转炉扭力杆缓冲装置三维非线性有限元分析

针对某厂扭力杆缓冲装置运行时出现的问题,运用有限元软件建立其整体装配非线性有限元模型,充分考虑螺栓预紧力、零件间过盈配合及接触非线性,分析扭力杆缓冲装置在最大倾动力矩与事故状态下的应力分布及强度,提出螺栓联接修改建议。研究结果表明:螺栓根部出现严重的应力集中现象,这与螺栓过早损坏是一致的;扭力杆在最大倾动力矩作用下安全裕度较大;在事故状态下最大应力出现在扭力杆键槽附近,其值接近材料疲劳强度极限。研究结果为螺栓联结的改进提供了依据,也为扭力杆的设计制造与检修提供理论依据。     

铜冶炼全悬挂转炉扭力杆有限元分析

针对某钢铁厂转炉缓冲扭力杆运行时出现的截面疲劳断裂以及弯曲应力变形,基于Pro/E建立扭力杆的三维实体模型,采用Ansys Workbench对扭力杆在转炉最大倾动力矩工况下的应力分布与变形、扭转位移、危险截面以及最大剪应力状态进行分析,确定扭力杆的结构力学特性,从而为扭力杆的设计制造与安全运行提供可靠数据来源.     

转炉旋转接头扭力杆防转装置及有限元分析

对比分析转炉H架型旋转接头防转装置和扭力杆型防转装置,并应用有限元法对扭力杆型防转装置的重要部件—外套和扭力杆系统进行了正常工作下两种工况的应力应变仿真分析,计算结果表明,扭力杆型防转装置主要部件应力均低于材料的许用应力,满足实际使用要求,能有效的缓冲旋转冲击负荷,安全性、可靠性高,具有较好的工程应用价值。     

浅谈轮式起重机力矩限制器

力矩限制器是防止超载的安全装置,该装置通过超载报警信号自动停止操作动作,保证起重机械更安全、可靠的工作,避免因超载造成的事故。本文介绍了力矩器的系统构造和工作原理,有多个传感器实时采集起重机的动态参数,经CPU实时计算出实际载荷,与机械当前状态额定负荷做比较,从而判断机械的工作状态是否安全。     

4^#转炉扭力杆保护装置最佳间隙的探讨

通过对阻力杆承受的静力矩、屈服极限，刚度等条件的分析，计算，探讨并确定４＾＃转炉扭力杆保护装置的最佳间隙值。     

300T转炉倾动系统扭力杆装置

扭力杆装置在转炉倾动过程中,对减速装置的安全起到了至关重要的作用,本文主要介绍转动扭力杆机构结构工作原理。     

转炉倾动力矩的测试与分析

为了解转炉的倾动情况,在建立转炉扭力杆力矩与耳轴处倾动力矩的换算关系的基础上,采用传递法,对某钢厂180t转炉的空炉、热态2种情况进行了现场力矩测试,并对转炉倾动机构进行了扭振分析,找出了转炉静力矩、动力矩及冲击载荷较大的工况及位置,提出了改进的建议。     

操作条件对开坯机联杆折断的影响

1.绪言爱知钢铁公司现有的开坯机,从安装使用到现在为止,已发生了几次联杆折断事故,普遍认为,其原因是钢锭大型化,以及为改善内部质量而采取的大压下操作规程所致。这种事故,除了明显的设计失误外,一般认为是操作时超过了轧机的设计强度,在超负荷的情况下发生的。从这个观点出发,笔者针对联杆的折断事故,实测了现有操作状况下的转矩,用模型将转矩与应力状态的关系明确化,并据此确立了预测联杆寿命(至折断为止)的方法,使预测联杆折断事故的技术水平得以提高。现将其结果介绍如下。 2.研究工作的开展方法根据操作条件与联杆模型试验,对目前使用过的三根联杆的寿命进行计算并进行比较研究,研究工作的开展方法示于表1。     

新型转炉倾动液压缓冲装置的应用

通过对AOD转炉原有连杆式扭力杆系统存在的缺陷进行分析,介绍了新型液压缓冲装置在转炉冶炼系统三种工作模式下的工作原理,液压缓冲装置在转炉倾动系统的成功应用,有效地吸收了转炉在冶炼过程中产生的冲击,很好满足了转炉炼钢生产的要求。     

钻杆刺穿失效初探

针对钻杆在使用过程中发生刺穿失效事故,详细分析了其产生的原因,认为主要来源于管体表皮下缺陷,即皮下夹渣在应力的作用下扩展成裂纹缺陷以及淬火时压辊位组织转变应力产生的显微裂纹最终导致钻杆刺穿失效.据此,提出了相应的措施.     

Nonuniform Torsion of Composite Bars by Boundary Element Method

In this paper a boundary element method is developed for the nonuniform torsion of composite bars of arbitrary constant cross section. The composite bar consists of a matrix surrounding a finite number of inclusions. The materials have different elasticity and shear moduli and are firmly bonded together. The bar is subjected to an arbitrarily concentrated or distributed twisting moment while its edges are restrained by the most general linear torsional boundary conditions. Because warping is prevented, besides the Saint-Venant torsional shear stresses, the warping normal stresses are also computed. Two boundary-value problems with respect to the variable along the beam angle of twist and to the warping function at the shear center are formulated and solved employing a boundary element method approach. Both the warping and the torsion constants are computed by employing an effective Gaussian integration over domains of arbitrary shape. Numerical results are presented to illustrate the method and demonstrate its efficiency and accuracy. The contribution of the normal stresses caused by restrained warping is investigated.     

Pregnancy complicated by primary aldosteronism

Lung or lobe torsion is a rare condition that must be included in the differential diagnosis when a partial or complete shadow is detected on the lung. We report a case of this rare complication after chest surgery. The bedside radiograph provided initial evidence of torsion. CT verified the diagnosis of lower lobe torsion. Prompt recognition and intervention is imperative in order to save the affected lung.     

沙钢大盘卷钢坯修磨线介绍

为了减少不合格的成品,沙钢建设了对钢坯进行探伤及处理的生产线,对该生产线的工艺布置、设备选型及生产能力进行介绍,并分析了该生产线的技术特点。该生产线投产后,减少了成品表面的裂纹、折叠、划痕、结疤等缺陷,提高了大盘卷的质量。     

扭力杆直径的优化设计

本文通过分析起动过程典型动荷类型的动态响应，在构造多目标优化问题数学模型的基础上，提出了选择扭力杆直径的新方法，并取得令人满意的结果，证明该方法可供设计扭力杆装置时直接引用。     

热带钢连轧机主传动系统的动态性能研究

对某热带钢连轧机主传动系统确立了扭振动力学模型,用拉格郎日方程建立了扭振数学模型,用Matlab计算软件求出了系统固有频率和振型,用系数法求出了扭矩放大系数,讨论了频差放大系数对扭矩放大系数的影响关系。该轧机扭矩放大系数偏大,应采取措施加以控制。     

Dynamic Axial-Moment Buckling of Linear Beam Systems by Power Series Stiffness

The paper applies the power series method to find the dynamic stiffness for the dynamics axial-moment buckling analyses of linear framed structures. Since the formulation is exact in classical sense, one element is good enough for the entire beam. The dynamic stiffness thus obtained can be decomposed into the stiffness, mass and initial stress matrices at a particular frequency, a particular axial force and a particular initial moment. The given axial force and moment can be nonuniformly distributed. The interaction diagrams in classical loading conditions of uniform moment, moment due to concentrated and distributed lateral force are given explicitly. The effects of warping rigidity, torsion rigidity, axial tension and compression are investigated in detail. The static and dynamic interaction buckling of a two-section I-beam structure is studied. Finally, we conclude that the three dimensional interaction diagram of the dynamic biaxial moment buckling can be obtained simply by rotating the three dimensional interaction diagram of the dynamic mono-axial moment buckling about the frequency axis if the bimoments are appropriately scaled. It is shown that application for non-uniform section is not suitable due to convergent problem. The method is very efficient that many interaction diagrams are produced for the first time.     

济钢25t转炉倾动系统扭振理论分析

通过对济钢２５ｔ转炉倾动系统扭转振动的计算与分析,阐明转炉倾动系统在工作过程中所产生的扭转振动,在转炉倾动系统的设计、使用、维护、修理和改造中是不可忽视的。其分析对于分析事故的原因以及对防止事故的发生都具有重要的指导意义。     

Identifying Root Causes of Construction Accidents

Construction accident investigation techniques and reporting systems identify what type of accidents occur and how they occurred. Unfortunately, they do not properly address why the accident occurred by identifying possible root causes, which is only possible by complementing these techniques with theories of accident causation and theories of human error. The uniqueness of the construction industry dictates the need to tailor many of the contemporary accident causation models and human error theories. This paper presents an accident root causes tracing model (ARCTM) tailored to the needs of the construction industry. ARCTM proposes that accidents occur due to three root causes: (1) Failing to identify an unsafe condition that existed before an activity was started or that developed after an activity was started; (2) deciding to proceed with a work activity after the worker identifies an existing unsafe condition; and (3) deciding to act unsafe regardless of initial conditions of the work environment. In addition, ARCTM emphasizes the need to determine how unsafe conditions exist before or develop after an activity is started and proposes that these unsafe conditions are due to four causes: (1) Management actions∕inactions; (2) unsafe acts of worker or coworker; (3) non-human-related event(s); (4) an unsafe condition that is a natural part of the initial construction site conditions. Thus, ARCTM acknowledges the possible contribution of both management and labor to the accident process. This perspective helps in better explaining accidents on construction sites and in identifying areas where prevention efforts should be directed, so that labor and management may provide more effective measures for preventing accident occurrence.