炼钢转炉托圈强度分析中的一个问题

摘自《冶金设备》1984年第3期,王一心、陈沪华的同名文章。作者就强度分析中托圈的力学计算模型这一关键问题进行探讨,并从一个简例的计算结果阐明其力学机理。认为就国内现有炼钢转炉和托圈的连结形式来说,托圈的强度分析不能归结为静定的力学模型。托圈的变形与炼钢转炉的变形密切相关。托圈应被看成“强性支承的薄壁曲粱”,是一个静不定问题(如果托圈和转炉的连结形式是三支承的,则托圈简化为独立的静定计算模型)。根据上述观点,提出了托圈与转炉一并考虑的力学计算模型,如图。     

有限元分析在曲柄摇杆式飞剪机架强度评估中的应用

为掌握某曲柄摇杆式飞剪机架强度及变形情况,采用理论分析的方法计算了剪切系统各铰接点的受力大小,在此基础上建立了该飞剪机架的有限元模型,并进行了仿真分析。结果表明机架在下刀架的支承处是机架薄弱环节,机架强度及变形均在安全范围内。     

120t炼钢转炉托圈支承结构改造

攀钢提钒炼钢厂针对120t转炉托圈支承结构承载能力已不满足当前炼钢生产规范扩大要求，对转炉托圈支承结构进行了技术改造。     

JN43—90型焦炉炉门、炉框、保护板

JN43—90型焦炉炉门、炉框、保护板是封闭焦炉炭化室、保护炉体的专用设备。它采用了6m焦炉弹簧门栓的新型结构,使门栓作固定式水平运动,刀边受力更加均匀;另外在炉框上增加了两个支承轮,使炉门在其支承上作滚动运动,避免了因热变形而产生的阻力或炉门悬挂不平的现象,并具     

炼钢转炉托圈强度分析中的一个问题

托圈是支承和带动炼钢转炉倾动的重要部件,本文就强度分析中托圈的力学计算模型这一关键问题进行探讨。作者从一个简例的计算结果阐明其力学机理,提出托圈与转炉一并考虑的力学计算模型,并简要引用某钢铁公司120吨转炉托圈强度计算的结果。     

炼钢厂150t转炉炉体支承系统的优化设计

随着转炉炼钢技术的发展,转炉设备也在不断更新换代,以适应转炉操作以及长寿命的要求。为此炼钢厂对2座80 t转炉异地扩容改造。文中重点介绍150 t转炉的炉体支承系统的设计选型。     

宝钢300t转炉炉壳变形测试研究

针对宝钢炼钢厂三座转炉炉壳发生的严重变形问题,通过现场测试,分析了炉壳变形的状态及规律,指出转炉使用镁碳砖炉衬后炉壳温度升高是造成炉壳变形的主要原因,并提出了解决这一问题的措施和建议。     

济钢120t转炉基础裂缝防治措施

混凝土施工出现裂缝的主要原因,一是混凝土受力;二是混凝土体积变形,即混凝土在硬化过程中由于温度变化而引起体积变化。济钢120t转炉基础属于大体积混凝土施工,为防止出现温度裂缝,重点采取了控制混凝土所用材料、配合比、内部降温等措施,取得了较好效果。     

转炉连杆连接装置的受力分析

在分析了转炉连杆连接装置结构特点的基础上,对其进行了受力分析,确定了托圈和转炉相互作用力的大小和方向,并利用该结论研究了转炉工作时的极限工况,从而为转炉、托圈、连杆等连杆连接装置零部件的强度计算、总体结构设计提供了可靠的依据。     

现代炼钢转炉的最新结构

德国曼内斯曼德马克冶金技术设备部，为提高转炉的使用寿命和适应现代炼钢采用各种新工艺的需要，以转炉炉体的设计正在进行不断地改进。在改进中特别强调对转炉炉体支承装置和冷却系统的开发以及对炼钢车间活动转炉的设计思想。     

Dislocation punching from spherical inclusions in a metal matrix composite

The dislocation punching (plastic relaxation) from spherical inclusions is examined. The plastic stran in the punched domain is determined by assuming that all geometrically necessary dislocations are punched out to the plastic-elastic boundary. By introducing impotent eigenstrains, the elastic state calculation is greatly simplified. The punching distance is determned by the balance between the punching force due to the elastic energy decrease and the retarding force due to the disspation energy needed for the plastic deformation. The punching distance is also examined in terms of stresses at the plastic domain boundary where the deformation carrying dislocations exist. The effect of the volume fraction of inclusions is discussed and is shown to sensitively depend on the elastic constants ofthe inclusions. An increase in flow stress due to statistically stored dislocations in the wake of punching is evaluated.     

眼镜框架铰链异型材扭曲原因初探

探讨了异型材扭曲的主要原因系加工率不均匀促使变形不均匀加剧，从而引起型材扭曲，分析了与此有关的型材加工过程，提出了解决措施。     

Fictitious Crack Propagation in Fiber-Reinforced Concrete Beams

A nonlinear cracked hinge model is developed, aimed at the analysis of the bending fracture of fiber-reinforced concrete beams. The model is based on the fracture mechanics concepts of the fictitious crack model with a bilinear stress-crack opening relationship. Closed-form solutions are presented for the moment-rotation relationship of the hinge as a crack propagates, and the case of a nonzero normal force is covered. Special shapes of the stress-crack opening relationship are treated separately. These shapes are the so-called drop-linear and the drop-horizontal for which simplified expressions are obtained. The applicability of the hinge model is demonstrated through analysis of the bending fracture process in the case of a three-point bending beam and an infinitely long beam on a Winkler foundation, the latter analysis comprising the effect of a constant tensile normal force.     

Effect of Internal Moment Release on the Eigenfrequencies of Combined Linear Systems

A method for analyzing the free vibration of complex structural systems, consisting of a simple oscillator attached to a beam with an internal hinge, is presented. A mathematical model possessing important features of singularity functions with their higher order derivatives is proposed to account for the effect of internal hinge and spring force interacting between the oscillator and supporting structure. The particular integral approach together with Laplace transformation is proved to be an efficient alternative to solve the generalized differential equation for the normal modes of dynamically combined systems. Exact vibration frequencies for clamped–pinned and pinned–pinned boundaries are determined. The results are extended to the cases in which the oscillator or internal hinge is removed from the structure. It is shown that the presence of internal hinge does not alter the generalized orthogonality relation for the combined system. The search for the optimal location of the internal hinge, which maximizes the desired natural frequency, is discussed. It is concluded that a combined system with an optimally positioned hinge vibrates with the same natural frequency as an equivalent system without a hinge.     

考虑空间位形力作用的微米软颗粒溶液微圆管流动规律

针对微米级软颗粒溶液在微小孔道流动不符合泊肃叶流动规律问题，考虑受固体管壁影响软颗粒形变产生的空间位形力作用，基于Navier-Stokes理论，推导软颗粒溶液在圆管中的流速分布及流量表达式，引入颗粒形变因子以表征空间位形力作用的影响；建立考虑空间位形力作用的圆管流动数学模型.由微尺度流动特征实验，得到软颗粒溶液微圆管流动规律，与泊肃叶流动对比，结果显示当管径小于颗粒直径时，相同压力梯度下考虑空间位形力作用的流速比泊肃叶流动拟合结果更接近于实验数据.通过数值计算分析发现，与泊肃叶流动下的速度分布和平均流量相比，当微圆管尺寸减小时，空间位形力作用随之增大，其更大程度上影响流体在微圆管内的流动规律；当颗粒呈非球形且最小投影面积相同时，偏离球形颗粒程度越大，空间位形力作用越大，因此空间位形力作用在微小孔道流动中不可忽略.      

The three-dimensional determination of internal loads in the lower extremity

A three-dimensional model of the lower limb containing 47 muscles was developed to study the differences between a two- and three-dimensional approach for determining internal loads, the role of the dynamic joint representation, and the behavior of different load-bearing criteria in walking and running. The problem of redundancy of the musculo-skeletal system was resolved by applying inverse dynamics and static optimization methods. Different hypothetical load-bearing capabilities of hinge, spherical and intermediate joint types for the knee and the ankle joints were tested. It was found that even almost planar movements such as walking and running are associated with significant three-dimensional intersegment moments, especially in the frontal plane. Thus, a two-dimensional approach may underestimate internal loads up to 60%. It is shown that pure hinge joints are inappropriate for modeling the dynamical joint function of the knee and ankle joints. A more flexible joint representation in combination with a squared muscle stress minimization criterion predicted a lot of synergistic as well as antagonistic muscle activation which was also found in the EMG patterns. The results indicate the importance of muscular joint stabilization in natural human movements. Compared to in vivo measurements it is speculated that the predicted force magnitudes are considerably overestimated due to error propagation and still insufficient anatomical models. Thus, increased efforts to improve further the reliability of internal load calculations should be made in the future.     

Screwdown load deviation model of 5 m heavy plate mill based on influence of back-up roll axial force

Screwdown load deviation threatens rolling mill safety and product quality. The contact between a 5?m rolling mill screwdown device and the back-up roll (BUR) bearing chock was simplified to a fixed hinge constraint, and the constraint of the keeper plates on the BUR bearing chock was simplified to a sliding hinge constraint. According to the BUR space force and moment equilibrium, a screwdown load deviation model affected by the BUR axial force was used to simulate the effect of the roll crossing degree on the screwdown load deviation. Screwdown load deviations were calculated for three rolling passes. The results are more consistent with the data than outputs calculated by a model that neglects axial force. Assumptions about the relationship between the load deviation and the work roll axial forces agree with the data. The results show that the BUR axial force causes a dynamic deviation of the screwdown load.     

Summary of SAC Case Study Building Analyses

Summarized in this paper are the major findings from analytical studies of nine steel moment frame buildings conducted under Phase 1 of the SAC Steel Project. The buildings range in height from two to seventeen stories and most of them experienced damage to welded beam-column connections during the Northridge earthquake of 1994. Elastic response spectrum, inelastic static pushover, and elastic and inelastic time-history analyses were conducted using ground motion data representative of the Northridge earthquake to establish the loading∕deformation demands that the buildings experienced. The primary performance indices obtained from the analyses were demand-to-capacity ratios, interstory drift ratios, and inelastic hinge rotations. Maximum ratios of elastic member force demands to plastic strengths ranged between 1.0 and 2.0; maximum inelastic hinge rotations were 0.005–0.010 rad; and maximum interstory drift ratios were from 1 to 2%. These damage indices increased by 50%–150% under more severe ground motions recorded during the Northridge earthquake at the Sylmar site. Accuracy of the analyses is shown to be sensitive to a number of modeling parameters including finite joint size, joint panel behavior, composite beam action, strain hardening, second-order (P-Δ) effects, and three-dimensional response. Overall, there was only modest correlation between the frame performance indices and the observed connection damage, due largely to the fact that significant aspects of the connection fracture behavior are not captured in the frame analyses.     

Numerical calculation of the electromagnetic expulsive force upon nonmetallic inclusions in an aluminum melt: Part II. Cylindrical particles

Insulating cylindrical obstacles of three configurations were studied by the numerical methods described in part I of this article, and the calculations mainly concentrated on the effect of the ends of a finitely long cylinder on the induced fluid flow as well as the electromagnetic expulsive force. Comparisons between the numerical results based on the theory for an infinitely long cylinder and the experimental data reported by others were made. It was found that induced three-dimensional flow appears in all three cases due to the rotational force field, and the flow pattern is the same as that of a spherical particle. The different extents of deformation of the electric streamlines by the side faces and the circular end faces of the cylinder contribute to the variation of the intensity of the induced fluid flow and the electromagnetic expulsive force for each case. Among the three cases studied, the disposition of highly elongated cylinders for case 2, in which the axis is parallel to the direction of the magnetic field, is unfavorable to their repulsion from a molten metal.     

大型转炉吊挂装置简介

随着转炉的逐步大型化及炉龄的增加,转炉托圈与炉壳的连接形式由传统的三点球面支承式逐步向连杆吊挂式和弹簧钢板吊笼式发展,通过国内外考察结合实际应用,介绍了常用的三种形式的特点,对新建转炉有一定的参考意义。