Enhanced mixed interpolation XFEM formulations for discontinuous Timoshenko beam and Mindlin‐Reissner plate

Shear locking is a major issue emerging in the computational formulation of beam and plate finite elements of minimal number of degrees of freedom as it leads to artificial overstiffening. In this paper, discontinuous Timoshenko beam and Mindlin‐Reissner plate elements are developed by adopting the Hellinger‐Reissner functional with the displacements and through‐thickness shear strains as degrees of freedom. Heterogeneous beams and plates with weak discontinuity are considered, and the mixed formulation has been combined with the extended finite element method (FEM); thus, mixed enrichment functions are used. Both the displacement and the shear strain fields are enriched as opposed to the traditional extended FEM where only the displacement functions are enriched. The enrichment type is restricted to extrinsic mesh‐based topological local enrichment. The results from the proposed formulation correlate well with analytical solution in the case of the beam and in the case of the Mindlin‐Reissner plate with those of a finite element package (ABAQUS) and classical FEM and show higher rates of convergence. In all cases, the proposed method captures strain discontinuity accurately. Thus, the proposed method provides an accurate and a computationally more efficient way for the formulation of beam and plate finite elements of minimal number of degrees of freedom.     

Evolution of M23C6 phase in HR3C steel aged at 650 °C

The evolution of the morphology, composition, and particle size of the M₂₃C₆ phase in HR3C steel aged at 650 °C was analysed, by means of metallographic microscopy, scanning electron microscopy, and transmission electron microscopy. The results showed that the Cr/Fe ratio in the M₂₃C₆ phase, in the form of irregular square and long strip, increased with the ageing time. Fe was gradually replaced by Cr in the M₂₃C₆ lattice. The M₂₃C₆ phase gradually evolved and then became stable after ageing for 2000 h.     

从新建项目人员配置问题看企业人力资源管理

某炼化企业油品质量升级项目即将在2013年投产,但人员准备工作出现了困难。分析发现该企业人才流失严重,人员结构存在问题,必须通过适当提高职工薪酬,优化人力资源结构,不断提高员工素质和能力,才能解决目前面临的困难。     

HR3C钢运行前后组织性能分析

通过SEM、EDS、冲击韧性试验机、万能拉伸机等实验手段对国内电厂运行15 960 h的过热器HR3C钢管与供货态样品的微观组织进行观察分析, 对其抗拉强度、硬度、冲击韧性等相关性能进行研究。结果表明, 供货态HR3C晶内分布大量的NbCrN第二相颗粒, 运行15 960 h后晶界上析出颗粒状M₂₃C₆与链状M₂₃C₆, 同时HR3C的综合力学性能大幅下降, 脆性增加, M₂₃C₆颗粒的析出是其冲击韧性下降的主要原因。     

企业人力资源管理信息系统的设计与实现

针对现阶段企业经营管理机制发生了转变但原有人事管理落后的情况 ,应企业需求开发此人力资源管理信息系统 ,实现企业人力资源规划、开发、利用与管理 ,为企业决策提供一定的依据 ,提高企业的竞争力 .     

人力资源管理理论探源及其发展趋势

结合我国社会主义市场经济条件,阐述劳动价值理论和人力资本理论对现行人力资源管理的指导意义,探讨我国人力资源管理的历史进程及发展趋势.     

冷模塑高回弹聚氨酯泡沫塑料配方研究

阐述用正交试验法优选出冷模塑、高回弹聚氨酯泡沫塑料的配方；讨论催化剂、变联剂，异氰酸酯指数和聚合物多元醇用量对泡沫塑料物理性能的影响。     

HR500-N型卧式离心机在蒸发生产中的应用

根据氯碱蒸发装置的特点,阐述了四川鸿鹤化工股份有限公司氯碱系统利用HR500-N型卧式离心机替代原WG型离心机生产干盐,从而提高盐卤综合利用效益的工业实践过程。     

850nm高亮度半导体激光器腔面膜技术研究

利用真空镀膜设备,采用电子束离子辅助蒸发技术,在条宽100μm腔长1mm的半导体激光器发光芯片的端面沉积光学介质膜。经测试采用这种技术制作出的高亮度半导体激光器发光芯片的输出功率达3.6W,与未镀膜的器件相比功率提高了2.5-3.1倍,外微分量子效率提高到89.76%,功率效率达到40.2%。激射波长为850.7nm。     

HR3C钢焊接接头高温时效后的显微组织和力学性能

通过光学金相显微镜、透射电子显微镜观察和力学性能试验,研究了HR3C钢焊接接头高温时效后的显微组织和力学性能。结果表明,经650℃时效,HR3C钢焊接接头的强度和硬度升高,焊缝硬度上升幅度大于母材;焊缝的时效脆化倾向明显,时效7000 h后缺口冲击吸收能量都保持在15 J以下。焊缝区晶界处M23C6相的连续网状分布及σ相、G相的存在导致了其较低的缺口冲击吸收能量和时效脆性,而晶内均匀细小Z相的沉淀强化作用则提高了接头的强度和硬度。