Inelastic initial local buckling of skew thin thickness-tapered plates with and without intermediate supports using the isoparametric spline finite strip method

In this paper, skew isotropic plates subjected to in-plane loadings are analyzed using a stability analysis based on the isoparametric spline finite strip method, which includes inelasticity. Using this method, the initial inelastic local buckling of skew plates with or without intermediate line supports is studied based on Ramberg–Osgood representation of the stress–strain curve using the deformation theory of plasticity. Stiffness and stability matrices are formulated by energy expressions using the small deflection theory. The effect of tapered section on the local buckling of skew plates is taken into account. Finally, the inelastic local buckling loads of these plates are obtained and the results are compared with known solutions in the literature.     

GB24511—2009《承压设备用不锈钢钢板及钢带》标准内容要点分析

GB24511—-2009《承压设备用不锈钢钢板及钢带》标准已经正式实施。对标准内容的要点进行分析。     

坝头单薄分水岭边坡支护方案探讨

大坝两岸单薄分水岭条形山体边坡支护对水库大坝安全运行起到重要意义,对此,阐述惠州抽水蓄能电站上水库单薄分水岭边坡支护采用钢筋砼框架锚杆加干砌石护坡面的处理措施.     

清水混凝土施工做法

根据某项目桥梁墩柱施工情况，从模板制作与安装、混凝土配制与浇筑、拆模、防裂措施及项目管理等方面探讨了如何保证清水混凝土施工，得出了该项目桥墩柱混凝土成型后颜色均匀一致，取得了良好效果的结论，积累了清水混凝土施工经验。     

邯宝炼钢厂板坯连铸机结晶器振动导向研究

针对板坯连铸机结晶器振动纵向横向偏摆问题，对结晶器振动装置应用情况进行研究分析，用硬度仪打硬度的方法分析了辊子单元导向的磨损情况。使用新型棍子材质并经热处理代替原进口辊子本体，重新改进润滑油路，采用更适应高温高湿环境的不锈钢内六角螺栓，重新设计制作了一种耐磨长寿命辊子单元，在线使用效果显示使用寿命已经达到18个月且仍然完好，偏摆问题得到纠正，达到预期目的。     

Influence of alkaline oxide on the deformation of ceramic shell mould at high temperatures during investment casting

In this investigation, the effect of alkaline oxides such as Na₂O and K₂O on the deformation of ceramic shell mould was studied at high temperatures. Two groups of ceramic shell mould samples were prepared by impregnating them with a solution of NaOH and KOH of different concentrations. Systematic creep test was conducted under different compression loads at 2?MPa, 4?MPa and 6?MPa using a specially designed creep testing equipment between 1200 and 1350?°C. The obtained results were analyzed based on Norton-Bailey-Arrhenius (NBA) equation. The phase transformation and micromorphology evolution of different samples were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. From the results it was observed that the activation energy of ceramic shell mould used was about 198?kJ/mol below 1300?°C, whereas it increased to 325?kJ/mol near 1350?°C with a stress exponent of around 1.50 at all the temperatures. Adding Na₂O and K₂O decreased the activation energy at low temperature and increased it at high temperature. Besides, the stress exponent obviously decreased to nearly 1.00 below 1300?°C indicated the dominance of interface sliding mechanism, which then increased back to 1.30–1.60 at 1350?°C suggesting a combined creeping mechanism. Based on the results of XRD and SEM, it could be noted that during the creeping process the temperature played an important role in changing the interface structure.     

Examination of Interpenetrating Polymer Networks of Polyurea in Silicone Molds Arising during Vacuum Casting Processes

We present an in-depth investigation of the aging effects in silicone molds for vacuum casting processes. Their lifetime is limited to a few production cycles due to contamination with the diisocyanate component of polyurethane casting materials. Using thermogravimetric analysis measurements, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and helium-ion-microscopy the chemical and physical mechanisms of the aging process have been identified. It has been shown that a diffusion process of diisocyanate into the cavity surface leads to the formation of interpenetrating polymer networks of polyurea derivatives in silicone rubber. This has been proven by extracting and analyzing polyurea of low molecular weights from the silicone.     

Buckling analysis of thin-walled sections under localised loading using the semi-analytical finite strip method

Thin-walled sections under localised loading may lead to web crippling of the sections. This paper develops the Semi-Analytical Finite Strip Method (SAFSM) for thin-walled sections subject to localised loading to investigate web crippling phenomena. The method is benchmarked against analytical solutions, Finite Element Method (FEM) solutions, as well as Spline Finite Strip Method (SFSM) solutions. The paper summarises the SAFSM theory then applies it to the buckling of plates, and channel sections under localised loading. Multiple series terms in the longitudinal direction are used to compute the pre-buckling stresses in the plates and sections, and to perform the buckling analyses using these stresses. Solution convergence with increasing numbers of series terms is provided in the paper. The more localised the loading and buckling mode, the more series terms are required for accurate solutions. The loading cases of Interior One Flange (IOF) and Interior Two Flange (ITF) are investigated in this paper using simply supported boundary conditions.     

Calculation and experimental evaluation of the service life of welded joints in a nodular graphite cast iron pipeline for mechanical loading conditions. Part I ‐ experimental procedure and material

The main types of flux-cored strip electrode materials for mechanized arc surfacing of alloyed and composite alloys are discussed. Surfacing with these strips results in the formation of the required properties of the working surfaces of components. Special features of the melting and formation of the deposited layer with the required welding and technological properties are also discussed, taking into account the production technology of flux-cored strips.