²-sec-rad.     

高强高模聚乙烯纤维对大掺量矿物掺合料高强混凝土抗冻性的影响

用快冻法研究高性能的高强高模聚乙烯(High elasticity module polyethylene,HEMP)纤维对大掺量矿物掺合料高强混凝土(High strength concrete,HSC)抗冻性的影响.结果表明,大掺量矿物掺合料HSC具有较好的抗冻性,但是其抗冻性对养护环境RH非常敏感,干燥养护条件下的冻融寿命仅有标准养护的38%～40%.掺加0.1%HEMP纤维虽然降低了大掺量矿物掺合料HSC的抗冻性,但能够显著改善其抗冻性对养护环境RH的敏感性,在30%RH～50%RH养护条件下的冻融寿命高达标准养护时的81%～90%.     

高速航空拖靶的总体方案和气动外形优化

针对某高速、低空恒高拖靶系统研制的需求,设计了一种有良好气动特性、结构简单、工艺性好、成本低的拖靶总体方案.为了进一步减少气动阻力,采用基于Kriging模型的优化方法对高速拖靶气动外形进行了优化设计.优化结果表明:在满足操纵力和稳定性要求前提下,优化后拖靶的气动阻力明显减小.本文研究结果为整个拖靶系统的进一步设计和论证奠定了基础.     

翼面隐身结构优化设计

隐身结构是指由蒙皮和多种内部材料组成的、能满足承载要求、并具有明显降低雷达散射截面的结构.本文首先阐述了一种典型的翼面隐身结构方案.为了进一步挖掘该隐身结构减缩RCS的潜力,应用基于代理模型的优化策略,对其进行电磁散射特性优化设计.研究结果表明,经过优化设计后,在方位和频域上能显著降低翼面隐身结构RCS.基于代理模型的优化策略是一种有效的隐身结构低RCS优化策略.     

灾变机制下的元胞遗传算法

文章提出了一种改进的加入灾难的元胞遗传算法.该算法是细粒式并行遗传算法和粗粒式并行遗传算法的混合形式.在遗传算法和元胞自动机的原理基础上,通过加入灾难的方式,用于求解复杂甬数优化问题,获得了较好的效果.     

新型方钢管混凝土柱-钢梁节点的试验与非线性有限元分析(英文)

介绍了新型方钢管混凝土柱与钢梁节点在低周反复荷载作用下的试验结果,分析了内填混凝土、加劲肋长度和梁柱相对尺寸等对节点抗震性能的影响.试验结果表明:各试件实测滞回曲线比较饱满,具有良好的耗能性能.运用ANSYS8.0对各节点试件在低周反复荷载作用下的滞回性能进行非线性模拟计算,分析内填混凝土、加劲肋长度等因素对节点受力性能的影响,结果表明:内填混凝土和加劲肋长度对节点受力性能的影响较大,有限元所得的骨架曲线与实测曲线吻合较好.